title: Characterization of extended-spectrum-beta-lactamase-producing Escherichia coli strains involved in maternal-fetal colonization: prevalence of E. coli ST131.
abstract: Maternal-fetal Escherichia coli infections, such as neonatal bacteremia and meningitis, are important causes of morbidity and mortality. From 2006 to 2010, we studied newborns and their mothers who were colonized with E. coli in a French hospital in order to document (i) the epidemiology and genetic characteristics of extended-spectrum-beta-lactamase (ESBL)-producing E. coli strains, (ii) the prevalence of associated virulence genes, (iii) the prevalence of clone sequence type 131 (ST131), and (iv) the genetic relationship among ESBL-producing strains. Among the 2,755 E. coli cultures recovered from vaginal or neonatal samples, 68 were ESBL producers (2.46%). We found a wide diversity of ESBL genes, with the majority being bla(CTX-M-14), bla(CTX-M-1), and bla(CTX-M-15), distributed among the 4 main phylogenetic groups. Genes encoding virulence factors were found in 90.7% of the isolates, with ≥ 2 virulence genes present in 76% of cases. The prevalence of ST131 among ESBL-producing E. coli isolates was 9.4% (6/64). Five of these 6 ST131 isolates possessed bla(CTX-M-15) enzymes (and also were resistant to quinolones), and one possessed bla(CTX-M-2) enzymes. Two possessed virulence genes, suggesting the presence of pathogenicity island IIJ96 (PAI IIJ96)-like domains. Pulsed-field gel electrophoresis (PFGE) revealed a high level of genomic diversity overall, except for 3 closely related isolates belonging to clonal group ST131. Repetitive PCR showed that the six ST131 isolates were closely related to ST131 control strains (>95% similarity). This study shows a high prevalence of ESBL-producing E. coli strains and clonal group ST131 in the French maternal-fetal population. These results suggest a widespread distribution of ESBL enzymes in the community and highlight the early transmission between mothers and neonates. These findings are worrisome, especially for this particularly vulnerable population.
authors.affiliation: Laboratoire de Microbiologie, Hôpital Robert Debré, Service de Microbiologie, Assistance Publique des Hôpitaux de Paris, Paris, France.
authors.forename: André
authors.initials: A
authors.lastname: Birgy
authors.forename: Patricia
authors.initials: P
authors.lastname: Mariani-Kurkdjian
authors.forename: Philippe
authors.initials: P
authors.lastname: Bidet
authors.forename: Catherine
authors.initials: C
authors.lastname: Doit
authors.forename: Nathalie
authors.initials: N
authors.lastname: Genel
authors.forename: Céline
authors.initials: C
authors.lastname: Courroux
authors.forename: Guillaume
authors.initials: G
authors.lastname: Arlet
authors.forename: Edouard
authors.initials: E
authors.lastname: Bingen
mesh_terms: D000328:Adult; D001769:Blood / Q000382:microbiology; D002555:Cerebrospinal Fluid / Q000382:microbiology; D016000:Cluster Analysis; D018562:Disease Transmission, Infectious; D004926:Escherichia coli / Q000145:classification* / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology* / Q000635:transmission*; D005260:Female; D005602:France; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D007231:Infant, Newborn; D017720:Molecular Epidemiology; D058889:Molecular Typing; D010802:Phylogeny; D015995:Prevalence; D014621:Vagina / Q000382:microbiology; D037521:Virulence Factors / Q000235:genetics; D001618:beta-Lactamases / Q000378:metabolism*
chemical_list: D037521:Virulence Factors; D001618:beta-Lactamases