ABSTRACT
Positive blood culture is one of the modified Duke's major criteria for diagnosis of infective endocarditis [IE]. Nevertheless, negative blood culture may occur in IE due to prior antimicrobial utilization or infection with fastidious microorganisms. Direct amplification of bacterial DNA by using broad-range PCR primers provides an alternative approach to the detection of pathogens from clinical specimens. Amplification of the 16S and 18S ribosomal RNA gene in DNA extracted from excised heart valve tissue [HV] has been used to provide etiological diagnosis in patients with culture-negative IE. In this study we aimed to assess the usefulness and the practicality of broad-range PCR [brPCR] in diagnosis of infective endocarditis for the first time in Endocarditis Service, Cairo University and for the first time in Egypt. HV surgically removed from 32 patients with definite IE were included in the study. H V were subjected to brPCR and culture. By brPCR, 20 [62.5%] valves were positive for bacteria, of these seven [35%] valves from blood culture positive patients and 13 [65%] of culture-negative patients. Eleven [34.4%] of all patients were positive for fungus by broad-range PCR, all from patients with negative blood culture for fungus. DNA amplification with universal primers is a promising diagnostic tool in infective endocarditis patients where routine laboratory culture failed to identify the pathogen and diagnosis in the coming decade will likely rely more on PCR-based methods