Rapid Diagnosis of Brucella Epididymo-Orchitis by Real-Time Polymerase Chain Reaction Assay in Urine Samples

Abstract

We studied the diagnostic yield of a real-time polymerase chain reaction assay in urine samples for the rapid diagnosis of brucella epididymo-orchitis compared to that of conventional microbiological techniques. We used an SYBR Green I LightCycler based real-time polymerase chain reaction to retrospectively study 10 urine samples from patients with Brucella epididymo-orchitis. The assay amplifies a 223 bp sequence of a gene that codes for the synthesis of an immunogenetic membrane protein specific for Brucella genus (BCSP31). After amplifying this 223 bp sequence we performed melting curve analysis to verify the specificity of polymerase chain reaction products. Brucella melitensis was isolated from blood cultures in 9 cases (90%). Wright's seroagglutination was negative or inconclusive in 30% of cases. Brucella was isolated from urine in only 1 case, whereas real-time polymerase chain reaction assay in urine was positive in 9 (90%). Also, results were available in 4 hours, whereas mean time to availability of the final blood culture results was 5.8 days (range 4.5 to 7). SYBR Green I LightCycler based real-time polymerase chain reaction assay in urine samples is highly sensitive and specific, and easy to perform. It could provide the clinician with results in less than 5 hours. The technique could be a practical and useful tool for the rapid diagnosis of genitourinary complications of human brucellosis.