TY  - JOUR
AU  - Ćurčić, Jovana
AU  - Dinić, Miroslav
AU  - Novović, Katarina
AU  - Vasiljević, Zorica
AU  - Kojić, Milan
AU  - Jovčić, Branko
AU  - Malešević, Milka
PY  - 2024
UR  - http://intor.torlakinstitut.com/handle/123456789/864
AB  - Infections caused by multidrug-resistant pathogens are one of the biggest challenges facing the healthcare system today. Quorum quenching (QQ) enzymes have the potential to be used as innovative enzyme-based antivirulence therapeutics to combat infections caused by multidrug-resistant pathogens. The main objective of this research was to describe the novel YtnP lactonase derived from the clinical isolate Stenotrophomonas maltophilia and to investigate its antivirulence potential against multidrug-resistant Pseudomonas aeruginosa MMA83. YtnP lactonase, the QQ enzyme, belongs to the family of metallo-β-lactamases. The recombinant enzyme has several advantageous biotechnological properties, such as high thermostability, activity in a wide pH range, and no cytotoxic effect. High-performance liquid chromatography analysis revealed the activity of recombinant YtnP lactonase toward a wide range of N-acyl-homoserine lactones (AHLs), quorum sensing signaling molecules, with a higher preference for long-chain AHLs. Recombinant YtnP lactonase was shown to inhibit P. aeruginosa MMA83 biofilm formation, induce biofilm decomposition, and reduce extracellular virulence factors production. Moreover, the lifespan of MMA83-infected Caenorhabditis elegans was prolonged with YtnP lactonase treatment. YtnP lactonase showed synergistic inhibitory activity in combination with gentamicin and acted additively with meropenem against MMA83. The described properties make YtnP lactonase a promising therapeutic candidate for the development of next-generation antivirulence agents.
T2  - International Journal of Biological Macromolecules
T1  - A novel thermostable YtnP lactonase from Stenotrophomonas maltophilia inhibits Pseudomonas aeruginosa virulence in vitro and in vivo
SP  - 130421
DO  - 10.1016/j.ijbiomac.2024.130421
ER  - 

@article{
author = "Ćurčić, Jovana and Dinić, Miroslav and Novović, Katarina and Vasiljević, Zorica and Kojić, Milan and Jovčić, Branko and Malešević, Milka",
year = "2024",
abstract = "Infections caused by multidrug-resistant pathogens are one of the biggest challenges facing the healthcare system today. Quorum quenching (QQ) enzymes have the potential to be used as innovative enzyme-based antivirulence therapeutics to combat infections caused by multidrug-resistant pathogens. The main objective of this research was to describe the novel YtnP lactonase derived from the clinical isolate Stenotrophomonas maltophilia and to investigate its antivirulence potential against multidrug-resistant Pseudomonas aeruginosa MMA83. YtnP lactonase, the QQ enzyme, belongs to the family of metallo-β-lactamases. The recombinant enzyme has several advantageous biotechnological properties, such as high thermostability, activity in a wide pH range, and no cytotoxic effect. High-performance liquid chromatography analysis revealed the activity of recombinant YtnP lactonase toward a wide range of N-acyl-homoserine lactones (AHLs), quorum sensing signaling molecules, with a higher preference for long-chain AHLs. Recombinant YtnP lactonase was shown to inhibit P. aeruginosa MMA83 biofilm formation, induce biofilm decomposition, and reduce extracellular virulence factors production. Moreover, the lifespan of MMA83-infected Caenorhabditis elegans was prolonged with YtnP lactonase treatment. YtnP lactonase showed synergistic inhibitory activity in combination with gentamicin and acted additively with meropenem against MMA83. The described properties make YtnP lactonase a promising therapeutic candidate for the development of next-generation antivirulence agents.",
journal = "International Journal of Biological Macromolecules",
title = "A novel thermostable YtnP lactonase from Stenotrophomonas maltophilia inhibits Pseudomonas aeruginosa virulence in vitro and in vivo",
pages = "130421",
doi = "10.1016/j.ijbiomac.2024.130421"
}

Ćurčić, J., Dinić, M., Novović, K., Vasiljević, Z., Kojić, M., Jovčić, B.,& Malešević, M.. (2024). A novel thermostable YtnP lactonase from Stenotrophomonas maltophilia inhibits Pseudomonas aeruginosa virulence in vitro and in vivo. in International Journal of Biological Macromolecules, 130421.
https://doi.org/10.1016/j.ijbiomac.2024.130421

Ćurčić J, Dinić M, Novović K, Vasiljević Z, Kojić M, Jovčić B, Malešević M. A novel thermostable YtnP lactonase from Stenotrophomonas maltophilia inhibits Pseudomonas aeruginosa virulence in vitro and in vivo. in International Journal of Biological Macromolecules. 2024;:130421.
doi:10.1016/j.ijbiomac.2024.130421 .

Ćurčić, Jovana, Dinić, Miroslav, Novović, Katarina, Vasiljević, Zorica, Kojić, Milan, Jovčić, Branko, Malešević, Milka, "A novel thermostable YtnP lactonase from Stenotrophomonas maltophilia inhibits Pseudomonas aeruginosa virulence in vitro and in vivo" in International Journal of Biological Macromolecules (2024):130421,
https://doi.org/10.1016/j.ijbiomac.2024.130421 . .

TY  - CONF
AU  - Ćurčić, Jovana
AU  - Jakovljević, Stefan
AU  - Novović, Katarina
AU  - Vasiljević, Zorica
AU  - Kojić, Milan
AU  - Jovčić, Branko
AU  - Malešević, Milka
PY  - 2023
UR  - http://intor.torlakinstitut.com/handle/123456789/803
AB  - Introduction: Quorum quenching (QQ) isthe enzymatic degradation of cell-to-cellsignaling molecules.
In this study, the potential of the novel YtnP lactonase, the quorum quenching enzyme derived from S.
maltophilia, to reduce P. aeruginosa quorum sensing and virulence factor gene expression was investigated.
Methods: MMA83 culture (adjusted to 1.5x105 CFU/ml) was treated with recombinant YtnP lactonase
(final concentration 50 μg/ml) at 37°C for 12 hours under aeration. RNA isolation of the treated and untreated MMA83 culture was performed using the RNeasy Mini Kit (Qiagen, Germany) according to the
protocol. Quantitative reverse transcription-polymerase chain reaction (RT-qPCR), was used to analyze
the effect ofYtnP lactonase on the relative mRNA levels of the LasI/LasR, RhiI/RhiR, and PQS signaling network genes of P. aeruginosa MMA83 and virulence factor genes. The rpsL was used as an endogenous
control to normalize obtained data following the 2-ΔΔCt method.
Results: The QS genes belonging to three QS networks – LasI/LasR, RhiI/RhiR, and PQS of P. aeruginosa
MMA83 treated with YtnP lactonase were significantly downregulated. The RT -qPCR results show that
treatment with YtnP-lactonase decreased the relative mRNA levels of genes involved in the production
of elastase (lasB approximately 2-fold), alginate (algK approximately 2.2-fold), pyocyanin (phzM approximately 3.5-fold), pyoverdin (pvdS approximately 2-fold), and rhamnolipid (rhlC approximately 4-fold).
These results suggest that YtnP lactonase exerts an antivirulence effect at the transcription level.
Conclusion: YtnP lactonase, a quorum quenching (QQ) enzyme, has the potential to be used as an innovative enzyme-based antivirulence therapeutic to combat infections caused by P. aeruginosa.
PB  - Institute of Molecular Genetics and Genetic Engineering (IMGGE), University of Belgrade
C3  - CoMBoS2 – the Second Congress of Molecular Biologists of Serbia, Abstract Book – Trends in Molecular Biology, Special issue 06-08 October 2023, Belgrade, Serbia
T1  - A novel YtnP lactonase reduces the expression of p. aeruginosa MMA83 quorum sensing andvirulence factors gene expression
EP  - 121
SP  - 121
UR  - https://hdl.handle.net/21.15107/rcub_intor_803
ER  - 

