Frequency and antibiotic susceptibility pattern of mycobacterial isolates from extra-pulmonary tuberculosis cases.

Objective: To determine the frequency and antimicrobial susceptibility pattern of extra-pulmonary tuberculosis in Rawalpindi.

Setting: Department of Microbiology, Armed Forces Institute of Pathology, Rawalpindi.

Methods: Between September 2000 and August 2002, 899 pulmonary and 460 extra-pulmonary specimens from suspected cases of tuberculosis were examined. The radiometric BACTEC 460 TB system was used for culture and antimicrobial susceptibility testing.

Results: Mycobacteria were isolated from 291 pulmonary specimens and 98 extra-pulmonary specimens. The frequency of extra-pulmonary tuberculosis was 25.2%. The commonest source of isolation was pus (44.9%, frequency 11.3%), followed by lymph nodes (13.3%, frequency 3.3%) and pleural fluid (13.3%, frequency 3.3%). We tested the anti-microbial susceptibility of the isolates to the four first line anti-tuberculous drugs, rifampicin, isoniazid, streptomycin and ethambutol. Of the extra-pulmonary isolates 13.3% were resistant to a single drug, 21.4% were multi-drug resistant and 9.2% were resistant to all the four drugs.

Conclusion: Increased awareness of the magnitude of the problem posed by extra-pulmonary tuberculosis is required so that appropriate control measures can be adopted.