The latest issue of the Journal of Natural Products carries a sobering assessment of our ongoing struggle against antibiotic resistant bacteria. Author Lester A. Mitscher, from the University of Kansas, contends that we may be losing the batle and calls for the development of more potent antibiotics necessary for humanity to manage drug-resistant breeds of microbes.
The first true antibiotic, penicillin, was employed widely during World War II and in the decades since, dozens of important antibiotics have been developed and marketed around the world. These were called miracle drugs, says Mitscher. "Unfortunately, that had a downside. They were so relatively safe and so effective that we became careless in their use and in our personal habits. That has caused much of the resistance phenomenon we have today."
Microbial resistance to these drugs has been an ever-increasing problem because of the speedy reproduction and evolution of microorganisms. "Bacteria that survive the initial onslaught of antibiotics then are increasingly resistant to them," said Mitscher. "The sensitive proportion of the bacterial population dies, but then the survivors multiply quickly — and they are less sensitive to antibiotics. The sensitivity goes all the way from requiring a longer course of therapy or a higher dose, to being totally unaffected by the antibiotic."
Humans have overused antibiotics in areas such as agriculture, worsening the dilemma of highly resistant bacteria. "People are surprised to learn that almost half of all the antibiotics produced in the world are used in animal husbandry," said Mitscher. "I'm not referring to using antibiotics for curing infections of animals — what I mean is use of antibiotics in relatively small doses as an animal-feed supplement. Animals then grow quicker to a marketable size, and this is seen as a universal good. The difficulty is that use of antibiotics in that setting is an invitation towards resistance. Unfortunately, humans get infected with resistant strains that were generated in animals in this manner."
Part of the solution, according to Mischer, is to use antibiotics sparingly for industrial, agricultural and medical purposes. But he adds that drug corporations must develop antibiotics with the potential not only to kill microbes but also to inhibit their ability to mutate. These new drugs would be made more effective still if they enlisted the body's own immune system to battle infections.
Unfortunately, such new treatments may be some time off. "The pace of antibiotic discovery has fallen off, partly because the intensive research on them has lead to increasingly diminishing returns," said Mitscher. "Pharmaceutical firms have, for a variety of commercial reasons, de-emphasized antibiotic research in recent decades."
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Source: University of Kansas