TB back in the news
Consider it another case of modern science connecting to past practice. Long before the discovery of antibiotics, patients suffering from “consumption” were often sent to special retreats for heliotherapy or phototherapy — that is, some rest and relaxation in the sun.
A new study lead by researchers out of Queen Mary, University of London is lending some science to the practice of a by-gone era. The study involved 95 patients who were suffering from TB. In addition to the standard antibiotic treatment, one group was given high doses of vitamin D while the other group was given a placebo. Researchers then analyzed the levels of inflammatory markers in the blood samples of participants and monitored how long the bacteria showed up in their sputum (mucus expelled from the lungs).
The results: Patients in the group taking vitamin D recovered faster and with less damage to their lungs. The bacteria that causes tuberculosis — Mycobacterium tuberculosis — disappeared from their sputum samples faster than from the control group’s samples. The difference is significant — an average of 23 days instead of 36.
Experts attribute the quicker recovery to the anti-inflammatory properties of vitamin D which helped counteract the inflammation caused by the infection. When comparing the blood samples between the groups, those given vitamin D saw their levels of inflammatory markers in the blood drop faster and drop farther than the control group’s.
“These findings are very significant. They indicate that vitamin D may have a role in accelerating resolution of inflammatory responses in tuberculosis patients,” said lead researcher Dr. Adrian Martineau in a Queen Mary press release. “This is important, because sometimes these inflammatory responses can cause tissue damage leading to the development of cavities in the lung. If we can help these cavities to heal more quickly, then patients should be infectious for a shorter period of time, and they may also suffer less lung damage.”
Bear in mind that this study is a relatively small one and the first of its kind. Experts aren’t ready to recommend that all TB patients take high doses of vitamin D — more research is needed. Still, the study’s results could apply to other types of lung infections too.
“More broadly, the ability of vitamin D to dampen down inflammatory responses without compromising the actions of antibiotics raises the possibility that supplementation might also have benefits in patients receiving antimicrobial therapy for pneumonia, sepsis and other lung infections,” Dr. Martineau added.
The study was conducted in collaboration with the Medical Research Council’s National Institute for Medical Research and funded by the Medical Research Council and the British Lung Foundation. The results were published online this week in the Proceedings of the National Academy of Sciences of the USA (PNAS).
Multi-drug resistant TB on the rise
The British study wasn’t the only reason TB was back in the news in recent weeks. A new study in The Lancet offered troubling news that multi-drug resistant tuberculosis (known as MDR TB for short) is on the rise around the world.
The study involved 1,278 MDR-TB patients from eight countries. Researchers at the U.S. Centers for Disease Control and Prevention tested samples for resistance to the antibiotics commonly used to treat TB. The study found that 44 per cent had already developed resistance to the two main drugs used to treat TB, as well as one of the second line antibiotics.
Incidence of the infection is increasing in Asia, Africa, Latin America and Europe — particularly in Latvia, where almost two thirds of MDR TB will no longer respond to at least one second-line medication. Expert fear the prevalence of MDR TB could be ten times higher in some areas than originally thought — and that number is especially problematic for places with poor health care and sanitation.
Worse yet, nearly 7 per cent of the patients had become resistant to two of the second line drugs — a form of the infection now known as extensively drug resistant tuberculosis or XDR TB. Experts say the prevalence of XDR TB is still unknown, but cases have shown up in 77 countries to date.
“The global emergency of extensively drug-resistant tuberculosis heralds the advent of widespread, virtually untreatable tuberculosis,” lead author Tracy Dalton of the U.S. Centers for Disease Control writes in the report.
It’s a scary proposition considering that TB can be transmitted from person to person via droplets in the air from coughing or sneezing. Thankfully, tuberculosis isn’t as infectious as chicken pox and other illnesses.
Why it is happening? As with other superbugs, experts think one factor behind the development of drug-resistant strains is people not taking antibiotics as prescribed — thereby allowing the bacteria to develop resistance. TB treatments involve typically last six months, so you can understand why patient compliance can be an issue.
Right now, the main message is for experts to better monitor cases of TB, MDR TB and XDR TB. There is still a lot that experts don’t know about the development of drug-resistant strains or how prevalent they are in the world. Prevention and early diagnosis will still be the focus, with groups like the World Health Organization calling for better awareness and monitoring.
For more information, see ABC News.
Quick Facts about TB
– According to the WHO, about one third of the world’s population carries the bacteria that causes TB. Our bodies are pretty good at “walling off” the bacteria, and about 10-15 per cent of people who carry the bacteria will develop active TB.
– 8.8 million people became sick with TB in 2010, reports the Stop TB Partnership. Between 1.4 and 1.7 million people die of the disease each year.
– While cases of “regular” TB have been declining slightly over time, more cases of MDR-TB are reported every year. The WHO estimates there were about 650,000 such cases in 2010.
– In Canada, there are about 1,600 cases of TB each year, according to Health Canada. The risk of developing the disease is pretty low for most Canadians.
For more information, see our previous article Tuberculosis: Where are we now?