Title : Non-albicans candidemia in intensive care units of a tertiary care hospital and the antifungal susceptibility pattern of the isolates along with biofilm formation
Abstract:
Background: Candida species are the commonest opportunistic fungal infections worldwide. In critically ill patients they may lead to fatal systemic infections. Candidemia is a fatal fungal infection with mortality ranging from 35% to 75%. Of all blood stream infections (BSI), yeasts belonging to genus Candida are amongst the top 10 microorganisms. In ICU patients, the incidence varies from 0.24-34.3 patients per 1000 ICU admissions according to western literature. A wide variety of risk factors contribute to altering the epidemiology of candidemia. There has been a shift towards non-albicans species namely Candida tropicalis, Candida parapsilosis, Candida krusei especially in neutropenic patients and Candida glabrata in patients with solid tumour. Newer Candida species like Candida auris, Candida duobushaemulonii and Candida pelliculosa have a greater propensity for nosocomial infections and are increasingly being reported as multi drug resistant in ICUs. Candida species form biofilms that are architecturally very complex and associated with high degree of antimicrobial resistance thereby making the infections difficult to treat.
Materials & Methods: The study was undertaken in the microbiology department with collaboration of the ICU clinicians for a period of 2 years. Blood cultures obtained from ICU patients suspected of BSI were sent to the microbiology laboratory in BACTEC bottles. The automated culture bottles were incubated in the machine. Whenever a bottle “FLASHED POSITIVE”, they were taken out and sub cultured on appropriate media for isolation of the pathogen. The pathogen was identified was MALDI-TOF. If the pathogen was a Non-albicans candida species, the clinical history of the patient was taken and antifungal susceptibility was performed by VITEK YST AFST cards. Biofilm formation was detected among the Non-albicans isolates by the Congo red agar method.
Results: A total of 1816 patients of suspected BSI were admitted in the ICUs during our study period. Blood culture specimens were sent for microbiological investigation from these patients. 63 of these samples were positive for growth of Non-albicans Candida species from suspected cases of BSI admitted in ICUs.
Surgical ICU had the highest candidemia rate. Commonest non-albicans species isolated were C.tropicalis (19) followed by C.parapsilosis (12). Candida auris was also found in 8 patients. Prolonged hospital stay of over 7 days, long term antibiotic therapy and surgery were found associated in a higher percentage among patients having non-albicans candidemia as compared to albicans candidemia with statistical significance.
Antifungal susceptibility of these candida isolates showed 100% susceptibility to Posaconazole and Flucytosine with lowest susceptibility for itraconazole and fluconazole.
9 isolates showed presence of biofilms.
Conclusion: Underlying comorbid conditions and risk factors of the ICU patients evaluated in the study will help the clinicians to suspect Non-albicans candidemia based on these conditions and start appropriate therapy as and when required.
The present study will guide clinicians about the type of candida species and their antifungal susceptibilities prevalent in different ICUs of the present setup.
