Prevalence and fimbrial genotype distribution of poultry Salmonella spp. isolates in China (2006-2012)

ABSTRACT

In this study, a total of 323 Salmonella enterica strains were isolated from 3,566 rectal swab samples of 51 poultry farms in seven regions of 12 provinces of China between 2006 to 2012. The prevalences of Salmonella spp. carriage were 12.4% in goose (66/533), 10.4% in turkey (32/309), 9.8% in chicken (167/1,706), 6.8% in duck (41/601) and 4.1% in pigeon (17/417), respectively. These isolates belonged to twenty serovars, in which the most frequent serovars were S. Pullorum (55 isolates, 17.0%), S. Typhimurium (50, 15.5%) and S. Enteritidis (39, 12.1%). Overall, S. Typhimurium was the most commonly detected serovar; among the individual species, S. Pullorum was most commonly isolated from chickens, S. Enteritidis in duck, S. Typhimurium in goose and pigeon, and S. Saintpaul in turkey. PCR determination of 20 fimbrial genes demonstrated the presence of bcfD, csgA, fimA, stdB and sthE genes and the absence of staA and stgA genes in these isolates, and other loci were variably distributed with frequency values ranging from 11.8-99.1%. These 323 Salmonella isolates were subdivided into 41 different fimbrial genotypes, and 285 strains (88.2%) of which had 12 to 14 fimbrial genes. Our findings indicated that the Salmonella isolates from different poultry species were phenotypically and genetically diverse, and some fimbrial genes are more frequently associated with serovars or serogroups.