副猪嗜血杆菌的多重耐药性及氨基糖苷类耐药基因分子流行病学分析OA北大核心CSTPCD

This study was aimed to investigate the drug resistance and responsible genes of Haemophilus parasuis(HPS)on large-scale pig farms in China.The drug resistance phenotypes and genes of 52 HPS isolates were examined and amino acid sequences of aminoglycoside resistance genes Aph(3')-Ia and StrB were also compared and analyzed in the present study.The results showed that multi-drug resistance genes were detected in these isolates,such as β-lactams,aminoglycosides,sulfa drugs and class Ⅰ integrons.The presence of resistance genes bla-TEM,Aph(3')-Ia,3'CS and Int1 were detected in 100％isolates.The resistance to streptomycin sulfate was found in 75％isolates.According to the sequence analysis of Aph(3')-Ia,some amino acids were identical to those of 6 other bacterial species rather than the known HPS.The amino acid sequence of StrB gene of the HPS strain JX-6 was significantly different from those of other bacteria at sites 14-19.Meanwhile,the site 18 of JX-6 StrB gene for the ATP binding was found mutated.Our study indicated a high prevalence of resistance genes Aph(3')-Ia and StrB of aminoglycoside drugs in HPS on large-scale pig farms and the differences in bacterial drug resistance and changes of resistance genes might be caused by mutation of some specific sites.This study laid a foundation for the study of the changes of HPS drug resistance genes on large-scale breeding farms and gave valuable insight into the prevention and control of related diseases.