TB

Public health officials are concerned about the implications of the first U.S. case of extremely drug-resistant tuberculosis, diagnosed in a 19-year-old Peruvian who is visiting here to study English, Homeland Security Today reported Dec. 29.

Oswaldo Juarez contracted the extremely drug-resistant XXDR-TB in 2007 without having had tuberculosis before. This form of drug-resistant TB is virtually impervious to all the drugs that are used to treat the disease.

Elsewhere, scientists have identified a strain of antibiotic-resistant tuberculosis that is resistant to rifampin, the front-line antibiotic to treat TB. The rifampin-resistant strain was identified in a patient in China and is described in a study that will appear in the January issue of The International Journal of Tuberculosis and Lung Disease.

The World Health Organization says multidrug-resistant TB (MDR-TB) is becoming especially dangerous because many patients do not adhere to their six-month TB treatment regimen.

The WHO reported, “TB can usually be treated with a course of four standard, or first-line, anti-TB drugs. If these are misused or mismanaged [that is, when drugs are taken in the wrong combination, are fewer than those prescribed, or are taken in insufficient doses or not at the proper time], multidrug-resistant TB can develop.”

And “if these drugs are also misused or mismanaged, extensively drug-resistant TB [XDR-TB] can develop.”

“There is probably no difference between the speed of transmission of MDR-TB or XDR-TB and those of any other forms of TB,” the WHO said. “The spread of TB bacteria depends on factors such as the number and concentration of infectious people in any one place and the time of exposure, along with the presence of people with a higher risk of being infected, such as those with HIV.”

Public health officials have been watching for cases of TB during the H1N1 influenza pandemic because of concerns that people most vulnerable to the pandemic strain of flu could also more easily be infected with TB because of their compromised immune system.

XDR-TB is still a relatively rare form of MDR-TB, but among those co-infected with HIV, the mortality rate is about 90 percent. XDR-TB alarms public health officials because the disease is transmitted, like other forms of TB, through coughs or sneezes of infected individuals.

The XXDR strain of TB is so rare that only a handful of other people in the world are thought to have had it. The strain is resistant to all tuberculosis drugs and is almost always fatal.

HSToday reported more than a year ago that while new cases of TB in the United States declined sharply during the 15 years up until 2007, there are growing concerns over the sudden escalation of the disease, especially the drug-resistant forms, some of which are highly contagious airborne strains of the disease.

“We should continue to fund AIDS vaccines and research into more effective antiretroviral medicines, but these are long-term projects,” said Dr. David Miller, an outspoken advocate for devoting research dollars to the fight against tuberculosis and an internationally known AIDS treatment activist,

"Today, more people with HIV are dying from tuberculosis, a disease with the potential to spread like wildfire in a crowded urban environment," Miller said in a statement Dec. 29.

Dr. David Ashkin, one of the nation's leading experts on tuberculosis, told The Associated Press that XXDR “is really the future. This is the new class that people are not really talking too much about. These are the ones we really fear because I'm not sure how we treat them."

Juarez spent most of the two years after his diagnosis at a quarantine hospital in Florida. 

"When he first came in we really had to throw everything and the kitchen sink at him," said Ashkin, the hospital's medical director, who experimented on Juarez with high doses of drugs, some not typically used for TB. "It was definitely cutting edge and definitely somewhat risky because it's not like I can go to the textbooks or ... journal articles to find out how to do this."

The treatments worked. Juarez, by then 21 years old, left the hospital in July.