Characterization of Biofilm-Forming Candida Species Isolated from Endotracheal Tubes in ICUs of Teaching Hospitals in Lagos State

Candida biofilms on endotracheal tubes are associated with ventilator-associated candidiasis, a complication carrying high mortality in intensive care unit (ICU) settings. This study characterized biofilm-forming Candida species from endotracheal tubes (ETTs) removed from mechanically ventilated patients in ICUs of two teaching hospitals in Lagos State, South West Nigeria. Eighty ETTs removed following extubation or device exchange were processed by vortexing and sonication to dislodge biofilm communities. Candida species were isolated on CHROMagar Candida, confirmed by API ID 32C, and speciated by ITS sequencing for ambiguous isolates. Biofilm formation was quantified by crystal violet assay and scanning electron microscopy was used to visualize biofilm architecture on tube segments. Antifungal susceptibility of biofilm-embedded Candida was compared to planktonic forms by EUCAST broth microdilution. Candida was isolated from 65 percent of ETTs, with C. tropicalis (38.5%), C. albicans (30.8%), and C. parapsilosis (19.2%) as predominant species. All species formed strong biofilms as confirmed by crystal violet and SEM visualization. Biofilm-embedded Candida demonstrated 8- to 64-fold higher MIC values than planktonic forms for fluconazole, and 4- to 16-fold higher for amphotericin B. These resistance amplifications have direct clinical implications for managing ETT-associated candidiasis. The findings argue for anti-biofilm surface coatings for ETTs and early echinocandin therapy for confirmed ventilator-associated candidiasis. Keywords: Candida biofilm, endotracheal tube, ICU, antifungal resistance, Lagos.