Colonization of voice prostheses by albicans and non-albicans Candida species

The purposes of the study were to assess the colonization of tracheoesophageal voice prostheses by albicans and non-albicans Candida species and to determine their susceptibility for three antimycotics that are frequently used for prophylaxis or treatment of oral candidiasis (i.e., miconazole, fluconazole, and nystatin).

In total, 101 patients, corresponding to 170 voice prostheses, were monitored over a period of 28 months.

An enzymatic two-step method was used for differentiation and presumptive identification of Candida species colonizing the voice prostheses. The identity of the isolates was confirmed by the germ-tube test, morphological appearance on cornmeal agar with 0.5% Tween 80, sugar assimilation tests, and appearance on CHROMagar Candida (CHROMagar Co., Paris), Albicans ID (BioMérieux Vitek, Hazelwood, MO), and Fluoroplate Candida (Merck, Darmstadt, Germany). Susceptibility testing for miconazole, fluconazole, and nystatin was performed according to the microdilution method of the National Committee for Clinical Laboratory Standards.

The predominant species isolated were Candida albicans (41.4%), Candida glabrata (33.1%), Candida krusei (15.9%), and Candida tropicalis (5.3%). A broad range of minimal inhibitory concentrations of the isolates was observed for miconazole and fluconazole. In contrast, minimal inhibitory concentration values for nystatin were narrowly distributed around 4 microg/mL for all isolates, suggesting uniform sensitivity.

Our data on the prevalence and susceptibility of yeast isolates will contribute to a rational choice of an antimycotic for prophylaxis of the early deterioration and leakage of tracheoesophageal voice prostheses.