ABSTRACT
Objectives: Brazil is the greatest exporter of chicken meat (CM) in the world. It is of utmost importance to monitor resistance to extended-spectrum cephalosporins (ESCs) in this sector because resistance to ESCs in Escherichia coli isolated from food-producing animals may contaminate humans through the food chain. Thus, the aim of this study was to characterize and compare ESC-resistant E. coli isolated from chickens and retail CM produced in south-eastern Brazil. Methods: Five CM samples and 117 chicken cloacal swabs (CCSs) were inoculated on MacConkey agar supplemented with cefotaxime. Presumptive E. coli colonies were identified and antimicrobial susceptibility was tested. Virulence and acquired blaESBL and blaAmpC genes were sought and genetic environments characterized. Isolates were typed by phylogenetic grouping, XbaI-PFGE and MLST. Results: All five CM samples and 36 CCSs (30.8%) were positive for the presence of ESC-resistant E. coli, leading to the selection of 58 resistant isolates. ESC resistance was mostly due to the presence of the chromosome-encoded blaCTX-M-2 gene, but plasmid-mediated blaCTX-M-2, blaCTX-M-8, blaCTX-M-15, blaCTX-M-55 and blaCMY-2 were also detected. Multireplicon plasmids were sporadically identified, such as IncHI2/P-blaCTX-M-2 and IncFII/N-blaCTX-M-55. Phylogroup D predominated, while PFGE and MLST revealed a high genetic diversity. Conclusions: Live Brazilian chickens and CM act as reservoirs of ESC-resistant E. coli and resistance genes are located on highly diverse genetic determinants. Potentially pathogenic strains, which may represent a threat to human health and a source of environmental contamination, were also identified. Active surveillance is therefore essential in Brazil's chicken production line.
Subject(s)
Anti-Bacterial Agents/pharmacology , Cephalosporins/pharmacology , Drug Resistance, Bacterial , Escherichia coli/drug effects , Plasmids/genetics , Poultry Products/microbiology , Animals , Bacterial Typing Techniques , Brazil/epidemiology , Chickens/microbiology , Cloaca/microbiology , Escherichia coli/isolation & purification , Escherichia coli/pathogenicity , Escherichia coli Infections/epidemiology , Escherichia coli Infections/veterinary , Genetic Variation , Microbial Sensitivity Tests , Multilocus Sequence Typing , Phylogeny , Poultry/microbiology , Virulence Factors/genetics , beta-Lactamases/geneticsABSTRACT
Polymyxins are antimicrobial agents capable of controlling carbapenemase-producing We report a cluster of four patients colonized or infected by polymyxin-resistant and Three patients were hospitalized in adjacent wards, and two were admitted to the intensive care unit. The index case maintained prolonged intestinal colonization by KPC-producing Colonization by KPC-producing
Subject(s)
Adult , Aged , Female , Humans , Male , Middle Aged , Anti-Bacterial Agents/pharmacology , Cross Infection/microbiology , Klebsiella Infections/microbiology , Klebsiella pneumoniae/drug effects , Polymyxins/pharmacology , Carbapenems/pharmacology , Drug Resistance, Bacterial , Klebsiella pneumoniae/isolation & purification , Microbial Sensitivity TestsABSTRACT
INTRODUCTION: Polymyxins are antimicrobial agents capable of controlling carbapenemase-producing Klebsiella pneumoniae infection. METHODS: We report a cluster of four patients colonized or infected by polymyxin-resistant and Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae. RESULTS: Three patients were hospitalized in adjacent wards, and two were admitted to the intensive care unit. The index case maintained prolonged intestinal colonization by KPC-producing K. pneumoniae. Three patients received polymyxin B before the isolation of polymyxin-resistant K. pneumoniae. CONCLUSIONS: Colonization by KPC-producing K. pneumoniae and previous use of polymyxin B may be causally related to the development of polymyxin-resistant microorganisms.