@conference{
author = "Ćurčić, Jovana and Jakovljević, Stefan and Novović, Katarina and Vasiljević, Zorica and Kojić, Milan and Jovčić, Branko and Malešević, Milka",
year = "2023",
abstract = "Introduction: Quorum quenching (QQ) isthe enzymatic degradation of cell-to-cellsignaling molecules.
In this study, the potential of the novel YtnP lactonase, the quorum quenching enzyme derived from S.
maltophilia, to reduce P. aeruginosa quorum sensing and virulence factor gene expression was investigated.
Methods: MMA83 culture (adjusted to 1.5x105 CFU/ml) was treated with recombinant YtnP lactonase
(final concentration 50 μg/ml) at 37°C for 12 hours under aeration. RNA isolation of the treated and untreated MMA83 culture was performed using the RNeasy Mini Kit (Qiagen, Germany) according to the
protocol. Quantitative reverse transcription-polymerase chain reaction (RT-qPCR), was used to analyze
the effect ofYtnP lactonase on the relative mRNA levels of the LasI/LasR, RhiI/RhiR, and PQS signaling network genes of P. aeruginosa MMA83 and virulence factor genes. The rpsL was used as an endogenous
control to normalize obtained data following the 2-ΔΔCt method.
Results: The QS genes belonging to three QS networks – LasI/LasR, RhiI/RhiR, and PQS of P. aeruginosa
MMA83 treated with YtnP lactonase were significantly downregulated. The RT -qPCR results show that
treatment with YtnP-lactonase decreased the relative mRNA levels of genes involved in the production
of elastase (lasB approximately 2-fold), alginate (algK approximately 2.2-fold), pyocyanin (phzM approximately 3.5-fold), pyoverdin (pvdS approximately 2-fold), and rhamnolipid (rhlC approximately 4-fold).
These results suggest that YtnP lactonase exerts an antivirulence effect at the transcription level.
Conclusion: YtnP lactonase, a quorum quenching (QQ) enzyme, has the potential to be used as an innovative enzyme-based antivirulence therapeutic to combat infections caused by P. aeruginosa.",
publisher = "Institute of Molecular Genetics and Genetic Engineering (IMGGE), University of Belgrade",
journal = "CoMBoS2 – the Second Congress of Molecular Biologists of Serbia, Abstract Book – Trends in Molecular Biology, Special issue 06-08 October 2023, Belgrade, Serbia",
title = "A novel YtnP lactonase reduces the expression of p. aeruginosa MMA83 quorum sensing andvirulence factors gene expression",
pages = "121-121",
url = "https://hdl.handle.net/21.15107/rcub_intor_803"
}

Ćurčić, J., Jakovljević, S., Novović, K., Vasiljević, Z., Kojić, M., Jovčić, B.,& Malešević, M.. (2023). A novel YtnP lactonase reduces the expression of p. aeruginosa MMA83 quorum sensing andvirulence factors gene expression. in CoMBoS2 – the Second Congress of Molecular Biologists of Serbia, Abstract Book – Trends in Molecular Biology, Special issue 06-08 October 2023, Belgrade, Serbia
Institute of Molecular Genetics and Genetic Engineering (IMGGE), University of Belgrade., 121-121.
https://hdl.handle.net/21.15107/rcub_intor_803

Ćurčić J, Jakovljević S, Novović K, Vasiljević Z, Kojić M, Jovčić B, Malešević M. A novel YtnP lactonase reduces the expression of p. aeruginosa MMA83 quorum sensing andvirulence factors gene expression. in CoMBoS2 – the Second Congress of Molecular Biologists of Serbia, Abstract Book – Trends in Molecular Biology, Special issue 06-08 October 2023, Belgrade, Serbia. 2023;:121-121.
https://hdl.handle.net/21.15107/rcub_intor_803 .

Ćurčić, Jovana, Jakovljević, Stefan, Novović, Katarina, Vasiljević, Zorica, Kojić, Milan, Jovčić, Branko, Malešević, Milka, "A novel YtnP lactonase reduces the expression of p. aeruginosa MMA83 quorum sensing andvirulence factors gene expression" in CoMBoS2 – the Second Congress of Molecular Biologists of Serbia, Abstract Book – Trends in Molecular Biology, Special issue 06-08 October 2023, Belgrade, Serbia (2023):121-121,
https://hdl.handle.net/21.15107/rcub_intor_803 .

TY  - JOUR
AU  - Filipić, Brankica
AU  - Malešević, Milka
AU  - Vasiljević, Zorica
AU  - Novović, Katarina
AU  - Kojić, Milan
AU  - Jovčić, Branko
PY  - 2022
UR  - http://intor.torlakinstitut.com/handle/123456789/724
AB  - Trimethoprim-sulfamethoxazole (SXT) is the preferable treatment option of the infections caused by Achromobacter spp. Our study aimed to analyze the SXT resistance of 98 Achromobacter spp. isolates from pediatric patients, among which 33 isolates were SXT-resistant. The presence of intI1 was screened by PCR and genome sequence analyses. The intI1 gene was detected in 10 of SXT-resistant isolates that had shorter intI1 PCR fragments named intI1S. Structural changes in intI1S were confirmed by genome sequencing and analyses which revealed 86 amino acids deletion in IntI1S protein compared to canonical IntI1 protein. All IntI1S isolates were of non-CF origin. Pan-genome analysis of intI1S bearing A. xylosoxidans isolates comprised 9052 genes, with the core genome consisting of 5455 protein-coding genes. Results in this study indicate that IntI1S isolates were derived from clinical settings and that cystic fibrosis (CF) patients were potential reservoirs for healthcare-associated infections that occurred in non-CF patients.
PB  - Springer Science and Business Media B.V.
T2  - Folia Microbiologica
T1  - Comparative genomics of trimethoprim-sulfamethoxazole-resistant Achromobacter xylosoxidans clinical isolates from Serbia reveals shortened variant of class 1 integron integrase gene
DO  - 10.1007/s12223-022-01026-8
ER  - 

@article{
author = "Filipić, Brankica and Malešević, Milka and Vasiljević, Zorica and Novović, Katarina and Kojić, Milan and Jovčić, Branko",
year = "2022",
abstract = "Trimethoprim-sulfamethoxazole (SXT) is the preferable treatment option of the infections caused by Achromobacter spp. Our study aimed to analyze the SXT resistance of 98 Achromobacter spp. isolates from pediatric patients, among which 33 isolates were SXT-resistant. The presence of intI1 was screened by PCR and genome sequence analyses. The intI1 gene was detected in 10 of SXT-resistant isolates that had shorter intI1 PCR fragments named intI1S. Structural changes in intI1S were confirmed by genome sequencing and analyses which revealed 86 amino acids deletion in IntI1S protein compared to canonical IntI1 protein. All IntI1S isolates were of non-CF origin. Pan-genome analysis of intI1S bearing A. xylosoxidans isolates comprised 9052 genes, with the core genome consisting of 5455 protein-coding genes. Results in this study indicate that IntI1S isolates were derived from clinical settings and that cystic fibrosis (CF) patients were potential reservoirs for healthcare-associated infections that occurred in non-CF patients.",
publisher = "Springer Science and Business Media B.V.",
journal = "Folia Microbiologica",
title = "Comparative genomics of trimethoprim-sulfamethoxazole-resistant Achromobacter xylosoxidans clinical isolates from Serbia reveals shortened variant of class 1 integron integrase gene",
doi = "10.1007/s12223-022-01026-8"
}

Filipić, B., Malešević, M., Vasiljević, Z., Novović, K., Kojić, M.,& Jovčić, B.. (2022). Comparative genomics of trimethoprim-sulfamethoxazole-resistant Achromobacter xylosoxidans clinical isolates from Serbia reveals shortened variant of class 1 integron integrase gene. in Folia Microbiologica
Springer Science and Business Media B.V...
https://doi.org/10.1007/s12223-022-01026-8

Filipić B, Malešević M, Vasiljević Z, Novović K, Kojić M, Jovčić B. Comparative genomics of trimethoprim-sulfamethoxazole-resistant Achromobacter xylosoxidans clinical isolates from Serbia reveals shortened variant of class 1 integron integrase gene. in Folia Microbiologica. 2022;.
doi:10.1007/s12223-022-01026-8 .

Filipić, Brankica, Malešević, Milka, Vasiljević, Zorica, Novović, Katarina, Kojić, Milan, Jovčić, Branko, "Comparative genomics of trimethoprim-sulfamethoxazole-resistant Achromobacter xylosoxidans clinical isolates from Serbia reveals shortened variant of class 1 integron integrase gene" in Folia Microbiologica (2022),
https://doi.org/10.1007/s12223-022-01026-8 . .

TY  - DATA
AU  - Ljubić, Verica
AU  - Milošević, Milena
AU  - Cvetković, Slobodan
AU  - Stojanović, Marijana
AU  - Novović, Katarina
AU  - Dinić, Miroslav
AU  - Popović, Mina
PY  - 2022
UR  - http://intor.torlakinstitut.com/handle/123456789/644
AB  - Using the universal primers (UNI16Sfw and UNI16Srev) [1], the representative isolates were identified by 16S rDNA sequencing. Amplification was carried out in a thermal cycler (Applied Biosystems, ThermoFisher Scientific) and DNA fragments were amplified as follows: initial denaturation at 94 °C for 5 min, followed by 30 cycles consisting of denaturation at 94 °C for 1 min, annealing at 55°C for 1 min, and polymerization at 72°C for 1 min, and a final extension at 72°C for 7 min. The expected length was 1549 bp. Aliquots (5 µl) of the amplified products were subjected to electrophoresis in 1% agarose gel (ThermoFisher Scientific) in TAE buffer (40 mM Tris acetate, 1 mM EDTA, pH 8.2). Gels were stained with ethidium bromide (500 ng/mL) and visualized under UV light (BioDoc Analyze). All amplicons were eluted and purified using GeneJet PCR Purification Kit (ThermoScientific) by following the manufacturer`s protocol. The PCR products that we obtained were sequenced by the Macrogen Sequencing Service (Macrogen, Amsterdam, The Netherlands) and analyzed by using BLAST algorithm (http://www.ncbi.nlm.nih.gov/index.html). Selected isolates were identified as follows: isolate B2 - Lacotbacillus reuteri, isolate H10 - Lactobacillus murinus, and isolate J7 - Klebsiella oxytoca [2]. The most numerous colonies belong to isolate B2, hence it was chosen for further characterization as a potential source for exopolysaccharide (EPS) production.
PB  - Springer
T2  - Biomass Conversion and Biorefinery
T1  - Supplementary information for the article: Ljubic, V.; Milosevic, M.; Cvetkovic, S.; Stojanovic, M.; Novovic, K.; Dinic, M.; Popovic, M. The New Exopolysaccharide Produced by the Probiotic Strain L. Reuteri B2: Extraction, Biological Properties, and Possible Application for Ni2+ Ion Removal from the Contaminated Water. Biomass Conversion and Biorefinery 2022. https://doi.org/10.1007/s13399-022-03292-5.
UR  - https://hdl.handle.net/21.15107/rcub_intor_644
ER  - 

