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Antimicrobial-resistant bacteria represent an important concern impacting both veterinary medicine and public health. The rising prevalence of extended-spectrum beta-lactamase (ESBL), AmpC beta-lactamase, carbapenemase (CRE) and fluoroquinolone-resistant Enterobacteriaceae continually decreases the efficiency of clinically important antibiotics. Moreover, the potential for zoonotic transmission of antibiotic-resistant enteric bacteria increases the risk to public health. Our objective was to estimate the prevalence of specific antibiotic-resistant bacteria on human contact surfaces in various animal environments. Environmental surface samples were collected from companion animal shelters, private equine facilities, dairy farms, livestock auction markets and livestock areas of county fairs using electrostatic cloths. Samples were screened for Enterobacteriaceae expressing AmpC, ESBL, CRE or fluoroquinolone resistance using selective media. Livestock auction markets and county fairs had higher levels of bacteria expressing both cephalosporin and fluoroquinolone resistance than did equine, dairy, and companion animal environments. Equine facilities harboured more bacteria expressing cephalosporin resistance than companion animal shelters, but less fluoroquinolone resistance. The regular use of extended-spectrum cephalosporins in livestock populations could account for the increased levels of cephalosporin resistance in livestock environments compared to companion animal and equine facilities. Human surfaces, as well as shared human and animal surfaces, were contaminated with resistant bacteria regardless of species environment. Detecting these bacteria on common human contact surfaces suggests that the environment can serve as a reservoir for the zoonotic transmission of antibiotic-resistant bacteria and resistance genes. Identifying interventions to lower the prevalence of antibiotic-resistant bacteria in animal environments will protect both animal and public health., (© 2018 Blackwell Verlag GmbH.)

Dogs are often present on livestock farms, where they serve important management and companion roles, yet may be involved in zoonotic pathogen transmission. Numerous factors can potentially alter the risk of exposure to zoonotic pathogens, such as the dog's access to livestock, close dog-human contact and an increasing immunocompromised human population. The objective of this study was to quantify and qualify dog ownership among livestock owners, their dog husbandry and biosecurity practices, the dogs' access to livestock and potential risks for zoonotic pathogen transmission. A questionnaire was developed and mailed to 2,000 presumed Ohio livestock owners. Data were collected on demographics, dog husbandry practices, attitudes surrounding zoonotic diseases and attachment to and preventive veterinary care for the dogs. There were 446 responders who met the study inclusion criteria as an Ohio livestock farm owner, with 297 (67%) also owning dogs. Approximately 52% of dog-owning households included at least one individual at higher disease risk (i.e., <5 years, ≥65 years, diagnosed with an immunocompromising condition). Most respondents had little/no concern for disease transmission from livestock to dogs (90%), from dogs to livestock (87%) and from dogs to people (94%). Dogs were allowed access to livestock by 70% of respondents and nearly all (96%; 198) indicated at least one higher risk dog-livestock management practice. In addition, many reported never leashing or fencing their dog (61%) and rarely to never picking up dog faeces (76%). Households with higher risk members reported similar husbandry, biosecurity and concern levels as households without those members (all p > .05). Numerous opportunities for zoonotic pathogen transmission and low level of zoonotic disease concern suggest a need for improved education and outreach for the livestock dog-owning community, particularly for higher risk households., (© 2017 Blackwell Verlag GmbH.)

In order to estimate the prevalence of AmpC- and ESBL β-lactamase-producing Enterobacteriaceae in the faecal flora of a healthy domestic canine population, faecal samples were obtained from healthy dogs receiving routine parasitology screening at the Ohio State University Veterinary Medical Center, between January 2013 and April 2013. Samples were screened for the presence of AmpC and ESBL β-lactamase phenotypes, and the clinically important genotypes, bla CMY and bla CTX -M , were confirmed via conventional PCR. Minimum inhibitory concentrations were determined for isolates and plasmids were characterized. Two hundred and twelve canine faecal samples were screened, of which 30 harboured isolates carrying the AmpC bla CMY , representing 14.2% of the population (95% CI: 9.4-18.9%). Nine samples harboured isolates that carried the ESBL bla CTX -M , representing 4.2% of the population (95% CI: 1.5-7.0%). Isolates containing bla CMY harboured multiple plasmid replicon types, while isolates containing bla CTX -M harboured few plasmid replicon types. Our results suggest that domestic dogs may serve as a reservoir for extended-spectrum cephalosporin resistance genes for other domestic animal populations as well as for their human companions. This represents a potential veterinary and public health risk that warrants further investigation and continued surveillance to ascertain the nature and extent of the risk. The high level of diversity of plasmid content among isolates harbouring bla CMY suggests broader dissemination relative to bla CTX -M isolates., (© 2017 Blackwell Verlag GmbH.)

