J. Lopez et al., Decrease in Candida albicans strains with reduced susceptibility to fluconazole following changes in prescribing policies, J HOSP INF, 48(2), 2001, pp. 122-128
This study was undertaken to identify prescribing policies likely to favour
or limit fluconazole resistance within a clinical department. Fluconazole
exposure within the infectious diseases and clinical haematology units was
investigated, and data were compared with in vitro susceptibility of Candid
a albicans isolates obtained in these units. Fluconazole utilization was de
termined by the number of fluconazole treatment-days per 100 hospitalizatio
n days (penetration index). In the infectious diseases unit, separate evalu
ations for low-dose fluconazole (50 mg) prescribed as intermittent or prolo
nged treatment, and for higher-dosing schedules (fluconazole 200 mg) were m
ade. Susceptibility of C. albicans isolates was surveyed in a broth microdi
lution assay by measuring the inhibitory concentration 50% (IC50) The penet
ration index (PI) for fluconazole 50 mg declined from 1992 to 1977 in infec
tious diseases (P = 0.0048). In the meantime, total usage of fluconazole in
creased, due to increased prescribing of fluconazole 200 mg (P = 0.0724). T
he IC50 of C. albicans isolates tested in infectious diseases decreased bet
ween 1994 and 1996 from 7.33 mug/ml to 1.64 mug/ml (P = 0.0075). In clinica
l haematology, declines in C. albicans IC50 and fluconazole PI were not sig
nificant (P = 0.35 and P = 0.07, respectively). These data suggest that pro
longed or repeated exposure to low-dose fluconazole, rather than total cumu
lative use, was associated with fluconazole resistance in the infectious di
seases unit. Moreover, restoration of a normal ecology was observed when lo
w-dose prolonged or intermittent prescriptions were reduced. (C) 2001 The H
ospital infection Society.