@misc{
author = "Ljubić, Verica and Milošević, Milena and Cvetković, Slobodan and Stojanović, Marijana and Novović, Katarina and Dinić, Miroslav and Popović, Mina",
year = "2022",
abstract = "Using the universal primers (UNI16Sfw and UNI16Srev) [1], the representative isolates were identified by 16S rDNA sequencing. Amplification was carried out in a thermal cycler (Applied Biosystems, ThermoFisher Scientific) and DNA fragments were amplified as follows: initial denaturation at 94 °C for 5 min, followed by 30 cycles consisting of denaturation at 94 °C for 1 min, annealing at 55°C for 1 min, and polymerization at 72°C for 1 min, and a final extension at 72°C for 7 min. The expected length was 1549 bp. Aliquots (5 µl) of the amplified products were subjected to electrophoresis in 1% agarose gel (ThermoFisher Scientific) in TAE buffer (40 mM Tris acetate, 1 mM EDTA, pH 8.2). Gels were stained with ethidium bromide (500 ng/mL) and visualized under UV light (BioDoc Analyze). All amplicons were eluted and purified using GeneJet PCR Purification Kit (ThermoScientific) by following the manufacturer`s protocol. The PCR products that we obtained were sequenced by the Macrogen Sequencing Service (Macrogen, Amsterdam, The Netherlands) and analyzed by using BLAST algorithm (http://www.ncbi.nlm.nih.gov/index.html). Selected isolates were identified as follows: isolate B2 - Lacotbacillus reuteri, isolate H10 - Lactobacillus murinus, and isolate J7 - Klebsiella oxytoca [2]. The most numerous colonies belong to isolate B2, hence it was chosen for further characterization as a potential source for exopolysaccharide (EPS) production.",
publisher = "Springer",
journal = "Biomass Conversion and Biorefinery",
title = "Supplementary information for the article: Ljubic, V.; Milosevic, M.; Cvetkovic, S.; Stojanovic, M.; Novovic, K.; Dinic, M.; Popovic, M. The New Exopolysaccharide Produced by the Probiotic Strain L. Reuteri B2: Extraction, Biological Properties, and Possible Application for Ni2+ Ion Removal from the Contaminated Water. Biomass Conversion and Biorefinery 2022. https://doi.org/10.1007/s13399-022-03292-5.",
url = "https://hdl.handle.net/21.15107/rcub_intor_644"
}

Ljubić, V., Milošević, M., Cvetković, S., Stojanović, M., Novović, K., Dinić, M.,& Popović, M.. (2022). Supplementary information for the article: Ljubic, V.; Milosevic, M.; Cvetkovic, S.; Stojanovic, M.; Novovic, K.; Dinic, M.; Popovic, M. The New Exopolysaccharide Produced by the Probiotic Strain L. Reuteri B2: Extraction, Biological Properties, and Possible Application for Ni2+ Ion Removal from the Contaminated Water. Biomass Conversion and Biorefinery 2022. https://doi.org/10.1007/s13399-022-03292-5.. in Biomass Conversion and Biorefinery
Springer..
https://hdl.handle.net/21.15107/rcub_intor_644

Ljubić V, Milošević M, Cvetković S, Stojanović M, Novović K, Dinić M, Popović M. Supplementary information for the article: Ljubic, V.; Milosevic, M.; Cvetkovic, S.; Stojanovic, M.; Novovic, K.; Dinic, M.; Popovic, M. The New Exopolysaccharide Produced by the Probiotic Strain L. Reuteri B2: Extraction, Biological Properties, and Possible Application for Ni2+ Ion Removal from the Contaminated Water. Biomass Conversion and Biorefinery 2022. https://doi.org/10.1007/s13399-022-03292-5.. in Biomass Conversion and Biorefinery. 2022;.
https://hdl.handle.net/21.15107/rcub_intor_644 .

Ljubić, Verica, Milošević, Milena, Cvetković, Slobodan, Stojanović, Marijana, Novović, Katarina, Dinić, Miroslav, Popović, Mina, "Supplementary information for the article: Ljubic, V.; Milosevic, M.; Cvetkovic, S.; Stojanovic, M.; Novovic, K.; Dinic, M.; Popovic, M. The New Exopolysaccharide Produced by the Probiotic Strain L. Reuteri B2: Extraction, Biological Properties, and Possible Application for Ni2+ Ion Removal from the Contaminated Water. Biomass Conversion and Biorefinery 2022. https://doi.org/10.1007/s13399-022-03292-5." in Biomass Conversion and Biorefinery (2022),
https://hdl.handle.net/21.15107/rcub_intor_644 .

TY  - JOUR
AU  - Velhner, Maja
AU  - Todorović, Dalibor
AU  - Novović, Katarina
AU  - Jovčić, Branko
AU  - Lazić, Gospava
AU  - Kojić, Milan
AU  - Kehrenberg, Corinna
PY  - 2021
UR  - http://intor.torlakinstitut.com/handle/123456789/710
AB  - Despite common resistance to antimicrobials in Escherichia coli isolates from farm animals in Serbia, no data are currently accessible on its occurrence in E. coli isolated from gulls. Therefore, 67 cloacal swabs and 70 fecal samples from black-headed gulls were investigated for the presence of antibiotic-resistant E. coli isolates. Ninety-nine isolates were obtained during the study. Resistotyping and resistance gene typing has shown that 44 isolates harbor resistance to one or more antibiotics. Multidrug resistance was detected in 24 E. coli isolates. Ten isolates were resistant to extended-spectrum cephalosporin antibiotics and were studied in detail including virulence gene typing, phylogenetic and multilocus sequence typing, and mating. These ten isolates belonged to phylogenetic groups B2 (five isolates), D (four isolates) and B1 (one isolate). Five different sequence types (ST38, ST2307, ST224, ST162 and ST34) were detected in E. coli isolates with AmpC phenotype and genotype. One isolate carried the Inc I2/FIB replicon type plasmid with the bla(CTX-M-1) gene. Nine isolates had bla(CMY-2) genes, which were detected on conjugative plasmids in seven isolates. The virulence genes hly, iroN, iss, ompT and cvaC were detected in one transconjugant. Ten isolates were found to be resistant to ciprofloxacin, whose MIC ranged from 4 to 32 mg/L. Genotyping revealed single or double mutations in the quinolone resistance determining region (QRDR) of the gyrA or gyrA, parC and parE genes, respectively. So, Black-headed gulls from Serbia may be colonized by multidrug-resistant E. coli, some of which are resistant to critically important antibiotics in medicine.
PB  - Springer, Dordrecht
T2  - Veterinary Research Communications
T1  - Characterization of antibiotic resistance in Escherichia coli isolates from Black-headed gulls (Larus ridibundus) present in the city of Novi Sad, Serbia
EP  - 209
IS  - 4
SP  - 199
VL  - 45
DO  - 10.1007/s11259-021-09801-7
ER  - 

@article{
author = "Velhner, Maja and Todorović, Dalibor and Novović, Katarina and Jovčić, Branko and Lazić, Gospava and Kojić, Milan and Kehrenberg, Corinna",
year = "2021",
abstract = "Despite common resistance to antimicrobials in Escherichia coli isolates from farm animals in Serbia, no data are currently accessible on its occurrence in E. coli isolated from gulls. Therefore, 67 cloacal swabs and 70 fecal samples from black-headed gulls were investigated for the presence of antibiotic-resistant E. coli isolates. Ninety-nine isolates were obtained during the study. Resistotyping and resistance gene typing has shown that 44 isolates harbor resistance to one or more antibiotics. Multidrug resistance was detected in 24 E. coli isolates. Ten isolates were resistant to extended-spectrum cephalosporin antibiotics and were studied in detail including virulence gene typing, phylogenetic and multilocus sequence typing, and mating. These ten isolates belonged to phylogenetic groups B2 (five isolates), D (four isolates) and B1 (one isolate). Five different sequence types (ST38, ST2307, ST224, ST162 and ST34) were detected in E. coli isolates with AmpC phenotype and genotype. One isolate carried the Inc I2/FIB replicon type plasmid with the bla(CTX-M-1) gene. Nine isolates had bla(CMY-2) genes, which were detected on conjugative plasmids in seven isolates. The virulence genes hly, iroN, iss, ompT and cvaC were detected in one transconjugant. Ten isolates were found to be resistant to ciprofloxacin, whose MIC ranged from 4 to 32 mg/L. Genotyping revealed single or double mutations in the quinolone resistance determining region (QRDR) of the gyrA or gyrA, parC and parE genes, respectively. So, Black-headed gulls from Serbia may be colonized by multidrug-resistant E. coli, some of which are resistant to critically important antibiotics in medicine.",
publisher = "Springer, Dordrecht",
journal = "Veterinary Research Communications",
title = "Characterization of antibiotic resistance in Escherichia coli isolates from Black-headed gulls (Larus ridibundus) present in the city of Novi Sad, Serbia",
pages = "209-199",
number = "4",
volume = "45",
doi = "10.1007/s11259-021-09801-7"
}

