Browsing by Author "Brkic, Snezana (57193991713)"

In the context of global efforts to combat antimicrobial resistance (AMR), the importance of comprehensive AMR data is more crucial than ever. AMR surveillance networks, such as the European Antimicrobial Resistance Surveillance Network (EARS-Net) and the Central Asian and European Surveillance of Antimicrobial Resistance (CAESAR), support member states in obtaining high-quality AMR data. Nevertheless, data gaps persist in some countries, including those in the Western Balkans (WBs), a region with high AMR rates. This review analyzed existing research on carbapenem-resistant Enterobacterales (CRE) to better understand the AMR landscape in the WB countries. The most prevalent CRE was Klebsiella pneumoniae, followed by Escherichia coli, Enterobacter cloacae, and Proteus mirabilis, with sporadic cases of Morganella morganii, Providencia spp., Klebsiella oxytoca, and Citrobacter sedlakii. Carbapenemase production was identified as the most common mechanism of carbapenem resistance, but other resistance mechanisms were not investigated. An increasing trend in carbapenem resistance has been observed over the last decade, alongside a shift in carbapenemase epidemiology from the NDM type in 2013–2014 to the OXA-48 type in recent years. Few studies have applied whole-genome sequencing for CRE analysis, which has demonstrated the spread of resistance determinants across different niches and over time, emphasizing the importance of molecular-based research. The overall low number of studies in the WB countries can be attributed to limited resources, highlighting the need for enhanced support in education, training, technology, and equipment to improve data collection and evaluation. © 2024 by the authors.

In the context of global efforts to combat antimicrobial resistance (AMR), the importance of comprehensive AMR data is more crucial than ever. AMR surveillance networks, such as the European Antimicrobial Resistance Surveillance Network (EARS-Net) and the Central Asian and European Surveillance of Antimicrobial Resistance (CAESAR), support member states in obtaining high-quality AMR data. Nevertheless, data gaps persist in some countries, including those in the Western Balkans (WBs), a region with high AMR rates. This review analyzed existing research on carbapenem-resistant Enterobacterales (CRE) to better understand the AMR landscape in the WB countries. The most prevalent CRE was Klebsiella pneumoniae, followed by Escherichia coli, Enterobacter cloacae, and Proteus mirabilis, with sporadic cases of Morganella morganii, Providencia spp., Klebsiella oxytoca, and Citrobacter sedlakii. Carbapenemase production was identified as the most common mechanism of carbapenem resistance, but other resistance mechanisms were not investigated. An increasing trend in carbapenem resistance has been observed over the last decade, alongside a shift in carbapenemase epidemiology from the NDM type in 2013–2014 to the OXA-48 type in recent years. Few studies have applied whole-genome sequencing for CRE analysis, which has demonstrated the spread of resistance determinants across different niches and over time, emphasizing the importance of molecular-based research. The overall low number of studies in the WB countries can be attributed to limited resources, highlighting the need for enhanced support in education, training, technology, and equipment to improve data collection and evaluation. © 2024 by the authors.

Klebsiella pneumoniae is a major cause of severe healthcare-associated infections and often shows MDR phenotypes. Carbapenem resistance is frequent, and colistin represents a key molecule to treat infections caused by such isolates. Here we evaluated the antimicrobial resistance (AMR) mechanisms and the genomic epidemiology of clinical K. pneumoniae isolates from Serbia. Consecutive non-replicate K. pneumoniae clinical isolates (n = 2,298) were collected from seven hospitals located in five Serbian cities and tested for carbapenem resistance by disk diffusion. Isolates resistant to at least one carbapenem (n = 426) were further tested for colistin resistance with Etest or Vitek2. Broth microdilution (BMD) was performed to confirm the colistin resistance phenotype, and colistin-resistant isolates (N = 45, 10.6%) were characterized by Vitek2 and whole genome sequencing. Three different clonal groups (CGs) were observed: CG101 (ST101, N = 38), CG258 (ST437, N = 4; ST340, N = 1; ST258, N = 1) and CG17 (ST336, N = 1). mcr genes, encoding for acquired colistin resistance, were not observed, while all the genomes presented mutations previously associated with colistin resistance. In particular, all strains had a mutated MgrB, with MgrBC28S being the prevalent mutation and associated with ST101. Isolates belonging to ST101 harbored the carbapenemase OXA-48, which is generally encoded by an IncL/M plasmid that was no detected in our isolates. MinION sequencing was performed on a representative ST101 strain, and the obtained long reads were assembled together with the Illumina high quality reads to decipher the blaOXA–48 genetic background. The blaOXA–48 gene was located in a novel IncFIA-IncR hybrid plasmid, also containing the extended spectrum β-lactamase-encoding gene blaCTX–M–15 and several other AMR genes. Non-ST101 isolates presented different MgrB alterations (C28S, C28Y, K2∗, K3∗, Q30∗, adenine deletion leading to frameshift and premature termination, IS5-mediated inactivation) and expressed different carbapenemases: OXA-48 (ST437 and ST336), NDM-1 (ST437 and ST340) and KPC-2 (ST258). Our study reports the clonal expansion of the newly emerging ST101 clone in Serbia. This high-risk clone appears adept at acquiring resistance, and efforts should be made to contain the spread of such clone. © Copyright © 2020 Palmieri, D’Andrea, Pelegrin, Mirande, Brkic, Cirkovic, Goossens, Rossolini and van Belkum.

