Paul T. Davidson

A Population-Based Survey of Tuberculosis Symptoms: How Atypical Are Atypical Presentations?

There is scant information on tuberculosis symptoms from a population-based perspective. We prospectively identified 526 tuberculosis cases reported in Los Angeles County over a 6-month period. Of 313 persons who completed our questionnaire, 72.7% had cough, 48.2% for >2 weeks, and 52.3% had fever, 29.4% for >2 weeks. Among those with pulmonary disease, only 52.4% had cough for >2 weeks. In a multivariate model, persons with significant symptoms typical of tuberculosis disease (defined as cough or fever for >2 weeks, weight loss, or hemoptysis) were associated with lack of medical insurance, negative tuberculin skin test, diagnosis during a process other than screening, and non-Asian race. In summary, classic symptoms of prolonged cough and fever are insensitive predictors of tuberculosis. Our data suggest that Asians may need to be added to the list of persons who present with tuberculosis atypically. We believe that the Infectious Diseases Society of America guidelines for community-acquired pneumonia should emphasize demographic features in addition to clinical symptoms when suggesting which patients require evaluation for Mycobacterium tuberculosis.

Tuberculosis in patients with HIV infection.

In the past 5 years, there have been significant advances in the understanding of the pathogenesis of TB in people infected with HIV and in the approach to diagnosis, treatment, and prevention in patients with HIV. Nucleic acid amplification tests and restriction fragment length polymorphism can contribute to the clinical management of TB patients. New guidelines are available for the treatment of active and latent TB infection in patients with HIV.

Cross-resistance in M. tuberculosis to kanamycin, capreomycin and viomycin

Drug resistant mutants to streptomycin, kanamycin, viomycin, capreomycin, and rifampicin were isolated from four strains of Mycobacterium tuberculosis. The mutants isolated from each parent were then tested for evidence of development of cross-resistance to other drugs. There was no cross-resistance between either streptomycin or rifampicin and any of the other drugs. Complete cross-resistance between viomycin and capreomycin was found. Cross-resistance between kanamycin and capreomycin, and kanamycin and viomycin was variable. A review of the medical histories of 27 patients with kanamycin-resistant tubercle bacilli indicated that cross-resistance with capreomycin and viomycin occurs, but is unpredictable. Because of this variability in cross-resistance and the fact that kanamycin is a more toxic drug than capreomycin, it is suggested that capreomycin be used in the first retreatment regimen for tuberculosis when streptomycin resistance has been demonstrated.

Rifampin in the Treatment of Drug-Resistant Mycobacterium tuberculosis Infections

Abstract Thirty patients with far advanced, multiple-drug-resistant pulmonary tuberculosis were treated with rifampin for four to 12 months. The regimens included rifampin in a daily dosage of 600 mg combined, whenever possible, with one or more other antituberculosis drugs to which in vitro susceptibility had been demonstrated. Quiescent status was achieved in 21 (70 per cent) of the patients, whereas in nine (30 per cent) cultures remained positive, or the patient relapsed after having initially achieved sputum negativity. The shortest duration of rifampin therapy producing culture conversion was 10 days, and the longest 90 days, with a mean of 40. In seven of the nine failures rifampin resistance developed, and all but one of these patients received rifampin without a satisfactory companion drug because of previously acquired resistance. However, 65 per cent of the patients receiving rifampin as the sole therapy attained quiescent status; to date only two have relapsed. No toxicity attributable to rifa...

Acquired resistance to rifampicin by Mycobacterium kansasii

Two patients with Mycobacterium kansasii infection of the lung had organisms sensitive to rifampicin. Following treatment, essentially with rifampicin alone, the patients began to excrete organisms completely resistant to rifampicin. The ability of M. kansasii to acquire resistance to rifampicin during treatment has been clearly demonstrated. This reinforces the need to treat this infection with an adequate multiple drug regimen.

Antituberculosis activity of 6 cyclo-octylamino-5,8-oquinolinequinone (CQQ)

A new compound, 6 cyclo-octylamino-5,8-quinolinequinone (CQQ), a dual analogue of vitamin K and coenzyme Q, was effective against several drug-susceptible and drug-resistant strains of Mycobacterium tuberculosis. In vitro studies indicated the bactericidal nature of its action at 1 microgram/ml. Pulse exposure studies using M. tuberculosis H37Rv showed that a growth lag period of 96 hours resulted with exposure to 1 microgram/ml for 24 hours or longer.