Velhner, M., Todorović, D., Novović, K., Jovčić, B., Lazić, G., Kojić, M.,& Kehrenberg, C.. (2021). Characterization of antibiotic resistance in Escherichia coli isolates from Black-headed gulls (Larus ridibundus) present in the city of Novi Sad, Serbia. in Veterinary Research Communications
Springer, Dordrecht., 45(4), 199-209.
https://doi.org/10.1007/s11259-021-09801-7

Velhner M, Todorović D, Novović K, Jovčić B, Lazić G, Kojić M, Kehrenberg C. Characterization of antibiotic resistance in Escherichia coli isolates from Black-headed gulls (Larus ridibundus) present in the city of Novi Sad, Serbia. in Veterinary Research Communications. 2021;45(4):199-209.
doi:10.1007/s11259-021-09801-7 .

Velhner, Maja, Todorović, Dalibor, Novović, Katarina, Jovčić, Branko, Lazić, Gospava, Kojić, Milan, Kehrenberg, Corinna, "Characterization of antibiotic resistance in Escherichia coli isolates from Black-headed gulls (Larus ridibundus) present in the city of Novi Sad, Serbia" in Veterinary Research Communications, 45, no. 4 (2021):199-209,
https://doi.org/10.1007/s11259-021-09801-7 . .

TY  - JOUR
AU  - Jovčić, Branko
AU  - Novović, Katarina
AU  - Filipić, Brankica
AU  - Velhner, Maja
AU  - Todorović, Dalibor
AU  - Matović, Kazimir
AU  - Rasić, Zoran
AU  - Nikolić, Sonja
AU  - Kiskarolj, Ferenc
AU  - Kojić, Milan
PY  - 2020
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/1349
UR  - http://intor.torlakinstitut.com/handle/123456789/744
AB  - The antimicrobial susceptibility testing was conducted on 174 single isolates from poultry farms in Serbia and it was determined that seven Salmonella spp. were multidrug resistant. Sixteen serotypes were detected, but only serotype Infantis confirmed reduced susceptibility to colistin. Seven colistin resistant Salmonella Infantis were studied in detail using the WGS approach. Three sequence types were identified corresponding to different epizootiology region. The isolate from the Province of Vojvodina 3842 and isolates from Jagodina (92 and 821) are represented by the sequence type ST413 and ST11, respectively. Four isolates from Kraljevo are ST32, a common S. Infantis sequence type in humans, poultry and food. The fosfomycin resistance gene fosA7 in isolate 3842 and the vgaA gene in isolate 8418/2948 encoding resistance to pleuromutilins were reported for the first time in serovar Infantis. The changes in relative expression of the phoP/Q, mgrB and pmrA/B genes were detected. Single nucleotide polymorphisms of the pmrB gene, including transitions Val164Gly or Val164Met, and Arg92Pro are described. Analyses of quinolone resistance determining region revealed substitutions Ser83Tyr in GyrA protein and Thr57Ser and Ser80Arg in ParC protein. Based on WGS data, there are two major clusters among analyzed Salmonella Infantis isolates from central Serbia.
PB  - MDPI, Basel
T2  - Antibiotics-Basel
T1  - Genomic Characteristics of Colistin-Resistant Salmonella enterica subsp. enterica Serovar Infantis from Poultry Farms in the Republic of Serbia
IS  - 12
VL  - 9
DO  - 10.3390/antibiotics9120886
ER  - 

@article{
author = "Jovčić, Branko and Novović, Katarina and Filipić, Brankica and Velhner, Maja and Todorović, Dalibor and Matović, Kazimir and Rasić, Zoran and Nikolić, Sonja and Kiskarolj, Ferenc and Kojić, Milan",
year = "2020",
abstract = "The antimicrobial susceptibility testing was conducted on 174 single isolates from poultry farms in Serbia and it was determined that seven Salmonella spp. were multidrug resistant. Sixteen serotypes were detected, but only serotype Infantis confirmed reduced susceptibility to colistin. Seven colistin resistant Salmonella Infantis were studied in detail using the WGS approach. Three sequence types were identified corresponding to different epizootiology region. The isolate from the Province of Vojvodina 3842 and isolates from Jagodina (92 and 821) are represented by the sequence type ST413 and ST11, respectively. Four isolates from Kraljevo are ST32, a common S. Infantis sequence type in humans, poultry and food. The fosfomycin resistance gene fosA7 in isolate 3842 and the vgaA gene in isolate 8418/2948 encoding resistance to pleuromutilins were reported for the first time in serovar Infantis. The changes in relative expression of the phoP/Q, mgrB and pmrA/B genes were detected. Single nucleotide polymorphisms of the pmrB gene, including transitions Val164Gly or Val164Met, and Arg92Pro are described. Analyses of quinolone resistance determining region revealed substitutions Ser83Tyr in GyrA protein and Thr57Ser and Ser80Arg in ParC protein. Based on WGS data, there are two major clusters among analyzed Salmonella Infantis isolates from central Serbia.",
publisher = "MDPI, Basel",
journal = "Antibiotics-Basel",
title = "Genomic Characteristics of Colistin-Resistant Salmonella enterica subsp. enterica Serovar Infantis from Poultry Farms in the Republic of Serbia",
number = "12",
volume = "9",
doi = "10.3390/antibiotics9120886"
}

Jovčić, B., Novović, K., Filipić, B., Velhner, M., Todorović, D., Matović, K., Rasić, Z., Nikolić, S., Kiskarolj, F.,& Kojić, M.. (2020). Genomic Characteristics of Colistin-Resistant Salmonella enterica subsp. enterica Serovar Infantis from Poultry Farms in the Republic of Serbia. in Antibiotics-Basel
MDPI, Basel., 9(12).
https://doi.org/10.3390/antibiotics9120886

Jovčić B, Novović K, Filipić B, Velhner M, Todorović D, Matović K, Rasić Z, Nikolić S, Kiskarolj F, Kojić M. Genomic Characteristics of Colistin-Resistant Salmonella enterica subsp. enterica Serovar Infantis from Poultry Farms in the Republic of Serbia. in Antibiotics-Basel. 2020;9(12).
doi:10.3390/antibiotics9120886 .

Jovčić, Branko, Novović, Katarina, Filipić, Brankica, Velhner, Maja, Todorović, Dalibor, Matović, Kazimir, Rasić, Zoran, Nikolić, Sonja, Kiskarolj, Ferenc, Kojić, Milan, "Genomic Characteristics of Colistin-Resistant Salmonella enterica subsp. enterica Serovar Infantis from Poultry Farms in the Republic of Serbia" in Antibiotics-Basel, 9, no. 12 (2020),
https://doi.org/10.3390/antibiotics9120886 . .

TY  - JOUR
AU  - Vukotić, Goran
AU  - Obradović, Mina
AU  - Novović, Katarina
AU  - Di Luca, Mariagrazia
AU  - Jovčić, Branko
AU  - Fira, Đorđe
AU  - Neve, Horst
AU  - Kojić, Milan
AU  - McAuliffe, Olivia
PY  - 2020
UR  - http://intor.torlakinstitut.com/handle/123456789/721
AB  - Acinetobacter baumanniiis a leading cause of healthcare-associated infections worldwide. Its various intrinsic and acquired mechanisms of antibiotic resistance make the therapeutic challenge even more serious. One of the promising alternative treatments that is increasingly highlighted is phage therapy, the therapeutic use of bacteriophages to treat bacterial infections. Two phages active against nosocomial carbapenem-resistantA. baumanniistrain 6077/12, vB_AbaM_ISTD, and vB_AbaM_NOVI, were isolated from Belgrade wastewaters, purified, and concentrated using CsCl gradient ultracentrifugation. The phages were screened against 103 clinical isolates ofA. baumanniifrom a laboratory collection and characterized based on plaque and virion morphology, host range, adsorption rate, and one-step growth curve. Given that phage ISTD showed a broader host range, better adsorption rate, shorter latent period, and larger burst size, its ability to lyse planktonic and biofilm-embedded cells was tested in detail. Phage ISTD yielded a 3.5- and 2-log reduction in planktonic and biofilm-associated viable bacterial cell count, respectively, but the effect was time-dependent. Both phages produced growing turbid halos around plaques indicating the synthesis of depolymerases, enzymes capable of degrading bacterial exopolysaccharides. Halos tested positive for presence of phages in the proximity of the plaque, but not further from the plaque, which indicates that the observed halo enlargement is a consequence of enzyme diffusion through the agar, independently of the phages. This notion was also supported by the growing halos induced by phage preparations applied on pregrown bacterial lawns, indicating that depolymerizing effect was achieved also on non-dividing sensitive cells. Overall, good rates of growth, fast adsorption rate, broad host range, and high depolymerizing activity, as well as antibacterial effectiveness against planktonic and biofilm-associated bacteria, make these phages good candidates for potential application in combatingA. baumanniiinfections.
PB  - Frontiers Media Sa, Lausanne
T2  - Frontiers in Medicine
T1  - Characterization, Antibiofilm, and Depolymerizing Activity of Two Phages Active on Carbapenem-ResistantAcinetobacter baumannii
VL  - 7
DO  - 10.3389/fmed.2020.00426
ER  - 

