Candida auris in a Tertiary Care Hospital in Oman: A Five-Year Study of Epidemiology, Clinical Characteristics, and Antifungal Susceptibility

Background Candida auris (C. auris) is an emerging multidrug-resistant pathogen known for causing persistent colonization, invasive infections, and healthcare-associated outbreaks. Its ability to survive in hospital environments, resist common antifungals, and affect critically ill patients makes it a major global health concern. Understanding local epidemiology and susceptibility patterns is essential to guide prevention and management strategies. Objective This study aimed to describe the temporal distribution and antifungal susceptibility patterns of C. auris at a tertiary care hospital in Oman (2017-2021) and compare clinical characteristics, risk factors, and outcomes between colonized and infected patients, including candidemia and non‑candidemia subgroups. Methods This retrospective, single‑center study included all patients with at least one C. auris-positive culture at Khoula Hospital, a tertiary care hospital in Oman (2017-2021). Species identification and susceptibility testing were performed using the VITEK® 2 system (bioMérieux, Marcy-l'Étoile, France) and confirmed at the Central Public Health Laboratories. Clinical and epidemiologic data were extracted from electronic medical records. Patients were classified as colonized or infected based on clinical and microbiologic findings, and the infected group was further subclassified into candidemia and non-candidemia subgroups. Statistical comparisons used Mann-Whitney U, chi-square, or Fisher's exact tests, and odds ratios (OR) with 95% confidence intervals (CI) were calculated for categorical variables, with significance at p < 0.05. Results A total of 129 patients (130 isolates) were identified. Cases peaked in 2019 and declined thereafter. Of all patients, 51 (39.5%) had confirmed infection, and 78 (60.5%) were colonized. Candidemia was the predominant invasive presentation (39/51, 76.5%). Infected patients had longer hospitalization (median, 73 versus 57.5 days; p = 0.027) and higher central venous catheter use (74.5% versus 56.4%; OR, 2.25; 95% CI, 1.04-4.89; p = 0.037) than colonized individuals. Crude mortality was higher in infected than colonized patients (43.1% versus 28.2%, p = 0.080). Among infected patients, candidemia was associated with greater mechanical ventilation use (94.9% versus 66.7%; OR, 9.25; 95% CI, 1.44-59.51; p = 0.008) and central-line utilization (82.1% versus 50.0%; OR, 4.57; 95% CI, 1.13-18.47; p = 0.026). Crude mortality was higher in candidemia than non-candidemia infections (48.7% versus 25.0%, p = 0.14). Susceptibility testing showed universal fluconazole resistance (100%), very limited amphotericin B activity (5.2%), intermediate voriconazole susceptibility (44.8%), and preserved echinocandin activity (caspofungin, 96.6%; micafungin, 100%) and flucytosine activity (80.0%). Conclusions The findings demonstrate that C. auris imposes a considerable burden on hospitalized patients, with marked morbidity in those who develop invasive disease, particularly candidemia. The organism's persistent multidrug resistance, with its capacity for sustained transmission, highlights the need for strengthened infection-control practices and continuous surveillance. Preservation of echinocandin susceptibility supports their role as first-line therapy, while high prevalence of azole and amphotericin B resistance emphasizes the importance of targeted antifungal stewardship and early risk identification to reduce both transmission and adverse clinical outcomes.