Klebsiella pneumoniae is a major cause of severe healthcare-associated infections and often shows MDR phenotypes. Carbapenem resistance is frequent, and colistin represents a key molecule to treat infections caused by such isolates. Here we evaluated the antimicrobial resistance (AMR) mechanisms and the genomic epidemiology of clinical K. pneumoniae isolates from Serbia. Consecutive non-replicate K. pneumoniae clinical isolates (n = 2,298) were collected from seven hospitals located in five Serbian cities and tested for carbapenem resistance by disk diffusion. Isolates resistant to at least one carbapenem (n = 426) were further tested for colistin resistance with Etest or Vitek2. Broth microdilution (BMD) was performed to confirm the colistin resistance phenotype, and colistin-resistant isolates (N = 45, 10.6%) were characterized by Vitek2 and whole genome sequencing. Three different clonal groups (CGs) were observed: CG101 (ST101, N = 38), CG258 (ST437, N = 4; ST340, N = 1; ST258, N = 1) and CG17 (ST336, N = 1). mcr genes, encoding for acquired colistin resistance, were not observed, while all the genomes presented mutations previously associated with colistin resistance. In particular, all strains had a mutated MgrB, with MgrBC28S being the prevalent mutation and associated with ST101. Isolates belonging to ST101 harbored the carbapenemase OXA-48, which is generally encoded by an IncL/M plasmid that was no detected in our isolates. MinION sequencing was performed on a representative ST101 strain, and the obtained long reads were assembled together with the Illumina high quality reads to decipher the blaOXA–48 genetic background. The blaOXA–48 gene was located in a novel IncFIA-IncR hybrid plasmid, also containing the extended spectrum β-lactamase-encoding gene blaCTX–M–15 and several other AMR genes. Non-ST101 isolates presented different MgrB alterations (C28S, C28Y, K2∗, K3∗, Q30∗, adenine deletion leading to frameshift and premature termination, IS5-mediated inactivation) and expressed different carbapenemases: OXA-48 (ST437 and ST336), NDM-1 (ST437 and ST340) and KPC-2 (ST258). Our study reports the clonal expansion of the newly emerging ST101 clone in Serbia. This high-risk clone appears adept at acquiring resistance, and efforts should be made to contain the spread of such clone. © Copyright © 2020 Palmieri, D’Andrea, Pelegrin, Mirande, Brkic, Cirkovic, Goossens, Rossolini and van Belkum.

Our aim was to investigate gut colonization with carbapenem-resistant Enterobacterales (CRE) in the population of preterm neonates at discharge from a tertiary care center in Serbia. The study included 350 randomly selected neonates/infants discharged in the period April 2018–May 2019. CRE colonization was present in 88/350 (25.1%) of patients. Klebsiella pneumoniae producing KPC and OXA-48 carbapenemase were detected in 45 and 42 subjects, respectively, while NDM producing Escherichia coli was identified in one patient only. All OXA-48 strains harbored blaCTX-M-15, while both blaTEM and blaSHV were present in all but one KPC-producing strain. CRE isolates exhibited a multidrug resistance pattern with uniform fluoroquinolone resistance, universal susceptibility to colistin, and variable susceptibility to aminoglycosides. Administration of carbapenems was common (~50%) and it was strongly associated with colonization, as well as the combinational therapeutic regimens that included meropenem, contrary to ampicillin–sulbactam/colistin therapy and prolonged course of the initial therapy (ampicillin/amikacin ≥ 7 days). Other risk factors for CRE carriage were level of immaturity, admission to neonatal intensive care unit, prolonged hospitalization and invasive procedures. Although the rate of clinically and/or laboratory proven systemic infections was significantly higher among colonized patients, CRE infection was confirmed in one patient only (1.1%) that was colonized with NDM E. coli. Clonal relatedness of CRE isolates was high, with seven and eight clusters detected among KPC (N = 30) and OXA-48 (N = 37) producing strains, respectively. The follow up of the 31 KPC-colonized patients after discharge from hospital revealed common decolonization within one month (~68%). In conclusion, our results demonstrated a high rate of CRE colonization that is most likely related to carbapenem consumption and lack of screening as important infection prevention practice. © 2023 by the authors.

