Identification of Multi-drug resistant (MDR) Mycobacterium tuberculosis among Tuberculous Patients using Polymerase Chains Reaction Technique

Abstract

The present study aimed to identify and to characterize multi drug resistant Mycobacterium tuberculosis among tuberculous patients in Khartoum state using Lowenstein Jensen Proportion method and polymerase chain reaction technique(PCR). One hundred and thirty ZN positive sputum specimens were collected from patients with tuberculosis referred to different T.B. centers in Khartoum state (88 specimens from National Health Center, 42 specimens from Abu Anga and El shaab hospitals). All sputum samples were cultivated on Lj medium .119 (91.5%) samples of AFB-positive showed characteristic growth of Mycobacterium tuberculosis,while 5 isolates showed typical growth of MOTTs and 6 speciemens showed no growth. Different biochemical tests were selected , these include catalase ,nitrate ,TCH and PNB,the results of these tests revealed the following,124(100%)isolates showed negative for catalase at 68 ْC while 122(93.3%) positive at RT,108(87%) were nitrate positive ,107(86.2%) showed resistance to TCH and 119(95.9%) were sensitive to PNB. Sixty five isolates were selected randomly and subjected to PCR,the result revealed that fifty six of the isolates showed typical band of 123bp,with sensitivity of 91% comparing with cultur technique. The result of antibiotics susceptibility testing using proportion conventional method revealed that 30 (23%) of the speciemens were Rifampicin resistant, 35 (26.9%) were Isoniazid resistant and 28 (21.5%) were resistant for both drugs (MDR). In contrast, PCR assay for drug resistance showed that a resistant rate of 20 (15.3%) for Rifampicin, 30 (23%) for Isoniazid and 15 (11.5%) for both drugs (MDR). In conclusion; the rapid specific PCR for the identification of MDR M.tuberculosis, can substitute the hazardous slow conventional methods. However, multiplex and nested PCR will provide accurate reliable results.