A group of scientists from the Harvard University, after identifying that certain soil microbes close to human pathogen subsist on even the most potent antibiotics, is planning to take studies further to help the pharma companies to overcome the antibiotic-resistant bacteria in human body for better therapeutic effect.

A study on 18 antibiotics, representing eight major classes of natural and synthetic origin, conducted by four scientists from the Department of Genetics, Harvard Medical School and the Programme of Biophysics, Harvard University, showed that 13 to 17 of them supported the growth of clonal bacteria from each of 11 diverse soils. The study was conducted on commonly used antibiotics including the most commonly used penicillin G, ciprofloxacin, levofloxacin, carbenicillin, sulfamethizole, gentamicin, vancomycin, D-cycloserine, amikacin and carbenicillin.

The study also suggested that many of the bacteria subsisting on antibiotics are closely related to human pathogens and each antibiotic-consuming isolate has shown resistance to multiple antibiotics at clinically relevant concentrations. "This phenomenon suggests that this unappreciated reservoir of antibiotic-resistance determinants can contribute to the increasing levels of multiple antibiotic resistance in pathogenic bacteria," according to the study published in Science magazine, in April.

Though the study was not conducted specifically on disease causing bacteria, the soil microbes closely related may transfer resistance to the former. However, the phenomenon has not been identified till in clinical conditions and further studies are on in this regard, said Dr Gautam Dantas, research fellow in genetics, Harvard Medical School. The bacteria were found to be able to sustain and chew higher dosage of antibiotics than the quantity used for treatment.

The team is currently in talks with the National Institute of Allergy and Infectious Diseases, US, for collaboration to fund the research and will conduct genome sequencing of these bacteria at Broad Institute, a research collaboration of MIT, Harvard and its affiliated hospitals and the Whitehead Institute, created to bring the power of genomics to medicine.

"Our further study would be useful for pharmaceutical companies in two ways. Primarily, we have identified the antibiotics which act as sole carbon source for these bacteria which would help the companies to develop a mechanism in new drugs to overcome the bacterial resistance. For instance, the antibiotics can be administered as combination therapy in which another chemical should be added to prevent the resisting bacteria from influencing the pathogen. On the other hand, the companies can also use these resistant bacteria to develop mechanism to decontaminate the chemical accumulated in human body after therapy," Dr Dantas told Pharmabiz.

The technology transfer office of Harvard is currently on the process of patenting the findings and will transfer the information to pharma stakeholders on royalty basis. Apart from Dr Dantas, Dr Rantimi D Oluwasegun and Dr George M Church with Department of Genetics, Harvard Medical School, Boston and Dr Morten O A Sommer who is working with both Department of Genetics and Program of Biophysics, Harvard University, Cambridge were in the team which analysed the bacteria subsisting on antibiotics.