@article{
author = "Vukotić, Goran and Obradović, Mina and Novović, Katarina and Di Luca, Mariagrazia and Jovčić, Branko and Fira, Đorđe and Neve, Horst and Kojić, Milan and McAuliffe, Olivia",
year = "2020",
abstract = "Acinetobacter baumanniiis a leading cause of healthcare-associated infections worldwide. Its various intrinsic and acquired mechanisms of antibiotic resistance make the therapeutic challenge even more serious. One of the promising alternative treatments that is increasingly highlighted is phage therapy, the therapeutic use of bacteriophages to treat bacterial infections. Two phages active against nosocomial carbapenem-resistantA. baumanniistrain 6077/12, vB_AbaM_ISTD, and vB_AbaM_NOVI, were isolated from Belgrade wastewaters, purified, and concentrated using CsCl gradient ultracentrifugation. The phages were screened against 103 clinical isolates ofA. baumanniifrom a laboratory collection and characterized based on plaque and virion morphology, host range, adsorption rate, and one-step growth curve. Given that phage ISTD showed a broader host range, better adsorption rate, shorter latent period, and larger burst size, its ability to lyse planktonic and biofilm-embedded cells was tested in detail. Phage ISTD yielded a 3.5- and 2-log reduction in planktonic and biofilm-associated viable bacterial cell count, respectively, but the effect was time-dependent. Both phages produced growing turbid halos around plaques indicating the synthesis of depolymerases, enzymes capable of degrading bacterial exopolysaccharides. Halos tested positive for presence of phages in the proximity of the plaque, but not further from the plaque, which indicates that the observed halo enlargement is a consequence of enzyme diffusion through the agar, independently of the phages. This notion was also supported by the growing halos induced by phage preparations applied on pregrown bacterial lawns, indicating that depolymerizing effect was achieved also on non-dividing sensitive cells. Overall, good rates of growth, fast adsorption rate, broad host range, and high depolymerizing activity, as well as antibacterial effectiveness against planktonic and biofilm-associated bacteria, make these phages good candidates for potential application in combatingA. baumanniiinfections.",
publisher = "Frontiers Media Sa, Lausanne",
journal = "Frontiers in Medicine",
title = "Characterization, Antibiofilm, and Depolymerizing Activity of Two Phages Active on Carbapenem-ResistantAcinetobacter baumannii",
volume = "7",
doi = "10.3389/fmed.2020.00426"
}

Vukotić, G., Obradović, M., Novović, K., Di Luca, M., Jovčić, B., Fira, Đ., Neve, H., Kojić, M.,& McAuliffe, O.. (2020). Characterization, Antibiofilm, and Depolymerizing Activity of Two Phages Active on Carbapenem-ResistantAcinetobacter baumannii. in Frontiers in Medicine
Frontiers Media Sa, Lausanne., 7.
https://doi.org/10.3389/fmed.2020.00426

Vukotić G, Obradović M, Novović K, Di Luca M, Jovčić B, Fira Đ, Neve H, Kojić M, McAuliffe O. Characterization, Antibiofilm, and Depolymerizing Activity of Two Phages Active on Carbapenem-ResistantAcinetobacter baumannii. in Frontiers in Medicine. 2020;7.
doi:10.3389/fmed.2020.00426 .

Vukotić, Goran, Obradović, Mina, Novović, Katarina, Di Luca, Mariagrazia, Jovčić, Branko, Fira, Đorđe, Neve, Horst, Kojić, Milan, McAuliffe, Olivia, "Characterization, Antibiofilm, and Depolymerizing Activity of Two Phages Active on Carbapenem-ResistantAcinetobacter baumannii" in Frontiers in Medicine, 7 (2020),
https://doi.org/10.3389/fmed.2020.00426 . .

TY  - JOUR
AU  - Malešević, Milka
AU  - Stanisavljević, Nemanja
AU  - Novović, Katarina
AU  - Polović, Natalija
AU  - Vasiljević, Zorica
AU  - Kojić, Milan
AU  - Jovčić, Branko
PY  - 2020
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/1338
UR  - http://intor.torlakinstitut.com/handle/123456789/705
AB  - Burkholderia cepacia is well known as the causative agent of infections in humans where often shares niche with other pathogens, like Pseudomonas aeruginosa. Clinical isolate Burkholderia sp. BCC4135 was selected due to its strong quorum quenching (QQ) activity. Whole genome sequencing unveiled this isolate as B. cepacia with unique sequence type ST1485 and a myriad of genes belonging to resistome and virulome. Two QQ lactonases YtnP and Y2-aiiA originated from B. cepacia BCC4135 were cloned, expressed, and functionally characterized. They were active against a broad substrate spectrum of the N-acyl-homoserine lactones (AHLs). The YtnP lactonase was inactive, while Y2-aiiA was active against N-tetradecanoyl-DL-homoserine lactone (C14-HSL) which could imply the difference in their biological roles from the aspect of its quorum sensing (QS) autoregulation and interference with the QS systems of bacteria residing within the same niche. Both YtnP and Y2-aiiA were able to attenuate virulence potential of P. aeruginosa MMA83 clinical isolate declining its biofilm formation and virulence factors production. B. cepacia BCC4135 lactonases interfered with the las, rhl, and even pqs QS circuit of P. aeruginosa MMA83 transcription and the effect of combined enzymes was even more prominent. B. cepacia BCC4135 also employs the CepI/R QS system for governing its own virulence traits and possibly self-regulates the QQ/QS network through the different expression and activity of YtnP and/or Y2-aiiA. Our findings pointed out that BCC4135 lactonases could be exploited as an effective antivirulence drugs against P. aeruginosa and gave us a new insight into B. cepacia QQ/QS machinery.
PB  - Academic Press Ltd- Elsevier Science Ltd, London
T2  - Microbial Pathogenesis
T1  - Burkholderia cepacia YtnP and Y2-aiiA lactonases inhibit virulence of Pseudomonas aeruginosa via quorum quenching activity
VL  - 149
DO  - 10.1016/j.micpath.2020.104561
ER  - 

@article{
author = "Malešević, Milka and Stanisavljević, Nemanja and Novović, Katarina and Polović, Natalija and Vasiljević, Zorica and Kojić, Milan and Jovčić, Branko",
year = "2020",
abstract = "Burkholderia cepacia is well known as the causative agent of infections in humans where often shares niche with other pathogens, like Pseudomonas aeruginosa. Clinical isolate Burkholderia sp. BCC4135 was selected due to its strong quorum quenching (QQ) activity. Whole genome sequencing unveiled this isolate as B. cepacia with unique sequence type ST1485 and a myriad of genes belonging to resistome and virulome. Two QQ lactonases YtnP and Y2-aiiA originated from B. cepacia BCC4135 were cloned, expressed, and functionally characterized. They were active against a broad substrate spectrum of the N-acyl-homoserine lactones (AHLs). The YtnP lactonase was inactive, while Y2-aiiA was active against N-tetradecanoyl-DL-homoserine lactone (C14-HSL) which could imply the difference in their biological roles from the aspect of its quorum sensing (QS) autoregulation and interference with the QS systems of bacteria residing within the same niche. Both YtnP and Y2-aiiA were able to attenuate virulence potential of P. aeruginosa MMA83 clinical isolate declining its biofilm formation and virulence factors production. B. cepacia BCC4135 lactonases interfered with the las, rhl, and even pqs QS circuit of P. aeruginosa MMA83 transcription and the effect of combined enzymes was even more prominent. B. cepacia BCC4135 also employs the CepI/R QS system for governing its own virulence traits and possibly self-regulates the QQ/QS network through the different expression and activity of YtnP and/or Y2-aiiA. Our findings pointed out that BCC4135 lactonases could be exploited as an effective antivirulence drugs against P. aeruginosa and gave us a new insight into B. cepacia QQ/QS machinery.",
publisher = "Academic Press Ltd- Elsevier Science Ltd, London",
journal = "Microbial Pathogenesis",
title = "Burkholderia cepacia YtnP and Y2-aiiA lactonases inhibit virulence of Pseudomonas aeruginosa via quorum quenching activity",
volume = "149",
doi = "10.1016/j.micpath.2020.104561"
}

Malešević, M., Stanisavljević, N., Novović, K., Polović, N., Vasiljević, Z., Kojić, M.,& Jovčić, B.. (2020). Burkholderia cepacia YtnP and Y2-aiiA lactonases inhibit virulence of Pseudomonas aeruginosa via quorum quenching activity. in Microbial Pathogenesis
Academic Press Ltd- Elsevier Science Ltd, London., 149.
https://doi.org/10.1016/j.micpath.2020.104561

Malešević M, Stanisavljević N, Novović K, Polović N, Vasiljević Z, Kojić M, Jovčić B. Burkholderia cepacia YtnP and Y2-aiiA lactonases inhibit virulence of Pseudomonas aeruginosa via quorum quenching activity. in Microbial Pathogenesis. 2020;149.
doi:10.1016/j.micpath.2020.104561 .

