When it comes to fighting tuberculosis (TB), some patients may not be cured by the standard combination of four or five different drugs. This may particularly be true if a patient is carrying TB bacteria that are resistant to one or more of the drugs, according to the World Health Organization (WHO).

The best strategy for controlling TB is called directly observed short-course treatment (DOTS), in which healthcare workers actually watch patients as they take several different types of medication.

This strategy has been adopted by 119 countries worldwide. Unfortunately, for many countries with TB resistant to multiple drugs, that strategy appears inadequate, according to Dr. Marcos Espinal from the World Health Organization in Geneva, Switzerland, and associates.

The investigators examined the effectiveness of the WHO TB control program in 6,402 patients from five participating countries, according to the report in the May 17th issue of The Journal of the American Medical Association.

More than 20% of new TB cases and nearly 45% of retreated TB cases were resistant to one of the initially-used drugs, the authors report. Nevertheless, 83% of the new cases and 57% of the retreated cases responded successfully to treatment.

New patients whose TB was resistant to at least one drug were more than five times as likely to experience treatment failure as patients whose TB was sensitive to all drugs, the investigators note. Those whose TB was resistant to several drugs were 15 times more likely than others to have treatment failure.

Results were similar for retreated patients, who were more than three times as likely to fail if they had any drug resistance and five times as likely to fail with multiple drug resistance, the researchers write.

According to Espinal's team, these findings suggest that the current WHO policy needs to be revised in settings with high rates of TB resistant to multiple drugs. In particular, they advise early identification and retreatment of patients who have failed medical therapy, as well as modification of the antituberculosis regimen according to the sensitivity of the TB in the area.

In a related editorial, Dr. C. Robert Horsburgh from Boston University in Massachusetts, writes that ``it is imperative that new treatment strategies be devised for patients with multidrug-resistant TB in these countries. However, it is also essential that an effective DOTS program be ensured before beginning a multidrug-resistant TB treatment program.''

Horsburgh warns, ``The genie of multidrug-resistant TB is irreversibly out of the bottle. Containing multidrug-resistant TB is a public health emergency.''