Earlier this week the CDC released a report showing the tuberculosis bacterium is exhibiting ever increasing resistance to conventional treatment. Since the mid 1960’s, the vast majority of tuberculosis cases have been effectively treated with a combination of Isoniazid (INH) and Rifampin. That landscape is changing, and threatening efforts to eradicate a disease that infects almost 9 million people and kills 1.4 million each year.
It is now estimated the overall incidence of multiple drug resistant tuberculosis (MDR) worldwide (i.e. cases that do not respond to INH and Rifampin) exceeds five percent, with prevalence up to ten times higher in some places. Even more alarming is the fact that almost half of MDR cases also show resistance to at least one second line drug in countries frequently visited such as Peru, the Philippines, Russia, South Africa, and Thailand. In recent years, researchers have designated such cases as extensively drug resistant tuberculosis (XDR). These strains show resistance not only to INH and Rifampin, but also to powerful antibiotics such as fluoroquinolones and aminoglycosides. XDR tuberculosis has been reported in 77 countries.
Further complicating matters is the fact that treatment options for MDR and XDR tuberculosis patients are “limited, expensive and toxic” according to Tom Evans, Chief Scientific Officer at Aeras, a nonprofit group working to develop new tuberculosis therapies. Medications for drug resistant TB can cost up to 200 times more than for normal tuberculosis and can cause severe side effects such as deafness and psychosis. Unlike conventional treatment, which usually takes less than a year to complete, drug resistant tuberculosis management may take up to two years.
Resources to control drug resistant tuberculosis are limited, particularly in developing countries where the incidence is higher than in Europe and the United States. Those with active tuberculosis cough and sneeze and spread germs through the air. Experts maintain that people affected can easily infect 10 to 15 new victims a year. Without adequate treatment, drug resistant tuberculosis cases will reverse global gains made over the last 60 years to eliminate the disease.
Photo by Microbe World.
