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.

[Diversity of human Salmonella isolates in the South Moravian Region in 2009-2012]. / Diverzita humánních izolátu salmonel v Jihomoravském kraji v letech 2009-2012.

STUDY OBJECTIVE: To characterize the diversity of human Salmonella isolates from one of the administrative regions of the Czech Republic in a time horizon of four years using different typing methods. MATERIAL AND METHODS: The following phenotyping methods were used: serotyping, phage typing, and the disk diffusion method for antimicrobial susceptibility testing. Genotyping was performed using DNA macrorestriction analysis resolved by pulsed-field gel electrophoresis (PFGE). RESULTS: The most common serotypes involved in human cases of salmonellosis in the South Moravian Region were Salmonella Enteritidis, Salmonella Typhimurium, and monophasic Salmonella 4,[5],12:i:-. Phage typing revealed the predominance of phage type 8 in S. Enteritidis and changes in phage types of S. Typhimurium over years. The resistance levels in S. Typhimurium, monophasic Salmonella, and some other serotypes give increasing cause for concern about multidrug resistant strains as human pathogens. The study isolates were assigned to the complexes implicated in both local and international outbreaks. Isolates of serotype 9,12:l,v:- were identified for the first time in the Czech Republic. CONCLUSIONS: The diversity of the study isolates from 2009-2012 collected in the South Moravian Region suggests a high heterogeneity of the sources of human salmonellosis. However, the detection of several cases likely to be epidemiologically linked points out the need for careful typing of human isolates and their comparison with the strains of non-human origin. Higher resistance levels in some serotypes is behind the need for the surveillance of multidrug resistant strains.