Involvement of multiple Cryptococcus neoformans strains in a single episode of cryptococcosis and reinfection with novel strains in recurrent infection demonstrated by random amplification of polymorphic DNA and DNA fingerprinting

Abstract

We compared the abilities of random amplification of polymorphic DNA and DNA fingerprinting, with oligonucleotide probes, to type five pairs of Cryptococcus neoformans clinical isolates recovered from five separate human immunodeficiency virus-positive patients in London, England. The two techniques had comparable discriminatory abilities when applied to these isolates. A total of eight different isolate types were demonstrated in these patients. No isolate type was observed in more than one patient. Two of the isolate pairs recovered from single episodes of cryptococcosis within 1 day of each other were genotypically indistinguishable by both methods. The other three pairs of isolates were all distinguishable. One of these isolate pairs was obtained from a single episode of cryptococcosis, while the other two were obtained from recurrent infections. These results indicate that multiple strains of C. neoformans may be responsible for a single episode of cryptococcosis and that recurrent infection may occur as a result of reinfection with a novel strain.

Random amplified polymorphic DNA analysis of clinically and environmentally isolated Cryptococcus neoformans in Nagasaki

“…It is interesting that the RAPD technique used in the present study detected less variation among isolates than previous RAPD studies (8,13). This may be due to the fact that we used purified, high-quality DNA instead of direct amplification from crude colony lysates.…”

“…Since it was first described by Williams et al (22) in 1990, the AP-PCR method has been used in several studies of bacteria and fungi (6,7,11,12). Only three studies have used RAPD analysis for C. neoformans (1,8,13); however, to our knowledge no study has examined environmental and clinical isolates of C. neoformans by RAPD analysis. In the present study, we used RAPD analysis to study the epidemiology of environmental and clinical isolates of C. neoformans in the southern Japanese prefecture of Nagasaki.…”

“…Only three studies have used RAPD analysis for C. neoformans (1,8,13), but none examined environmental and clinical isolates of C. neoformans in limited geographic areas. We have recently demonstrated the patterns of 21 clinical isolates and 1 environmental isolate (the same strains identified in the present study) in Nagasaki Prefecture using the RFLP method (AccI-digested DNA probed with UT-4p) (9).…”

Characterization of Cryptococcus neoformans by random DNA amplification

“…Other methods for identifying strains of C. neoformans have been developed. Random fragment length polymorphism (RFLP) fingerprinting (Spitzer and Spitzer 1992 ;Varma et al 1992 ;Haynes et al 1995), electrophoretic karyotyping (Polacheck and Lebens 1989 ;Kwon-Chung et al 1992) and multilocus enzyme electrophoresis (MEE) (Brandt et al However, these methods have not established a link between a particular profile and epidemiological factors.…”

“…We adapted this method to study the epidemiology of C. neoformans. Other PCR-based protocols applied to C. neoforrnans, have used primers directed against microsatellite DNA (Meyer et al 1993) or conventional RAPD analysis using single, short primers (Crampin et al 1993 ;Haynes et al 1995 ;Brandt et al 1995 ;Yamamoto et al 1995).…”