The Fluorescence in Situ Hybridization Technique (FISH) for Early Diagnosis of Fungal Sepsis in Immunocompromised Patients

Background: Sepsis is a serious clinical condition that characterized by a systemic inflammatory response syndrome. The mortality rate was reported to range between 13-20 million cases per year worldwide. In order to treat sepsis the detection of the causative pathogen is extremely crucial; especially fungal invasion in immunocompromised patients. Fungi are increasingly recognized as major pathogens in critically ill patients. Candida species and Cryptococcus species are the yeasts most frequently isolated in clinical practice. Methods: Forty nine patients in ICU represented the material for this study and Fluorescence in Situ Hybridization (FISH) was evaluated as a method for diagnosis compared to conventional diagnosis methods. Important questions considered to be answered; these include sensitivity, accuracy, robustness, frequency of testing, experience needed, duration to get the results, promptness, and consequently the cost. Results: FISH had sensitivity and specificity of 100% that compared to 100% specificity of traditional method and sensitivity of 92%. The mean times to diagnosis offer the detection of microbial growth in the automated blood culture system were 5 hours, and 6 days for detection by FISH and traditional microbiological approaches respectively. Conclusion: The study revealed that FISH is a rapid and reliable method for direct identification and differentiation of fungal growth in blood cultures. FISH is relatively cheap, valid, and appropriate for daily routine work. FISH can elucidate that earlier fungal identification results in earlier appropriate antimicrobial therapy and in a better clinical outcome for the patients.