Antibiotics induce sex-specific effects on the gut microbiomes of male and female rats. The corresponding study was published in Frontiers in Microbiology.
Although gut microbiome composition differs between males and females, sex is rarely considered when prescribing antibiotics. Furthermore, sex-based differences in gut microbiome recovery following antibiotic treatment are poorly understood. To change this, in the present study, researchers set out to see whether antibiotic treatment affects the stool and small bowel microbiome differently in male and female rats.
For the study, the researchers gave one group of male and female rats a multi-drug antibiotic cocktail, including ampicillin and neomycin, and kept another group as unexposed controls. Following treatment, rats were monitored for a 13-day recovery period before being euthanized. The researchers collected stool samples from the rats before, during, and after treatment.
Whereas male and female rat microbiome composition were similar at baseline, by antibiotic exposure day 8, male rats experienced a greater loss of stool microbial diversity compared to females. The relative abundance of numerous microbes also significantly differed between exposed males and females.
By Day 13 post-treatment, the stool samples remained significantly different from baseline, and differences between males and females also remained. The small bowel microbiomes of treated and unexposed mice differed significantly as well.
The researchers concluded that broad-spectrum antibiotics have significant sex-specific effects on gut microbial populations in both stool and the small bowel microbiome and that the recovery of these populations differs between sexes. They thus say that their findings may have clinical implications for prescribing antibiotics.
"Sex is a biological variable, and like any variable, it needs to be taken into consideration in basic and medical research. Currently, we consider factors such as kidney function and weight when dosing medications for patients. Depending on the results of further research, specifically in humans, the sex of patients may one day be an important consideration when prescribing antibiotics," said Ruchi Mathur, MD, the study's principal investigator.