Comparison of the activities of amphotericin B, itraconazole, and voriconazole against clinical and environmental isolates of Aspergillus species.

BACKGROUND

Invasive fungal infections are a significant cause of morbidity and mortality in immunocompromised populations.

AIMS

To evaluate the susceptibility pattern of our isolates against amphotericin B, itraconazole, and voriconazole and to compare the antifungal activities of these agents with each other against the Aspergillus species tested.

SETTINGS AND DESIGN

A prospective study was designed to include clinical and environmental isolates of Aspergillus species.

MATERIALS AND METHODS

420 sputum samples, 70 bronchoalveolar lavage fluids, 160 oral washings, and 47 environmental samples were collected. Direct microscopy by potassium hydroxide and lactophenol cotton blue mounts followed by culture on Sabourad`s dextrose agar (SDA) was done. Susceptibility testing was performed by the broth microdilution technique as per Clinical Laboratory Standards Institute standards (M-38A). Additionally, all the isolates were also tested by the colorimetric microdilution technique using Alamar Blue dye.

STATISTICAL ANALYSIS

It was done by the Chi-square test and Z-test using SPSS statistical software version 12.0.

RESULTS AND CONCLUSION

Twenty-seven isolates (47.3%) were recovered from patients with chronic bronchial asthma followed by fibrocavitary pulmonary tuberculosis in 9 (15.7%), allergic bronchopulmonary aspergillosis (ABPA) in 6 cases (10.5%), bronchiectasis in 3 (5.2%), bronchogenic carcinoma in 5 (8.7%) and those receiving radiotherapy for head and neck cancer 7 (12.2%). Thirteen environmental isolates were also included in the study. The most common isolate was A. fumigatus 28 (40%), followed by A. niger 22 (31%), A. flavus 13 (19%), and A. terreus 7(10%). All isolates were susceptible to amphotericin B, itraconazole, and voriconazole. Among the three agents tested, voriconazole exhibited lowest MICs (≤1 μg/ml) against all Aspergillus species.