Investigation of drug resistance and multilocus sequence typing for differentiation of strains of Candida tropicalis of Shanghai / 中华预防医学杂志

ABSTRACT

Objective@#To analyze the drug resistance of clinical isolates of Candida tropicalis in patients with infectious diseases, and preliminarily study their molecular characteristics.@*Methods@#95 strains of Candida tropicalis were isolated from the fungal culture specimens of 87 patients with infectious diseases in Shanghai Public Health Clinical Center from 2012 to 2015. Meanwhile, basic clinical data of patients were collected. The drug resistance of the strains to fungal drugs was analyzed by ATB FUNGUS 3 drug sensitivity test strips. All strains were classified by Multilocus sequence typing(MLST). Then, homology analysis was conducted by MEGA 5.2 software, and the evolutionary tree was mapped by using UPGMA method.@*Results@#Patients distribution of strains was rendered as following: 31 strains from TB patients, 21 strains from HIV/AIDS patients, 19 strains from patients with liver disease, and 24 strains from rare cause infection or fever patients. The drug resistance rate to five antifungal drugs commonly used in clinical (amphotericin B, 5-fluorine cytosine, fluconazole, itraconazole, voriconazole) were 2.11% (2 strains), 0, 26.32% (25 strains), 26.32% (25 strains), and 26.32% (25 strains) respectively. Among the 25 azole-resistant strains: 14 strains were from rare cause infection or fever patients, 8 strains were from HIV/AIDS patients, and 3 strains were from tuberculosis patients. In MLST, 72 sequence types (ST types) were produced, 70 of which were new types. Evolutionary tree analysis showed that 95 strains of clinical strains distribute as three large clusters. 24 azole resistant strains (96.0%) were located in CLUSER Ⅰ.@*Conclusion@#The isolated Candida tropicalis were mainly resistant to azole drugs. MLST typing indicates that they was closely related to their genetic background.