Scientists in the United States have revealed chemicals behind jigsaw – puzzle that baffled the experts microbiologist for many – years: bahwasannya in a colony of bacteria that live in the presence of antibiotics in the natural environment, an individual who is sensitive to the antibiotics they can coexist with nature ytang resistant, where logic would dictate that only the resistant bacteria can survive.
The key to this mystery came back on an antibiotic product that is damaged, according to new research by Adam Palmer, Elaine Angelino and Roy Kishony at Harvard University.
Scientists learn how the products that failed in the emergence of antibiotic tetracycline polyketide naturally affect the populations of E. coli is exposed to antibiotics.
In that environment, tetracycline, which is produced by bakteriStreptomyces in the soil, naturally broken into several products. This team is simulating acid damage from these compounds, to produce three main ingredients: stereoisomers of the tetracycline-called epitetracycline (ETC); together – the same as dehydration products of both itself and tetracycline isomer, called anhydrotetracycline (ATC) and anhydroepitetracycline (AETC ).
Degraded tetracycline into the composition of bioactive compounds, which causes the sensitive strain of E. coli to release the strain resistant Then, they expose both regangantetracycline-resistant and tetracycline-sensitive strains of E. coli to mix antibiotics and degradation products. Typically, where the two populations – sensitivity and resistance – are, one of which would be expected that exposure to tetracycline resistant strain will survive. However, in the presence of defective products will release the sensitive strain resistant strain. ‘We find that the soup of tetracycline degradation products of tetracycline-resistant bacteria in the competition with his cousin, regardless of their sensitive,’ said Kishony.
One important factor is the degradation products is relatively stable and fixed so that the bacteria are exposed to them for some time. This does not usually exist in the case in clinical and agricultural areas, where drugs – drugs tend to be cleaned by dilution rather than on degradation.
The precise molecular mechanism whereby the degradation products for endurance seleski reverse is not entirely understood, although like what Kishony explained, ‘One of the degradation products, anhydrotetracycline, understood as a potent inducer of the expression of tetracycline efflux pumps [a protein involved in resistance mempompa drugs - drugs come out of cells - bacterial cells]. An excessive production of efflux pumps have a high cost for resistant bacteria. “
Julian Davies, a leading microbial ecologist at the University of British Columbia in Canada, describes this study as’ a brilliant series of studies which has provided an explanation for the success of the survival of antibiotic sensitive and resistant bacteria in the presence of obstacle. “
Do these findings have clinical significance? ‘Unfortunately stereoisomers toxic to the kidneys, and subsequently did not like what was recommended for a therapy, “said Palmer. He added, however, ‘This might provide such a lead compound to isolate a compound of non – toxic to select against resistance. More generally these results suggest that antibiotics may have potential derivative that acts as a selector against resistance. “
Simon Hadlington
Reference
A C Palmer, E Angelino and R Kishony, Nat. Chem. Biol., 2009, doi: 10.1038/nchembio.289
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