Abstract:
This study aimed to identify and characterize Mycobacterium tuberculosis
among tuberculous patients in Khartoum state by using polymerase chain
reaction (PCR).
Sputum Specimens were collected from Abu Anga Hospital, Alsha’ab
Teaching Hospital and Tuberculosis Reference Laboratory. Patients were
consented and informed. All sputum samples that showed AFB-positive
results were included. 66 (93%) samples of AFB-positive showed typical
growth of Mycobacterium tuberculosis.
Cultural properties of all isolates of Mycobacterium tuberculosis complex on
Lowenstein Jensen medium at 37°C were almost the same and all colonies
showed appearance of Mycobacterium tuberculosis complex ( dry, rough
and pale yellow ).
Out of 71 samples, 57 (80.2%) of the isolates were Mycobacterium
tuberculosis complex organisms, biochemical tests showed 68 (95.8%) were
sensitive for Para-nitrobenzoic acid ( growth was inhibited by PNB); 56
(78.9%) were resistant to Thiophene – 2 – Carboxylic Acid Hydrazide TCH;
68 (95.8%) were positive for nitrate reduction and 65 (91.6%) isolates were
catalase negative at 68°C. while 5 (7.1%) revealed no growth.
Sixty six Mycobacterium tuberculosis complex isolates were subjected to
PCR. Fifty two (78.8%) isolates showed a band typical in size ( 123 bp ) to
the target gene ( IS 6110 ) as indicated by the standard DNA marker.
.Fourteen (21.2%) isolates were negative
This results revealed clearly the importance of conventional methods
including Z.N stain and culture techniques in the diagnosis of TB especially
if there is other invaders like Mycobacteria other than tuberculosis are
.suspected