The dissemination of Enterobacteriaceae expressing resistance to extended-spectrum cephalosporins, which are therapeutically used in both human and veterinary medicine, is of critical concern. The normal commensal flora of food animals may serve as an important reservoir for the zoonotic food-borne transmission of Enterobacteriaceae harbouring β-lactam resistance. We hypothesized that the predominant AmpC and ESBL genes reported in US livestock and fresh retail meat products, bla CMY -2 and bla CTX -M , would also be predominant in human enteric flora. We recovered enteric flora from a convenience sample of patients included in a large tertiary medical centre's Clostridium difficile surveillance programme to screen for and estimate the frequency of carriage of AmpC and ESBL resistance genes. In- and outpatient diarrhoeic submissions (n = 692) received for C. difficile testing at the medical centre's clinical diagnostic laboratory from July to December, 2013, were included. Aliquoted to a transport swab, each submission was inoculated to MacConkey broth with cefotaxime, incubated at 37°C and then inoculated to MacConkey agars supplemented with cefoxitin and cefepime to select for the AmpC and ESBL phenotypes, with bla CMY and bla CTX -M genotypes confirmed by PCR and sequencing. From the 692 diarrhoeic submissions, our selective culture yielded 184 isolates (26.6%) with reduced susceptibility to cefotaxime. Of these, 46 (6.7%) samples harboured commensal isolates carrying the AmpC bla CMY . Another 21 (3.0%) samples produced isolates harbouring the ESBL bla CTX -M : 19 carrying CTX-M-15 and 2 with CTX-M-27. Our results indicate that β-lactam resistance genes likely acquired through zoonotic food-borne transmission are present in the enteric flora of this hospital-associated population at lower levels than reported in livestock and fresh food products., (© 2016 Blackwell Verlag GmbH.)

Multistate outbreaks of salmonellosis associated with live poultry contact have been occurring with increasing frequency. In 2013, multistate outbreaks of salmonellosis were traced back to exposure to live poultry, some of which were purchased at a national chain of farm stores (Farm store chain Y). This study was conducted at 36 stores of Farm store chain Y and was concurrent with the timing of exposure for the human outbreaks of salmonellosis in 2013. We used environmental swabs of arriving shipment boxes of hatchling poultry and shipment tracking information to examine the distribution, diversity and anti-microbial resistance of non-typhoidal Salmonella (NTS) across farm stores and hatcheries. Isolates recovered from shipment boxes underwent serotyping, anti-microbial resistance (AMR) testing and pulsed-field gel electrophoresis (PFGE). Postal service tracking codes from the shipment boxes were used to determine the hatchery of origin. The PFGE patterns were compared with the PFGE patterns of NTS causing outbreaks of salmonellosis in 2013. A total of 219 hatchling boxes from 36 stores in 13 states were swabbed between 15 March 2013 and 18 April 2013. NTS were recovered from 59 (27%) of 219 hatchling boxes. Recovery was not significantly associated with species of hatchlings, number of birds in the shipment box, or the presence of dead, injured or sick birds. Four of the 23 PFGE patterns and 23 of 50 isolates were indistinguishable from strains causing human outbreaks in 2013. For serotypes associated with human illnesses, PFGE patterns most frequently recovered from shipment boxes were also more frequent causes of human illness. Boxes positive for the same PFGE pattern most frequently originated from the same mail-order hatchery. Only one of 59 isolates was resistant to anti-microbials used to treat Salmonella infections in people. This study provides critical information to address recurrent human outbreaks of salmonellosis associated with mail-order hatchling poultry., (© 2014 Blackwell Verlag GmbH.)