Prevalence and species distribution of Candida bloodstream infection in children and adults in two teaching university hospitals in Egypt: first report of Candida kefyr

{"Background": "Candidemia is a growing problem in tertiary care hospitals worldwide, associated with significant morbidity, mortality, and healthcare costs. Although Candida albicans has historically been the dominant pathogen, a progressive shift toward non-albicans Candida (NAC) species has been observed globally. More than 90% of candidemia cases are attributed to five species: C. albicans, C. parapsilosis, C. tropicalis, C. glabrata, and C. krusei. Recently, uncommon species such as C. guilliermondii, C. lusitaniae, and C. kefyr have emerged as new health threats. Epidemiology differs between pediatric and adult populations, and local surveillance is essential for optimizing prevention and treatment. This study aimed to determine the prevalence of Candida bloodstream infections, species distribution, and emergence of rare Candida species in two Egyptian university hospitals.", "Methods": "This retrospective cross-sectional study was conducted in the clinical microbiology laboratories of two Cairo University hospitals (Kasr El-Ainy and CUSPH Cairo University Specialized Pediatric Hospital) from January 2019 to January 2020. All Candida species isolated from blood culture specimens of patients with septicemia were included. For pediatric patients, approximately 3 ml of blood was inoculated into BACTEC Peds Plus/F bottles and processed using the BACTEC 9050 system. For adults, 5\u201310 ml of blood was collected for the BacT/ALERT 3D system. Positive cultures were confirmed by Gram staining and subculture on blood agar. Candida isolates were identified to species level using chromogenic Candida agar (Oxoid, England) and the Vitek 2 YST identification card (bioM\u00e9rieux, France). Candida kefyr, isolated for the first time in these hospitals, was confirmed by chip array (Fungi 2.1; Chipron GmbH, Berlin, Germany) following DNA extraction using the NucleoSpin Tissue mini kit, PCR amplification, and hybridization onto LCD chips capable of discriminating 25 fungal species. Descriptive statistics were used to summarize findings.", "Key Results": "Among 3321 blood cultures from adult patients, 34.1% (1134/3321) were positive for at least one organism, with Candida accounting for only 1.6% (18/1134) of positive cultures. Among pediatric patients, 28.9% of blood cultures were positive, with Candida species identified in 10.8% (93/860) of positive cultures. In adults, C. albicans represented 27.8% (5/18) of candidemia cases, while NAC species accounted for 72.2% (13/18). C. tropicalis was the most common NAC in adults (27.8%), followed by C. parapsilosis (16.7%) and C. glabrata (11.1%). One isolate each of C. lusitaniae, C. utilis, and C. kefyr (5.5% each) was detected in adults. Uncommon Candida species (other than C. albicans, C. parapsilosis, C. tropicalis, C. glabrata, and C. krusei) represented 16.6% of adult candidemia. In pediatric patients, C. albicans was more prevalent than in adults but still represented less than half of cases (48.3%, 45/93), with NAC species comprising 51.6% (48/93). C. tropicalis was the most common NAC in pediatrics (22.5%), followed by C. parapsilosis (10.8%), C. lusitaniae (6.4%), C. krusei (4.3%), C. famata (4.3%), and C. utilis (2.2%). One C. kefyr isolate (1.1%) was also recovered from a pediatric patient. Uncommon Candida species represented 14% of pediatric candidemia.", "Clinical Implications": "This study confirms a notable shift from C. albicans to NAC species in both adult and pediatric populations in Egyptian hospitals, with C. tropicalis and C. parapsilosis emerging as the predominant NAC species. The higher incidence of uncommon Candida species (14\u201316.6%) compared to the generally reported rate of less than 10% is alarming and may reflect improved diagnostic capabilities or true emergence of opportunistic pathogens, particularly in immunocompromised patients. The first report of C. kefyr in these hospitals, albeit at low frequency (5.5% in adults, 1.1% in pediatrics), adds to growing global evidence of its emergence, especially given reports of acquired echinocandin resistance. The predominance of NAC species is concerning due to their variable and often increased antifungal resistance profiles, particularly to fluconazole and echinocandins. These findings underscore the critical need for routine identification of Candida isolates to species level, implementation of antifungal stewardship programs, and establishment of local epidemiological surveillance to guide empirical antifungal therapy. Study limitations include the small number of uncommon Candida isolates, lack of clinical data on underlying risk factors and prior antifungal use, and absence of antifungal susceptibility testing."}