Mycobacterium tuberculosis complex identification by polymerase chain reaction from positive culture in patients from Jamot and Mbalmayo district hospitals

Abstract

mycobacteria (NTM) such as Para nitro benzoic acid (PNB) inhibition tests are often time consuming. This study aim at using PCR amplification of specific markers (hupB, IS6110, IS1081, oxyR and rpoB) for more rapid detection of MTBC in positive cultures. The study was conducted in Jamot Hospital, the largest urban treatment center for tuberculosis in Cameroon and in Mbalmayo District Hospital, a small rural district hospital. Mycobacterial culture was performed on all smear positive sputa. All positive cultures were subjected to drug susceptibility testing (DST) using the indirect proportion method. On the same  way, MTBC  were differentiated from other mycobacreia using the PNP inhibition test. DNA extracted from positive cultures was subjected to PCR amplification using specific primers (hupB, IS6110, IS1081, oxyR and rpoB). Analysis of PCR products was done by agarose gel electrophoresis. A total of 79 smear positive pulmonary tuberculosis patients were enrolled at the two sites. Drug susceptibility carried out showed that among the samples analyzed, 68 (86.08%) were susceptible to all TB drugs tested, while 11 (13.92%) were resistant to at least one of them. Resistance to streptomycin was the most frequent (8.86%), followed by resistance to isoniazid (5.06%). Identification by PCR using specific markers as hupB, IS6110, IS1081, oxyR and rpoB revealed that the mycobacterium strains belonged to the MTBC.In short, identification by PCR using these specific makers  revealed that mycobacterium species responsible for pulmonary tuberculosis in patients from Jamot and Mbalmayo District Hospital  belonged to the MTBC. Also PCR technique is more rapid compared to the PNP inhibition test.
 
Key words: Mycobacterium tuberculosis complex, polymerase chain reaction (PCR), Cameroon.