The pathogenicity of
Cryptococcus neoformans
is heterogeneous and is associated with the expression of viru-
lence factors. This study aimed to correlate the pathogenicity of
C. neoformans var.
grubii in BALB/c mice with in
vitro virulence factors, fluconazole minimal inhibitory concentrations (MICs) and molecular profiles, before and
after animal passage. Ten environmental isolates and one ATCC strain of
C. neoformans var.
grubii mating type α
were evaluated. Most isolates (91%) killed 50% or more of the infected animals by day 24 postinfection and were
recovered from the lungs and brains of surviving animals on days 7 and 14 postinfection. The burden of yeast in the
lungs was more variable than that in the brain. The differences in the expression of virulence factors (growth at 37º
C,
presence and size of the capsule and production of melanin, urease, proteinase and phospholipase) by most isolates
pre and postpassage in animals were not statistically significant. The fluconazole MICs in postpassaged lines differed by a one-dilution from the MIC of the corresponding prepassaged line for six isolates. Using molecular typing
[polymerase chain reaction-fingerprinting with (GACA)
4
and M13], eight isolates were identified as VNI and three
as VNII. We concluded that different isolates with the same molecular and phenotypic profiles, including isolates
that are markedly hypervirulent, span a wide range of virulence and there were no changes in virulence factors in
the postpassaged lines when compared with the corresponding nonpassaged lines.