ABSTRACT
Twenty extended-spectrum ß-lactamase (ESBL)-producing E. coli strains were isolated from imported meat in South Korea. ESBL strains of E. coli were detected in chicken (14/20) more often than in pork (6/20) and beef (0/20); the highest number (12/20) was detected in Brazilian meats. The blaCTX-M genes were predominant in meats from many countries. E. coli from pork imported from France produced the blaCTX-M-58 enzyme, which has never been documented previously in ESBL-producing bacteria from clinical or environmental sources. Additionally, the coexistence of the blaCTX-M-2 and blaOXA-1 enzymes in EC12-5 isolate was found for the first time in an ESBL E. coli isolate. A rare blaCTX-M type, blaCTX-M-25, was found in 40% of ESBL E. coli isolates. Phenotypic susceptibility testing showed that E. coli isolates were resistant to up to eleven antibiotics, including ciprofloxacin. For the first time, a new combination in an integron gene cassette, aacA4-cmlA6-qacEΔ1, was found in an E. coli isolate from poultry imported from Brazil. Three E. coli ST117 isolates, from an avian pathogenic lineage producing CTX-M-94, harbored fimH, fyuA, iutA, papC, rfc, and traT virulence genes and were not susceptible to quinolones. For the first time, rfc and papG virulence factors were detected in ESBL E. coli strains isolated from meat products. Even though E. coli CC21 and CC22 were obtained from meats from the USA and Brazil, respectively, they had a similarity coefficient higher than 99% in rep-PCR and the same MLST type (ST117), phenotypic antibiotic resistance pattern, integron gene (qacEΔ1), and plasmid DNA profile. This study indicates that imported meat products may be a source of ESBL-producing E. coli strains in South Korea.
Subject(s)
Escherichia coli Proteins/genetics , Escherichia coli/genetics , Food Microbiology/methods , Meat/microbiology , beta-Lactamases/genetics , Anti-Bacterial Agents/pharmacology , Bacterial Typing Techniques , Consumer Product Safety , Drug Resistance, Multiple, Bacterial/genetics , Escherichia coli/drug effects , Escherichia coli/enzymology , Escherichia coli/pathogenicity , Escherichia coli Infections/microbiology , Escherichia coli Proteins/metabolism , Foodborne Diseases/microbiology , Genotype , Meat-Packing Industry , Microbial Sensitivity Tests , Phenotype , Poultry Products/microbiology , Red Meat/microbiology , Republic of Korea , Risk Assessment , Virulence/genetics , beta-Lactamases/metabolismABSTRACT
During a nationwide surveillance in Korea, 13 methicillin-resistant Staphylococcus aureus (MRSA) strains were isolated from imported and domestic meat between 2009 and 2011. The predominant MRSA genotype was SCCmec type V, and only two agr types (I and II) were found. Unexpectedly, sequence type ST72 comprised more than 50% of the isolates; this is the first instance of type ST72 in food from Canada. Two Spanish pork isolates were ST398, which caused human disease in Europe, and they carried leukotoxin genes, lukS, lukF, and lukE-lukD. Furthermore, P71 and P6 harbored all of the known leukocidin genes, lukS-lukF-lukE-lukD-lukM. Our collected MRSA strains were multidrug resistant with various antimicrobial and heavy-metal resistance genes. Toxin genes that are commonly found in clinical MRSA also were detected in our meat strains. One MRSA strain exhibited an uncommon type of enterotoxin, sec-see-seg-sei-sel-sem-sen-seo-sep. Plasmids (1.5-15.0 kb) were found in 12 of the 13 MRSA isolates. Repetitive sequence-based polymerase chain reaction of the genomic DNA showed 3 clusters with 95% similarity. The presence of multidrug-resistant and toxigenic MRSA in meat products suggests that comprehensive surveillance should be continued for imported meats in Korea.
