Abstract:
|
Background:
This study was conducted in Kassala Teaching Hospital, Kassala State, Sudan
(January 2006–June 2008) to determine the rate of mycobacterium drug resistance to
anti-tuberculous treatment and to explore the genotype of
Mycobacterium tuberculosis
resistant isolates using
rpoB
gene.
Methods:
53 isolates of mycobacterium isolated from pulmonary tuberculosis (PTB) patients
from Kassala State were subjected to drug susceptibility testing (DST) to anti-tuberculous
drugs; 10
M. tuberculosis
complex (MTBC) resistant isolates were subjected to polymerase
chain reaction (PCR), and commercially the amplified DNA was sequenced.
Results:
DST detected resistance in 23/53 (43.39%) isolates, among which rifampicin had a
high number of resistant isolates (13/23), followed by streptomycin (11/23), and multi-drug
resistance was detected in 5 isolates.
DNA sequence analysis of 10 MTBC-resistant isolates detected variations within and out-
side the rifampicin resistant determining region (RRDR). Variation within RRDR was
detected at positions 512 (AGC/ATC, Ser/Ile), and 528 (CGC/CTC, Arg/Leu). Outside the RRDR
region variations were detected at positions 498 (GTG/GGG, Val/gly), 488 (ACA/ACC, Thr/
Thr), which is a silent mutation. Insertions were observed at positions 484, 496 (GTG/GTGA,
CGG/CAGG, respectively). Deletion was observed at position 487 (ATC/_TC).
Discussion and conclusion:
This study revealed that high resistance to rifampicin was asso-
ciated with various point mutations in and out of the RRDR of the
rpoB
gene. Molecular
methods are needed for early detection of TB disease and drug resistance. |