Prevalence and Fimbrial Genotype Distribution of Poultry Salmonella Isolates in China (2006 to 2012)

Abstract

ABSTRACTIn this study, a total of 323Salmonella entericastrains were isolated from 3,566 rectal swab samples of 51 poultry farms in seven regions of 12 provinces of China between 2006 and 2012. The prevalences ofSalmonellasp. carriage were 12.4% in geese (66 positive/533 samples), 10.4% in turkeys (32/309), 9.8% in chickens (167/1,706), 6.8% in ducks (41/601), and 4.1% in pigeons (17/417), respectively. These isolates belonged to 20 serovars, in which the most frequent serovars wereS. entericaserovar Gallinarum biovar Pullorum (herein,S. Pullorum) (55 isolates, 17.0%),S. entericaserovar Typhimurium (50 isolates, 15.5%), andS. entericaserovar Enteritidis (39 isolates, 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 was most common in ducks,S. Typhimurium was most common in geese and pigeons, andS. entericaserovar Saintpaul was most common in turkeys. PCR determination of 20 fimbrial genes demonstrated the presence ofbcfD,csgA,fimA,stdB, andsthEgenes and the absence ofstaAandstgAgenes in these isolates, and other loci were variably distributed, with frequency values ranging from 11.8 to 99.1%. These 323Salmonellaisolates were subdivided into 41 different fimbrial genotypes, and of these isolate, 285 strains (88.2%) had 12 to 14 fimbrial genes. Our findings indicated that theSalmonellaisolates from different poultry species were phenotypically and genetically diverse and that some fimbrial genes are more frequently associated with serovars or serogroups.