Validity of PCR for Diagnosis of Experimental Enterococcal Bacteremia in Rat

Background and Bacteremia is one of the most common infective diseases. Rapid diagnosis of bacteremia could be of great benefit in treatment of the disease and could result in a successful treatment by prescribing effective antibiotics. Bacteremia due to Enterococcus faecalis is more common in hospitals and resistant strains are the usual causes. Routine method for diagnosis of bacteremia is time consuming and more rapid assays are preferred. The aim of this study was evaluating a PCR assay for rapid diagnosis of bacteremia in rat model similar to human bacteremia. To establish experimental bacteremia we used a standard strain to prepare suspensions with 10 8 cfu/ml bacteria for inoculate into 10 rats. Blood samples were taken from all rats after 24, 48, and 72 hours. PCR and routine assay was performed for all rats’ specimens. Ten blood samples of healthy rats were used as control cases. Culture was positive for all specimens. Two specimens were found positive in PCR in the first day, seven samples in second day, and eight specimens in third day after inoculation. Routine and PCR assays were negative for all control samples. Sensitivity and specificity of PCR were 69.8% and 100%, respectively. PCR is a more rapid assay than routine method for diagnosis of bacteremia and could be very effective on successful treatment. Therefore, it could be considered as an alternative method for culture but for increasing sensitivity of the test, we recommend using a more efficient DNA extraction method.