Study finds way to enhance the treatment of multi-drug resistant TB

A study by Dr. Lalita Ramakrishnan of the University of Washington in collaboration with Dr. Paul Edelstein of the University of Pennsylvania has found that blocking bacterial efflux pumps may enhance the treatment of multi-drug resistant tuberculosis.

An efflux pump is a structure deployed by TB bacteria that allows it to grow within human white blood cells called macrophages, reports. Once the macrophage is infected by TB bacteria, the TB bacteria then sends out more efflux pumps that flush away medications.

This flushing of medications is one of the factors that gives bacteria more time to become resistant to what can be a longer than six month drug treatment for MDR-TB.

“Thus the TB drugs get caught in the crossfire in this pitched battle between bacterium and host,” Ramakrishnan said, according to

There are some particularly inexpensive medications that are available that can inhibit efflux pumps and potentially reduce multi-drug tolerance, according to the research. One of those is the calcium channel blocker verapamil, which is used to treat angina, some heart rhythm problems and high blood pressure.

The research suggests that if this medication is added to currently approved TB therapy or if new medications are developed to specifically block efflux pumps in TB, this might lead to a reduction in multi-drug tolerance and an improvement in treatment, reports.

Previous beliefs about multi-drug resistance were based on the theory that the TB drugs tended to target only rapidly growing and multiplying TB organisms and neglect dormant TB bacteria. This neglect could lead the dormant bacteria to grow resistance to the TB drugs administered.