A Combination of Antibiotics and Phage Therapy to Eliminate Dormant Infections Recommended

After studying the way some types of bacteria avoid destruction by antibiotics through entering a dormant state, a team comprising microbiologists and biophysicists have suggested two methods for making the bacteria more vulnerable to treatment.

Investigators at the Hebrew University of Jerusalem (Israel) worked with cultures of Escherichia coli bacteria. They observed the fate of populations of organisms as well as using advanced techniques, including long-term time-lapse microscopy, to trace the fate of single cells. In addition to analyzing the effects of antibiotic treatment, the investigators also looked at the interaction between dormant E. coli and bacteriophages.

They reported in the April 21, 2008, online issue of the Proceedings of the [U.S.] National Academy of Sciences (PNAS) and the May 20, 2008, issue of the journal PLOS Biology that protein production continued for a short time in dormant bacteria, immediately after exiting the stationary phase. By treating the entire bacteria population with antibiotics during this time frame, a significant reduction was obtained in the number of dormant bacteria that survived.

An intriguing pattern was found when the newly dormant bacteria were infected with bacteriophages. Although processing of the viral genome was suppressed during the dormant period, return to normal growth allowed the infecting phages to resume the process of gene expression, ultimately causing cell lysis.

Senior author Dr. Nathalie Q. Balaban, professor of biophysics at the Hebrew University of Jerusalem, said, "These results might lead to new phage therapies for fighting infections that persist despite the antibiotics.”

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Hebrew University of Jerusalem