Penis Microbes Linked to Increased Risk of HIV Infection

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During the past few years, scientists are studying about genital microbiomes. These genital microbiomes are connected with one of the deadliest diseases in the world: HIV.


The studies focus more on the possible connection of these microbiomes with the HIV incidents for people. This is particularly with men and their penile microbiome. The microbiome is the community of the microorganisms living on the penis.

There was also some studies that investigation about the connection between HIV and circumcision. According to The Nature America, there is a connection between the male circumcision and the reduced HIV incidents in Uganda.

Based on the 2010 study, circumcision is associated with the decrease of the anaerobic bacteria for men. These anaerobic bacteria are microbes that live in areas deprived of oxygen. These anaerobic bacteria reside underneath the foreskin. Usually in the penises of men who are HIV-negative.


According to the studies published in MBio, researchers were able to follow-up the research. This is by investigating and quantifying the relationship between the anaerobic bacteria in the penile microbiome as well as the risks of HIV.

The findings suggest that there are certain microbial strains that can increase the risk for uncircumcised men. These men can also contract HIV easier than those who were circumcised.

There is also a new study conducted by researchers from the George Washington University, Northern Arizona University, John Hopkins University, the Rakai Health Sciences Program and the University of Toronto. These researchers used penile swabs collected from 182 uncircumcised men.

These men were all heterosexual and are ranging from 15 to 49 years old from Uganda. During the study, 46 of these men were infected by HIV while 136 were uninfected. Based on the result, the risk of a man to get infected with HIV after a single instance of vaginal intercourse with an HIV-positive partner is 950 times higher.


The researchers also focused on ten strains of anaerobic bacteria which were living under the penile foreskin. Upon thorough checking, about 62% of the subjects with penile bacteria were infected with HIV.

Most of the people who remained HIV-negative used condom use and numbers of sexual partners. During the study, men who contract HIV have larger populations of the penile anaerobic organism. These organisms were Murdochiella, Dialister, Prevotella, Peptostreptococcus, and Mobiluncus.


The researchers also think that the higher rates of HIV were among men can also be confined in the penis from the carrier. According to the genetic epidemiologist Lance Price, the addition of anaerobic bacteria found in the foreskin produces cytokines.

It is believed that the cytokines can be passed from one person to another during intercourse. It is also associated with bacterial vaginosis. This is an infection caused by the imbalance of vaginal bacteria. Thus, HIV can be passed during sexual intercourse.

According to the HIV immunologist, Clive Gray, from the University of Cape Town, the hypothesis that the microbiome from the penis moves around is already a risk factor. If there will be no action made with these penis microbes, the number of HIV-infected people will be higher.