Our aim was to investigate gut colonization with carbapenem-resistant Enterobacterales (CRE) in the population of preterm neonates at discharge from a tertiary care center in Serbia. The study included 350 randomly selected neonates/infants discharged in the period April 2018–May 2019. CRE colonization was present in 88/350 (25.1%) of patients. Klebsiella pneumoniae producing KPC and OXA-48 carbapenemase were detected in 45 and 42 subjects, respectively, while NDM producing Escherichia coli was identified in one patient only. All OXA-48 strains harbored blaCTX-M-15, while both blaTEM and blaSHV were present in all but one KPC-producing strain. CRE isolates exhibited a multidrug resistance pattern with uniform fluoroquinolone resistance, universal susceptibility to colistin, and variable susceptibility to aminoglycosides. Administration of carbapenems was common (~50%) and it was strongly associated with colonization, as well as the combinational therapeutic regimens that included meropenem, contrary to ampicillin–sulbactam/colistin therapy and prolonged course of the initial therapy (ampicillin/amikacin ≥ 7 days). Other risk factors for CRE carriage were level of immaturity, admission to neonatal intensive care unit, prolonged hospitalization and invasive procedures. Although the rate of clinically and/or laboratory proven systemic infections was significantly higher among colonized patients, CRE infection was confirmed in one patient only (1.1%) that was colonized with NDM E. coli. Clonal relatedness of CRE isolates was high, with seven and eight clusters detected among KPC (N = 30) and OXA-48 (N = 37) producing strains, respectively. The follow up of the 31 KPC-colonized patients after discharge from hospital revealed common decolonization within one month (~68%). In conclusion, our results demonstrated a high rate of CRE colonization that is most likely related to carbapenem consumption and lack of screening as important infection prevention practice. © 2023 by the authors.

Wastewater (WW) is considered a source of antibiotic-resistant bacteria with clinical relevance and may, thus, be important for their dissemination into the environment, especially in countries with poor WW treatment. To obtain an overview of the occurrence and characteristics of carbapenem-resistant Gram-negative bacteria (CR-GNB) in WW of Belgrade, we investigated samples from the four main sewer outlets prior to effluent into international rivers, the Sava and the Danube. Thirty-four CR-GNB isolates were selected for antimicrobial susceptibility testing (AST) and whole-genome sequencing (WGS). AST revealed that all isolates were multidrug-resistant. WGS showed that they belonged to eight different species and 25 different sequence types (STs), seven of which were new. ST101 K. pneumoniae (blaCTX-M-15/blaOXA-48) with novel plasmid p101_srb was the most frequent isolate, detected at nearly all the sampling sites. The most frequent resistance genes to aminoglycosides, quinolones, trimethroprim-sulfamethoxazole, tetracycline and fosfomycin were aac(6′)-Ib-cr (55.9%), oqxA (32.3%), dfrA14 (47.1%), sul1 (52.9%), tet(A) (23.5%) and fosA (50%), respectively. Acquired resistance to colistin via chromosomal-mediated mechanisms was detected in K. pneumoniae (mutations in mgrB and basRS) and P. aeruginosa (mutation in basRS), while a plasmid-mediated mechanism was confirmed in the E. cloacae complex (mcr-9.1 gene). The highest number of virulence genes (>300) was recorded in P. aeruginosa isolates. Further research is needed to systematically track the occurrence and distribution of these bacteria so as to mitigate their threat. © 2023 by the authors.

Wastewater (WW) is considered a source of antibiotic-resistant bacteria with clinical relevance and may, thus, be important for their dissemination into the environment, especially in countries with poor WW treatment. To obtain an overview of the occurrence and characteristics of carbapenem-resistant Gram-negative bacteria (CR-GNB) in WW of Belgrade, we investigated samples from the four main sewer outlets prior to effluent into international rivers, the Sava and the Danube. Thirty-four CR-GNB isolates were selected for antimicrobial susceptibility testing (AST) and whole-genome sequencing (WGS). AST revealed that all isolates were multidrug-resistant. WGS showed that they belonged to eight different species and 25 different sequence types (STs), seven of which were new. ST101 K. pneumoniae (blaCTX-M-15/blaOXA-48) with novel plasmid p101_srb was the most frequent isolate, detected at nearly all the sampling sites. The most frequent resistance genes to aminoglycosides, quinolones, trimethroprim-sulfamethoxazole, tetracycline and fosfomycin were aac(6′)-Ib-cr (55.9%), oqxA (32.3%), dfrA14 (47.1%), sul1 (52.9%), tet(A) (23.5%) and fosA (50%), respectively. Acquired resistance to colistin via chromosomal-mediated mechanisms was detected in K. pneumoniae (mutations in mgrB and basRS) and P. aeruginosa (mutation in basRS), while a plasmid-mediated mechanism was confirmed in the E. cloacae complex (mcr-9.1 gene). The highest number of virulence genes (>300) was recorded in P. aeruginosa isolates. Further research is needed to systematically track the occurrence and distribution of these bacteria so as to mitigate their threat. © 2023 by the authors.