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目的探索非典型O1群埃尔托型霍乱弧菌在福建省1962-2005年霍乱菌株中的存在及其意义。方法选择1962-2005年代表性霍乱菌株69株(稻叶21、小川48),运用PCR技术进行ctxB、tcpA、rstR、hlyA各毒力因子的古典型(Cl)和埃尔托型(El)基因的扩增;同时对部分菌株的ctxB和rstR基因的序列进行测定和比对;分析福建省O1群埃尔托型霍乱弧菌(EVC)中非典型菌株出现的时间和存在意义。结果 1962年福建省分离的O1群EVC菌株中携带有ctxB-Cl、tcpA-Cl、hlyA-Cl基因;rstR-Cl基因仅在1994-2000年的霍乱菌株中检出。序列比对结果发现ctxB基因出现新的204位碱基突变位点(T→G);同时报道两种新的ctxB基因型别(10和11),且发现存在于同一个菌株中;ctxB基因型11的115位碱基为C,表现为古典型ctxB位点特征,203位碱基为T,表现为埃尔托型ctxB位点特征。结论福建省在1962年的O1群EVC菌株中就出现杂合有ctxB-Cl、tcpA-Cl、hlyA-Cl基因的非典型EVC菌株,是迄今为止报道出现非典型EVC最早的年代;1994年以后出现整合有rstR-Cl基因的非典型EVC菌株。另外,在福建省O1群EVC中存在国内外未曾报道的新的ctxB碱基突变位点和ctxB基因型别;同时在同一菌株中存在不同的ctxB基因型别杂合形式;ctxB序列也存在不同生物型别的特异位点组合形式。福建省O1群EVC表现为独特的地方性分子特征。
Objective To explore the existence and significance of the Elder Vibrio cholerae serogroup O1 at Cholera strain 1962-2005 in Fujian Province. Methods Ninety-nine strains of cholera (Inaba 21 and Ogawa 48) from 1962 to 2005 were selected and the classical (Cl) and Elto (El) virulence factors of ctxB, tcpA, rstR and hlyA virulence factors were detected by PCR. The sequences of ctxB and rstR genes of some isolates were determined and compared. The occurrence and the significance of atypical strains of V. cholerae (EVC) from O1 population in Fujian province were analyzed. Results The strains of ctxB-Cl, tcpA-Cl and hlyA-Cl were isolated from the EV1 isolates in Fujian province in 1962. The rstR-Cl gene was only detected in the cholera strains of 1994-2000. Sequence alignment revealed a new nucleotide mutation of 204 bp (T → G) in ctxB gene. Two novel ctxB genotypes (10 and 11) were also reported and found in the same strain. The ctxB gene The 115th base of type 11 is C, which shows the classical ctxB locus, and the 203th base is T, showing Elto type ctxB locus. Conclusion The atypical EVC isolates that hybridize with ctxB-Cl, tcpA-Cl and hlyA-Cl genes were found in 1962 O1 EVC strains in Fujian Province, which is the earliest date of atypical EVC reported so far. After 1994 Atypical EVC strains incorporating the rstR-Cl gene appear. In addition, new ctxB base mutation sites and ctxB genotypes that have not been reported at home and abroad exist in the O1 population EVC in Fujian Province; at the same time, there are heterozygous forms of different ctxB genotypes in the same strain; ctxB sequences also have different Biotypes of specific site combinations. Fujian Province O1 group EVC showed a unique local molecular characteristics.