Epidemiology of oropharyngeal Candida colonization and infection in patients receiving radiation for head and neck cancer

Oral mucosal colonization and infection with Candida are common in patients receiving radiation therapy for head and neck cancer. Infection is marked by oral pain and/or burning and can lead to significant patient morbidity, The purpose of this study was to identify Candida strain diversity in this population by using a chromogenic medium, subculturing, molecular typing, a nd antifungal susceptibility testing of clinical isolates. These results we re then correlated with clinical outcome in patients treated with fluconazo le for infection. Specimens from 30 patients receiving radiation therapy fo r head and neck cancer were cultured weekly for Candida, Patients exhibitin g clinical infection were treated with oral fluconazole, All isolates were plated on CHROMagar Candida and RPMI medium, subcultured, and submitted for antifungal susceptibility testing and molecular typing. Infections occurre d in 27% of the patients and were predominantly due to Candida albicans (78 %), Candida carriage occurred in 73% of patients and at 51% of patient visi ts. Yeasts other than C. albicans predominated in carriage, as they were is olated from 59% of patients and at 52% of patient visits. All infections re sponded clinically, and all isolates were susceptible to fluconazole. Molec ular typing showed that most patients had similar strains throughout their radiation treatment. One patient, however, did show the acquisition of a ne w strain. With this high rate of infection (27%), prophylaxis to prevent in fection should be evaluated for these patients.