Tomasz Źródłowski
Department of Internal Medicine, St. John’s Episcopal Hospital, NY, USA
Title: Classical Microbiological Diagnostics of Bacteremia - Are The Negative Results Really Negative? What is Laboratory Result Telling us About “Gold Standard�
Biography
Biography: Tomasz Źródłowski
Abstract
Introduction: Standard blood cultures require at least 24-120 hours to be reported as preliminary positive.
Objectives: The objective of this study was to compare the reliability of Gram staining and fluorescent in-situ hybridization (FISH), for detecting bacteremia in otherwise negative blood culture bottles.
Patients and methods: We performed Gram stain and FISH to 82 sets of negative blood cultures and 82 blood samples taken from post-operative septic patients and 57 blood samples taken from healthy volunteers.
Results: Using Gram stain in 62.2% of blood samples, 35.4% of the negative aerobic bottles, and in 31.7% of the negative anaerobic bottle’s bacteria were visualized. Utilizing FISH, we detected bacteria respectively in 75.6%, 56.1% and 64.6% of samples. Among the blood samples from healthy volunteers, FISH detected bacteremia in 64.9% of the blood while Gram stain detected bacteria in only 38.6%. The time needed to obtain the study results using Gram stain was 1 hour, for FISH 4 hours and for the culture method, considering the duration of growth, 5 days.