Characterisation & drug susceptibility patterns of extrapulmonary mycobacterial isolates.

BACKGROUND & OBJECTIVES: There is a paucity of information on extrapulmonary tuberculosis as much of the attention is focussed on pulmonary tuberculosis. This prospective study aimed at identification and characterisation of mycobacterial isolates from extra pulmonary sites and the evaluation of the drug susceptibility patterns of Mycobacterium tuberculosis isolates from extrapulmonary sites using the conventional method and the E-test. METHODS: A total of 350 specimens from patients of extrapulmonary tuberculosis with varied presentation, were studied. Speciation and characterisation of isolates were done on the basis of growth and biochemical characteristics. Drug susceptibility testing for M. tuberculosis isolates was done by proportion method for isoniazid, rifampicin, ethambutol and pyrazinamide, whereas resistance ratio method was used for streptomycin. E-test (AB Biodisk, Sweden) was carried out to compare susceptibility patterns of the M. tuberculosis isolates for isoniazid and rifampicin with the conventional method. RESULTS: Thirty two of 350 (9.14%) patients clinically suspected to have extrapulmonary tuberculosis were culture positive for mycobacteria. On characterisation, 20 of the 32 isolates were identified as M. tuberculosis and 12 as non-tubercular mycobacteria (NTM) with 5 of the 12 being Mycobacterium avium complex. Among M. tuberculosis isolates both initial and acquired resistance was highest for streptomycin followed by isoniazid, rifampicin and ethambutol. No strain showed resistance to pyrazinamide. Two strains were found to be multidrug resistant. Drug susceptibility patterns by conventional method corroborate with the E-test results. INTERPRETATION & CONCLUSION: This study shows that the characterisation and species identification of mycobacterial isolates along with drug susceptibility testing help in better understanding of extrapulmonary tuberculosis. E-test had the advantage of being rapid and simple without need for additional equipment.

HIV associated chronic atypical osteomyelitis by mycobacterium fortuitum--Chelonae group--a case report.

In developing countries where tuberculosis is endemic, the HIV patients have tuberculosis as one of the major opportunistic infections. Commonly M. tuberculosis, M. Avium-intracellular are the causative agents of pulmonary, extra-pulmonary and disseminated infection in AIDS patients. Here is a report of a 32 year old HIV positive male who presented as chronic atypical osteomyelitis of right tibia. Core biopsy confirmed the diagnosis by histopathology, direct microscopy and culture of M. fortuitum-chelonae group identified by the biochemical tests. TB IgG ELISA was strongly positive. ELISA for HIV antibodies was reactive on three occasions. Western blot was positive for HIV-1 antibodies. Patient responded well to ciproflox and antitubercular treatment and is currently under a follow up.

Cytologic diagnosis of tuberculous lymphadenitis in children by fine needle aspiration.

One hundred consecutively diagnosed cases of tuberculous lymphadenitis in children have been analysed retrospectively. All cases were stained by May Grunwald Giemsa for cytomorphology and Ziehl Neelsen stain for acidfast bacilli (AFB). In 52 cases the material was sufficient and AFB cultures were possible. A diagnosis of tuberculosis was made when smears showed epithelioid cell granulomas or AFB on either smears or culture. M. tuberculosis and atypical mucobacteria were cultured in 26 and 3 cases respectively. In 6 cases the diagnosis of tuberculosis would have been missed but for culture studies, the cytologic smears were necrotic and stains for AFB negative.

R plasmids from clinical and environmental Klebsiella pneumoniae.

A total of 200 strains of K. pneumoniae, 150 from clinical and 50 from hospital environmental source were studied for antibiotic resistance pattern. The strains from clinical source showed higher incidence of drug resistance as compared to environmental strains. 50 clinical and 32 environmental multidrug resistant strains were tested for R plasmids. The biogroup 1 showed higher incidence of autotransferring and non autotransferring R plasmids.