STD Awareness: The Vaginal Microbiome and Cervical Cancer

Posted on September 9, 2019 by Anna C.

Cervical cancer is caused by human papillomavirus (HPV), which has been nicknamed “the common cold of STDs” — because pretty much every sexually active person will get it at some point. Luckily, that scary stat is poised to change as more people receive the HPV vaccination, which protects against nine major strains of the virus.

HPV jumps easily from person to person, spread by pretty much all types of sexual contact. For most people, the infection clears up within 8 to 13 months, but sometimes the infection develops into a chronic condition, which increases risk for certain cancers — including cervical cancer, but also cancers of the anus, genitals, and throat. Unfortunately, it’s hard to predict if your immune system will vanquish your infection, or if you’ll develop a chronic infection.

Members of the lactobacilli family, keeping vaginas healthy across the globe. Image: Josef Reischig

Luckily, the vagina has some tricks up its sleeve to protect itself from HPV, and some of its best weapons are bacteria. Yep — a healthy vagina isn’t germ-free. To the contrary, it needs lactobacilli and other beneficial microbes to maintain a healthy environment. Bacteria from the Lactobacillus genus produce lactic acid and other chemicals, which help keep dangerous bugs away. Vaginal environments in which Lactobacillus gasseri dominate, for example, are more likely to clear HPV infections. L. crispatus helps trap HIV in a thick mucus, reducing infection risk. Other lactobacilli species secrete chemicals that ward off yeast infections. Sometimes, however, good bacteria lose this turf war, and “bad guys” move in.

The population of microbes that live in your vagina are known collectively as the vaginal microbiome.

University of Arizona researchers in Phoenix performed a “census” of the vaginal microbial communities of 100 premenopausal women. They learned that women who have cervical cancer or precancerous abnormalities have drastically different vaginal microbiomes. Healthy vaginas were generally dominated by lactobacilli, but as cervical health declined, their populations declined, and “bad” bacteria took over. One such bad guy, called Sneathia, was linked to HPV infection, precancer, and cervical cancer.

Which Came First?

Finding a new vaginal “bad guy” was exciting, and Sneathia had previously been linked to other gynecological problems, ranging from bacterial vaginosis to pregnancy complications. But the researchers were looking at a snapshot in time — they didn’t know what came first, the Sneathia or the cervical abnormalities. Were lactobacilli protecting the cervix whereas Sneathia were harming it, or did a chronic HPV infection set the stage for Sneathia to move in and thrive? It’s a real “chicken-and-egg” conundrum. Continue reading →

STD Awareness: Is Bacterial Vaginosis a Sexually Transmitted Disease?

Posted on November 2, 2015 by Anna C.

Gardnerella vaginalis under a microscope. Image: K.K. Jefferson/Virginia Commonwealth University

Bacterial vaginosis, or BV, is the most common vaginal infection among people 15 to 44 years of age. It’s caused by an overgrowth of harmful bacteria, such as Gardnerella vaginalis. A healthy vagina hosts thriving populations of Lactobacillus bacteria species, but when these “good” bacteria are crowded out by certain types of “bad” bacteria, the vaginal ecosystem can be shifted, causing BV.

There is a lot of confusion about BV. Is it a sexually transmitted disease (STD)? What are the symptoms? How can you avoid it?

All good questions. Let’s examine them one by one.

Is BV an STD?

The consensus seems to be that BV isn’t officially an STD, but even reliable sources have somewhat contradictory information. Planned Parenthood doesn’t list BV as an STD on their informational webpages. The Centers for Disease Control and Prevention (CDC) does include BV on their STD website, but also says that “BV is not considered an STD.”

On the other hand, the Office on Women’s Health says that “BV can … be caused by vaginal, oral, or anal sex” and that “you can get BV from male or female partners.” And there’s an entire chapter devoted to BV in the premier medical textbook on STDs, and its authors say that, while sexually inexperienced females can get BV, “the weight of evidence supports sexual transmission” of G. vaginalis, the bacteria species most famously implicated in BV infections.

The same webpage on which the CDC declared BV not to be an STD also says that it can be transferred between female sexual partners. Indeed, women who have sex with women have higher rates of BV. Since vaginal fluid could spread BV, partners can change condoms when a sex toy is passed from one to another, and use barriers like dental dams when engaging in cunnilingus (oral contact with the female genitalia) or rimming (oral contact with the anus).

What about heterosexual transmission? Continue reading →

Does Douching Work?

Posted on April 20, 2015 by Anna C.

illustration of a douching apparatus from an 1882 medical handbook

As a newly minted teenager, I was helping my mother go through some of my recently deceased great-grandmother’s things. I held a mysterious object in my hands and studied it curiously, puzzling over its unfamiliar form, pastel color scheme, and floral pattern. Finally, I gave up: “What is this?” I exclaimed. My mom, instantly uncomfortable, muttered her answer through clenched teeth: “It’s a douche bag,” she replied.

