scholarly journals Antifungal susceptibility testing.

1993 ◽  
Vol 6 (4) ◽  
pp. 367-381 ◽  
Author(s):  
J H Rex ◽  
M A Pfaller ◽  
M G Rinaldi ◽  
A Polak ◽  
J N Galgiani
Keyword(s):  
Susceptibility Testing ◽  
Incubation Temperature ◽  
Clinical Laboratory ◽  
Antifungal Susceptibility ◽  
Inoculum Size ◽  
Antifungal Susceptibility Testing ◽  
National Committee ◽  
Candida Spp ◽  
Interlaboratory Variability ◽  
Future Work

Unlike antibacterial susceptibility testing, reliable antifungal susceptibility testing is still largely in its infancy. Many methods have been described, but they produce widely discrepant results unless such factors as pH, inoculum size, medium formulation, incubation time, and incubation temperature are carefully controlled. Even when laboratories agree upon a common method, interlaboratory agreement may be poor. As a result of numerous collaborative projects carried out both independently and under the aegis of the Subcommittee on Antifungal Susceptibility Testing of the National Committee for Clinical Laboratory Standards, the effects of varying these factors have been extensively studied and a standard method which minimizes interlaboratory variability during the testing of Candida spp. and Cryptococcus neoformans has been proposed. This review summarizes this work, reviews the strengths and weaknesses of the proposed susceptibility testing standard, and identifies directions for future work.

Use of spectrophotometric reading for in vitro antifungal susceptibility testing ofAspergillusspp.

1999 ◽  
Vol 45 (10) ◽  
pp. 871-874 ◽  
Author(s):  
Eric Dannaoui ◽  
Florence Persat ◽  
Marie-France Monier ◽  
Elisabeth Borel ◽  
Marie-Antoinette Piens ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Susceptibility Testing ◽  
Clinical Laboratory ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
Antifungal Susceptibility Testing ◽  
Aspergillus Species ◽  
National Committee ◽  
Broth Microdilution Method

A comparative study of visual and spectrophotometric MIC endpoint determinations for antifungal susceptibility testing of Aspergillus species was performed. A broth microdilution method adapted from the National Committee for Clinical Laboratory Standards (NCCLS) was used for susceptibility testing of 180 clinical isolates of Aspergillus species against amphotericin B and itraconazole. MICs were determined visually and spectrophotometrically at 490 nm after 24, 48, and 72h of incubation, and MIC pairs were compared. The agreement between the two methods was 99% for amphotericin B and ranged from 95 to 98% for itraconazole. It is concluded that spectrophotometric MIC endpoint determination is a valuable alternative to the visual reference method for susceptibility testing of Aspergillus species.Key words: antifungal, susceptibility testing, Aspergillus, spectrophotometric reading.

Antifungal Susceptibility Testing in Teaching Hospitals

2003 ◽  
Vol 37 (2) ◽  
pp. 192-196 ◽  
Author(s):  
Manjunath P Pai ◽  
Susan L Pendland
Keyword(s):  
Susceptibility Testing ◽  
Clinical Laboratory ◽  
Antifungal Susceptibility ◽  
Antifungal Susceptibility Testing ◽  
Teaching Hospitals ◽  
National Committee ◽  
American Hospital ◽  
American Hospital Association ◽  
Initial Mailing ◽  
Blood Specimens

BACKGROUND: An assessment of antifungal susceptibility testing (AST) has not been conducted since the introduction of the National Committee for Clinical Laboratory Standards (NCCLS) M27-A document. OBJECTIVE: To determine AST practices in teaching hospitals. METHODS: A questionnaire was mailed to the heads of 386 randomly assigned microbiology departments from teaching hospitals identified through the 2000 American Hospital Association Guide. Identifiers were used to delineate responders from nonresponders. A reminder letter was mailed 3 weeks after the initial mailing to all nonresponders. The hospital bed-size and number of inpatient days for respondents were obtained through the American Hospital Directory. RESULTS: The questionnaire was returned by 171 (44.3%) institutions. The total and median (range) number of candida isolates were 137 088 and 8.5 (1–145)/1000 inpatient days for the year 2000, respectively. Approximately 1% (1300) of candida isolates, from predominantly blood specimens, underwent AST. AST was reported by 115 (67.2%) hospitals, with testing on site at 27 hospitals and off site for 88 hospitals. NCCLS methodology (80% broth microdilution) was used by 75% of the hospitals performing on-site AST. The median time to obtain AST results was significantly lower when testing was performed on site (3 d) compared with off site (7–10 d). SUMMARY: A large number of candida bloodstream isolates undergoes AST annually. AST results are obtained sooner when performed on site compared with off site.

