한국에서 분리된 Cryptococcus neoformans 임상균주의 분자역학적 연구

Abstract

Cyptococcosis is generally caused by Cryptococcus neoformans, the opportunistic agent which has two species, Cryptococcus neoformans and Cryptococcus gattii. Both C.neoformans/C.gattii species contain a number of genetically diverse subgroups that can be differentiated by various molecular typing methods. We conducted a molecular epidemiological analysis of 30 clinical isolates of the C.neoformans from cryptococcosis patients who had been had been hospitalized between 2008 and 2010 in medical centers located in Seoul and Busan in Korea. To determine the genetic diversity, 30 strains of C.neoformans were typed using PCR fingerprinting with the microsatellite specific primer of the phage M13 and the restriction fragment length polymorphism (RFLP) of orotidine monophosphosphate pyrophosphorylase (URA5) gene. All isolates were identified as serotype A, mating type MATα and molecular type VNI. The random amplified polymorphic DNA (RAPD) profiles obtained by using two primers revealed a single pattern. Our study shows that 30 strains of clinical C.neoformans are genetically homogeneous with all of the isolates were molecular type VN1,serotype A, mating type MATα. Epidemiological characteristic of 30 strains isolated from patients diagnosed with cryptococcosis between 2008 and 2010 shows that there is relatively high isolation rate in the year of 2009(56.7%), and the mean age was 62.7. Among 30 patients, 17(56.7%) were female and annual female distribution was constantly increasing. Of the 30 patients, about 24(80%) had underlying diseases and the most common condition was HCC(20.8%) followed by lung cancer and HIV infection 3(12.5%) respectively. This study demonstrates that the clinical features of cryptococcosis between 2008 and 2010 are different from the existing research results which report higher incidence of male patients. Because of an aging society, the mean age at the point of diagnosis was increased from 51.7, 59.1 to 62.7 years. Additionally cryptococcosis has been mostly diagnosed in non-HIV patients and the major predisposing factor was HCC.