Prevalence and Virulence Potential of Candida Species for Proteinase and Phospholipase Activity in Head and Neck Cancer Patients: A Cross-sectional Pilot Study

ABSTRACT
Introduction: Head and neck cancer patients undergoing Chemotherapy (CT) and Radiation Therapy (RT) are at a high-risk of oral Candida infections, mainly due to immune suppression and mucosal damage. Candida spp. most commonly implicated in such conditions are Candida albicans, Candida glabrata, Candida tropicalis, Candida parapsilosis, and Candida krusei. Candida spp. also has some virulence factors, which include secreted aspartyl proteinase and phospholipases. They can enhance the ability of Candida spp. to colonise and penetrate host tissue along with evasion of the host immune system.
Aim: To determine the prevalence of Candida species and evaluate their virulence markers, specifically proteinase and phospholipase activity, in head and neck cancer patients.
Materials and Methods: This hospital-based cross-sectional pilot study was conducted in the Department of Microbiology, Fakhruddin Ali Ahmed Medical College and Hospital, Barpeta, Assam, India, from January 2022 to December 2022. Forty-three patients with histologically confirmed head and neck cancer, planned for 3-4 cycles of CT, RT, or both, and willing to provide informed consent were included. Saliva samples were collected using the spitting technique and inoculated with chloramphenicol on Sabouraud Dextrose Agar (SDA) slants. Germ tube tests identified Candida albicans morphologically, while Chrom agar incubation for 48 hours in the dark aided speciation. Proteinase activity was assessed using the modified SDA with 1% bovine serum albumin method, and phospholipase activity was evaluated using the modified SDA with egg yolk emulsion method. Demographic parameters, including age, gender, and tumour stage, were recorded. Statistical analysis employed Pearson’s Chi-square tests, with significance set at p-value <0.05
Results: Among 43 patients, Candida spp. were isolated in 35 (81.3%), with Candida albicans being the most prevalent, 32 (74.4%). Non NCAC (Non–Candida albicans Candida)3 (6.9%) included two Candida krusei and one Candida tropicalis. Proteinase and phospholipase activities were detected in 34/35 (97% ) and 33/35 (94%) of isolates, respectively, with all C. albicans isolates expressing both enzymes. Concurrent chemoradiation was often accompanied by Candida positivity 17/35 (48.6%), but this association did not reach statistical significance.
Conclusion: The high prevalence of Candida species, particularly C. albicans, with significant expression of virulence factors underscores their pathogenic potential in immunocompromised patients with head and neck cancer. These findings emphasise the need for early detection and antifungal prophylaxis to manage infections in this population.
Keywords; Head and neck neoplasms, Oral candidiasis, Prevalence, Saliva