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目的调查福建省1962-2005年不同流行时期、不同流行血清型的O1群埃尔托型霍乱弧菌(EVC)毒力基因分布情况;探讨霍乱弧菌(VC)不同毒力基因特征与霍乱流行能力的关系。方法运用PCR扩增技术,检测1962-2005年69株(稻叶21、小川48)霍乱患者分离株的ctxA基因,同时进行ctxB、tcpA、rstR、hlyA毒力因子的古典型(Cl)和埃尔托型(El)基因亚型的扩增;结合流行病学资料分析不同毒力特征菌株的流行能力。结果 69株O1群霍乱弧菌ctxA基因阳性62株,ctxA基因阴性的菌株均不同程度地携带有其他各相关毒力基因;各毒力因子古典型和埃尔托型的阳检率分别为ctxB60.9%(42株)和72.5%(50株),rstR37.7%(26株)和72.5%(50株),tcpA4.35%(3株)和69.57%(48株),hlyA65.22%(45株)和79.71%(55株)。ctxB-Cl、rstR-Cl基因以及菌株同时携带rstR-Cl和rstREl基因的阳性率在稻叶型(阳性率分别为38.1%、0和0)和小川型(阳性率分别为70.8%、54.2%和35.4%)菌株中的差异有统计学意义(P均<0.05)。ctxB-El、rstR-Cl、rstR-El基因的阳性率在1962-1964年、1978年、1994-2000年的小川型3个不同流行时期(阳性率分别为ctxB-El:100.0%、100.0%、44.8%;rstR-Cl:0、0、89.7%;rstR-El:100.0%、87.5%、58.6%)的差异有统计学意义(P均<0.05)。ctxB-Cl、ctxB-El、rstR-El基因的阳性率在1980-1986年、2005年稻叶型两个不同流行时期(阳性率分别为ctxB-Cl:13.3%、100.0%;ctxB-El:100.0%、66.7%;rstR-El:93.3%、50.0%)的差异有统计学意义(P均<0.05)。结论福建省1962-2005年O1群霍乱菌株不同程度地携带有相关的毒力因子;各毒力因子埃尔托型基因片段的检出率均要高于古典型,以rstR和tcpA基因的差异最明显;相对于稻叶血清型,小川血清型更容易整合古典型的ctxB和rstR基因片段;ctxB和rstR基因的类型和不同血清型霍乱菌株的流行能力有相关性。
Objective To investigate the distribution of virulence genes of V. cholerae (EVC) from different epidemic serotypes in Fujian Province from 1962 to 2005, and to explore the relationship between different virulence genes of V. cholerae (VC) and cholera epidemic Ability of the relationship. Methods PCR amplification was used to detect the ctxA gene of 69 strains (Inaba 21, Ogawa 48) isolated from cholera patients from 1962 to 2005. At the same time, the ctxA gene of ctxB, tcpA, rstR and hlyA virulence factors were also detected. Elto type (El) gene subtype amplification; combined with epidemiological data analysis of the virulence of different strains of endemic capacity. Results There were 62 positive ctxA genes of 69 strains of Vibrio cholerae O1 and ctxA negative strains carrying other related virulence genes to varying degrees. The positive rates of classical virulence factor and Elto type were ctxB60 (42 strains), 72.5% (50 strains), rstR37.7% (26 strains) and 72.5% (50 strains), tcpA4.35% (3 strains) and 69.57% (48 strains), hlyA65.22 % (45 strains) and 79.71% (55 strains). The positive rates of both rstR-Cl and rstRE1 genes in ctxB-Cl, rstR-Cl genes and strains in rice leaf type (positive rates were 38.1%, 0 and 0) and Ogawa type (positive rates were 70.8% and 54.2% And 35.4% respectively) (P <0.05). The positive rates of ctxB-El, rstR-Cl and rstR-El genes in three different epidemic periods of Ogawa type in 1962-1964, 1978 and 1994-2000 (the positive rates were 100.0% and 100.0%, respectively, , 44.8%; rstR-Cl: 0,0,89.7%; rstR-El: 100.0%, 87.5%, 58.6%, respectively) were statistically significant (all P <0.05). The positive rates of ctxB-Cl, ctxB-El and rstR-El were between 1980-1986 and 2005 respectively. The positive rates were ctxB-Cl: 13.3% and 100.0% 100.0%, 66.7%; rstR-El: 93.3%, 50.0%) were statistically significant (all P <0.05). Conclusion The strains of Cholera O1 from 1962 to 2005 in Fujian province carry related virulence factors to varying degrees. The detection rates of Elto type gene fragments of all virulence factors are higher than those of classical type. The differences of rstR and tcpA genes Most significantly, Ogawa serotypes more easily integrated the classical ctxB and rstR gene fragments relative to the rice leaf serotypes; the types of ctxB and rstR genes correlated with the prevalence of different serotypes of cholera strains.