Abstract:

Objective To investigate the molecular epidemiological characteristic of azole-resistant Candida albicans from patients with Candida albicans vaginitis by multilocus sequence typing（MLST）,and to analyze the genotype difference between resistant and sensitive isolates and the relationship between genetic diversity and population. Methods The leucorrhoea specimens were collected from patients with Candida albicans vaginitis in Shanghai Jiading District Central Hospital from July 2015 to June 2016 for culturing,identification and susceptibility test in vitro. A total of 60 isolates being resistant or multi-resistant to fluconazole,itraconazole and/or voriconazole and 38 sensitive isolates were collected. All of them were analyzed by MLST. By BioNumerics 7.6 software,affinity and cluster analysis was performed. Results There were 14 sequence types（ST） in drug resistant group,9 of which had been reported,and the main types were ST310,ST1364,ST2551 and ST135. There were 19 ST in drug sensitive group,12 of which had been reported,and the main types were ST2048 and DST1474. The ratio of ST of drug resistant group to the number of isolates was lower than that of drug sensitive group,and the numbers of ST in the 2 groups showed a linear positive correlation with the number of isolates（drug resistant group：r=0.995,P=0.005;drug sensitive group：r=0.989,P=0.011）. Affinity analysis showed that the affinity of each genotype of drug resistant isolates was close to that of sensitive isolates. Cluster analysis showed that the population of drug resistant isolates formed multistage branches. ST310,ST1364 and ST2551 were in the 1st branch,and ST135 was in the 2nd branch. There was obvious clustering distribution in main ST. Conclusions Using MLST,the isolates of Candida albicans found in Shanghai Jiading District Central Hospital are multiple cloning,and the genotype distribution of drug resistant isolates is more concentrated than that of sensitive isolates. The affinity of each genotype of drug resistant isolates is close to that of sensitive isolates,and the genotypes of their populations are clustered.

Key words: Candida albicans, Azole, Drug resistant isolate, Multilocus sequence typing