An X-ray of a turbercular patient from The Virtual Hospital © 1992-1997 the University of Iowa. All rights reserved.
Mycobacterium tuberculosis. Courtesy of University of Minnesota Academic Health Center. Dept of Microbiology; Teaching Lab, University of Minnesota.
Once upon a time, tuberculosis -- a bacterial infection of the lungs and occasionally other body parts -- was highly responsive to antibiotics. No longer.
TB remains a global menace, afflicting 7.5 million people, according to the World Health Organization, and killing as many as 2.5 million people each year. That makes it the leading cause of death among infectious diseases. TB is particularly severe in AIDS patients, those who can't afford medical care, and patients who disobey doctors. According to the WHO, the pathogen infects one-third of all humans.
Perhaps most ominous, some strains of the disease-causing organism, Mycobacterium tuberculosis, have become resistant to a series of antibiotics. So now just having enough money to buy antibiotics no longer guarantees a cure.
New York City is the epicenter of the TB infection, with 17 percent of the national cases in 1992. In 1992, Harlem had a TB rate of 222 per 100,000 people, more than 20 times the U.S. average. New York is also headquarters of the drug resistance problem, with 61 percent of the national caseload in 1991.
The root of the problem
The problem was that patients were not taking their medicine, says Frantz Medard, director of the TB program at Harlem Hospital. The treatment period ranges from six months -- for an otherwise healthy person with a bug susceptible to antibiotic -- to two years for an AIDS patient. Yet it's very clear that a proper course of treatment can cure the disease, experts say.
Ironically enough, effective treatment is a major cause of the resistance problem, he says. "Within two months, the patient will start feeling well, and stop taking the drugs. But that just causes more problems, because it offers the organism a chance to have the emergence of multi-drug resistance." As the pathogen randomly mutates, the presence of the antibiotic puts selective pressure on it, allowing only the resistant forms to survive. Indeed, it may mutate several times in several places, thus gaining multiple resistance. And anyone who is infected with this strain starts off with an antibiotic-resistant disease.
Furthermore, TB is essentially a disease of poverty, which, at Harlem Hospital, means many patients have AIDS, drug addiction or are homeless. People with these problems, Medard says, "have different priorities, and their health may come last."
The frightening rise in drug-resistant TB in New York City in the early 1990s spurred the city to develop a program called "directly observed therapy," or DOT. Essentially, the idea is not to hand out the drugs, but to watch patients take them. To make the program more humane and effective, Harlem Hospital uses a "family model" of treatment. "Patients are embraced by the staff, they are respected," Medard says. Presents for birthdays and celebrations for patients who haven't missed a dose help boost morale and the success rate.
And how does it work? According to research published in 1996 (see "Directly Observed Therapy for Tuberculosis: The Harlem Hospital Experience" in the bibliography) patients made 91 percent of their visits, and 88 percent completed the therapy (as compared to just 11 percent in an unobserved therapy study from the late 1980s). Although New York's epidemic has abated, about 5 percent of patients at Harlem Hospital have drug-resistant TB, and about 2 to 3 percent have strains that are resistant to several drugs.
The slow decline in New York's TB rate is entirely due to the establishment of DOT clinics, Medard says, adding that success is not a reason to discontinue funding, but rather a reason to continue it.
The larger picture
At the end of the four-year study, 85 percent of the 1,967 patients who survived had completed treatment, a strong testimony to the ability of rural shopkeepers and health workers to bring the therapy to the patient. (See "Directly Observed Therapy for Tuberculosis in Rural South Africa" and "Tuberculosis Control in Resource-Poor Settings" in the bibliography).
Want to look at a picture of the flu virus.
But can countries with less money for health programs use this relatively expensive technique for curing tuberculosis and preventing the emergence of drug-resistant strains? Surprisingly, the "watch-them-gobble-the-pills" technique has worked well in rural South Africa. In the hilly region where the test was done, 58 percent of TB patients also were infected with HIV, the AIDS virus. The treatment supervisors were entrusted with delivering the twice-weekly dose during the six-month course of treatment. Some of the supervisors were clinic staffers, more were shopkeepers.
Is there a way to fix the antibiotic resistance problem before some little bug fixes us?
