Fecal Carriage of Extended-Spectrum β-Lactamase-Producing Enterobacteriaceae in Swine and Cattle at Slaughter in Switzerland

Abstract

During the past decade, extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae have become a matter of great concern in human medicine. ESBL-producing strains are found in the community, not just in hospital-associated patients, which raises a question about possible reservoirs. Recent studies describe the occurrence of ESBL-producing Enterobacteriaceae in meat, fish, and raw milk; therefore, the impact of food animals as reservoirs for and disseminators of such strains into the food production chain must be assessed. In this pilot study, fecal samples of 59 pigs and 64 cattle were investigated to determine the occurrence of ESBL-producing Enterobacteriaceae in farm animals at slaughter in Switzerland. Presumptive-positive colonies on Brilliance ESBL agar were subjected to identification and antibiotic susceptibility testing including the disc diffusion method and E-test ESBL strips. As many as 15.2% of the porcine and 17.1% of the bovine samples, predominantly from calves, yielded ESBL producers. Of the 21 isolated strains, 20 were Escherichia coli, and one was Citrobacter youngae. PCR analysis revealed that 18 strains including C. youngae produced CTX-M group 1 ESBLs, and three strains carried genes encoding for CTX-M group 9 enzymes. In addition, eight isolates were PCR positive for TEM β-lactamase, but no bla(SHV) genes were detected. Pulsed-field gel electrophoresis showed a high genetic diversity within the strains. The relatively high rates of occurrence of ESBLproducing strains in food animals and the high genetic diversity among these strains indicate that there is an established reservoir of these organisms in farm animals. Further studies are necessary to assess future trends.

Prevalence and Antibiogram of Generic Extended-Spectrum β-Lactam-Resistant Enterobacteria in Healthy Pigs

“…There have been improvements in isolation of ESBL-resistant enterobacteria in food-producing animals worldwide (Geser et al, 2011). Zoonotic transmission of ESBL-producing enterobacteria has been reported (Ewers et al, 2012;Schmeidel et al, 2014).…”

“…Beta-lactam resistance genes present in the discharged enterobacteria could be acquired by horizontal transfer to pathogenic human bacteria, thereby complicating infections and compromising antibacterial therapy (GarciaGraells et al, 2010). Presence of ESBL-resistant enterobacteria in faecal samples of food-producing animals represents a risk for carcass contamination at slaughter and subsequent potential for contamination of retail meat products (Geser et al, 2011). This contamination risk is particularly important in developing countries, such as Nigeria, where inadequate hygienic practices are employed during meat processing.…”

“…cefotaxime, ceftriaxone, cefpodoxime, ceftazidime] and 4th-[e.g. cefepime] generation cephalosporins) has led to selection pressure and development of resistance to these drugs by enterobacteria (Geser et al, 2011). These 3 rd and 4 th -generation cephalosporins are extended-spectrum β-lactams (ESBL) whose resistance in enterobacteria is mediated by extended-spectrum beta-lactamases (ESBLs) (Garcia-Graells et al, 2010;Geser et al, 2011).…”

“…This contamination risk is particularly important in developing countries, such as Nigeria, where inadequate hygienic practices are employed during meat processing. Consumption of contaminated meat results in colonization of humans with ESBL-resistant bacteria, jeopardizing subsequent antibacterial therapies in carriers (Geser et al, 2011).…”

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).…”