HPV infection and bacterial microbiota in the semen from healthy men

Aberrant microbiota composition has been linked to disease development at numerous anatomical sites. Microbiota changes in reaction to viral infections, such as human papillomavirus (HPV), have been investigated almost exclusively in the female reproductive tract. However, HPV infection may also affect male health by reducing semen quality and fertility. The aim of this study was to investigate whether present HPV DNA is associated with detectable changes in semen bacterial microbiota composition and diversity.

This study relied on stored semen samples from 31 fertile healthy men who participated in the Finnish family HPV Study during the years 1998-2001. DNA was extracted from semen with PCR template preparation kit. HPV was genotyped using Luminex-based Multimetrix® assay. Microbiota was analyzed from the V3-V4 region of 16S rDNA gene following sequencing on an Illumina MiSeq platform. All statistical analyses were performed with Calypso software version 8.84.

HPV DNA was detected in 19.4% (6/31) of the semen samples. HPV status in the semen did not impact the α-diversity estimations, as measured by Chao1 and Shannon indices, nor ß-diversity. Nevertheless, HPV-positive semen samples exhibited differences in the taxonomic composition of the bacterial microbiota including higher abundances of Moraxellaceae (p = 0.028), Streptococcus (p = 0.0058) and Peptostreptococcus (p = 0.012) compared to HPV-negative semen samples.

HPV infection is associated with altered bacterial microbiota composition in semen, and this might have in impact to male health in general. As of present, it is unclear whether these changes result from HPV infection or whether altered bacterial microbiota increases susceptibility to HPV infection. More research is needed on viral-bacterial interactions in the male reproductive system.