Genetic Variations of Candida glabrata Clinical Isolates from Korea using Multilocus Sequence Typing

Abstract

Background: Although Candida albicans is considered to be the major fungal pathogen of candidemia, severe infections by non-albicans Candida (NAC) spp. have been on the increase in recent years. Among NAC spp., C. glabrata has emerged as the second most common pathogen. Unlike other Candida spp., it is often resistant to various azole antifungal agents, such as fluconazole. However, few studies have been conducted to investigate its structure, epidemiology, and basic biology. Recently, multi-locus sequence typing (MLST) has been developed as a highly useful and portable molecular biology technique. Methods: In the present study, MLST was performed with a total of 102 C. glabrata clinical isolates that were isolated from various types of clinical specimens. The present study was performed with a total of 102 C. glabrata clinical isolates that were isolated from various types of clinical specimens. The fungal internal transcribed spacer (ITS) gene wad amplified and sequenced to identify and confirm C. glabrata clinical isolates. For MLST, six housekeeping genes including 1,3-beta-glucan synthase (FKS), 3-isopropylmalate dehydrogenase (LEU2),myristoyl-CoA, protein Nmyristoyltransferase (NMT1), phosphoribosyl-anthranilate isomerase (TRP1), UTP-glucose-1-phosphate uridylyltransferase (UGP1), and orotidine-5'-phosphate decarboxylase (URA3) were amplified and sequenced. The results were analyzed by using the C. glabrata database. Results: Of a total of 3,345 base-pair DNA sequences, 49 (1.5%) variable nucleotide sites were found and the results showed that a total of 12 different sequence types (STs) were identified from the 102 clinical isolates. As classified by STs, The ST138 was the most predominant sequence type (ST) in this study as a result of 52.9% (54/102), and the following most predominant ST was the ST63 as a result of 23.5% (24/102). Conclusion: In conclusion, this data demonstrated that the ST138 was the most predominant ST in Korea. Further, we found eight undetermined STs (USTs) and then seven STs among these STs were given the number by PubMLST database. The data from this study might provide a fundamental database for further studies on C. glabrata, including its epidemiology, and evolution. Furthermore, the data might also contribute to the development of novel antifungal agents and diagnostic tests.