Drug resistant mycobacterium tuberculosis in previously treated patients in yemen

Abstract AR

Objectives : The aims of this study are to determine the anti-tuberculosis drug resistance pattern of M.

tuberculosis complex isolated from previously treated Yemeni patients against the four common anti-tuberculosis drugs, isoniazid, rifampicin, streptomycin, and ethambutol, and to detect the emergence of multi-drug resistant strains of M.

tuberculosis in Yemen.

Methods : The 100 clinical isolates of M.

tuberculosis complex included in this study were collected from August 2001 to December 2002 from patients with positive sputum smears who had been treated previously with the four above mentioned anti-tuberculosis drugs for more than two months.

The isolates were identified by their colonial morphology, pigmentation, shape on smears, growth on cultural media, and biochemical reactions as niacin and nitrate tests.

A proportional method was used for the in vitro drug sensitivity testing of the four anti-tuberculosis drugs.

Results: Of the 100 M.

tuberculosis tested isolates, 35 (35%) were resistant to one or more drugs: 14 for one drug, 12 for two drugs, 6 for three drugs and 3 for four drugs.

The first two categories were not statistically significant (?/= 0.59 and 0.01 respectively, P>0.05), whereas, the two latter categories were statistically significant (j- 7.5 and 16.5 respectively, P<0.001).

Concerning the resistance to individual drugs, of the 100 isolates, 20 were resistant to RMP, 23 to INH, 27 to SM, and 5 to ETM.

These results were highly statistically significant (/ = 11.6, 22.3, 42, and 10 respectively, P = < 0.001).

The incidence of multi-drug resistance (against RMP and INH with or without other drugs, were found in 9 isolates of the 100 tested isolates.

This result was not statistically significant (/ = 2.04, P>0.05).

Conclusion: This study showed significant drug resistance among the studied isolates and the emergence of MDR strains of M.

tuberculosis in Yemen.

The directly observed therapy (DOTS) strategy recommended by the WHO should be introduced on a wider scale.