scholarly journals Interpretation of Trailing Endpoints in Antifungal Susceptibility Testing by the National Committee for Clinical Laboratory Standards Method

1998 ◽  
Vol 36 (1) ◽  
pp. 153-156 ◽  
Author(s):  
Sanjay G. Revankar ◽  
William R. Kirkpatrick ◽  
Robert K. McAtee ◽  
Annette W. Fothergill ◽  
Spencer W. Redding ◽  
...  
Keyword(s):  
Susceptibility Testing ◽  
Clinical Laboratory ◽  
Antifungal Susceptibility ◽  
Antifungal Susceptibility Testing ◽  
National Committee ◽  
Oropharyngeal Candidiasis ◽  
Length Polymorphisms ◽  
Immunodeficiency Virus ◽  
Agar Dilution ◽  
Different Strains

Trailing endpoints remain a problem in antifungal susceptibility testing using the National Committee for Clinical Laboratory Standards (NCCLS) method. For isolates for which trailing endpoints are found, MICs of ≤1 μg/ml at 24 h and of >64 μg/ml at 48 h are usually observed. In a study of human immunodeficiency virus (HIV)-infected patients with oropharyngeal candidiasis, we identified three patients with multiple serial isolates for which trailing endpoints were observed with fluconazole. At 24 h, MICs were generally ≤1 μg/ml by both broth macro- and microdilution methods. However, at 48 h, MICs were >64 μg/ml, while the organism remained susceptible by agar dilution testing with fluconazole. Most episodes of oropharyngeal candidiasis with trailing-endpoint isolates responded to doses of fluconazole as low as 100 mg/day. Two patients had both susceptible and trailing-endpoint isolates by NCCLS broth macro- and microdilution testing; these isolates were found to be the same strain by pulsed-field gel electrophoresis using restriction fragment length polymorphisms. Another patient had two different strains, one for which trailing endpoints were observed and one which was susceptible at 48 h. Trailing endpoints may be seen with selected isolates of a strain or may be a characteristic finding for most or all isolates of a strain. In addition, with isolates for which trailing endpoints are observed, reading the endpoint for the NCCLS method at 24 h may be more appropriate.

scholarly journals Correlation between E-Test, Disk Diffusion, and Microdilution Methods for Antifungal Susceptibility Testing of Fluconazole and Voriconazole

2003 ◽  
Vol 47 (5) ◽  
pp. 1647-1651 ◽  
Author(s):  
Madonna J. Matar ◽  
Luis Ostrosky-Zeichner ◽  
Victor L. Paetznick ◽  
Jose R. Rodriguez ◽  
Enuo Chen ◽  
...  
Keyword(s):  
Susceptibility Testing ◽  
Clinical Laboratory ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
Antifungal Susceptibility Testing ◽  
Disk Diffusion ◽  
National Committee ◽  
Broth Microdilution ◽  
Microdilution Method ◽  
Test Disk

ABSTRACT The activities of fluconazole and voriconazole against isolates of Candida spp. (n = 400) were tested by the E-test, disk diffusion, and the National Committee for Clinical Laboratory Standards (NCCLS) M27-A2 broth microdilution-based reference methods. More than 96% of isolates found to be susceptible to fluconazole by the reference method were identified as susceptible by the agar-based methods. Lesser degrees of correlation with the reference method were seen for isolates identified as resistant by the agar-based methods. Interpretive categories are not available for voriconazole, but results qualitatively similar to those for fluconazole were seen. The agar-based E-test and disk diffusion methods are reliable alternatives to the NCCLS M27-A2 reference microdilution method for isolates that test susceptible to fluconazole.

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