Inhibitor-resistant TEM- And OXA-1-producing Escherichia coli isolates resistant to amoxicillin-clavulanate are more clonal and possess lower virulence gene content than susceptible clinical isolates
Oteo-Iglesias, Jesús (Centro Nacional de Microbiología (Espanya))
González, Juan José (Hospital Universitari Vall d'Hebron)
Ortega, Adriana (Centro Nacional de Microbiología (Espanya))
Quintero Zarate, Julieth Nàtalia (Universitat Autònoma de Barcelona. Departament de Genètica i de Microbiologia)
Bou, German (Complejo Hospitalario Universitario de A Coruña)
Cercenado, Emilia (Hospital General Universitario Gregorio Marañón)
Conejo, M. Carmen (Universidad de Sevilla. Departamento de Microbiología)
Martínez-Martínez, Luis (Hospital Universitario Marqués de Valdecilla (Santander, Cantabria))
Navarro Risueño, Ferran (Institut d'Investigació Biomèdica Sant Pau)
Oliver, Antonio (Hospital Universitari Son Espases (Palma de Mallorca, Balears))
Bartolomé Comas, Rosa Maria (Hospital Universitari Vall d'Hebron)
Campos, José (Centro Nacional de Microbiología (Espanya))

Date:	2014
Abstract:	In a previous prospective multicenter study in Spain, we found that OXA-1 and inhibitor-resistant TEM (IRT) β-lactamases constitute the most common plasmid-borne mechanisms of genuine amoxicillin-clavulanate (AMC) resistance in Escherichia coli. In the present study, we investigated the population structure and virulence traits of clinical AMC-resistant E. coli strains expressing OXA-1 or IRT and compared these traits to those in a control group of clinical AMC-susceptible E. coli isolates. All OXA-1-producing (n = 67) and IRT-producing (n = 45) isolates were matched by geographical and temporal origin to the AMC-susceptible control set (n = 56). We performed multilocus sequence typing and phylogenetic group characterization for each isolate and then studied the isolates for the presence of 49 virulence factors (VFs) by PCR and sequencing. The most prevalent clone detected was distinct for each group: group C isolates of sequence type (ST) 88 (C/ST88) were the most common in OXA-1 producers, B2/ST131 isolateswere the most common in IRT producers, and B2/ST73 isolates were the most common in AMC-susceptible isolates. The median numbers of isolates per ST were 3. 72 in OXA-1 producers, 2. 04 in IRT producers, and 1. 69 in AMC-susceptible isolates; the proportions of STs represented by one unique isolate in each group were 19. 4%, 31. 1%, and 48. 2%, respectively. The sum of all VFs detected, calculated as a virulence score, was significantly higher in AMC-susceptible isolates than OXA-1 and IRT producers (means, 12. 5 versus 8. 3 and 8. 2, respectively). Our findings suggest that IRT- and OXA-1-producing E. coli isolates resistant to AMC have a different and less diverse population structure than AMC-susceptible clinical E. coli isolates. The AMC-susceptible population also contains more VFs than AMC-resistant isolates.
Grants:	Instituto de Salud Carlos III RD12/0015
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Language:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Published in:	Antimicrobial Agents and Chemotherapy, Vol. 58, Núm. 7 (July 2014) , p. 3874-3881, ISSN 1098-6596

DOI: 10.1128/AAC.02738-13
PMID: 24777096

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