Antifungal Susceptibility Testing, 9 Drug Panel

Pure culture yeast isolate

Mycology or bacterial culture medium (slant or plate) packaged as an etiologic agent (ie, Sabouraud dextrose, SABHI, BHI, chocolate, etc.)

Routine antifungal susceptibility testing is not recommended. Testing may be warranted under certain circumstances such as:

• aid in patient management of refractory oropharyngeal infections due to Candida spp in patients who appear to be experiencing therapeutic failure of the standard antifungal agents at standard doses;

• aid in management of invasive infections due to Candida spp when the utility of the azole antifungal agents (ie, fluconazole, itraconazole) is uncertain (ie, non-Candida albicans isolate);

• establish antibiograms for a specific institution.

Interpretive categories include the following:

SUSCEPTIBLE: This category implies that an infection due to the strain may be appropriately treated with the dosage of the recommended agent unless otherwise contraindicated.

INTERMEDIATE: Susceptibility is not certain since the available data does not permit categorization as either susceptible or resistant.

SUSCEPTIBLE DOSE DEPENDENT: Susceptibility is dependent upon achieving the maximal possible blood level. Doses of 400 mg/day or more of Fluconazole may be required in adults with normal renal function. Measures to assure adequate drug absorption and plasma concentration >0.5 ug/mL may be required for optimal response with Itraconazole.

RESISTANT: Strains falling in this category are not inhibited by the usually achievable systemic concentration of the agent with normal dosage schedules and/or fall in the range where specific microbial resistance mechanisms are likely, and/or clinical efficacy has not been reliable in treatment studies.

Minimum inhibitory concentration (MIC) interpretive guidelines are based substantially on experience with mucosal infections, but are consistent with limited information for invasive infections due to Candida species. The clinical relevance of non-Candida isolates and non-FDA approved drugs remains uncertain at this time. MIC values without interpretations are reported for non-FDA approved drugs and or drugs without CLSI guidelines.

This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.

Microbroth Dilution (MIC)