Totally drug resistant tuberculosis?

From Maryn McKenna’s blog, Superbug, at Wired.com,  Link

Tuberculosis is one of the world’s most lethal communicable diseases, accounting  for  9.4 million cases and 1.7 million deaths in 2009, according to the World Health Organization. That death toll may soon be much higher.

Due to incomplete and incorrect treatment regimens, the bacteria has developed resistance to all drugs known to effectively treat it, according to a group of doctors in Mumbai, India.

The World Health Organization takes issue with the notion that the bacteria is totally drug-resistant, or TDR, since experimental drugs have not yet been tried.

Excerpts:

News of some of the cases was published Dec. 21 in an ahead-of-print letter to the journal Clinical Infectious Diseases…

On Saturday, the Times of India disclosed that there are actually 12 known cases just in one hospital, the P. D. Hinduja National Hospital and Medical Research Centre; in the article, Hinduja’s Dr. Amita Athawale admits, “The cases we clinically isolate are just the tip of the iceberg.” And as a followup, the Hindustan Times reported yesterday that most hospitals in the city — by extension, most Indian cities — don’t have the facilities to identify the TDR strain, making it more likely that unrecognized cases can go on to infect others.

***

Because of the mismatch between treatment and symptoms, people often don’t take their full course of drugs — and from that (and some other factors I’ll talk about in a minute) we get multi-drug resistant and extensively drug-resistant, MDR and XDR, TB. MDR is resistant to the first-choice drugs, requiring that patients instead be treated with a larger cocktail of “second-line” agents, which are less effective, have more side effects, and take much longer to effect a cure, sometimes 2 years or more. XDR is resistant to the three first-line drugs and several of the nine or so drugs usually recognized as being second choice.

***

As of last spring, according to the WHO, there were about 440,000 cases of MDR-TB per year, accounting for 150,000 deaths, and 25,000 cases of XDR. At the time, the WHO predicted there would be 2 million MDR or XDR cases in the word by 2012.

That was before TDR-TB.

The first cases, as it turns out, were not these Indian ones, but an equally under-reported cluster of 15 patients in Iran in 2009. They were embedded in a larger outbreak of 146 cases of MDR-TB, and what most worried the physicians who saw them was that the drug resistance was occurring in immigrants and cross-border migrants as well as Iranians: Half of the patients were Iranian, and the rest Afghan, Azerbaijani and Iraqi. The Iranian team raised the possibility at the time that rates of TDR were higher than they knew, especially in border areas where there would be little diagnostic capacity or even basic medical care.

The Indian cases disclosed before Christmas demonstrate what happens when TB patients don’t get good medical care. The letter to CID describes the course of four of the 12 patients; all four saw two to four doctors during their illness, and at least three got multiple, partial courses of the wrong antibiotics. The authors say this is not unusual: