Young and his colleagues used a culture-independent technique, using sequence analysis of 16S rRNA-encoding gene libraries, to profile the bacterial communities in the gut. It allows them to look for many more kinds of microbes than was possible with more limited methods. The result is a much more complete picture of the diversity of microbes in the gut.
Mice, which normally develop a diverse set of microbes after being born without one, then were given either cefoperazone, a broad-spectrum cephalosporin antibiotic, or a combination of three antibiotics (amoxicillin, bismuth and metronidazole). The scientists then observed what changes in the gut microbiota occurred immediately after the antibiotics were stopped or six weeks following the end of treatment.
"Both antibiotic treatments caused significant changes in the gut microbial community. However, in the mice given cefoperazone, there was no recovery of normal diversity. In other mice given the amoxicillin-containing combination, the microbiota largely recovered, but not completely," says Young.
However, Young's team found that a little socializing sparked recovery in even the most severely affected mice. Some of the mice given cefoperazone soon recovered normal microbes after an untreated mouse was placed in the same cage. That wasn't a complete surprise, since mice have a habit of eating the feces of their cage mates and therefore picked up normal gut microbes quickly.
Not a lesson applicable to humans? In patients with refractory antibiotic-associated diarrhea due to C. difficile, there have been limited trials of treatments using "fecal transplants" to replace lost gut microbiota. Although this is a pretty unpalatable treatment at first glance, the clinical response was quite remarkable, Young says.
Although cefaperazone is not commo
|Contact: Anne Rueter|
University of Michigan Health System