鸭致病性大肠杆菌的分离鉴定及其生物学特性分析

CHARACTERIZATION OF DUCK PATHOGENIC ESCHERICHIA COLI

鸭致病性大肠杆菌病是危害养鸭业的最为重要的细菌性传染病之一。本研究分离鉴定了65株鸭致病性大肠杆菌,并对其O血清型、耐药谱以及毒力相关基因进行了检测。结果表明:大肠杆菌O78,O2和O1为主要流行血清型,各占分离株的75%、11%和5%。对15种常规抗菌素或药物的药敏试验结果表明:100%的分离株对利福平和红霉素耐药;94%以上的分离株对头孢噻吩等10种抗菌素或药物耐受;70%以上的分离株对氯霉素、卡那霉素、庆大霉素、壮观霉素和头孢噻肟敏感。对14种可能的大肠杆菌毒力相关基因的检测结果表明:ompA、pfs和luxS三种基因高度保守,在分离菌株中的检出率为100%;iss、iuCD、tsh、fimC、cvaC和iroC基因的检出率达到72%以上,为重要的鸭致病性大肠杆菌毒力相关基因。

Duck pathogenic Escherichia coli （E. coli） infections causes significant economic losses to the duck breed industry in the world. In this study, 65 E. coli strains were isolated from ducks died of colibacillosis. The O serotypes, drug sensitivity and E. coli virulence associated genes of the strains were detected. The results revealed that the predominant O serotypes of the strains were O78, O2 and O1 which accounted for 75% ; 11% or 5% of the tested strains, respectively. Drug sensitivity test found that all the strains tested were resistant to both Rifampicin and Erythromycin. 94% of the strains were resistant to 10 of the 15 antibiotics tested. HoWever, more than 70% the strains were sensitive to chloramphenicol, kanamycin, gentamycin, spectinomycin and cephalosporin. The PCR amplification of 14 E. coli virulence associated genes showed that ompA ,pfs and luxS genes were highly conserved, which were amplified from all the strains. Genes of iss, iuCD, tsh,fimC, cvaC and iroC were amplified from more than 72% of the strains tested, which were critical for the E. coli pathogenicity.