Rapid dissemination and diversity of CTX-M extended-spectrum β-lactamase genes in commensal Escherichia coli isolates from healthy children from low-resource settings in Latin America

Lucia Pallecchi, Alessandro Bartoloni, Costanza Fiorelli, Antonia Mantella, Tiziana Di Maggio, Herlan Gamboa, Eduardo Gotuzzo, Göran Kronvall, Franco Paradisi, Gian Maria Rossolini

Research output: Contribution to journalArticle

Abstract

A survey carried out in 2005 among members of a healthy population of children living in Bolivia and Peru revealed that fecal carriage of Escherichia coli strains resistant to expanded-spectrum cephalosporins was remarkably increased compared to that observed in the same settings in 2002 (1.7% in 2005 versus 0.1% in 2002). In this work, we demonstrated that this phenomenon was mainly related to the dissemination of CTX-M-type extended-spectrum β-lactamase (ESBL) determinants among commensal E. coli strains. Of 50 ESBL-producing isolates collected in the 2005 survey, 44 harbored a CTX-M-type and 6 an SHV-type (SHV-2 or SHV-12) ESBL. Compared to 2002 results, an increased diversity of CTX-M-type ESBLs was also observed: members of the CTX-M-1 group (CTX-M-15) emerged in Bolivia (where only CTX-M-2 was observed in 2002), while members of the CTX-M-9 group (CTX-M-14 and CTX-M-24) emerged in Peru (where only CTX-M-15 and CTX-M-2 were observed in 2002). A new CTX-M-2 variant named CTX-M-56 was also detected. Molecular characterization of the CTX-M-producing isolates and gene transfer experiments suggested that different mechanisms could be involved in the spreading of different CTX-M group determinants and revealed that additional resistance determinants for non-β-lactam antibiotics were preferentially carried by plasmids encoding certain CTX-M variants (CTX-M-15 and variants of the CTX-M-2 group). Three CTX-M-15-encoding conjugative plasmids from Peruvian isolates carried the new fluoroquinolone resistance gene aac(6′)-Ib-cr. To our best knowledge, this is the first report of the detection of aac(6′)-Ib-cr in Latin America.

Original languageEnglish
Pages (from-to)2720-2725
Number of pages6
JournalAntimicrobial Agents and Chemotherapy
Volume51
Issue number8
DOIs
Publication statusPublished - Aug 2007

ASJC Scopus subject areas

  • Pharmacology (medical)

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    Pallecchi, L., Bartoloni, A., Fiorelli, C., Mantella, A., Di Maggio, T., Gamboa, H., Gotuzzo, E., Kronvall, G., Paradisi, F., & Rossolini, G. M. (2007). Rapid dissemination and diversity of CTX-M extended-spectrum β-lactamase genes in commensal Escherichia coli isolates from healthy children from low-resource settings in Latin America. Antimicrobial Agents and Chemotherapy, 51(8), 2720-2725. https://doi.org/10.1128/AAC.00026-07