title: Oral infections caused by yeasts in patients with head and neck cancer undergoing radiotherapy. Identification of the yeasts and evaluation of their antifungal susceptibility.
abstract: Yeasts occur as part of the normal human microbiota. Nevertheless, some species are opportunistic, affecting immunocompromised patients such as those undergoing oncologic treatment.
  
  
  OBJECTIVE
  To detect the presence of yeasts in patients suffering from head and neck cancer who are receiving radiation therapy and display lesions in the oral cavity, compatible with candidiasis; and to evaluate the antifungal susceptibility of the isolates recovered.
  
  
  METHODS
  Sixty samples from patients were obtained by swabbing the oral mucosa. Identification of isolates were performed by classical taxonomic, morphological and biochemical methods as well as by using commercial identification kits. Susceptibility to antifungal drugs was determined by the agar diffusion method with Neosensitabs(®) disks.
  
  
  RESULTS
  Forty-six samples (77%) yielded positive findings, and species recovered were: Candida albicans (22 isolates), Candida tropicalis (13 isolates), Candida parapsilosis (six strains), Candida krusei (three strains), Candida dubliniensis and Saccharomyces cerevisiae (one each). All strains were susceptible to itraconazole, clotrimazole, voriconazole, nystatin and amphotericin B. On the other hand, 65% of strains were miconazole-susceptible while 35%, showed intermediate susceptibility. With regard to ketoconazole, only three strains (7%) corresponding to C. albicans (one isolate) and C. krusei (two isolates) displayed intermediate susceptibility. Only C. krusei strains were resistant to fluconazole while all the other species were susceptible. Eventually, only six isolates (13%) were susceptible to terbinafine while the remaining strains were resistant in vitro.
  
  
  CONCLUSIONS
  Early detection of etiological agents causing lesions, as well as the evaluation of their susceptibility to commonly used drugs, are crucial in order to choose the appropriate treatment that will minimize complications while improving the quality of patients' lives.
authors.affiliation: CEREMIC (The Mycology Reference Center, Rosario), School of Biochemistry and Pharmacy, National University of Rosario (UNR), Suipacha 531, 2000 Rosario, Argentina. lbulacio@fbioyf.unr.edu.ar
authors.forename: L
authors.initials: L
authors.lastname: Bulacio
authors.forename: M
authors.initials: M
authors.lastname: Paz
authors.forename: S
authors.initials: S
authors.lastname: Ramadán
authors.forename: L
authors.initials: L
authors.lastname: Ramos
authors.forename: C
authors.initials: C
authors.lastname: Pairoba
authors.forename: M
authors.initials: M
authors.lastname: Sortino
authors.forename: L
authors.initials: L
authors.lastname: Escovich
authors.forename: C
authors.initials: C
authors.lastname: López
mesh_terms: D000666:Amphotericin B / Q000494:pharmacology / Q000627:therapeutic use; D000935:Antifungal Agents / Q000494:pharmacology / Q000627:therapeutic use*; D002180:Candidiasis, Oral / Q000453:epidemiology / Q000209:etiology / Q000382:microbiology*; D025141:Drug Resistance, Fungal; D006258:Head and Neck Neoplasms / Q000150:complications / Q000532:radiotherapy*; D006801:Humans; D008826:Microbial Sensitivity Tests; D009181:Mycoses / Q000453:epidemiology / Q000209:etiology / Q000382:microbiology*; D009281:Naphthalenes / Q000494:pharmacology / Q000627:therapeutic use; D009761:Nystatin / Q000494:pharmacology / Q000627:therapeutic use; D009894:Opportunistic Infections / Q000453:epidemiology / Q000209:etiology / Q000382:microbiology*; D012441:Saccharomyces cerevisiae / Q000302:isolation & purification; D013045:Species Specificity; D000077291:Terbinafine; D014230:Triazoles / Q000494:pharmacology
chemical_list: D000935:Antifungal Agents; D009281:Naphthalenes; D014230:Triazoles; D009761:Nystatin; D000666:Amphotericin B; D000077291:Terbinafine