Prevalence of multidrug resistant tuberculosis at tertiary care hospital

Background

Tuberculosis continues to plague the world and remains the major global health problem. Simultaneously the incidence of drug resistant Mycobacterium tuberculosis strains is also increasing in almost all industrialized and developing countries.

Methods

This prospective study was done at NMC, Nellore from July 2008-December 2009. Samples received at microbiology lab for acid fast staining were included in this study. Smears were stained by Ziehl-Neelsen’s technique. Samples were cultured on Lowenstein-Jensen media after processing by modified Petroff’s method and incubated according to CLSI guidelines. Identification of Mycobaterium tuberculosis was done based on morphology, nitrate reduction test and catalase test. Drug susceptibility for first line anti- tubercular drugs was performed by proportion ratio method.

Results

A total of 2031 samples were included in this study. 120 samples were smear positive by acid fast staining, 110 were culture positive for Myobacterium tuberculosis. 16 (14.5%) samples were resistant to one or more antitubercular drugs. 10 (9.09%) samples showed monodrug resistance, Isoniazid (3.63%) followed by Rifampicin (2.72%) Ethambutol (1.81%) and Streptomycin (0.90%). Isoniazid and Ethambutol resistance in one sample (0.90%). Isoniazid and Rifampicin resistance in two samples (1.88%). Three samples were resistant to Isoniazid and Rifampicin along with other drugs (2.72%). HIV co-infection among MDR-TB was 2.7%.

Conclusion

According to the present study prevalence of MDR-TB was 4.54%. Among the patients on treatment higher incidence of resistance was attributed to poor patient compliance in spite of effective DOTS programme.