The gut microbiota is known to vary depending on lifestyle and demographics. We performed a case-control study to characterize the gut microbiota in acne patients before and after antibiotics, and examined associations with race, intake of milk/yogurt, acne severity, and stress. 8 acne patients (3 Caucasian, 3 African American, and 2 Asian) were matched to 8 controls by age, race, and sex. Stool was collected from all participants at baseline and from acne patients after 4 weeks of oral minocycline therapy (100 mg BID). Bacterial community profiling was performed via Illumina MiSeq sequencing of the 16S rRNA gene (V3V4 region) and sequence analyses using the QIIME, MetaStats 2.0 and SPSS-25 software. Notable variations were observed at the phylum level in the Firmicutes to Bacteroidetes (F/B) relative abundance ratio. A lower F/B ratio has been linked to a Western diet and also with acne. We found the F/B ratio to be highest in Caucasians, followed by African Americans and then Asians at each time point. Using independent t-tests, the F/B ratio was significantly reduced (p=0.027) following antibiotics in Asians only. The F/B ratio was significantly higher in those consuming both milk and yogurt compared to those consuming neither, both before (p=0.031) and after (p=0.021) antibiotics. The F/B ratio was at baseline higher among those who later experienced minimal efficacy from antibiotics than among those who later derived a moderate benefit. The F/B ratio was higher before antibiotics in both moderate and high stress groups, nearing significance in the high stress group (p=0.057). Although the sample size was small, our data demonstrated important trends in the gut microbiota across demographic and lifestyle groups. In particular, race and diet were observed to significantly impact the F/B ratio in acne patients undergoing antibiotic therapy.

Impact of lifestyle and demographics on the gut microbiota of acne patients and the response to minocycline