Short term ciprofloxacin and clindamycin combination antibiotic therapy before and after transrectal ultrasound scan and prostate biopsy: Its impact on major components of gut microbiome.

The perturbation of gut microbiome is a risk factor for a number of adverse conditions. Among other factors antibiotic therapy is a common culprit. We characterized the short-term alteration of gut microbiome after antibiotic therapy. Nine patients (age (median [range]): 67 [57-75 years]) were subjected to prostate biopsy. Ciprofloxacin and clindamycin, 500 mg and 150 mg, respectively, were administered twice a day; this combination therapy was started the day before and continued until 5th and 8th day, respectively, following biopsy. 16s RNA sequencing data from fecal swabs taken before antibiotic therapy and 14 days after biopsy were analysed. At phylum level, the abundance of Actinobacteria and Firmicutes decreased, while that of Bacteroides and Proteobacteria increased after antibiotic therapy. The ratio of Firmicutes:Bacteroides inversed (from 2.81 to 0.74, p = 0.035). At order level, the abundance of Bacteroidales and Veillonellales increased, while that of Clostridiales and Coriobacteriales decreased. At genus level the abundance of Bacteroides increased, while those of Roseburia, Faecalibacterium and Collinsella decreased. These findings indicate that short-term antibiotic exposure skews gut microbiome composition. The current level of knowledge does not allow to decide whether this skewness is detrimental and has any long-term effect on disease including prostate pathology.