ISOLATION AND IDENTIFICATION OF MYCOBACTERIUM TUBERCULOSIS AND STUDY OF MULTIDRUG RESISTANCE (MDR-TB)
Dr. Mothanna A. S. Almahdawi, Dr. Ahmmed A. Mankh* and Mohammed Mustfa Kdban
ABSTRACT
The current study aimed to monitor and control the multidrug resistance of Mycobacterium tuberculosis bacteria isolates and to detect its prevalence. The study was conducted at the Institute of Chest & Respiratory Diseases / Baghdad. Different clinical samples were collected from 500 patients to detect the presence of Mycobacterium tuberculosis bacteria by using conventional methods. The direct microscopic examination of Zeihl-Neelsen stained smears showed that 64 (12.8%) out of 500 of the samples were positive for the bacteria. All samples were cultured on Lownstein Jensen (L.J) medium, and
90(18%) of them showed true growth of tuberculosis bacteria. Microscopic examination and culture on Lownstein Jensen medium of sputum sample showed the highest positive percentage (15.9% and 23.1%) respectively, and the results of the biochemical and differential tests showed that all the isolates belonged to M. tuberculosis bacteria. No significant differences were found in the incidence of tuberculosis between males and females (51% and 49%) respectively, while significant differences (P<0.01) were shown in the incidence of the disease among different age groups 23% in the age group (21-30) years followed by 22% in the age groups (31-40) and (41-50). The sensitivity of all tuberculosis isolates (90 samples) were tested against the first-line anti-tuberculosis drugs (streptomycin, rifampicin, isoniazid and ethambutol) by using the proportion methods, which showed that 53.35% (38 out of 90 isolates) were resistant to those drugs, and 30% (27% isolates) were resistant to one of them, while 12% (11 isolates) were resistant to more than one of these drugs, whereas 11.1% (10 isolates) showed TB multi-drug resistance characteristics (MDR-TB). The highest resistance of the isolates was to isoniazid (38.9%) followed by (25.6%) to rifampicin followed by (17.8%) to streptomycin, while the lowest resistance (11.1%) was to ethambutol with highly significant differences at (P <0.01). The current study showed a real problem was found in the resistance of TB bacilli to antibiotics, because of the high percentage of isolates of these bacteria which resisted the first line anti-tuberculosis drugs. The study also found that Isoniazid and Rifampicin had the highest resistance, which leads to a real risk to the development of MDR-TB isolates in Iraq.
Keywords: Mycobacterium tuberculosis, isolation, identification, multidrug resista.
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