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Tuberculosis and more so the multi drug resistant variety has been thrust into the forefront as a serious and life threatening illness in recent years. The advent of AIDS contributes to this substantially, especially in the developed world where it had become practically non- existent. We reviewed our data over the past 20 years with a view to determine when drug resistance began to manifest in the strains.

Background: Post-transplant tuberculosis (post-TxTB) occurs in 12 to 20% of patients in India and results in the death of 20 to 25% of those patients. Prospective studies on post-TxTB are few., Methods: Renal allograft recipients were studied prospectively for 3.1 (0 to 13.9) median (range) years for incidence, manifestations, risk factors, and prognosis for post-TxTB. Kaplan-Meier analysis was used to study the survival rates. The extended Cox proportional model for time-dependent covariates was used to measure the risk factors when the hazard was nonuniform., Results: Of the 1414 patients considered for inclusion, multiple-transplant subjects (N = 37) and patients who developed pre-transplant TB (pre-TxTB; N = 126) were excluded from the study. The prevalence of post-TxTB was 13.3% (N = 166). The risk of post-TxTB when on cyclosporine (CsA) therapy was 2.5 (P = 0.0311) and 1.9 (P = 0.0430) times at < or =6 and < or =12 months, respectively, compared with patients on prednisolone plus azathioprine (PRED + AZA). The risk of post-TxTB in the presence of diabetes mellitus, chronic liver disease, and other co-existing infections [including deep mycoses, cytomegalovirus (CMV), Pneumocystis carinii pneumonia (PCP), nocardia] was 2.2 (P = 0.0011), 1.7 (P = 0.0010) and 2.4 (P < 0.0001) times, respectively. Of the 166 patients with post-TxTB, 53 patients died, and of those deaths, 17 (32%) were due to post-TxTB; 11 (65%) of the 17 had co-existing infections. The factors associated with death were HLA mismatches, PRED + AZA immunosuppression, pre- and post-TxTB, diabetes mellitus, post-transplant diabetes (PTDM), and other co-existing infections. The extended Cox model for death as the outcome variable showed the following to be significant risk factors: post-TxTB> 2 years (P = 0.0036), chronic liver disease> 6 years (P = 0.0457), PTDM> 5 years (P = 0.0729), diabetes mellitus (P = 0.0091), human lymphocyte antigen match < or =1 antigen (P = 0.0134), two to three antigens (P = 0.0448), and the presence of other co-existing infections (P < 0.0001)., Conclusions: Cyclosporine therapy is associated with early post-TxTB. Diabetes mellitus and chronic liver disease are risk factors for post-TxTB. The occurrence of both pre-TxTB and post-TxTB (>2 years) along with hyperglycemia, liver disease, and other co-existing infections are important risk factors for death.

Objective: To assess genetic diversity and drug resistance of Mycobacterium tuberculosis isolates collected at Christian Medical College Hospital (CMCH), Vellore, India, between July 1995 and May 1996., Materials and Methods: Isolates were subjected to IS6110-based restriction fragment length polymorphism (RFLP) analysis and tested for resistance to isoniazid, rifampin, ethambutol, streptomycin, and pyrazinamide, and DNA from selected strains was sequenced in regions associated with drug resistance., Results: One hundred and one M. tuberculosis isolates were collected from 87 patients with pulmonary tuberculosis. Charts of 69 patients were reviewed for history of tuberculosis illness and treatment. DNA from 29 strains was sequenced in katG, rpoB, and gyrA, and sometimes pncA regions. Analysis by RFLP revealed a high degree of genetic diversity, with no identifiable clusters of infection. Of the strains tested, 51% were resistant to at least one antibiotic, and 43% were resistant to more than one drug. There was a high rate of resistance observed in patients whose charts indicated a history of improperly administered tuberculosis treatment, whereas little drug resistance was observed in patients never previously treated for tuberculosis. Sequencing of genes associated with drug resistance revealed several previously unreported mutations in resistant strains., Conclusions: This analysis suggests that the cases of tuberculosis in the sample are largely reactivation of long-standing infections and that the drug resistance among patients in CMCH is largely acquired or secondary rather than attributable to the spread of drug-resistant strains.