An overview on drug resistant tuberculosis in India

Tuberculosis remains one of the major public health problems in India. It has been estimated that about 30% of the world’s tuberculosis patients are residing in India1. Since the control measures for tuberculosis such as BCG vaccination and chemoprophylaxis seem to be unsatisfactory, treatment with anti-tuberculosis drugs becomes inevitable. In recent years, the treatment of tuberculosis has been threatened by the increasing number of patients with drug resistant tuberculosis. Although the phenomenon of drug resistance to Mycobacterium tuberculosis was observed even in the early days of streptomycin usage, the current threat is due to the emergence of strains resistant to the potent bactericidal anti-tuberculosis drugs such as isoniazid and rifampicin which are used in the tuberculosis control programmes

Status of drug resistance in tuberculosis after the introduction of rifampicin in India.

The current threat in tuberculosis treatment lies on the fact of emergence of strains resistant to two most antituberculous drugs, isoniazid and rifampicin. Drug resistance to TB may be classified as primary and acquired. Causes of drug resistance are inefficient administration of effective treatment, poor case handling, use of sub-standad drugs, ignorance of healthcare workers, etc. Multidrug resistant TB (MDR-TB) prevalence (median) in new case is highest (14.1%) in Estonia. Studies undertaken in different regions in India by Tuberculosis Research Centre (TRC) during 1997-2000 revealed acquired MDR-TB resistance levels of 25- 100%. The key to successful prevention of the emergence of drug resistance remains adequate case finding, prompt and correct diagnosis and effective treatment of infective patients

Two speedier phenotypic methods on drug susceptibility testing of Mycobacterium tuberculosis

The introduction of drugs beginning with streptomycin for the treatment of tuberculosis (TB) and the subsequent emergence of drug resistant Mycobacterium tuberculosis strains has made the testing for susceptibility of the latter a basic necessity. The World Health Organization (WHO) recognized the importance of these laboratory issues even in the early sixties and conducted extensive studies by involving laboratories from both disease endemic developing countries (DEDCs) and disease non endemic countries to standardize the susceptibility (DEDCs) testing procedures for M. tuberculosis for all the three methods that were in vogue, viz., absolute concentration method, resistance ratio method (RR) and the proportion susceptibility testing method (PST)

Newer Methods For The Diagnosis of Childhood Tuberculosis

For an infectious disease like tuberculosis, which is transmitted by aerosol droplets, the rapid and accurate detection of M.tuberculosis is essential, not only to speed up the treatment of the patient but also to control the spread of the disease. Tuberculosis in childhood occurs with different manifestations. All these forms of tuberculosis, except when cavitation occurs in pulmonary tuberculosis, are paucibacillary in nature. For this reason, even though at the present time bacteriological confirmation is still the final proof of tuberculous disease, it is difficult to obtain. Depending on the form of disease manifestation, several specimens like sputum and/or gastric lavage, as children are often unable to produce sputum, lymph nodes and other biopsy specimens, pus, ascitic fluid, pleural or cerebrospinal fluid (CSF) need to be collected. If delay is anticipated, relevant specimens may be collected in suitable transport medium for sending it to the laboratory. There are two ways to address diagnosis of tuberculosis. The direct approach is concerned with the detection of the bacteria by microscopy or culture, detection of tuberculostearic acid (bacterial wall component), detection and identification of mycobacterial antigen by the use of polyclonal or monoclonal antibodies, analysis of lipid composition by chromatography, and the detection of DNA or RNA of mycobacterial origin by hybridization with a DNA probe with or without amplification of nucleic acids. The indirect approach relates to measurement of host immune response against the mycobacteria. This includes humoral immunity via the detection of antibodies against the bacteria and cellular response via skin tests

Study on environmental mycobacteria obtained from South Indian BCG trial area

Non Tuberculous Mycobacteria (NTM) are widely distributed in our environment and man is being constantly exposed to these organisms by various means(l). This immunologically important contact may be involved in the modulation of immunity to tuberculosis. Prior sensitization with NTM has beep considered as one of the explanations for the failure of BCG to provide protection against tuberculosis in the South Indian trial. Tuberculosis surveys using PPD-B have shown that in this area, prevalence of sensitization reaches 90%. in persons by age 14(2). Identification of NTM isolates from sputum samples in this area has shown M.avium-intracellulare and M.scrofulaceum to be among the important species(3). However. the actual distribution profile of the various NTM species in the environment of this area is not known

Productivity, water use efficiency and economics of system of rice intensification (SRI) in Nichabanadhi sub basin of southern Tamil Nadu

