Well I didn't think I'd be blogging on the penile microbiome, but Cindy Liu, Assistant Research Prof from George Washington Milken Institute School of Public Health gave such a fascinating talk on the role of the penile microbiome in relation to circumcision on acquisition of HIV that I wanted to at least highlight this research. It is of interest to my role as CNC of Victorian NPEP Service given that circumcision is taken into account when assessing HIV risk for men having insertive intercourse.. My understanding of why circumcision is protective has just increased. 

Firstly, microbiome throughout the body is being increasingly recognised in playing a role in certain diseases.

Circumcision is known to be protective against HIV acquisition for the following reasons:

1. Decrease in at-risk surface area i.e. epithelial lining of foreskin

2. Increase of keratinisation 

3. Change in the sub-preputial micro-environment 

4. Change in penile microbiome

The study involved taking a swab from the coronal sulcus at baseline and 12 months in 2 groups of men - those who were circumcised and those who were uncircumcised.

There was an increase in both the type and density of anaerobic bacteria in uncircumcised men, and a small increase in skin associated "good" bacteria. The anaerobic bacteria found were pro-inflammatory, therefore attracting cytokines to the area, activating HIV target cells, such as Langerhans cells and increasing risk of HIV acquisition.

That is it in a nutshell and I am looking forward to Cindy's next talk this afternoon on BV, a condition we know is characterised by proliferation of anaerobes, and HIV acquisition