Longitudinal Study of Extended-Spectrum-β-Lactamase- and AmpC-Producing Enterobacteriaceae in Household Dogs

Abstract

A longitudinal study was performed to (i) investigate the continuity of shedding of extended-spectrum-beta-lactamase (ESBL)-producing Enterobacteriaceae in dogs without clinical signs, (ii) identify dominant plasmid-mediated ESBL genes, and (iii) quantify ESBL-producing Enterobacteriaceae in feces. Fecal samples from 38 dogs were collected monthly for 6 months. Additional samples were collected from 7 included dogs on a weekly basis for 6 weeks. Numbers of CFU per gram of feces for nonwild-type Enterobacteriaceae were determined by using MacConkey agar supplemented with 1 mg/liter cefotaxime (MCC), and those for total Enterobacteriaceae were determined by using MacConkey agar. Cefotaxime-resistant isolates were screened by PCR and sequence analysis for the presence of bla CTX-M , bla CMY , bla SHV , bla OXA , and bla TEM gene families. Bacterial species were identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis. PCR-negative isolates were tested by a double-disk synergy test for enhanced AmpC expression. A total of 259 samples were screened, and 126 samples were culture positive on MCC, resulting in 352 isolates, 327 of which were Escherichia coli. Nine dogs were continuously positive during this study, and 6 dogs were continuously negative. Monthly or weekly shifts in fecal shedding were observed for 23 dogs. Genotyping showed a large variety of ESBL genes and gene combinations at single and multiple consecutive sampling moments. The ESBL genes bla CTX-M-1 , bla CTX-M-14 , bla CTX-M-15 , bla SHV-12 , and bla CMY-2 were most frequently found. The mean number of CFU of non-wild-type Enterobacteriaceae was 6.11 ؋ 10 8 CFU/g feces. This study showed an abundance of ESBL-producing Enterobacteriaceae in dogs in the Netherlands, mostly in high concentrations. Fecal shedding was shown to be highly dynamic over time, which is important to consider when studying ESBL epidemiology.A substantial share of the present global emergence of antimicrobial resistance is represented by extended-spectrumbeta-lactamase (ESBL)-producing Enterobacteriaceae. So far, these bacteria have been isolated from a large variety of sources, including humans, animals, and the environment. Together, these sources seem to form a complex network of reservoirs and transmission routes where ESBL-producing Enterobacteriaceae are circulating (1).High prevalences of ESBL-producing Enterobacteriaceae were found in Dutch poultry, pigs, and cattle (2). High prevalences of ESBL-producing Enterobacteriaceae were also found in Dutch companion animals, i.e., 45% in dogs without clinical signs and 55% in diarrheic dogs (3). As companion animals live in close contact with humans, they might contribute substantially to the exposure of humans to ESBL-producing Enterobacteriaceae. Similar ESBL gene types, i.e., CTX-M-14, CTX-M-15, SHV-12, and CMY-2, were found in strains originating from humans and companion animals (1). Additionally, transmission of CTX-M-15-carrying ST131 and ST648 Escherichia coli stra...

Attributable sources of community-acquired carriage of Escherichia coli containing β-lactam antibiotic resistance genes: a population-based modelling study

“…1 Historically, ESBL-EC and pAmpC-EC infections have been associated with healthcare settings, 2 but their acquisition in the community has been increasingly reported in several countries since 2000-10. 3 Although a high prevalence of ESBL-EC and pAmpC-EC has been reported in livestock (particularly poultry), 4 chicken meat, 2 and companion animals, 5 their role as sources of human infection with ESBL-EC and pAmpC-EC remains controversial. 2,6,7 Human exposure to ESBL-EC and pAmpC-EC might occur via animals, food, the environment, and human-to-human transmission; however, their relative contributions are yet to be quantified.…”

Raw diets for dogs and cats: a review, with particular reference to microbiological hazards

“…There was a strong association between raw feeding and the likelihood of faecal shedding of E. coli exhibiting AmpC‐type resistance among therapy dogs in Canada over the course of 18 months (Lefebvre et al ). Two Dutch longitudinal studies reported associations between raw feeding and faecal E. coli from dogs showing ESBL resistance (Baede et al ) or faecal Enterobacteriaceae from cats showing ESBL/AmpC resistance (Baede et al ). This last study also found that, where phenotypically resistant Enterobacteriaceae were isolated, the mean count (colony‐forming units per gram faeces) for such isolates among raw‐fed cats was over two orders of magnitude higher than among controls.…”

Occurrence of beta-lactamase producing Escherichia coli in healthy and diarrhoeic dogs in Andhra Pradesh, India

“…In a study from Pennsylvania, failure to detect beta-lactamase genes in 20 out of 60 beta-lactam resistant E. coli isolated from companion animals was reported (O'Keefe et al, 2010). Several explanations had been put forward by many workers for the possible expression of resistant phenotype in the absence of betalactamase genes (Drieux et al, 2008 andBaede et al, 2015).…”

“…One explanation could be the contribution of other resistance mechanisms, such as enhanced expression of efflux pumps (Sun et al, 2010 andBaede et al, 2015).…”