Abstract
Cryptococcus neoformans is an encapsulated yeast causing mainly opportunistic infections. DNA molecular typing techniques divided C. neoformans into four major molecular types (AFLP1/VNI, AFLP1A/VNB/VNII, AFLP1B/ VNII, AFLP3/VNIII, AFLP2/VNIV) characterized by different pathogenicity, geographical distribution and susceptibility to antifungal treatments. In this study 170 Italian C. neoformans clinical isolates (CI) and 32 environmental isolates (EI), collected and serotyped during a ten-year period (1985 to 1995), were genotyped using [GACA]4 microsatellite PCR fingerprinting. The molecular types were compared to their geographic distribution, specimen sources and patient’s risk factors. All four molecular types were described among the CI and only VNI and VNIV among the EI. VNIV molecular type was isolated with significant prevalence among the CI and VNI among the EI. A different geographical distribution of molecular types was detected: VNIV was the most prevalent in the North and Center of Italy; VNIII was isolated almost exclusively in the Center. No significant correlation among molecular types versus predisposing diseases or isolation sources was detected. The strains isolated from different body sites of the same patient (17 cases) were of the same genotype. Five out 9 cases relapsed with a different molecular type. This preliminary investigation shows a high intraspecies variability and reveals a nonhomogeneous distribution of C. neoformans molecular types in Italy.
Highlights
Our results revealed that VNIV molecular type was the most prevalent species causing infection (58%) in the population considered in this study, especially in AIDS patients
Cryptococcus molecular types were not homogeneously distributed among Italy with a clear prevalence of VNIV in the north, while VNI prevailed in the south, both among the clinical isolates (CI) that among the environmental isolates (EI)
C. neoformans var. grubii has a worldwide distribution and is responsible for more than 80% of cryptococcal diseases [11] [12], whereas C. neoformans var. neoformans is found predominantly in Western Europe [9] [13] and South America [12] [14]
Summary
A new taxonomic proposal splits C. neoformans into two species (C. neoformans and Cryptococcus deneoformans) and C. gattii into a total of five species (C. gattii, Cryptococcus bacillisporus, Cryptococcus deuterogattii, Cryptococcus tetragattii and Cryptococcus decagattii) [2] Since this is still under discussion [3], in this study we continue to adopt the classical taxonomy which classifies the agents of cryptococcosis into two species, C. neoformans and C. gattii. Several molecular typing methods have been used for studying the molecular epidemiology of C. neoformans/C. gattii species complex. Grubii (serotype A/VNI genotype) has a worldwide distribution and is responsible for more than 80% of cryptococcal diseases [11] [12], whereas C. neoformans var. In the Mediterranean area of Europe, a higher prevalence of C. neoformans serotype AD hybrids (VNIII genotype) has been reported [15] [16]
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