Study explains why some TB cases are more resistant

A new study by researchers from the Harvard School of Public Health helps to explain why some tuberculosis cases are more resistant to treatment with antibiotics.

The research, which appears in the online edition of the journal Science, details how the division and growth of Mycobacteria tuberculosis cells determines their susceptibility to antibiotic regimens, according to

“We have found that the consequences of the simple and unexpected patterning of mycobacterial growth and division means some bacterial cells have the capacity to survive in the face of antibiotics,” Bruce Aldridge, a post-doctoral fellow at HSPH and a co-author of the study, said, reports.

Along with colleagues from Massachusetts General Hospital, the HSPH researchers attempted to determine what distinguishes a cell that lives from one that dies. In order to do so, they designed a microfluidic chamber to grow Mycobacterium smegmatis cells, which behave like M. tuberculosis cells, and then filmed them with a live-cell imaging system.

The scientists then treated the cells with different classes of antibiotics and observed how the physiologically different subpopulations of daughter cells responded.

The experiment showed that the daughter cells exhibited varying degrees of growth and susceptibility to the treatments, providing strong evidence that the subpopulations contained cells that were inherently more tolerant to antibiotics.

“It is surprising to discover that mycobacteria differ from other bacteria such as E. coli in such a fundamental way,” senior author Sarah Fortune said, reports. “It is easy to assume that most bacteria work in a similar fashion. While that’s true sometimes, this study shows that bacterial species, such as TB, may be strikingly different from each other and thus require different methods of treatment.”