Dalsgaard A, Albert M J, Taylor D N, Shimada T, Meza R, Serichantalergs O, Echeverria P
Department of Veterinary Microbiology, Royal Veterinary and Agricultural University, Frederiksberg, Denmark.
J Clin Microbiol. 1995 Oct;33(10):2715-22. doi: 10.1128/jcm.33.10.2715-2722.1995.
In February 1994, an outbreak of diarrhea caused by non-O1 Vibrio cholerae occurred among volunteers in a vaccine trial study area in Lima, Peru. Clinically, 95% of the patients presented with liquid diarrhea with either no or mild dehydration. Serogrouping of 58 isolates recovered from diarrheal patients affected in the outbreak revealed seven different serogroups, with serogroups O10 (21%) and O12 (65%) being predominant. Most of these isolates were susceptible to a variety of antimicrobial agents. None of the 58 isolates hybridized with a DNA probe previously used to detect the gene encoding the heat-stable enterotoxin NAG-ST or produced cholera toxin as assessed by GM1 ganglioside enzyme-linked immunosorbent assay. Ribotyping exhibited 10 different BglI ribotype patterns among the 58 V. cholera non-O1 strains studied. However, ribotyping showed that all isolates belonging to serogroup O12 exhibited identical ribotypes and that 83% of the serogroup O10 isolates belonged to another identical ribotype, thus showing excellent correlation between ribotypes and serogroups. Among a group of O10 and O12 isolates selected for virulence studies, none produced enterotoxin whereas the majority produced a cytotoxin, as assessed in Y1 and HeLa cells. These isolates were also negative for the gene encoding zonula occludens toxin (Zot) as assessed by a PCR assay. The isolates tested showed strong adherence and some degree of invasion in the HEp-2 cell assay, whereas none of the isolates was positive in the PCR assay for the gene encoding the toxin coregulated pilus subunit A antigen (tcpA). In the removable intestinal tie adult rabbit diarrhea model, O10 and O12 serogroup isolates produced severe diarrhea and occasionally death when rabbits were challenged with 10(10) bacterial cells. Fluid accumulation was shown in the rabbit intestinal loop test when whole cultures were injected. No significant difference in virulence was shown between serogroup O10 and O12 isolates. This study provides further evidence that V. chlorae non-O1 non-O139 strains have diarrhegenic potential for humans through a yet-undefined mechanism(s) and that such strains can cause outbreaks.
1994年2月，秘鲁利马一个疫苗试验研究区域的志愿者中发生了由非O1群霍乱弧菌引起的腹泻暴发。临床上，95%的患者表现为水样腹泻，无脱水或仅有轻度脱水。从暴发中受影响的腹泻患者分离出的58株菌株进行血清分型，发现有7种不同的血清群，其中O10血清群（21%）和O12血清群（65%）占主导。这些分离株大多对多种抗菌药物敏感。58株分离株中没有一株与先前用于检测编码热稳定肠毒素NAG-ST的基因的DNA探针杂交，也没有通过GM1神经节苷脂酶联免疫吸附测定法检测到产生霍乱毒素。在所研究的58株非O1群霍乱弧菌菌株中，核糖体分型显示出10种不同的BglI核糖体分型模式。然而，核糖体分型显示，所有属于O12血清群的分离株具有相同的核糖体分型，并且83%的O10血清群分离株属于另一种相同的核糖体分型，因此显示出核糖体分型与血清群之间具有良好的相关性。在一组选择用于毒力研究的O10和O12分离株中，没有一株产生肠毒素，而大多数产生细胞毒素，这是在Y1和HeLa细胞中评估得出的。通过聚合酶链反应（PCR）测定法评估，这些分离株编码小带闭合毒素（Zot）的基因也呈阴性。在人喉表皮样癌细胞（HEp-2细胞）试验中，所测试的分离株表现出很强的黏附性和一定程度的侵袭性，而在编码毒素协同调节菌毛亚基A抗原（tcpA）的基因的PCR测定中，没有一株分离株呈阳性。在可移除肠袢成年兔腹泻模型中，当用10¹⁰个细菌细胞攻击兔子时，O10和O12血清群分离株会导致严重腹泻，偶尔会导致死亡。当注射全菌培养物时，在兔肠袢试验中显示有液体蓄积。O10和O12血清群分离株之间的毒力没有显著差异。这项研究进一步证明，非O1非O139群霍乱弧菌菌株通过一种尚未明确的机制对人类具有致腹泻潜力，并且这些菌株可引起暴发。
