Evaluation of amphotericin B interpretive breakpoints for Candida bloodstream isolates by correlation with therapeutic outcome.
One hundred seven Candida bloodstream isolates (51 C. albicans, 24 C. glabrata, 13 C. parapsilosis, 13 C. tropicalis, 2 C. dubliniensis, 2 C. krusei, and 2 C. lusitaniae strains) from patients treated with amphotericin B alone underwent in vitro susceptibility testing against amphotericin B using five different methods. Fifty-four isolates were from patients who failed treatment, defined as death 7 to 14 days after the incident candidemia episode, having persistent fever of >or=5 days' duration after the date of the incident candidemia, or the recurrence of fever after two consecutive afebrile days while on antifungal treatment. MICs were determined by using the Clinical Laboratory Standards Institute (formally National Committee for Clinical Laboratory Standards) broth microdilution procedure with two media and by using Etest. Minimum fungicidal concentrations (MFCs) were also measured in two media. Broth microdilution tests with RPMI 1640 medium generated a restricted range of MICs (0.125 to 1 microg/ml); the corresponding MFC values ranged from 0.5 to 4 microg/ml. Broth microdilution tests with antibiotic medium 3 produced a broader distribution of MIC and MFC results (0.015 to 0.25 microg/ml and 0.06 to 2 microg/ml, respectively). Etest produced the widest distribution of MICs (0.094 to 2 microg/ml). However, none of the test formats studied generated results that significantly correlated with therapeutic success or failure.
Mycotic Diseases Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Rd., N.E., Mailstop C-09, Atlanta, GA 30333, USA. bip5@cdc.gov
Benjamin J
BJ
Park
Beth A
BA
Arthington-Skaggs
Rana A
RA
Hajjeh
Naureen
N
Iqbal
Meral A
MA
Ciblak
Wendy
W
Lee-Yang
Mario D
MD
Hairston
Maureen
M
Phelan
Brian D
BD
Plikaytis
Andre N
AN
Sofair
Lee H
LH
Harrison
Scott K
SK
Fridkin
David W
DW
Warnock
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000666:Amphotericin B / Q000494:pharmacology*; D000935:Antifungal Agents / Q000494:pharmacology*; D002175:Candida / Q000187:drug effects*; D002177:Candidiasis / Q000188:drug therapy*; D002648:Child; D002675:Child, Preschool; D005260:Female; D016469:Fungemia / Q000188:drug therapy* / Q000382:microbiology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D017211:Treatment Failure
D000935:Antifungal Agents; D000666:Amphotericin B