So you’ve just finished a hot, relaxing shower with your favorite shower gel and then you brush your teeth with your brand new electric toothbrush. You feel sparkling clean as you dress for a date. Well, in reality, you are essentially a walking sewer of bacteria. No matter how clean you may think you are, your body is a seething cauldron of bacteria and other microorganisms. Sound scary? No worries. It’s all good.
It’s estimated that our bodies host anywhere from 10 to 100 trillion bacteria. That’s Trillion with a “T”! Throughout our bodies, a healthy person has communities of bacteria and these species are vitally important to our health because they carry out many important functions. This is especially true for the bacteria in our intestines, but for other areas as well. Specialized communities of bacteria live in our oral cavity, lungs, skin, intestines and reproductive tract. These healthy bacteria are called the normal flora.
We are increasingly beginning to understand that diseases can be linked to changes in the normal flora, when bacteria that aren’t so friendly displace bacteria that are normal flora creating an imbalance. Also, antibiotics used to treat infections from invading bacteria can sometimes damage the normal flora and possibly lead to an imbalance between bacterial species.The variety of bacterial species in an organ, whether they reflect health or disease, are referred to as the microbiome (my-crow-BI-ome).
The risks of acquiring or transmitting HIV are related to the microbiome in the reproductive tract. We will focus on the vaginal microbiome and the risk for HIV infection.
One species of bacteria that is important normal flora in the vagina is called Lactobacillus. Studies have shown that when Lactobacillus is the most common bacteria in the vagina, there is a reduced risk of HIV transmission.There appear to be racial differences in the levels of Lactobicillus in the vagina, where this species is the major bacterial species in white women, but is found at a lower percentage in African, Asian and Hispanic women.
This observation could contribute to the higher rates of HIV in these populations, but there are many other factors that affect the risk of HIV transmission. Bacteria that are not normally present in a healthy vagina can take over and cause an infection called bacterial vaginosis, a reproductive tract infection. Gardnarella is a species of bacteria that is a clear bad guy and can cause bacterial vaginosis.
How do Gardnarella and other types of bacteria increase the risk of HIV transmission? For one thing, it is important that the vagina keep a low pH, usually, less than about 4.8 and Lactobacillus supports this. Bacteria like Gardnarella increase the vaginal pH.
When bacteria that are not normally present invade the vagina, the body launches an attack which results in inflammation. This inflammatory response also make the barrier of cells that protect the vagina less effective. So all these actions together, particularly the inflammation and weakened barrier, increase the chance that bad organisms like HIV and other STD’s can infect a woman with a reproductive tract infection.
If a woman is already infected with HIV and not controlled on medication, infections like Gardnarella can increase the chance of her infecting her sexual partner, or if pregnant, passing the infection to her infant during delivery. Talk to your medical provider about ways to keep a healthy microbiome as discuss what types of douches and other products are safest to use.
If you have signs and symptoms of an infection, be sure to get the problem evaluated and treated. Gardnarella and other reproductive tract infections should be promptly treated. Trichomonas vaginalis is a parasite microorganism that also increases the risk of HIV, but can be easily treated. We will next discuss how HIV infection can cause changes in the intestinal microbiome which can contribute to problems from the disease.
Dr. Crawford received a B.S degree in Biology from Cornell University and a B.S. in Pharmacy from Temple University. He completed a residency in clinical pharmacy at the National Institutes of Health. He earned a doctorate in Pharmacology from the Uniformed Services University of the Health Sciences in Bethesda, Maryland. He completed a post-doctoral fellowship at the National Institutes of Health, studying microbial biochemistry and genetics.
He is currently with the Division of AIDS at the National Institutes of Health. He has over 25 years of experience in HIV treatment and clinical research. This article reflects his personal views and opinions.