Four hundred and sixteen on-farm demonstrations on system of rice intensification (SRI) were carried out in 350 hectares of farmer’s fields in Sankarankovil, Vasudevanallur and Kuruvikulam blocks of Tirunelveli district of Tamil Nadu from 2008-09 to 2010-11 under Tamil Nadu – Irrigated Agriculture Modernization and Water Bodies Restoration and Management (TN-IAMWARM) project. Two methods viz., SRI and conventional were compared. The results revealed that the adoption of SRI favorable influenced yield attributes and yield of rice. The maximum grain yield (8222 kg ha-1) obtained from SRI which was higher than conventional method (6534 kg ha-1). Higher grain yield coupled with substantial water saving to the tune of 37.1 per cent resulted in higher water use efficiency of rice under SRI method. The best net income ( Rs. 50, 587) and benefit: cost ratio (3.64) were also associated with SRI than conventional method of rice cultivation. The cost of cultivation was comparatively lesser in SRI which re-sulted in gaining an additional income of Rs. 8080 ha-1 as compared to conventional method of rice cultivation. The system of rice intensification (SRI) proved its benefits in this basin

Laboratory diagnosis of childhood tuberculosis (Editorial)

Tuberculosis in childhood occurs with different manifestations. All these forms of tuberculosis, except when cavitation occurs in pulmonary tuberculosis, are paucibacillary in nature. For this reason, even though at the present time bacteriological confirmation is still the final proof of tuberculous disease, it is difficult to obtain. Depending on the form of disease manifestation, several specimens like sputum and/or gastric lavage, as children are often unable to produce sputum, lymphnodes and other biopsy specimens, pus, ascitic fluid, pleural or cerebrospinal fluid (CSF) need to be collected. If delay is anticipated, biopsy specimens may be collected in suitable transport medium for sending it to laboratory

Use of vancomycin in the culture of Mycobacterium tuberculosis from gastric lavage

Background & objectives: Earlier studies from the Tuberculosis Research Centre, Chennai, on culture of Mymbocterium (tuberculosis from gastric lavage (GL) specimens in selective Kirchner's medium (SK) resulted in a loss of 60 per cent culture results due to contamination with aerobic spore bearers (ASB). Addition of vancomycin to SK (SKV) effectively reduced the contamination rate to 20 per cent. The objective of the present study was to further reduce the contamination by collecting the specimens in bottles containing vancomycin, thus providing continuous exposure of the sample to the drug, which is bactericidal to ASB. Methods: One thousand GL specimens coIIected from children in vancomycin containing bottles were decontaminated and cultured in SK medium, with and without vancomycin, subcultured on Lowenstein Jensen (W) medium and the culture results compared. Results: The contamination of cultures in SK and SKV was 15 and 4 per cent respectively when the specimens were collected in bottles containing vancomycin compared to 60 and 20 per cent contamination reported in the earlier studies. interpretation & conclusion: The reduced contamination in SK and SKV is most likely due to the collection of sample in vancomycin containing bottles. Although a concurrent comparison of samples processed in vancomycin free conditions would have been ideal, it could not be done due to practical difficulties. The study thus confirms the value of vancomycin as a major deterrent for contamination due to aerobic spores and better results can be obtained if vancomycin is used in sample collection bottles, transport media and liquid culture media used in mycobacteriology laboratories particularly in humid and tropical environment

Rapid methods for culture of mycobacteria

Tuberculosis remains a major health problem in many parts of the world. Rapid and accurate detection of M. Tuberculosis is essential not only to speed up the treatment of patients but also to control the disease in the population. Bacteriological investigations play a key role in the diagnosis of different forms of tuberculosis

Tuberculosis: Epidemiology and Diagnosis

Despite the discovery of the tubercle bacillus more than a hundred years ago, and all the advances in our knowledge of the disease since then, tuberculosis still remains one of the major health problems facing mankind, particularly in developing countries. About one third of the World’s population is infected with M. tuberculosis. It is estimated that currently there are about 9 million new cases of tuberculosis with 3 million deaths worldwide. More people die of tuberculosis than any other infectious disease. Death from tuberculosis comprises 25% of all avoidable deaths in developing countries. Ninety five per cent of tuberculosis cases and 98% of tuberculosis deaths are in developing countries and 75% of tuberculosis cases are in the economically productive age group1. Geographically, the regions with the highest prevalence and infection rates are the eastern fringe of Asia, the Indian subcontinent, the South eastern part of Africa, South-east Europe, Central America and the Western part of the South America. The WHO has declared a global emergency in 1993 with respect to reemerging menace of tuberculosis