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目的探索福建省非典型埃尔托霍乱弧菌(aEVC)的进化变迁规律,了解aEVC的变异株种类、基因特征,并分析不同类别变异株对霍乱流行趋势的影响。方法运用单基因片段分析技术,选择1962-2005年代表性O1群埃尔托霍乱菌株49株,对ctxB基因扩增产物进行序列测定和比对分析,确定ctxB基因型;同时对毒力因子tcpA和rstR基因分别进行古典型(Cl)和埃尔托型(El)特异的PCR扩增,确定其基因型别。结合ctxB、tcpA、rstR3种基因不同型别的组合形式,确定福建省aEVC菌株的多样性。结果1986年前菌株ctxB基因以埃尔托型B3型为主占92.00%(23/25),而1994年后菌株以古典型B1型为主占95.83%(23/24)。根据ctxB、rstR、tcpA3种基因不同型别的组合形式,1986年前菌株88.00%(22/25)表现为埃尔托型基因特征B3、El、El,1994年后菌株100.00%(24/24)表现为杂合型(Hybrid)变异株基因特征B1、El和(或)Cl、El。结论福建省霍乱菌株存在aEVC进化事件。ctxB、rstR、tcpA基因表现为B1、El和(或)Cl、El的杂合型变异株是福建省aEVC的主要特征型别,此类菌株于1994年后全面取代原来流行的埃尔托霍乱弧菌。不同血清型的aEVC变异株对菌株流行能力的影响不同,稻叶型埃尔托型菌株比杂合型流行时间要长,而小川型杂合型菌株比埃尔托型流行时间要持久。
Objective To explore the evolvement rules of aEVC in Fujian Province and to understand the types and gene characteristics of aEVC mutants and to analyze the influence of different types of mutants on the prevalence of cholera epidemics. Methods Single-gene fragment analysis was used to select 49 strains of El Ocholopsic in O1 group from 1962 to 2005, and the ctxB genotypes were determined by sequencing and comparison of amplified products of ctxB gene. At the same time, the virulence factors tcpA And rstR gene respectively by classical (Cl) and Elto type (El) specific PCR amplification to determine the genotype. Combined with different types of combinations of ctxB, tcpA and rstR3 genes, the diversity of aEVC strains in Fujian Province was determined. Results The strains of ctxB mainly accounted for 92.00% (23/25) before 1986, while the strains of classical type B1 accounted for 95.83% (23/24) after 1994. According to the combinations of ctxB, rstR and tcpA3, 88.00% (22/25) of the strains showed Elto type B3, El and El genotype in 1986, and 100.00% ) Showed heterozygous (Hybrid) mutant B1, El and / or Cl, El. Conclusion Cholera strains in Fujian Province have aECV evolutionary events. The ctxB, rstR and tcpA genes were B1, El and / or Cl, El heterozygous variants were the main characteristic types of aEVC in Fujian Province. These strains completely replaced the original El Too Cholera Vibrio. The effects of aEVC variant strains with different serotypes on the epidemic ability of strains were different. Elto type strains of rice leaf type had longer prevalence than heterozygous strains, while the Ogawa type heterozygous strains had longer lasting life than Elto type strains.