Genotyping, antifungal susceptibility, enzymatic activity, and phenotypic variation in Candida albicans from esophageal candidiasis

J Clin Lab Anal. 2021 Jul;35(7):e23826. doi: 10.1002/jcla.23826. Epub 2021 May 14.


Background: Esophageal candidiasis is the most frequent form of esophagitis. The pathogenicity of Candida spp. is related to a combination of microbial factors, hydrolytic enzyme secretion and phenotypic switching. This study was designed to investigate esophageal candidiasis, antifungal activity, enzymatic activity patterns, phenotyping, and genotyping profiles of Candida albicans species.

Methods: Nine hundred thirty-three visited patients were evaluated, and esophageal biopsies from patients were included in this study during 2019-2020. Direct smear, Gram staining, and culture on CHROMagar were performed for each sample. Isolated species were identified with conventional procedures and PCR-RFLP. Susceptibility to antifungals was determined according to CLSI guidelines. ABC typing, phenotype switching, hemolysin, proteinase, phospholipase, and esterase activity were also determined with the appropriate protocols.

Results: Twenty-three (2.5%) patients (mean age 55.2 years) were diagnosed with esophageal candidiasis. The species isolated were 19(82.6%) C. albicans, 3(13.1%) C. glabrata, and 1(4.3%) C. tropicalis. Genotype A (57.9%) was the predominant type in C. albicans isolates. 50% of C. albicans isolates exhibited a white phenotype. A high level of phospholipase (47.4%), hemolysin (68.4%), and proteinase activity (36.8%) was observed in the C. albicans isolates. Only three C. glabrata isolates displayed non-wild type susceptibility to voriconazole and itraconazole.

Conclusion: This study shows that C. albicans are still the most frequent isolates from patients with esophageal candidiasis. The predominance of genotype A, the white phenotype, and strong hemolysin activity may indicate a high prevalence of pathogenicity in these isolates. Sensitivity to antifungal drugs was greatest for amphotericin and fluconazole.

Keywords: Candida albicans; antifungals; enzymatic activity; esophageal candidiasis; genotyping; phenotypic variation.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Antifungal Agents / pharmacology*
  • Candida albicans / drug effects
  • Candida albicans / enzymology*
  • Candida albicans / genetics*
  • Candida albicans / isolation & purification
  • Candidiasis / complications
  • Candidiasis / microbiology*
  • Esophagitis / complications
  • Esophagitis / microbiology*
  • Female
  • Fluconazole / pharmacology
  • Genotype
  • Humans
  • Male
  • Microbial Sensitivity Tests
  • Middle Aged
  • Phenotype
  • Young Adult


  • Antifungal Agents
  • Fluconazole