Ba. Lasker et al., Molecular epidemiology of Candida albicans strains isolated from the oropharynx of HIV-positive patients at successive clinic visits, MED MYCOL, 39(4), 2001, pp. 341-352
Candida albicans strain diversity and fluconazole resistance were prospecti
vely analyzed in oral strains from 29 adult human immunodeficiency virus (H
IV)-positive patients followed for >1 year who had five or more culture-pos
itive clinic visits. Molecular typing consisted of genomic blots probed wit
h the Ca3 repetitive element. Sixteen patients had one or more episodes of
oropharyngeal candidiasis (OPC), 12 (75%) maintained the original genotype,
whereas the remaining four patients had a succession of 2-3 genotypes. The
original genotype, either alone or mixed with another strain or with non-C
. albicans Candida spp., was recovered from oral lesions in 13 of 15 evalua
ble (86.7%) patients. C dubliniensis was the infecting yeast in the remaini
ng two patients. Different patterns of fluconazole resistance occurred in t
hree OPC patients. One patient's infecting strain became less susceptible.
A second patient was infected with a resistant genotype and a progressively
more susceptible minor genotype variant. C dubliniensis isolates from the
third patient varied in susceptibility. Thirteen colonized patients who nev
er developed OPC harbored a greater variety of C. albicans genotypes (2-6)
than their infected counterparts (P=0.35). OPC patients maintained their or
iginal endogenous C albicans strains for prolonged periods, whether or not
they demonstrated decreased in vitro susceptibility to fluconazole. The ada
ptation and maintenance of an endogenous C albicans strain within its host
may be linked to as yet uncharacterized factors.