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   Unwanted impact of antibiotics broader, more complex than previously known    
      
      
        
   2 hours ago    
      
   Staphylococcus aureus - Antibiotics Test plate. Credit: CDC    
   Researchers at Oregon State University have discovered that antibiotics have   
   an impact on the microorganisms that live in an animal's gut that's more broad   
   and complex than previously known.    
   The findings help to better explain some of the damage these medications can   
   do, and set the stage for new ways to study and offset those impacts.    
   The work was published online in the journal Gut, in research supported by   
   Oregon State University, the Medical Research Foundation of Oregon and the   
   National Institutes of Health.    
      
   Researchers have known for some time that antibiotics can have unwanted side   
   effects, especially in disrupting the natural and beneficial microbiota of the   
   gastrointestinal system. But the new study helps explain in much more detail   
   why that is happening,   
    and also suggests that powerful, long-term antibiotic use can have even more   
   far-reaching effects.    
      
   Scientists now suspect that antibiotic use, and especially overuse, can have   
   unwanted effects on everything from the immune system to glucose metabolism,   
   food absorption, obesity, stress and behavior.    
      
   The issues are rising in importance, since 40 percent of all adults and 70   
   percent of all children take one or more antibiotics every year, not to   
   mention their use in billions of food animals. Although when used properly   
   antibiotics can help treat life-   
   threatening bacterial infections, more than 10 percent of people who receive   
   the medications can suffer from adverse side effects.    
      
   "Just in the past decade a whole new universe has opened up about the   
   far-reaching effects of antibiotic use, and now we're exploring it," said   
   Andrey Morgun, an assistant professor in the OSU College of Pharmacy. "The   
   study of microbiota is just    
   exploding. Nothing we find would surprise me at this point."    
      
   This research used a "cocktail" of four antibiotics frequently given to   
   laboratory animals, and studied the impacts.    
      
   "Prior to this most people thought antibiotics only depleted microbiota and   
   diminished several important immune functions that take place in the gut,"   
   Morgun said. "Actually that's only about one-third of the picture. They also   
   kill intestinal epithelium.   
    Destruction of the intestinal epithelium is important because this is the   
   site of nutrient absorption, part of our immune system and it has other   
   biological functions that play a role in human health."    
      
   The research also found that antibiotics and antibiotic-resistant microbes   
   caused significant changes in mitochondrial function, which in turn can lead   
   to more epithelial cell death. That antibiotics have special impacts on the   
   mitochondria of cells is    
   both important and interesting, said Morgun, who was a co-leader of this study   
   with Dr. Natalia Shulzhenko, a researcher in the OSU College of Veterinary   
   Medicine who has an M.D. from Kharkiv Medical University.    
      
   Mitochondria plays a major role in cell signaling, growth and energy   
   production, and for good health they need to function properly.    
      
   But the relationship of antibiotics to mitochondria may go back a long way. In   
   evolution, mitochondria descended from bacteria, which were some of the   
   earliest life forms, and different bacteria competed with each other for   
   survival. That an antibiotic    
   would still selectively attack the portion of a cell that most closely   
   resembles bacteria may be a throwback to that ingrained sense of competition   
   and the very evolution of life.    
      
   Morgun and Schulzhenko's research group also found that one of the genes   
   affected by antibiotic treatment is critical to the communication between the   
   host and microbe.    
      
   "When the host microbe communication system gets out of balance it can lead to   
   a chain of seemingly unrelated problems," Morgun said.    
      
   Digestive dysfunction is near the top of the list, with antibiotic use linked   
   to such issues as diarrhea and ulcerative colitis. But new research is also   
   finding links to obesity, food absorption, depression, immune function,   
   sepsis, allergies and asthma.   
       
      
   This research also developed a new bioinformatics approach named "transkingdom   
   network interrogation" to studying microbiota, which could help further speed   
   the study of any alterations of host microbiota interactions and antibiotic   
   impact. This could    
   aid the search for new probiotics to help offset antibiotic effects, and   
   conceivably lead to systems that would diagnose a person's microbiome,   
   identify deficiencies and then address them in a precise and individual way.    
      
   Healthy microbiota may also be another way to address growing problems with   
   antibiotic resistance, Morgun said. Instead of trying to kill the "bad"   
   bacteria causing an illness, a healthy and functioning microbiota may be able   
   to outcompete the unwanted    
   microbes and improve immune function.    
      
        
   Provided by Oregon State University    
      
   Explore further    
      
      
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   http://m.medicalxpress.com/news/2015-02-unwanted-impact-antibiot   
   cs-broader-complex.html   
      
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