Molecular epidemiology of Cryptococcus neoformans species complex isolates from HIV-positive and HIV-negative patients in southeast China

Abstract

This study investigated the molecular types of the Cryptococcus neoformans species complex isolates and their clinical manifestations among human immunodeficiency virus (HIV)-positive and HIV-negative patients in southeast China in the past 15 years. The molecular types of 109 isolates from 108 patients were analyzed by the PCR fingerprinting method, sequences of internal transcribed spacers of rDNA (ITS region), and sequences of the capsule-associated gene (CAP59). In HIV-positive patients, clinical isolates were grouped into molecular types VNI (75%, 15/20), VNII (15%, 3/20), and VNIII (10%, 2/20). In HIV-negative patients, the majority of the clinical isolates were grouped into molecular types VNI (72%, 64/89), VNII (13%, 12/89), VGI (12%, 11/89), VNIII (1%, 1/89), and VGII (1%, 1/89). In reference to the mating type of the isolates, 97% (106/109) were of the MATα, 2% (2/109) were of the MATα/- and 1% (1/109) were of the MATα/a. As for the clinical manifestations of the molecular types among the patients, the average cerebrospinal fluid (CSF) pressure of the patients infected by the C. gattii was higher than that of the patients infected by the C. neoformans. These results suggest that both HIV-positive and HIV-negative cryptococcal patients in the southeast of China are mostly infected by the C. neoformans strains. No C. gattii strains were found in HIV-positive patients.

Keywords

Cryptococcus neoformans / Cryptococcus gattii / cryptococcosis / molecular epidemiology / molecular type / mating type