复发性外阴阴道假丝酵母菌病患者反复发作期阴道分离菌株的同源性及耐药性分析

Analysis of homology and drug sensitivity of vaginal isolates of 10 patients with recurrent vulvovaginal candidiasis in recurrent episodes

目的检测复发性外阴阴道假丝酵母菌病(RVVC)患者反复发作期假丝酵母菌的核型同源性,了解假丝酵母菌菌株随临床进展对抗真菌药物的敏感性变化情况。方法2018年9月至2019年6月在首都医科大学附属北京妇产医院初次确诊的RVVC患者10例,收集其确诊RVVC时及在本院治疗后再发时的阴道分泌物,分离纯化并鉴定假丝酵母菌菌株,采用基因组DNA限制性内切酶分析方法(使用限制性内切酶BssHⅡ)联合脉冲场凝胶电泳方法检测分离自同一患者菌株的核型,同时检测临床分离的菌株对5种抗真菌药物(克霉唑、氟康唑、咪康唑、伊曲康唑及制霉菌素)的敏感性。结果(1)10例RVVC患者首诊及复发时分离的20株菌株均为白假丝酵母菌,其染色体DNA经内切酶BssHⅡ酶切后电泳图谱极其相似,来自同一患者的前后(首诊及复发时)分离菌株的电泳条带完全一致。(2)10例患者经药物治疗后复发时,临床分离的白假丝酵母菌菌株对除制霉菌素外的其他4种抗真菌药物的敏感性普遍下降,制霉菌素(首诊和复发:100%敏感、100%敏感)>克霉唑(首诊和复发:100%敏感、90%敏感)>氟康唑(首诊和复发:80%敏感、70%敏感)>伊曲康唑(首诊和复发:60%敏感、50%敏感)>咪康唑(首诊和复发:30%敏感、20%敏感)。结论(1)阴道内同一定植菌株的潜伏可能是RVVC反复发作的原因。(2)抗真菌药物对真菌存在选择性诱导耐药作用,同时真菌对抗真菌药物存在交叉耐药,RVVC患者反复发作时重复进行真菌培养及药物敏感性分析对正确选择敏感的抗真菌药物十分重要。

Objective To detect karyotype homology of vaginal isolates from patients with recurrent vulvovaginal candidiasis (RVVC) in recurrent episodes, and to discuss changes of susceptibility of Candida strains to antifungal drugs with clinical progress.Methods Ten patients were recruited from Beijing Obstetrics and Gynecology Hospital, Capital Medical University from September 2018 to June 2019, who were firstly diagnosed with RVVC. Vaginal discharges were collected before first treatment and after first relapse. Vaginal strains were isolated, purificated and identificated. Then karyotype of 20 strains isolated from 10 patients were detected by restriction endonuclease analysis of genomic DNA (REAG) using enzyme BssHⅡand pulsed field gel electrophoresis (PFGE) methods, and sensitivity of clinical isolates to 5 antifungal drugs (clostridium, fluconazole, miconazole, itraconazole and nystatin) was also detected using disk diffusion method.Results (1) All 20 strains of 10 patients with RVVC were Candida albicans, and their chromosomes were extremely similar after BssHⅡ enzyme digestion. The gene bands of isolated strains from the same patient were completely identical. (2) After clinical medication, the sensitivity of vaginal isolates to azoles was generally decreased, but remained highly sensitive to nystatin, nystatin (first and second clinical isolates: 100% sensitivity and 100% sensitivity)>clotrimazole (100% sensitivity and 90% sensitivity)>fluconazole (80% sensitivity and 70% sensitivity)>itraconazole (60% sensitivity and 50% sensitivity)>miconazole (30% sensitivity and 20% sensitivity).Conclusions (1) The latency of the same colonized strain in the vagina may be the cause of repeated RVVC episodes. (2) Antifungal agents could selectively induce drug resistance to Candidas, and Candidas show cross-resistance to antifungal agents. Repeated fungal culture and drug sensitivity test in patients with RVVC are very necessary for correct selection of antifungals.