Identification of mycobacterial MPT-64 and ESAT-6 proteins in urogenital tuberculosis patients by real-time immuno-PCR

Abstract

Aim: Diagnosis of urogenital tuberculosis (UGTB) is difficult and there is an immediate need to develop a reliable diagnostic test. Methods: A real-time immuno-PCR (RT-I-PCR) was developed to identify a cocktail of MPT-64 + ESAT-6 in both male/female UGTB patients comprising five confirmed cases, 40 clinically suspected cases and 37 non-TB controls, from whom mid-stream urine specimens were collected, while endometrial biopsies of female patients were obtained on day 1 of their menstrual cycle. Results obtained by RT-I-PCR were compared with I-PCR/ELISA and GeneXpert. Results: A wide range (500 fg/ml–10 ng/ml) of MPT-64 + ESAT-6 was detected in UGTB specimens by RT-I-PCR, although ELISA showed a narrow range (2.5–11 ng/ml). Sensitivities of 80% and 82.2% were obtained by RT-I-PCR in clinically suspected and total UGTB cases, respectively, whereas 94.6% specificity was obtained. Concurrently, RT-I-PCR revealed significantly higher (p < 0.05–0.001) sensitivity than I-PCR/ELISA and GeneXpert. Conclusion: After improving the specificity, the authors may develop RT-I-PCR into a diagnostic kit.