The spread of antibiotic-resistant Enterobacteriaceae in the community is one of the main challenges for antibiotic treatment of community-onset infections. We evaluated the microbiological and molecular characteristics of stool samples from adults with comprehensive health examinations. Of 109 fecal samples, bacterial growth was observed in 86 samples and 61 gram-negative bacterial isolates were identified, of which 45 were Escherichia coli isolates (73.8%). Two isolates of Raoultella showed imipenem resistance, and both E. coli and Citrobacter freundii showed intermediate resistance to imipenem. Colistin resistance was identified in isolates of Klebsiella variicola and Salmonella subterranean, but no isolates carried mcr-1. As for E. coli genotypes, 35 sequence types were identified. blaTEM-1, blaTEM-30, and blaCTX-M were identified in 15, 1, and 4 E. coli isolates, respectively. In addition, all four Klebsiella pneumoniae isolates carried blaSHV. Many genotypes that have been identified in isolates causing human infections were found in isolates in this study. There is a need to control the rise and spread of antibiotic-resistant pathogens by fecal carriage.
Keywords: CTX-M; Enterobacteriaceae; extended spectrum β-lactamase (ESBL).