Genetic Background ofEscherichia coliand Extended-spectrum β-Lactamase Type

Abstract

ESBL-producing E. coli may arise from interactions between ESBL type, strain genetic background, and selective pressures in various ecologic niches.

Detection of virulence and antimicrobial resistance genes in Escherichia coli isolates from diarrhoiec dogs in Iran

“…Therefore, the 42.9% bla(SHV) detection rate in this study suggested that many dogs with diarrhoea in Iran may harbor extended-spectrum β-lactam (ESBL)-resistant E. coli. This finding is a cause for concern because extended-spectrum β-lactams are critical for treatment of bacterial infections in humans and animals (Bradford 2001) and E. coli isolates habouring bla(SHV) have been reported to exhibit multidrug resistance (Branger et al 2005, Bush and Jacoby 2010, Geser et al 2011. Thus, the presence of bla(SHV) gene in the examined isolates in this study, pose serious threat to public health as well as that of the examined dogs since compromise in antibacterial therapy may result following zoonotic transmission of the organisms (Warren et al 2001).…”

Dissemination of Clonally RelatedEscherichia coliStrains Expressing Extended-Spectrum β-Lactamase CTX-M-15

“…Phylogroups A (18%) and B1 (7%), which are associated with animal or human commensal strains, were less frequently represented. All isolates of phylogroups B2, A, and D corresponded to subgroups B2 3 , A 1 , and D 1 , respectively, which are the most common ones within each phylogenetic group (31). The 43 clinical isolates were classifi ed into 32 PFGE types (B2 3 , 13; D 1 , 10; A 1 , 6; and B1, 3).…”

Intermediate Mutation Frequencies Favor Evolution of Multidrug Resistance in Escherichia coli

“…This collection has 52.6% of strains resistant to amoxicillin, a well-known indicator of the frequency of antibiotic resistance in bacterial populations. Identical patterns of the relationship between antibiotic resistance and mutation frequencies were obtained with two other collections encompassing both commensal and extra-intestinal pathogenic strains: a collection of 117 highly resistant strains producing extended spectrum b-lactamases (100% of strains resistant to amoxicillin) (Branger et al 2005) and a collection of 119 strains isolated in the 1980s with a low level of antibiotic resistance (11.8% of strains resistant to amoxicillin) (data not shown).…”