Background Salmonella species are widespread in the environment, and occur in cattle, pigs, and birds, including poultry and free-living birds. In this study, we determined the occurrence of Salmonella in different wild bird species in Poland, focusing on five Salmonella serovars monitored in poultry by the European Union: Salmonella serovars Enteritidis, Typhimurium, Infantis, Virchow, and Hadar. We characterized their phenotypic and genetic variations. Isolates were classified into species and subspecies of the genus Salmonella with a polymerase chain reaction (PCR) assay. The prevalence of selected virulence genes ( spv B, spi A, pag C, cdt B, msg A, inv A, sip B, prg A, spa N, org A, tol C, iron N, sit C, ipf C, sif A, sop B, and pef A) among the isolated strains was determined. We categorized all the Salmonella ser. Typhimurium strains with enterobacterial repetitive intergenic consensus (ERIC)-PCR. Results Sixty-four Salmonella isolates were collected from 235 cloacal swabs, 699 fecal samples, and 66 tissue samples (6.4% of 1000 samples) taken from 40 different species of wild birds in Poland between September 2011 and August 2013. The largest numbers of isolates were collected from Eurasian siskin and greenfinch: 33.3% positive samples for both. The collected strains belonged to one of three Salmonella subspecies: enterica (81.25%), salamae (17.19%), or houtenae (1.56%). Eighteen strains belonged to Salmonella ser. Typhimurium (28.13%), one to ser. Infantis (1.56%), one to ser. Virchow (1.56%), and one to ser. Hadar (1.56%). All isolates contained spiA , msg A, inv A, lpf C, and sif A genes; 94.45% of isolates also contained sit C and sop B genes. None of the Salmonella ser. Typhimurium strains contained the cdtB gene. The one Salmonella ser. Hadar strain contained all the tested genes, except spv B and pef A; the one Salmonella ser. Infantis strain contained all the tested genes, except tspv B, pef A, and cdtB ; and the one Salmonella ser. Virchow strain contained all the tested genes, except spv B, pef A, cdtB , and tolC . The Salmonella ser. Typhimurium strains varied across the same host species, but similarity was observed among strains isolated from the same environment (e.g., the same bird feeder or the same lake). Conclusions Our results confirm that some wild avian species are reservoirs for Salmonella serotypes, especially Salmonella ser. Typhimurium.
【저자키워드】 Poland, ERIC-PCR, virulence genes, Salmonella spp, Free-living birds,