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目的分析比较分离自病例与环境的霍乱弧菌的病原学特征,为霍乱防治工作提供实验依据。方法选取分离自霍乱病例(患者和密切接触者)和环境(水体和海水产品)的霍乱弧菌,采用血清学、药物敏感性试验、多重PCR检测毒力基因和脉冲场凝胶电泳(PFGE)分子分型等方法,分析不同来源的霍乱弧菌在菌型分布、药物敏感性、毒素基因携带以及分子分型方面的异同。结果 2005―2014年佛山市共分离各类来源霍乱弧菌39株,其中病例来源菌株6株、环境来源菌株33株。2种来源菌株的菌型构成均以O1群稻叶型为主;病例来源菌株以产毒株为主,ctx A毒力基因携带率为66.67%,携带8种毒力基因阳性率为50.00%;环境来源菌株以非产毒株为主,ctx A毒力基因携带率为21.21%,携带8种毒力基因阳性率为6.06%。药物敏感性试验结果显示,不同来源的菌株对萘啶酸均有较高的耐药率(>50.00%);病例来源菌株对复方新诺明的耐药率(83.33%)高于环境来源菌株(18.18%)。PFGE聚类分析结果显示,39株霍乱弧菌可分为35个PFGE型别,菌株PFGE带型相似度为72.5%~100.0%。结论佛山市霍乱弧菌血清型、毒力基因和遗传特征复杂多样,霍乱防控形势严峻,需要加强霍乱弧菌常规药敏和菌株型别变异情况的监测。
Objective To analyze and compare the etiological characteristics of Vibrio cholera isolated from cases and environment and provide experimental evidence for prevention and control of cholera. Methods Vibrio cholerae isolated from cholera cases (patients and close contacts) and the environment (water and sea products) were selected for serological and drug susceptibility tests and virulence genes and pulsed-field gel electrophoresis (PFGE) Molecular typing and other methods to analyze the different sources of Vibrio cholerae in the distribution of bacteria, drug sensitivity, toxins gene carrying and molecular typing similarities and differences. Results From 2005 to 2014, 39 strains of Vibrio cholerae were isolated from Foshan city, including 6 cases of pathogenic origin and 33 strains of environmental origin. The bacterial strains of the two strains were all O1-type rice leaves. The main strains of the strains were toxin-producing strains, the ctx A virulence gene carrying rate was 66.67%, and the carrying virulence gene carrying rate was 50.00% The strains of environmental origin were mainly non-virus-producing strains. The carrying rate of ctx A virulence gene was 21.21%, and the positive rate of carrying 8 virulence genes was 6.06%. Drug susceptibility test results showed that different strains of nalidixic acid have a higher resistance rate (> 50.00%); case-source strains of cotrimoxazole resistance (83.33%) higher than the strains of environmental sources (18.18%). PFGE clustering analysis showed that 39 strains of V. cholerae could be divided into 35 PFGE types, and the PFGE patterns of strains were 72.5% -100.0%. Conclusion The serotypes, virulence genes and genetic characteristics of Vibrio cholerae in Foshan are complex and diverse. The status of prevention and control of cholera is very serious. It is necessary to strengthen the monitoring of Vibrio cholerae conventional drug sensitivity and strain type variation.