Malešević, Milka, Stanisavljević, Nemanja, Novović, Katarina, Polović, Natalija, Vasiljević, Zorica, Kojić, Milan, Jovčić, Branko, "Burkholderia cepacia YtnP and Y2-aiiA lactonases inhibit virulence of Pseudomonas aeruginosa via quorum quenching activity" in Microbial Pathogenesis, 149 (2020),
https://doi.org/10.1016/j.micpath.2020.104561 . .

TY  - JOUR
AU  - Lilić, Branislav
AU  - Filipić, Brankica
AU  - Malešević, Milka
AU  - Novović, Katarina
AU  - Vasiljević, Zorica
AU  - Kojić, Milan
AU  - Jovčić, Branko
PY  - 2019
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/1278
UR  - http://intor.torlakinstitut.com/handle/123456789/742
AB  - The aim of this study was to evaluate the contribution of plasmid-mediated genes and efflux to fluoroquinolone resistance in collection of Achromobacter spp. gathered during a 3-year period. Susceptibility to ciprofloxacin and levofloxacin was tested by disk diffusion and microdilution tests for a collection of 98 Achromobacter spp. clinical isolates. Identification of fluoroquinolone-resistant isolates was performed by sequencing and phylogenetic analyses of the nrdA gene. Genetic relatedness among resistant isolates was determined by pulsed-field gel electrophoresis (PFGE) analysis. The influence of an H+ conductor cyanide m-chlorophenyl hydrazone (CCCP) and a resistance-nodulation-division-type efflux pump inhibitor phenylalanine-arginine beta-naphthylamide (PAN) on minimal inhibitory concentration (MIC) value was evaluated by broth microdilution. The presence of the plasmid-mediated qnrA, qnrB, qnrC, qnrS, and aac-(6)-Ib-cr genes was investigated by PCR and sequencing. Achromobacter spp. isolates that were resistant or intermediately resistant to fluoroquinolones in disk diffusion tests (44/98) were subjected to microdilution. As a result, 20/98 isolates were confirmed to be resistant to ciprofloxacin while 10/98 was resistant to levofloxacin. CCCP decreased twofold MIC value for ciprofloxacin in six isolates and more than 16 times in one isolate, while MIC value for levofloxacin was decreased in all isolates (twofold to more than eightfold). Fluoroquinolone-resistant isolates were identified as A. xylosoxidans with the nrdA gene sequencing. PFGE revealed that resistant isolates belonged to seven different genotypes. Ten isolates belonging to four genotypes were positive for the aac-(6)-Ib-cr gene. Although resistance to fluoroquinolones was not widespread among analyzed isolates, detected contribution of efflux pumps and the presence of the aac-(6)-Ib-cr gene present a platform for emergence of more resistant strains.
PB  - Springer, Dordrecht
T2  - Folia Microbiologica
T1  - Fluoroquinolone-resistant Achromobacter xylosoxidans clinical isolates from Serbia: high prevalence of the aac-(6)-Ib-cr gene among resistant isolates
EP  - 159
IS  - 2
SP  - 153
VL  - 64
DO  - 10.1007/s12223-018-0639-7
ER  - 

@article{
author = "Lilić, Branislav and Filipić, Brankica and Malešević, Milka and Novović, Katarina and Vasiljević, Zorica and Kojić, Milan and Jovčić, Branko",
year = "2019",
abstract = "The aim of this study was to evaluate the contribution of plasmid-mediated genes and efflux to fluoroquinolone resistance in collection of Achromobacter spp. gathered during a 3-year period. Susceptibility to ciprofloxacin and levofloxacin was tested by disk diffusion and microdilution tests for a collection of 98 Achromobacter spp. clinical isolates. Identification of fluoroquinolone-resistant isolates was performed by sequencing and phylogenetic analyses of the nrdA gene. Genetic relatedness among resistant isolates was determined by pulsed-field gel electrophoresis (PFGE) analysis. The influence of an H+ conductor cyanide m-chlorophenyl hydrazone (CCCP) and a resistance-nodulation-division-type efflux pump inhibitor phenylalanine-arginine beta-naphthylamide (PAN) on minimal inhibitory concentration (MIC) value was evaluated by broth microdilution. The presence of the plasmid-mediated qnrA, qnrB, qnrC, qnrS, and aac-(6)-Ib-cr genes was investigated by PCR and sequencing. Achromobacter spp. isolates that were resistant or intermediately resistant to fluoroquinolones in disk diffusion tests (44/98) were subjected to microdilution. As a result, 20/98 isolates were confirmed to be resistant to ciprofloxacin while 10/98 was resistant to levofloxacin. CCCP decreased twofold MIC value for ciprofloxacin in six isolates and more than 16 times in one isolate, while MIC value for levofloxacin was decreased in all isolates (twofold to more than eightfold). Fluoroquinolone-resistant isolates were identified as A. xylosoxidans with the nrdA gene sequencing. PFGE revealed that resistant isolates belonged to seven different genotypes. Ten isolates belonging to four genotypes were positive for the aac-(6)-Ib-cr gene. Although resistance to fluoroquinolones was not widespread among analyzed isolates, detected contribution of efflux pumps and the presence of the aac-(6)-Ib-cr gene present a platform for emergence of more resistant strains.",
publisher = "Springer, Dordrecht",
journal = "Folia Microbiologica",
title = "Fluoroquinolone-resistant Achromobacter xylosoxidans clinical isolates from Serbia: high prevalence of the aac-(6)-Ib-cr gene among resistant isolates",
pages = "159-153",
number = "2",
volume = "64",
doi = "10.1007/s12223-018-0639-7"
}

Lilić, B., Filipić, B., Malešević, M., Novović, K., Vasiljević, Z., Kojić, M.,& Jovčić, B.. (2019). Fluoroquinolone-resistant Achromobacter xylosoxidans clinical isolates from Serbia: high prevalence of the aac-(6)-Ib-cr gene among resistant isolates. in Folia Microbiologica
Springer, Dordrecht., 64(2), 153-159.
https://doi.org/10.1007/s12223-018-0639-7

Lilić B, Filipić B, Malešević M, Novović K, Vasiljević Z, Kojić M, Jovčić B. Fluoroquinolone-resistant Achromobacter xylosoxidans clinical isolates from Serbia: high prevalence of the aac-(6)-Ib-cr gene among resistant isolates. in Folia Microbiologica. 2019;64(2):153-159.
doi:10.1007/s12223-018-0639-7 .

Lilić, Branislav, Filipić, Brankica, Malešević, Milka, Novović, Katarina, Vasiljević, Zorica, Kojić, Milan, Jovčić, Branko, "Fluoroquinolone-resistant Achromobacter xylosoxidans clinical isolates from Serbia: high prevalence of the aac-(6)-Ib-cr gene among resistant isolates" in Folia Microbiologica, 64, no. 2 (2019):153-159,
https://doi.org/10.1007/s12223-018-0639-7 . .

TY  - JOUR
AU  - Malešević, Milka
AU  - Mirković, Nemanja
AU  - Lozo, Jelena
AU  - Novović, Katarina
AU  - Filipić, Brankica
AU  - Kojić, Milan
AU  - Jovčić, Branko
PY  - 2019
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/1297
UR  - http://intor.torlakinstitut.com/handle/123456789/696
AB  - 16S rRNA gene-based metagenomic approach was used to assess the biodiversity of bacterial communities in the sediments of selected glacial lakes in the Western Balkans and to assess the impact of human population on these microbial communities. Sediment samples were collected from three glacial lakes, viz., Plav Lake (in a zone of the highest impact of human population), Black Lake (a zone of medium impact of human population), and Donje Bare Lake (a remote lake with minimal impact of human population). Canonical correlation analysis analysis indicated correlation between the distance of the lake from urbanized population and bacterial diversity in Donje Bare Lake sediment. Bacterial diversity of Black Lake sediment was correlated with high content of phosphorous and pH value. Chemical compounds exhibiting the most prominent correlation with bacterial diversity of Plav Lake were NH4-N, K2O, CaCo3, and total nitrogen . Additionally, CCA analysis indicated that population density was correlated with biodiversity of bacterial communities in Plav Lake sediment, which is the most exposed to human population. Multivariate regression revealed the highest correlation between the presence of Proteobacteria classes and population density and levels of NH4-N. The influence of human population was observed to be important for shaping the sediment communities in addition to biological and chemical factors.
PB  - Taylor & Francis
T2  - Geomicrobiology Journal
T1  - Bacterial Diversity among the Sediments of Glacial Lakes in the Western Balkans: Exploring the Impact of Human Population
EP  - 270
IS  - 3
SP  - 261
VL  - 36
DO  - 10.1080/01490451.2018.1550128
ER  - 

