华东地区致初生仔猪腹泻大肠杆菌的O血清型和毒力因子

Serogroups and Virulence Factors of Escherichia coli Associated with Diarrhea in Piglets in Eastern China

从江苏、江西、安徽等 7个省疑似黄、白痢直肠棉拭及病死猪的十二指肠和肠系膜淋巴结中分离鉴定出 339株病原性大肠杆菌。经O血清型鉴定 ,除 77株未能定型、4 1株自凝外 ,测定出 2 2 1个分离株的O血清型 ,这些分离株覆盖了 6 4个血清型 ,以O1 0 7、O1 0 1 、O2 0 、O93、O1 1 和O1 49为主 ,共 99株 ,占定型菌株的 4 4 80 %。这些血清型与已报道的常见血清型间存在一定差异。运用黏附素单抗对以上菌株进行F4、F5、F6、F1 8、F4 1 5种黏附素检测 ,共 97个分离株表达黏附素 (2 8 6 1 % ) ,而表达两种和 3种黏附素的菌株分别有 2 2株和 8株 ,它们分别占表达黏附素菌株的2 2 6 8%和 8 2 5 % ,其中单独表达F4、F6、F5 +F4 1黏附素菌株分别有 1 8、30、1 5株 ,分别占表达黏附素菌株的1 8 5 6 %、30 93%和 1 5 4 6 % ;同时运用多重PCR对其中 1 4 5个分离株进行毒素基因 (STa、STb、LT、SLT 2e)的检测 ,拥有STa和STb毒素基因的菌株分别占检测菌株的 5 1 72 %和 37 2 4 %。F6、F4、F5 +F4 1和STa。

The purpose of this study was to determine the present distribution of O serogroups and virulence factors among pathogenic Escherichia coli isolates collected from diarrheal piglets from 7 provinces in eastern China. 339 strains were identified with Escherichia coli isolates in 10 biochemical reactions. Among 339 E.coli isolates, serogroups of 221 strains were determined while 77 were unable to be classified as certain groups, and 41 were self agglutinated. These isolates distributed in 64 serogroups and 44 80% (99/221) out of which belonging to 6 O serogroups: O 107 、O 101 、O 20 、O 93 、O 11 and O 149 . Several uncommon O serogroups were discovered in this study. 339 E.coli isolates were used for determination of F4,F5,F6,F18 and F41 by slide agglutination with monoclonal antibodies and 145 E.coli strains were examined for toxin STa,STb,LT and SLT 2e genes by means of multiple PCR assay. 97 strains (28 61%) carried the fimbrial adhesions, 67 E.coli strains expressed one fimbriae and 30 strains expressed two or more fimbriae. Among 339 E.coli isolates, the positive percents for F6、F4、F5+F41 were 30 93%, 18 56% and 15 46%, respectively. PCR analysis showed that nearly seventy two percent (75/145) of those isolated harboured the genes for enterotoxin STa, and thirty seven percent (54 /145) possessed the genes for enterotoxin STb. The above adhesions and heat stable enterotoxins seemed to be the common virulence factors in tested isolates.