2009年杭州市01群霍乱弧菌的分子特征及耐药性

Molecular characteristics and antibiotic resistances of Vibrio cholerae O1 isolates in Hangzhou in 2009

目的研究2009年杭州市O1群霍乱弧菌分离株的分子特征及菌株耐药情况。方法选取2009年分离自杭州市7个区县的30株O1群霍乱弧菌分离株，用PCR检测其肠毒素A基因（ctxA）和毒素共调菌毛A基因（tcpA），以脉冲场凝胶电泳（pulsed—fieldgelelectrophoresis，PFGE）进行分子分型并作相似度分析，用改良K—B纸片法检测菌株的耐药谱。结果30株01群霍乱弧菌分离株中，ctxA-并tcpA＋基因型菌株有24株，占80．00％；ctxA-并tcpa-基因型菌株有4株，占13．33％；ctxA＋并tcpA＋基因型菌株有2株，占6．67％。27株菌（3株因降解未分型）分为11种PFGE型别（P1～P11）；23株ctxA-并tcpA＋基因型菌株（1株因降解未分型）分为P1～P7等7种型别，相似度≥91．4％，其中P1型占56．52％（13／23）。7株从同一起暴发事件中分离的ctxA-并tcpA＋菌株的PFGE型别分别为P1（6株）和P2（1株），相似度为97．6％。24株ctxA-并tcpa＋菌株对氨苄西林、妥布霉素和阿米卡星的耐药率分别为20．83％（5／24）、4．17％（1／24）和4．17％（1／24）。结论2009年杭州市01群霍乱弧菌流行株的基因型是ctxA-并tcpA＋型；ctxA-并tcpA＋型01群霍乱弧菌菌株的耐药情况尚不严重。

Objective To study the molecular characteristics and antibiotic resistances of Vibrio cholerae（ V. cholerae） O1 isolates in Hangzhou in 2009. Methods The virulence genes ctxA and tcpA of the thirty V. cholerae O1 isolates from 7 counties and districts of Hangzhou were detected by PCR. Pulsed-field gel electrophoresis （PFGE） was performed for molecular typing and similarity analysis. Antibiotic resistances of these isolates were measured by the Kirby-Bauer method. Results Virulence gene analysis showed that 80. 00% （24/30） of the genotype in V. cholerae isolates was ctxA - and tcpA ＋, 13.33% （4/30） was ctxA - and tcpA - ,and 6. 67% （2/30） was ctxA ＋ and tcpA ＋. Twenty-seven isolates tested were typed into 11 PFGE patterns （ P1 - P11 ）. Twenty-three isolates with genotype ctxA - and tcpA ＋ were clustered into 7 PFGE patterns （ P1 - PT, termed Pl-like cluster） with the similarity to be equal or greater than 91.4% , and 56.52% （13/23） of them belong to P1. 7 isolates with very high similarity （97.6%）, belonging to P1 （6 isolates）, and P2 （ 1 isolate）, respectively, were collected from one foodborne disease outbreak. The resistant rates of the 24 isolates with genotype ctxA - and tcpA ＋ to ampicillin, tobramicin and amikacin were 20. 83% （ 5/24 ）, 4. 17% （ 1/24 ） and 4. 17% （ 1/24 ）, respectively. Conclusion The genotype of the epidemic strains of V. cholerae O1 isolates in Hangzhou in 2009 with high similarity was ctxA - and tcpA ＋ ; The level of drug resistances of this kind of V. cholerae O1 isolates were not high.