@article{
author = "Malešević, Milka and Mirković, Nemanja and Lozo, Jelena and Novović, Katarina and Filipić, Brankica and Kojić, Milan and Jovčić, Branko",
year = "2019",
abstract = "16S rRNA gene-based metagenomic approach was used to assess the biodiversity of bacterial communities in the sediments of selected glacial lakes in the Western Balkans and to assess the impact of human population on these microbial communities. Sediment samples were collected from three glacial lakes, viz., Plav Lake (in a zone of the highest impact of human population), Black Lake (a zone of medium impact of human population), and Donje Bare Lake (a remote lake with minimal impact of human population). Canonical correlation analysis analysis indicated correlation between the distance of the lake from urbanized population and bacterial diversity in Donje Bare Lake sediment. Bacterial diversity of Black Lake sediment was correlated with high content of phosphorous and pH value. Chemical compounds exhibiting the most prominent correlation with bacterial diversity of Plav Lake were NH4-N, K2O, CaCo3, and total nitrogen . Additionally, CCA analysis indicated that population density was correlated with biodiversity of bacterial communities in Plav Lake sediment, which is the most exposed to human population. Multivariate regression revealed the highest correlation between the presence of Proteobacteria classes and population density and levels of NH4-N. The influence of human population was observed to be important for shaping the sediment communities in addition to biological and chemical factors.",
publisher = "Taylor & Francis",
journal = "Geomicrobiology Journal",
title = "Bacterial Diversity among the Sediments of Glacial Lakes in the Western Balkans: Exploring the Impact of Human Population",
pages = "270-261",
number = "3",
volume = "36",
doi = "10.1080/01490451.2018.1550128"
}

Malešević, M., Mirković, N., Lozo, J., Novović, K., Filipić, B., Kojić, M.,& Jovčić, B.. (2019). Bacterial Diversity among the Sediments of Glacial Lakes in the Western Balkans: Exploring the Impact of Human Population. in Geomicrobiology Journal
Taylor & Francis., 36(3), 261-270.
https://doi.org/10.1080/01490451.2018.1550128

Malešević M, Mirković N, Lozo J, Novović K, Filipić B, Kojić M, Jovčić B. Bacterial Diversity among the Sediments of Glacial Lakes in the Western Balkans: Exploring the Impact of Human Population. in Geomicrobiology Journal. 2019;36(3):261-270.
doi:10.1080/01490451.2018.1550128 .

Malešević, Milka, Mirković, Nemanja, Lozo, Jelena, Novović, Katarina, Filipić, Brankica, Kojić, Milan, Jovčić, Branko, "Bacterial Diversity among the Sediments of Glacial Lakes in the Western Balkans: Exploring the Impact of Human Population" in Geomicrobiology Journal, 36, no. 3 (2019):261-270,
https://doi.org/10.1080/01490451.2018.1550128 . .

TY  - JOUR
AU  - Miljković, Marija
AU  - Marinković, Pavle
AU  - Novović, Katarina
AU  - Jovčić, Branko
AU  - Terzić-Vidojević, Amarela
AU  - Kojić, Milan
PY  - 2018
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/1110
UR  - http://intor.torlakinstitut.com/handle/123456789/686
AB  - The ability of lactic acid bacteria to form multi-cellular aggregates via self-aggregation is regarded as an important mechanism for stress tolerance, adhesion, colonization and genetic material exchange. The novel aggLr gene encoding for the auto-aggregation promoting protein (AggLr) of Lactococcus raffinolactis BGTRK10-1 was cloned. Heterologous expression of AggLr enabled auto-aggregation, higher hydrophobicity and collagen and fibronectin binding of the carrier strains. Domain analysis and the type of aggregates formed by cells expressing AggLr confirmed that this aggregation factor belongs to the family of high molecular weight proteins that the authors propose to be called Snow-flake Forming Collagen Binding Aggregation Factors (SFCBAF). An additional feature of SFCBAF is that they are rich in threonine and lysine and are free of cysteine in all of the aggregation factors described so far. In contrast to previously discovered SFCBAF, the gene encoding for AggLr is located on the chromosome in the strain BGTRK10-1.
PB  - Taylor & Francis Ltd, Abingdon
T2  - Biofouling
T1  - AggLr, a novel aggregation factor in Lactococcus raffinolactis BGTRK10-1: its role in surface adhesion
EP  - 698
IS  - 6
SP  - 685
VL  - 34
DO  - 10.1080/08927014.2018.1481956
ER  - 

@article{
author = "Miljković, Marija and Marinković, Pavle and Novović, Katarina and Jovčić, Branko and Terzić-Vidojević, Amarela and Kojić, Milan",
year = "2018",
abstract = "The ability of lactic acid bacteria to form multi-cellular aggregates via self-aggregation is regarded as an important mechanism for stress tolerance, adhesion, colonization and genetic material exchange. The novel aggLr gene encoding for the auto-aggregation promoting protein (AggLr) of Lactococcus raffinolactis BGTRK10-1 was cloned. Heterologous expression of AggLr enabled auto-aggregation, higher hydrophobicity and collagen and fibronectin binding of the carrier strains. Domain analysis and the type of aggregates formed by cells expressing AggLr confirmed that this aggregation factor belongs to the family of high molecular weight proteins that the authors propose to be called Snow-flake Forming Collagen Binding Aggregation Factors (SFCBAF). An additional feature of SFCBAF is that they are rich in threonine and lysine and are free of cysteine in all of the aggregation factors described so far. In contrast to previously discovered SFCBAF, the gene encoding for AggLr is located on the chromosome in the strain BGTRK10-1.",
publisher = "Taylor & Francis Ltd, Abingdon",
journal = "Biofouling",
title = "AggLr, a novel aggregation factor in Lactococcus raffinolactis BGTRK10-1: its role in surface adhesion",
pages = "698-685",
number = "6",
volume = "34",
doi = "10.1080/08927014.2018.1481956"
}

Miljković, M., Marinković, P., Novović, K., Jovčić, B., Terzić-Vidojević, A.,& Kojić, M.. (2018). AggLr, a novel aggregation factor in Lactococcus raffinolactis BGTRK10-1: its role in surface adhesion. in Biofouling
Taylor & Francis Ltd, Abingdon., 34(6), 685-698.
https://doi.org/10.1080/08927014.2018.1481956

Miljković M, Marinković P, Novović K, Jovčić B, Terzić-Vidojević A, Kojić M. AggLr, a novel aggregation factor in Lactococcus raffinolactis BGTRK10-1: its role in surface adhesion. in Biofouling. 2018;34(6):685-698.
doi:10.1080/08927014.2018.1481956 .

Miljković, Marija, Marinković, Pavle, Novović, Katarina, Jovčić, Branko, Terzić-Vidojević, Amarela, Kojić, Milan, "AggLr, a novel aggregation factor in Lactococcus raffinolactis BGTRK10-1: its role in surface adhesion" in Biofouling, 34, no. 6 (2018):685-698,
https://doi.org/10.1080/08927014.2018.1481956 . .

TY  - JOUR
AU  - Novović, Katarina
AU  - Mihajlović, Sanja
AU  - Dinić, Miroslav
AU  - Malešević, Milka
AU  - Miljković, Marija
AU  - Kojić, Milan
AU  - Jovčić, Branko
PY  - 2018
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/1119
UR  - http://intor.torlakinstitut.com/handle/123456789/684
AB  - Acinetobacter baumannii has been recognized as one of the most challeging pathogens in clinical settings worldwide. Outer membrane porins play a significant role in Acinetobacter antibiotic resistance and virulence. A. baumannii carbapenem resistance and virulence factor porin Omp33-36 was the subject of this study. We investigated the omp33-36 gene transcriptional response in the growth phase, its response to carbapenems, and the effect of contact with host cells. Additionally, the cytotoxic effect of A. baumannii towards keratinocytes was assessed, as well as correlation between omp33-36 gene transcription and cytotoxicity. Further, Acinetobacter spp. Omp33-36 was classified and its characteristics relevant for vaccine candidature were determined. The level of the omp33-36 gene transcription varied between growth phases, but a common pattern could not be established among different strains. Treatment with subinhibitory concentrations of carbapenems decreased, while contact with keratinocytes increased omp33-36 expression in the analysed A. baumannii strains. Variations in omp33-36 mRNA levels did not correlate with cytotoxicity levels. Decrease of omp33-36 mRNA during treatment with subinhibitory concentrations of carbapenems, indicated the importance of transcriptional changes in reversible resistance to carbapenems due to the absence of Omp33-36. The transcription of omp33-36 increased after contact with keratinocytes, indicating the important role of de novo transcription during the initial phase of A. baumannii infection. Primary structural analysis of Acinetobacter spp. Omp33-36 revealed three distinct groups (among four A. baumannii variants). Although we have shown that Omp33-36 was highly polymorphic, we propose a potential antigen (PLAEAAFL motif) for vaccine development. According to PROVEAN analysis, the highly polymorphic structure of Omp33-36 porin should not influence its function significantly.
PB  - Public Library Science, San Francisco
T2  - PLoS One
T1  - Acinetobacter spp. porin Omp33-36: Classification and transcriptional response to carbapenems and host cells
IS  - 8
VL  - 13
DO  - 10.1371/journal.pone.0201608
ER  - 

