Multi-Drug Resistant TB on the Rise in Australia

MELBOURNE – Showing that the incidences of multi-drug resistant tuberculosis (MDR-TB) are on the rise, a report has stressed the need for an overhaul of Australia’s TB strategy.

Based on a review of Victorian Health Department data, the report points out that 31 persons were diagnosed with MDR-TB, a mutant strain that is resistant to two of the most effective antibiotics used to treat TB, from 1998 to 2007.

It further reveals that most of the cases occurred in the final few years of the 10-year review window, with seven recorded in each of 2004, 2006 and 2007.

“Our study revealed that there was a clear increase in the number of patients diagnosed with MDR-TB,” the Australian quoted Caroline Lavender, a scientist at the Victorian Infectious Diseases Reference Laboratory, as writing.

“New data available since the completion of our study reveal that the increase … appears to have been sustained in 2008,”

According to the review, the cases of MDR-TB have risen five-fold as a proportion of all TB notifications in Victoria.

In a paper published in the Medical Journal of Australia, Lavender says that the upward trend has “significant implications for public health policy and planning”.

MDR-TB is the result of improper use of these antibiotics during treatment of patients with ordinary TB.

People with the resistant strain must be put on alternate, and less effective, TB-fighting drugs that require specialist nurses and a longer hospital stay, treatment in a negative-pressure rooms and more lab tests.

About 29 out of 31 MDR-TB patients were born overseas, with almost two thirds coming from India, Vietnam or China.

Lavender says that new TB control strategies are needed, and the use of molecular tests should be increased for the rapid detection of drug resistance.

“Another measure that might prove useful is providing information to people at high risk of TB on arrival to Australia, so they know to seek medical attention early should they develop a persistent cough or other symptoms suggesting of TB,” she said.

Scientists Uncover New Anti-TB Compounds

ITHICA – Scientists from Weill Cornell Medical College have identified certain compounds that would inhibit the sophisticated mechanism used by tuberculosis bacteria for surviving dormant in infected cells.

The researchers said most of the people infected with TB remain symptom-free because the Mycobacterium tuberculosis, the disease-causing bacteria, is kept in check within immune system cells.

These cells produce compounds such as nitric oxide, which scientists believe damage or destroy the bacteria’s proteins. If these compounds are allowed to accumulate, the damaged proteins would kill the bacteria.

However, a protein-cleaving complex known as a proteasome breaks down that damaged proteins and allows the bacteria to remain dormant.

The researchers suggest that finding drugs to disable the proteasome would be a new way to fight TB.

During the study, the researchers examined 20,000 compounds for TB proteasome inhibition activity, and identified and synthesized a group of inhibitors, which they then tested for their ability to inhibit the proteasome inside the mycobacteria.

“We believe these findings represent a new approach for developing antibiotics in the fight against TB,” Nature magazine quoted Dr. Carl Nathan, senior author and chairman of the Department of Microbiology and Immunology, R.A. Rees Pritchett Professor of Microbiology and director of the Abby and Howard P.

Milstein Program in Chemical Biology of Infectious Disease at Weill Cornell Medical College, as saying

“This is important because we are running out of effective antibiotics that are currently available. There are few drugs that successfully combat TB in its dormant stage, which makes the bacterium so resilient in the body.

“More important, there are many antibiotics that kill bacteria by blocking the synthesis of proteins, but there are none that kill bacteria by interfering with protein breakdown, as we have found here,” Nathan added.