Multidrug-resistant Escherichia coli from canine urinary tract infections tend to have commensal phylotypes, lower prevalence of virulence determinants and ampC-replicons

Abstract

Multidrug-resistant Escherichia coli is an emerging clinical challenge in domestic species. Treatment options in many cases are limited. This study characterized MDR E. coli isolates from urinary tract infections in dogs, collected between 2002 and 2011. Isolates were evaluated in terms of β-lactamase production, phylogenetic group, ST type, replicon type and virulence marker profile. Comparisons were made with antibiotic susceptible isolates also collected from dogs with urinary tract infections. AmpC β-lactamase was produced in 67% of the MDR isolates (12/18). Of these, 8 could be specifically attributed to the CMY-2 gene. None of the isolates tested in either group expressed ESBLs. Phylo-group distribution was as expected in the susceptible isolates, with an over representation of the pathogenic B2 phylo-group (67%). In contrast, the phylogenetic background for the MDR group was mixed, with representation of commensal phylo-groups A and B1. The B2 phylo-group represented the smallest proportion (A, B1, B2 or D was 28%, 22%, 11% and 33%, respectively). Virulence marker profiles, evaluated using Identibac® microarray, discriminated between the two groups. Marker sequences for a core panel of virulence determinants were identified in most of the susceptible isolates, but not in most of the MDR isolates. These findings indicate that for MDR isolates, plasmid-mediated AmpC is an important resistance mechanism, and while still capable of causing clinical disease, there is evidence for a shift towards phylogenetic groups of reduced inferred virulence potential. There was no evidence of zoonotic potential in either the susceptible or MDR urinary tract isolates in this study.

Nosocomial Infections and their Surveillance in Veterinary Hospitals

“…Managing E. coli infections in veterinary hospitals has become more challenging task due to the emergence of multiple-antimicrobial-resistant E. coli in food animals and pet animals (Bischoff et al, 2001;Wagner et al, 2014;). The growing predominance of infections with organisms generating broad spectrum b-lactamses such as the ESBLs (mainly the CTX-M type), AmpC and carbapenemase enzymes are threatening the future of the b-lactam drug.…”

Preventing canine urinary tract infection (UTI) using an asymptomatic bacteriuria (ASB) Escherichia coli strain

“…A more recent paper examined phylogenetic group distribution in both susceptible and MDR E. coli (12 and 18 isolates, respectively) from canine urinary tract infections and found similarly that the B2 phylo-group accounted for 67% of susceptible isolates and D for 20% (triplex PCR). The distribution was more even for MDR isolates; A, B1, B2 and D were represented by 28%, 22%, 11%, and 33%, respectively (Wagner et al, 2014). As previously noted, some group D isolates would be reclassified to phylo-groups E, F and cryptic clade I and some A to group C using a new quadruplex PCR (Clermont et al, 2013).…”

“…One concerning trend documented in recent years has been the increased prevalence of nonsusceptibility to antimicrobials observed in canine urinary tract isolates, in particular to fluoroquinolones, third generation cephalosporins, and clavulanic acid-potentiated β-lactams (Cooke et al, 2002;Mazzuli, 2002;Ball et al, 2008;Sidjabat et al, 2009;Platell et al, 2011a;Hall et al, 2013;Wagner et al, 2014;Chang et al, 2015;Rzewuska et al, 2015). The availability of many of these drugs in oral forms that reach high concentrations in the urine following absorption, along with their efficacy against Gram-negative pathogens in particular, has resulted in their widespread use in companion animals.…”

“…Multidrug-resistant E. coli (MDREC) isolates from canine urinary tract infection have been associated with numerous resistance genes (Feria et al, 2001;Sanchez et al, 2002;Sidjabat et al, 2006a;Wagner et al, 2014;Chang et al, 2015). Similar isolates also carrying several resistance genes were isolated from cases of nosocomial infection, rectal carriers, and the environment of a large veterinary teaching hospital in Australia (Sidjabat et al, 2006b).…”

“…Fluoroquinolone-resistant strains with decreased VFs are common in asymptomatic bacteriuria (ASB), frequently identified in humans with disorders predisposing to UTI (Vranes et al, 2003). Wagner et al (2014) (Mulvey et al, 2000).…”