[Source: Antimicrobial Agents and Chemotherapy, full page: (LINK). Abstract, edited.]
Emergence and dominance of E. coli ST131 CTX-M-27 in a community paediatric cohort study: independent host factors and bacterial genetic determinants
André Birgy, Corinne Levy, Marie-Hélène Nicolas-Chanoine, Aurélie Cointe, Claire A. Hobson, Mélanie Magnan, Stéphane Bechet, Philippe Bidet, Robert Cohen, Stéphane Bonacorsi
The recent emergence and diffusion in the community of Escherichia coli isolates belonging to the multidrug-resistant and CTX-M-27-producing ST131 C1-M27 cluster, makes this cluster potentially as epidemic as the worldwide E coli ST131 subclade C2 composed of multidrug resistant isolates producing CTX-M-15. Thirty-five extended-spectrum beta-lactamase (ESBL) producing ST131 isolates were identified in a cohort of 1,885 French children over a 5 year-period. They were sequenced to characterize the ST131 E. coli isolates producing CTX-M-27 recently emerging in France. ST131 isolates producing CTX-M-27 (n=17), and particularly those belonging to the C1-M27 cluster (n=14), carried many resistance-encoding genes and predominantly a F1:A2:B20 plasmid type. In multivariate analysis, having been hospitalized since birth (OR=10.9; 95%CI=2.4;48.8; p=0.002) and being cared for in a day-care center (OR=9.4;95%; CI=1.5;59.0; p=0.017) were independent risk factors for ST131 CTX-M-27 fecal carriage compared with ESBL-producing non-ST131 isolates. No independent risk factor was found when comparing CTX-M-15 (n=11) and CTX-M-1/14 (n=7)-producing ST131 isolates with ESBL-producing non-ST131 isolates or with non-ESBL-producing isolates. Several factors may contribute to the increase in fecal carriage of CTX-M-27-producing E. coli isolates: resistance to multiple antibiotics, capacity of the CTX-M-27 enzyme to hydrolyze both cefotaxime and ceftazidime, carriage of a peculiar F-type plasmid, and/or capacity to colonize children who have been hospitalized since birth or who attend day-care centers.
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Keywords: Antibiotics; Drugs Resistance; E. Coli; Pediatrics; Cefotaxime; Ceftazidime.