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

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

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

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.

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.

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