ENTEROTOXIGENICITY OF VIBRIO-PARAHAEMOLYTICUS WITH AND WITHOUT GENES ENCODING THERMOSTABLE DIRECT HEMOLYSIN
ENTEROTOXIGENICITY OF VIBRIO-PARAHAEMOLYTICUS WITH AND WITHOUT GENES ENCODING THERMOSTABLE DIRECT HEMOLYSIN
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DOI：
10.1128/iai.60.9.3539-3545.1992
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发表时间：
1992-09-01
影响因子：
3.1
通讯作者：
KAPER, JB
中科院分区：
文献类型：
--
作者：
NISHIBUCHI, M;FASANO, A;KAPER, JB
副溶血弧菌产生一种耐热直接溶血素 (TDH)，该素与该微生物引起的腹泻病的发病机制有关。然而，之前试图证明溶血素对毒力的贡献的研究尚未得出结论。我们通过使用通过特异性灭活编码 TDH 的 tdh 基因的两个拷贝构建的同基因 TDH 阴性（TDH-）菌株来研究这种假定的毒力因子。通过向安装在Ussing室中的兔回肠组织中添加无菌培养物上清液来测试亲本菌株(AQ3815)和突变菌株的肠毒性。与TDH-突变体引起的变化相比，亲本菌株的培养滤液产生了短路电流(Isc)的显着增加。 AQ3815的培养滤液增加Isc的能力通过用抗TDH血清中和而降低，并且克隆的tdh基因返回到TDH-突变体恢复了增加Isc的能力。这些结果通过兔回肠环测定得到证实，其中AQ3815引起液体积聚，但TDH突变体则不然。在暴露于任一菌株的培养滤液的粘膜组织中均未观察到微观损伤。这些结果表明，TDH 对兔小肠具有产肠毒素作用，并且可能是副溶血性弧菌引起的水样腹泻的原因。
Vibrio parahaemolyticus produces a thermostable direct hemolysin (TDH) that has been implicated in the pathogenesis of diarrheal disease caused by this organism. However, previous studies attempting to demonstrate the contribution of the hemolysin to virulence have been inconclusive. We investigated this putative virulence factor by using an isogenic TDH-negative (TDH-) strain constructed by specifically inactivating the two copies of the tdh gene encoding TDH. The enterotoxigenicities of the parent strain (AQ3815) and the mutant strain were tested by adding sterile culture supernatants to rabbit ileal tissue mounted in Ussing chambers. The culture filtrate of the parent strain produced a significant increase in short-circuit current (Isc), compared with the change induced by the TDH- mutant. The capacity of the culture filtrate of AQ3815 to increase the Isc was reduced by neutralization with anti-TDH serum, and the return of the cloned tdh gene to the TDH- mutant restored the ability to increase the Isc. These results were corroborated by rabbit ileal loop assays in which AQ3815 caused fluid accumulation but the TDH- mutant did not. No microscopic damage was seen in mucosal tissues exposed to the culture filtrate of either strain. These results indicate that TDH has an enterotoxigenic effect on rabbit small intestine and could be responsible for the watery diarrhea seen with V. parahaemolyticus.