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.

In vitro susceptibility testing of Mycobacterium tuberculosis strains to trifluoperazine.

The presence of calmodulin-like protein (CAMLP) has been demonstrated in mycobacteria and it has been observed that there is a positive correlation between levels of CAMLP, phospholipids as well as lipids and growth. Thus the use of trifluoperazine, which is a calmodulin antagonist, would inhibit the growth of mycobacterial cells. The authors carried out in vitro susceptibility testing of Mycobacterium tuberculosis strains to trifluoperazine with their minimum inhibitory concentrations (MIC) determination. 70 strains of M. tuberculosis isolated from cases of pulmonary as well as extrapulmonary tuberculosis were included. The following antimycobacterial drugs: streptomycin, isonized, rifampicin, ethambutol were tested on Lowerstein and Jenson (LJ) slopes using the resistance ratio method and the proportion method for pyrazinamide testing. All strains and the control H37RV were cultured into Youmans and Karlson's liquid medium and MICS were determined for trifluoperazine. Trifluoperazine MICs ranged between 8-32 microg/ml for strains susceptible to routine antimycobacterial drugs while strains resistant to streptomycin and isoniazid had lower MIC values, between 8-16 microg/ml. As trifluoperazine is already in human use for psychotic disorders, its antitubercular activity could pave the way for human trials as an antitubercular drug.

Effect of trifluoperazine, a potential drug for tuberculosis with psychotic disorders, on the growth of clinical isolates of drug resistant Mycobacterium tuberculosis.

The effect of the antipsychotic drug trifluoperazine (TFP) on the in-vitro growth of 50 clinical isolates of Mycobacterium tuberculosis was tested. Of these isolates, 29 were susceptible to all five of the antitubercular drugs isoniazid, rifampicin, streptomycin, ethambutol and pyrazinamide, and 21 were resistant to one or more of the five drugs. The minimum inhibitory concentration (MIC) of TFP was 4 microg/ml for 40% of both the susceptible (12/29) and resistant (8/21) isolates and 8 microg/ml for 55% (16/29) and 48% (10/21) of the susceptible and resistant isolates respectively. Further analysis of the data for resistant isolates indicated that the MIC of TFP was 4 microg/ml and 16 microg/ml respectively for 50% (4/8) and 75% (6/8) of the isolates resistant to one drug only from isoniazid, streptomycin or pyrazinamide. Of the nine isolates resistant to two drugs, isoniazid and streptomycin, the MIC was 4 microg/ml for 33% (3/9) and 16 microg/ml for 80% (7/9). The MIC of TFP for two isolates resistant to the three drugs isoniazid, rifampicin and streptomycin was 8 microg/ml for one and 32 microg/ml for the other. Of two isolates resistant to all five drugs, it is of interest to note that the MIC of TFP was only 4 microg/ml for one but 32 microg/ml for the other. Because the above MICs are for TFP as a single drug, it would be desirable to study the antitubercular activity of the serum of tuberculosis patients with psychotic problems receiving regular antitubercular therapy supplemented with TFP at its recommended and tolerated dose.

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.

Trifluoperazine and CEF-allicin from garlic (Allium sativum) as potential new antitubercular drugs active against drug resistantMycobacterium tuberculosis.

Trifluoperazine (TFP) and a compound called CEF-allicin purified from garlic (Allium sativum) possess antitubercular activity against both drug susceptible and resistant clinical isolates ofMycobacterium tuberculosis. They are bactericidal in nature with multiple sites of primary action. This new use for known drug TFP was based on our observation that mycobacteria have calmodulin like protein which regulates their metabolism and a calmodulin antagonist has antitubercular activity. The minimum inhibitory concentration (MIC) of TFP againstM. tuberculosis was 4-5 µg/ml. It inhibited considerably by 6hrs, the synthesis of total lipids from(14)C-acetate and proteins and DNA as judged by the uptake of(14)C-glycine and(3)H-thymidine respectively by the bacilli. With 50 clinical isolates from our hospital at Delhi, the MIC was 4µg/ml, for 40% and 8µg/ml, for 50% of the isolates susceptible as well as resistant to one or more of the five drugs isoniazid, rifampicin, streptomycin, ethambutol and pyrazinamide. The MIC of CEF-allicin was 25µg/ml, for bothMycobacterium tuberculosis and isoniazid resistant clinical isolate TRC-C 1193. It inhibited in 6hrs or less the synthesis of total lipids completely and proteins and DNA ofM. tuberculosis from its labeled precursors almost completely.

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.