Genetic heterogeneity and predominance of blaCTX‐M‐15 in cefotaxime‐resistant Enterobacteriaceae isolates colonizing hospitalized children in Tunisia.

Extended‐spectrum β‐lactamase (ESBL)‐producing Enterobacteriaceae have emerged as important nosocomial pathogens. Community infections by these organisms have been also reported and were associated with previous intestinal colonization. We aimed to characterize cefotaxime‐resistant Enterobacteriaceae (CTX‐R‐En) isolated from hospitalized children in a Tunisian paediatric ward. Seventy CTX‐R‐En isolates were collected from 227 rectal swabs from hospitalized children in a paediatric ward. Antimicrobial susceptibility testing was determined according to the EUCAST guidelines. Isolates were characterized by polymerase chain reaction (PCR, genes encoding: ESBLs, pAmpC, carbapenemases, plasmid‐mediated quinolone resistance, virulence factors in Escherichia coli and Klebsiella pneumoniae isolates, occurrence of classes 1 and 2 integrons, phylogenetic groups of E. coli isolates, ERIC‐PCR and PCR‐based replicon typing) and conjugal transfer experiments. In total, 65 out of 227 (28·6%) hospitalized children were colonized with CTX‐M‐R‐En, and 70 isolates were identified. Isolates were 59 ESBL‐, 7 plasmidic‐AmpC (pAmpC)‐, 3 ESBL+pAmpC‐, and one ESBL+carbapenemase producers. The following bla genes were identified: blaCTX‐M‐15 (n = 54), blaCTX‐M‐1 (n = 5), blaCTX‐M‐9 (n = 2), blaCTX‐M‐13 (n = 1) and blaCTX‐M‐14 (n = 1), blaCMY‐2 (n = 5), blaCMY‐4 (n = 4), blaACC‐1 (n = 1) and blaOXA‐48 (n = 1). Our results showed that hospitalized children were colonized with various CTX‐R‐En‐producing several beta‐lactamase enzymes. [ABSTRACT FROM AUTHOR]