Objectives: Young children could act as important carriers of cefotaxime-resistant Enterobacteriaceae. However, most studies on these bacteria have focused on hospitalized adults. Therefore, we determined the prevalence and characteristics of ESBL-, plasmid-determined AmpC-type β-lactamase (PABL)- and carbapenemase-producing diarrhoeagenic Escherichia coli isolates mainly from infants and children in the south-west region of Korea over a 10 year period.
Methods: Non-duplicate E. coli clinical isolates were recovered from diarrhoeagenic patient specimens at 12 hospitals in Gwangju, Korea, between January 2007 and December 2016. Antimicrobial susceptibilities and molecular features of ESBL- and carbapenemase-producing isolates were determined.
Results: A total of 1047 pathogenic E. coli isolates were collected and 58 cefotaxime-resistant E. coli isolates (5.5%) were identified. The prevalence and types of β-lactamase genes increased steadily from 5.7% in 2007 to 11.6% in 2016 with some fluctuations. CTX-M-14 (53.4%) was the predominant CTX-M genotype. PFGE revealed high genetic heterogeneities among diarrhoeagenic E. coli isolates, suggesting horizontal transfer of antibiotic resistance genes, which was also proved by conjugation assay.
Conclusions: Progressive increases in carriage rates and the number of β-lactamase types, and the possibility of community outbreaks of these food-borne bacteria in young children, may pose tangible public health threats.
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