Occurrence of plasmid-mediated quinolone resistance genes in Escherichia coli and Klebsiella spp. recovered from Corvus brachyrhynchos and Corvus corax roosting in Canada.

The spread of antimicrobial resistance from human activity derived sources to natural habitats implicates wildlife as potential vectors of antimicrobial resistance transfer. Wild birds, including corvid species can disseminate mobile genetic resistance determinants through faeces. This study aimed to determine the occurrence of plasmid-mediated quinolone resistance (PMQR) genes in Escherichia coli and Klebsiella spp. isolates obtained from winter roosting sites of American crows (Corvus brachyrhynchos) and common ravens (Corvus corax) in Canada. Faecal swabs were collected at five roosting sites across Canada. Selective media isolation and multiplex PCR screening was utilized to identify PMQR genes followed by gene sequencing, pulse-field gel electrophoresis and multilocus sequence typing to characterize isolates. Despite the low prevalence of E. coli containing PMQR (1·3%, 6/449), qnrS1, qnrB19, qnrC, oqxAB and aac(6')-Ib-cr genes were found in five sequence types (ST), including E. coli ST 131. Conversely, one isolate of Klebsiella pneumoniae contained the plasmid-mediated resistance gene qnrB19. Five different K. pneumoniae STs were identified, including two novel types. The occurrence of PMQR genes and STs of public health significance in E. coli and Klebsiella pneumoniae recovered from corvids gives further evidence of the anthropogenic derived dissemination of antimicrobial resistance determinants at the human activity-wildlife-environment interface. SIGNIFICANCE AND IMPACT OF THE STUDY: This study examined large corvids as possible vector species for the dissemination of antimicrobial resistance in indicator and pathogenic bacteria as a means to assess the anthropogenic dissemination of plasmid-mediated quinolone resistance (PMQR) genes. Although rare, PMQR genes were found among corvid populations across Canada. The clinically important Escherichia coli strain ST131 containing aac(6')-Ib-cr gene along with a four-class phenotypic antimicrobial resistance (AMR) pattern as well as one Klebsiella pneumoniae strain containing a qnrB19 gene were identified in one geographical location. Corvids are a viable vector for the circulation of PMQR genes and clinically important clones in wide-ranging environments.

Prevalence, characterization and antibiotic resistance of Salmonella isolates in large corvid species of europe and north America between 2010 and 2013.

It is well understood that Salmonella is carried by animals and in majority of cases as asymptomatic hosts. Surveillance efforts have focused on the role of agriculture and contamination points along the food chain as the main source of human infection; however, very little attention has been paid to the contribution of wildlife in the dissemination of Salmonella and what effect anthropogenic sources have on the circulation of antibiotic resistant Salmonella serovars in wildlife species. A purposive survey was taken of large corvids roosting yearly between November and March in Europe and North America. Two thousand and seven hundred and seventy-eight corvid faecal specimens from 11 countries were submitted for Salmonella spp. culture testing. Presumptive positive isolates were further serotyped, susceptibility tested and analysed for antibiotic resistance genes. Overall, 1.40% (39/2778) (CI = 1.01, 1.90) of samples were positive for Salmonella spp. Salmonella Enteritidis was the most prevalent serovar followed by S. Infantis, S. Montevideo and S. Typhimurium. No significant difference (P > 0.05) was found in the proportion of Salmonella recovered in Europe versus North America. The most variability of serovars within a site was in Kansas, USA with five different serovars recovered. European sites were significantly more likely to yield Salmonella resistant to more than one antibiotic (OR 71.5, P < 0.001, CI = 3.77, 1358) than North American sites, where no resistance was found. Resistance to nalidixic acid, a quinolone, was recovered in nine isolates from four serovars in four different sites across Europe. Large corvids contribute to the transmission and dissemination of Salmonella and resistance genes between human and animal populations and across great distances. This information adds to the knowledge base of zoonotic pathogen prevalence and antibiotic resistance ecology in wild birds.

Toxoplasma gondii in Ireland: seroprevalence and novel molecular detection method in sheep, pigs, deer and chickens.

Toxoplasma gondii is among the most studied parasites worldwide but there is not much information about it published in Ireland. The objectives of this study were to determine the seroprevalence of T. gondii in sheep, pigs, deer and chickens and the molecular detection of T. gondii DNA in muscle tissue. Serum samples were collected from these species at the time of slaughter at Irish abattoirs during 2007 and tested for anti-T. gondii antibodies using a commercial semi-quantitative latex agglutination test. Antibodies (titre ≥1 : 64) were found in 36% (105/292) sheep, 4.7% (15/317) pigs and 6.6% (23/348) deer. In chickens, 18% (65/364) had antibody titres, ranging between 1 : 5 and 1 : 1024. Significant (P ≤ 0.05) age-related differences in seroprevalence were found in adult sheep (58.1%) and pigs (23.1%). Significant gender differences in seroprevalence was also found in sheep with more females (43%) than males (22.4%) being positive. However, when adjusted for age through logistic regression gender was no longer significant. Seroprevalence was also evaluated on farm locations grouped to NUTS level 3, but the prevalence was too low to draw any statistical conclusions. Using a nested PCR, the presence of T. gondii DNA was detected in diaphragm samples from 3.6% (3/83) sheep, 13.0% (3/23) pig and 4.2% (3/71) deer. Meat digestion liquids from a Trichinella spp. survey in pigs were also used for the first time to detect T. gondii. Toxoplasma gondii DNA was detected in 50% (10/20) of pooled samples. This is the first in depth study of T. gondii seroprevalence in animals in Ireland and a novel method, using digestion liquid from pooled diaphragm samples, for PCR detection in pigs is described.

In vitro culture combined with quantitative TaqMan PCR for the assessment of Toxoplasma gondii tissue cyst viability.

Toxoplasma gondii is a serious food-borne pathogen with a worldwide distribution. In order to assess the risk of contracting toxoplasmosis from certain foods, many studies rely on the molecular detection of T. gondii DNA. However, determining the viability of parasites in positive samples is much more problematic. In this paper we describe a novel viability assay that relies on semi-quantitative comparison of the amount of parasite DNA present in samples used to infect host cell monolayers in vitro, and the amount of DNA detected in the same monolayers after 23 days incubation. Our assay is robust, easy to perform and interpret and offers a viable alternative to bioassays, for use in epidemiological studies, or the evaluation of specific food safety treatments.