Prevalence of multidrug resistance tuberculosis identified by bactec and PCR techniques using rifampicin as a surrogate marker in Nairobi Hospital
The emergence of multidrug-resistant strains of M.tuberculosis threatens tuberculosis (TB) control and prevention efforts. It is so far the most severe form of bacterial resistance with a high mortality rate. Lack of proper TB control treatment programs often leads to improper and incomplete chemotherapy, which is one of the major factors contributing to MDRTB out breaks. The aim of the study was to determine the prevalence of MDRTB by both radiometric Bactec 460 TB system and polymerase chain reaction (PCR) amplification technique using riampcin as a surrogate marker. The study also determine the prevalence of MTB complex by both smear microscopy and culture by Bactec. The study also looked in to some of the factors associated with development of resistance. Information on patients were obtained through a questioner, which was given to the clinicians to fill. Seven hundreds samples, both pulmonary and extra-pulmonary were collected prospectively over a period of six months. They were all processed and cultured by Bactec radiometric technique. Smears were made, stained by Zielh-Neelsen (ZN) technique and examined microscopically. Identification and drug sensitivity testing was done by the same method on all MTB isolates. Out of 700 samples processed, 91 (13%) were positive for tuberculosis by culture and 46 (6.6%) were positive by smear microscopy. On identification, 86 (94.5%) isolates were MTB complex and 5 (5.5%) were Mycobacterium other than tuberculosis (MOTT). Eight (8) out of 81 MTB isolates (9.3%) were identified as MDRTB by both techniques. This shows an increase in prevalence of MDRTB from 3% to 9.3%, while that of MTB complex declined from 23% to 13%. These figures may not represent the national figures TB prevalence in Kenya as the hospital takes care of able patients. Smear microscopy detection technique is insensitive and is likely to miss half of TB cases (smear negative TB cases). It is very difficulty to detect TB from extra-pulmonary sites by smear microscopy technique. Eighty seven (87.5%) of the MDRTB was secondary infection and were HIV positive. HIV and incorrect treatment plan were the factors mostly associated with development of drug resistance TB. Twice the men were more affected than women.