Tag Archives: fimbriae

STD Awareness: Three Sexually Transmitted Bacteria That Will Shock and Amaze You

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It’s hard to appreciate a pubic louse as an intriguing creature in its own right. Not when an infestation with pubic lice is such a vexing experience. The same can be said for the germs that cause any number of human diseases. But, just as you might have marveled at the microorganisms you spied under the microscope in your high school biology class, the bacteria and other microbes that cause sexually transmitted diseases (STDs) can be fascinating, strictly as scientific subjects.

Let’s look at a few of these fascinating bacteria!

Treponema pallidum, the causative agent of syphilis, is seen in this electron micrograph adhering to a surface with the tapered end of its structure. Image obtained from the CDC’s Public Health Image Library.

Image: Public Health Image Library, CDC

Treponema pallidum: the bacteria that cause syphilis

Before the age of antibiotics, syphilis was the most feared STD out there. Untreated, it can cause serious, sometimes fatal, damage to the body, and can also spread to a fetus during pregnancy. But did you know that earlier versions of syphilis might have been even worse?

Written records of syphilis date back to 1495 when it seemed to appear in Europe for the first time. According to a 1519 description, it caused

Boils that stood out like Acorns, from whence issued such filthy stinking Matter, that whosoever came within the Scent, believed himself infected. The Colour of these was of a dark Green and the very Aspect as shocking as the pain itself, which yet was as if the Sick had laid upon a fire.

Interestingly, such descriptions don’t match modern forms of syphilis, which suggests that it might have evolved into a less virulent form, possibly in response to selective pressure against symptoms that render the host sexually unappealing. Basically, that means that someone with boils emitting “filthy stinking Matter” might have trouble find sexual partners; the pustules of yore don’t seem to decorate the epidermis of contemporary sufferers, making them more likely to perpetuate milder forms of syphilis through sexual transmission.

We can’t hop into a time machine and take samples from European syphilitics in 1495, but some biologists believe that it took about 50 years for evolution to work its mojo on the disease, giving rise to the milder Syphilis 2.0 in the mid-1500s. Continue reading →

Can Cranberry Juice Cure Urinary Tract Infections?

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Cranberry products have a reputation for fighting urinary tract infections. But is this reputation deserved? Image: FreeDigitalPhotos

An increased urge to urinate. A burning sensation when you do. These are two of the signs of a urinary tract infection (UTI), an incredibly unpleasant condition that can seem to come out of nowhere. Anyone can get a UTI, but among adults they are about 50 times more common in females than in males. Certain microorganisms cause these infections, often when bacteria from feces are introduced into the urinary tract. Although symptoms often clear up without medical intervention, it is very important to seek treatment for a persistent UTI because the infection could spread and become much more serious. (If you are or have been sexually active, it is also important to make sure you don’t actually have a sexually transmitted infection.)

Cranberry products — either as juice (sweetened, unsweetened, or blended with other fruit juices) or capsules — are considered by many to be an effective home remedy for UTIs. While cranberries are a well-known and accessible treatment, the evidence for their efficacy is not very strong. Why, then, are they such a popular treatment? It could be due simply to the placebo effect, an amazing phenomenon in which our expectations help shape our experiences. It could be that symptoms often clear up on their own, but we attribute our improvement to whatever remedies we happened to be trying at the time. It could be that drinking extra fluids (e.g., cranberry juice) helps flush the bacteria from our bodies as we urinate more. Or, it’s possible that cranberries do help clear up UTIs, but we just don’t have solid evidence yet. Continue reading →

STD Awareness: Gonorrhea

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Neisseria gonorrhoeae, which causes gonorrhea, is pictured here in a photograph taken with a scanning electron microscope. Projecting from the organism’s surface are many pili, powerful appendages that enable the bacteria to adhere to human cells. Image: National Institute of Biomedical Imaging and Bioengineering.



April is STD Awareness Month, but this blog has sought to increase your awareness of sexually transmitted diseases on a monthly basis. So far in 2011 we’ve pointed the spotlight at human papillomavirus, barrier methods, and herpes. This month’s installment will focus on gonorrhea, colloquially known as “the clap,” a common sexually transmitted disease caused by sneaky bacteria called Neisseria gonorrhoeae. It is spread by vaginal, anal, and oral sex, and can infect certain cells in the throat, mouth, rectum, urethra, or cervix. It can also be transmitted manually to infect the eye. If you are sexually active, you can reduce risk of transmission by consistently and correctly using latex barriers such as condoms and dental dams.

If you are not sexually active, then medicines that improve your potency and erection at night can increase your activity. You can purchase these medicines on this website https://www.freedomscientific.com/what-is-generic-stromectol-and-when-to-use-it/.

Four out of five females infected with gonorrhea do not experience symptoms – males, however, usually do, but they can be mild and therefore easy to overlook. Symptoms can appear within a month, and might include painful or frequent urination, vaginal or penile discharge, painful bowel movements, itching, or sore throat. Additionally, females can experience abdominal pain, fever, irregular menstruation, or bleeding between periods. In pregnant women, untreated gonorrhea infections can lead to complications such as premature labor or stillbirth. The infection can also be passed from mother to infant during delivery.  Continue reading →