I remember being rather scandalized, but also a bit amused to be holding a piece of ancient misogynist history in my hands. Even as a junior high student, I knew that douching was marketed toward women with the message that their vaginas were “dirty” and in need of “cleansing” — scientifically invalidated ideas to which we surely no longer adhered. It seemed fitting that we were sorting through the belongings of a person born in the 19th century, dividing them into the useful and useless. Surely the douche bag belonged in the latter category.

Just because douching products are available in drugstores doesn’t mean they’re safe or effective.

Little did I know, more than 20 years ago, that douching hasn’t exactly been relegated to a historical footnote. Overall, nearly 25 percent of American women 15 to 44 years old douche regularly — which is down from nearly a third in 2002. Douching rates may vary by ethnic group: CDC data from 2005 found that 59 percent of non-Hispanic black women, 36 percent of Latinas, and 27 percent of white women douche. Socioeconomic status and education level can also be a factor.

For those of you who don’t know, vaginal douching is the practice of flushing the vagina with a liquid, which is administered through a nozzle that is inserted into the vagina. Some people believe that douching cleanses or deodorizes the vagina, or can prevent pregnancy or infections. Some might think their partners expect them to douche, or that douching will “tighten” or “rejuvenate” their vaginas. Continue reading →

Can Yogurt Prevent Yeast Infections?

Posted on February 28, 2012 by Anna C.

Yogurt has a reputation for preventing yeast infections. But is this reputation deserved?

Yeast infections are common conditions that can pop up in many areas of the human body, including the vulvovaginal region. They are usually caused by a fungus called Candida albicans, which starts to grow profusely, leading to the white discharge associated with yeast infections. Fungi are not killed by antibiotics, which are only effective against bacteria. As such, yeast infections may be encouraged when their bacterial competitors are wiped out by antibiotics — especially broad-spectrum antibiotics. Candida albicans can also grow on other areas of the body; for instance, when it proliferates in the mouth, the resulting condition is called thrush.

The Lactobacillus species in yogurt are different from those found in the vagina.

The vagina is habitat to bacteria from the Lactobacillus genus, members of which produce lactic acid and sometimes hydrogen peroxide. This helps to inhibit the growth of bacteria that aren’t able to thrive in acidic environments or in the presence of hydrogen peroxide. If you have a vagina, there is about a 10 to 25 percent chance that yours is home to Candida albicans — but this doesn’t necessarily mean you’ll develop a yeast infection. The lactobacilli are usually able to keep C. albicans in check.

Yogurt is often touted as a cure or preventive measure for yeast infections. Yogurt is milk that has been inoculated with bacteria that have been allowed to grow. When the yogurt is being manufactured, it is held at a temperature that allows the bacteria to thrive; when yogurt is kept in the refrigerator, the bacteria don’t die, but they aren’t able to reproduce either. Don’t worry, these bacteria won’t harm you — such bacteria, when used in foods or supplements, are often referred to as “probiotics.” Continue reading →

STD Awareness: Bacterial Vaginosis and Chancroid

Posted on August 22, 2011 by Anna C.

Editor’s Note: Please see our post of November 2, 2015 to learn if bacterial vaginosis (BV) can cause sores, and to get the scoop on whether or not it’s actually an STD.

Sexually transmitted diseases can be caused by viruses, bacteria, protozoans, and even animals. Bacterial vaginosis and chancroid are both infections caused by bacteria, which means that they can be treated with antibiotics. While bacterial vaginosis only affects people with vaginas, chancroid disproportionately affects people with penises. You can seek diagnosis and treatment for bacterial vaginosis and chancroid at a Planned Parenthood health center, as well as health clinics, private health-care providers, and health departments.

Bacterial vaginosis is caused by an imbalance of bacteria species in the vagina. Image: renjith krishnan / FreeDigitalPhotos.net

Bacterial Vaginosis
Bacterial vaginosis seems to be most commonly caused by the bacteria species Gardnerella vaginalis. Scientists aren’t quite sure how this infection is caused, but risk seems to correlate with a change in sexual partners, having multiple sexual partners, douching, or using an intrauterine device; it can also occur in females who have never been sexually active. It is more common in pregnant women. There is no counterpart to this infection in males, although G. vaginalis can be found in their urethras; this raises the possibility that bacterial vaginosis can be sexually transmitted, in which case it could be directly transmitted between two females or indirectly transmitted from one female to another via a male.

Bacterial vaginosis seems to result from an imbalance in the vaginal flora (“flora” is a somewhat fanciful term for the bacteria that live in your body; under normal circumstances they are harmless and even beneficial). Vaginas usually are habitat to a population of bacteria called Lactobacillus, which produce hydrogen peroxide as a byproduct. When the number of Lactobacillus declines, G. vaginalis is able to move in on Lactobacillus’ old territory. The decrease in Lactobacillus and increase in G. vaginalis leads to a rise in the vagina’s pH. The new vaginal environment is less acidic and more alkaline; a vaginal pH of more than 4.5 is one criterion for the diagnosis of bacterial vaginosis. Another symptom includes a vaginal discharge that may smell somewhat fishy. There might also be genital itching or pain during urination. It is also possible not to have symptoms. Continue reading →