@article{
author = "Novović, Katarina and Mihajlović, Sanja and Dinić, Miroslav and Malešević, Milka and Miljković, Marija and Kojić, Milan and Jovčić, Branko",
year = "2018",
abstract = "Acinetobacter baumannii has been recognized as one of the most challeging pathogens in clinical settings worldwide. Outer membrane porins play a significant role in Acinetobacter antibiotic resistance and virulence. A. baumannii carbapenem resistance and virulence factor porin Omp33-36 was the subject of this study. We investigated the omp33-36 gene transcriptional response in the growth phase, its response to carbapenems, and the effect of contact with host cells. Additionally, the cytotoxic effect of A. baumannii towards keratinocytes was assessed, as well as correlation between omp33-36 gene transcription and cytotoxicity. Further, Acinetobacter spp. Omp33-36 was classified and its characteristics relevant for vaccine candidature were determined. The level of the omp33-36 gene transcription varied between growth phases, but a common pattern could not be established among different strains. Treatment with subinhibitory concentrations of carbapenems decreased, while contact with keratinocytes increased omp33-36 expression in the analysed A. baumannii strains. Variations in omp33-36 mRNA levels did not correlate with cytotoxicity levels. Decrease of omp33-36 mRNA during treatment with subinhibitory concentrations of carbapenems, indicated the importance of transcriptional changes in reversible resistance to carbapenems due to the absence of Omp33-36. The transcription of omp33-36 increased after contact with keratinocytes, indicating the important role of de novo transcription during the initial phase of A. baumannii infection. Primary structural analysis of Acinetobacter spp. Omp33-36 revealed three distinct groups (among four A. baumannii variants). Although we have shown that Omp33-36 was highly polymorphic, we propose a potential antigen (PLAEAAFL motif) for vaccine development. According to PROVEAN analysis, the highly polymorphic structure of Omp33-36 porin should not influence its function significantly.",
publisher = "Public Library Science, San Francisco",
journal = "PLoS One",
title = "Acinetobacter spp. porin Omp33-36: Classification and transcriptional response to carbapenems and host cells",
number = "8",
volume = "13",
doi = "10.1371/journal.pone.0201608"
}

Novović, K., Mihajlović, S., Dinić, M., Malešević, M., Miljković, M., Kojić, M.,& Jovčić, B.. (2018). Acinetobacter spp. porin Omp33-36: Classification and transcriptional response to carbapenems and host cells. in PLoS One
Public Library Science, San Francisco., 13(8).
https://doi.org/10.1371/journal.pone.0201608

Novović K, Mihajlović S, Dinić M, Malešević M, Miljković M, Kojić M, Jovčić B. Acinetobacter spp. porin Omp33-36: Classification and transcriptional response to carbapenems and host cells. in PLoS One. 2018;13(8).
doi:10.1371/journal.pone.0201608 .

Novović, Katarina, Mihajlović, Sanja, Dinić, Miroslav, Malešević, Milka, Miljković, Marija, Kojić, Milan, Jovčić, Branko, "Acinetobacter spp. porin Omp33-36: Classification and transcriptional response to carbapenems and host cells" in PLoS One, 13, no. 8 (2018),
https://doi.org/10.1371/journal.pone.0201608 . .

TY  - JOUR
AU  - Vasiljević, Z. V.
AU  - Novović, Katarina
AU  - Kojić, Milan
AU  - Minić, Predrag
AU  - Sovtić, A.
AU  - Đukić, S.
AU  - Jovčić, Branko
PY  - 2016
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/908
UR  - http://intor.torlakinstitut.com/handle/123456789/704
AB  - The Burkholderia cepacia complex (Bcc) organisms remain significant pathogens in patients with cystic fibrosis (CF). This study was performed to evaluate the prevalence, epidemiological characteristics, and presence of molecular markers associated with virulence and transmissibility of the Bcc strains in the National CF Centre in Belgrade, Serbia. The Bcc isolates collected during the four-year study period (2010-2013) were further examined by 16 s rRNA gene, pulsed-field gel electrophoresis of genomic DNA, multilocus sequence typing analysis, and phylogenetic analysis based on concatenated sequence of seven alleles. Fifty out of 184 patients (27.2 %) were colonized with two Bcc species, B. cenocepacia (n = 49) and B. stabilis (n = 1). Thirty-four patients (18.5 %) had chronic colonization. Typing methods revealed a high level of similarity among Bcc isolates, indicating a person-to-person transmission or acquisition from a common source. New sequence types (STs) were identified, and none of the STs with an international distribution were found. One centre-specific ST, B. cenocepacia ST856, was highly dominant and shared by 48/50 (96 %) patients colonized by Bcc. This clone was characterized by PCR positivity for both the B. cepacia epidemic strain marker and cable pilin, and showed close genetic relatedness to the epidemic strain CZ1 (ST32). These results indicate that the impact of Bcc on airway colonization in the Serbian CF population is high and virtually exclusively limited to a single clone of B. cenocepacia. The presence of a highly transmissible clone and probable patient-to-patient spread was observed.
PB  - Springer, New York
T2  - European Journal of Clinical Microbiology & Infectious Diseases
T1  - Burkholderia cepacia complex in Serbian patients with cystic fibrosis: prevalence and molecular epidemiology
EP  - 1284
IS  - 8
SP  - 1277
VL  - 35
DO  - 10.1007/s10096-016-2662-4
ER  - 

@article{
author = "Vasiljević, Z. V. and Novović, Katarina and Kojić, Milan and Minić, Predrag and Sovtić, A. and Đukić, S. and Jovčić, Branko",
year = "2016",
abstract = "The Burkholderia cepacia complex (Bcc) organisms remain significant pathogens in patients with cystic fibrosis (CF). This study was performed to evaluate the prevalence, epidemiological characteristics, and presence of molecular markers associated with virulence and transmissibility of the Bcc strains in the National CF Centre in Belgrade, Serbia. The Bcc isolates collected during the four-year study period (2010-2013) were further examined by 16 s rRNA gene, pulsed-field gel electrophoresis of genomic DNA, multilocus sequence typing analysis, and phylogenetic analysis based on concatenated sequence of seven alleles. Fifty out of 184 patients (27.2 %) were colonized with two Bcc species, B. cenocepacia (n = 49) and B. stabilis (n = 1). Thirty-four patients (18.5 %) had chronic colonization. Typing methods revealed a high level of similarity among Bcc isolates, indicating a person-to-person transmission or acquisition from a common source. New sequence types (STs) were identified, and none of the STs with an international distribution were found. One centre-specific ST, B. cenocepacia ST856, was highly dominant and shared by 48/50 (96 %) patients colonized by Bcc. This clone was characterized by PCR positivity for both the B. cepacia epidemic strain marker and cable pilin, and showed close genetic relatedness to the epidemic strain CZ1 (ST32). These results indicate that the impact of Bcc on airway colonization in the Serbian CF population is high and virtually exclusively limited to a single clone of B. cenocepacia. The presence of a highly transmissible clone and probable patient-to-patient spread was observed.",
publisher = "Springer, New York",
journal = "European Journal of Clinical Microbiology & Infectious Diseases",
title = "Burkholderia cepacia complex in Serbian patients with cystic fibrosis: prevalence and molecular epidemiology",
pages = "1284-1277",
number = "8",
volume = "35",
doi = "10.1007/s10096-016-2662-4"
}

Vasiljević, Z. V., Novović, K., Kojić, M., Minić, P., Sovtić, A., Đukić, S.,& Jovčić, B.. (2016). Burkholderia cepacia complex in Serbian patients with cystic fibrosis: prevalence and molecular epidemiology. in European Journal of Clinical Microbiology & Infectious Diseases
Springer, New York., 35(8), 1277-1284.
https://doi.org/10.1007/s10096-016-2662-4

Vasiljević ZV, Novović K, Kojić M, Minić P, Sovtić A, Đukić S, Jovčić B. Burkholderia cepacia complex in Serbian patients with cystic fibrosis: prevalence and molecular epidemiology. in European Journal of Clinical Microbiology & Infectious Diseases. 2016;35(8):1277-1284.
doi:10.1007/s10096-016-2662-4 .

Vasiljević, Z. V., Novović, Katarina, Kojić, Milan, Minić, Predrag, Sovtić, A., Đukić, S., Jovčić, Branko, "Burkholderia cepacia complex in Serbian patients with cystic fibrosis: prevalence and molecular epidemiology" in European Journal of Clinical Microbiology & Infectious Diseases, 35, no. 8 (2016):1277-1284,
https://doi.org/10.1007/s10096-016-2662-4 . .