STD Awareness: The Surprising Sexual Transmission of Non-STDs

What is a sexually transmitted disease, or STD? If someone catches their partner’s cold during sex, is that cold an STD? According to the Office on Women’s Health, an STD is “an infection passed from one person to another person through sexual contact.” Unless the cold was passed through sexual contact, rather than mouth-to-mouth contact, it would not be considered an STD. Others say that, for an infection to be considered an STD, its sexual transmission must make it significantly more common in the population. So, a disease like the common cold would probably be just as common even if people never had sex.


MRSA, meningitis, and the virus that causes pinkeye can be transmitted sexually.


However, there are some infections, such as hepatitis C or bacterial vaginosis, whose status as official STDs is controversial. While researchers argue with one another over where to draw the line between an STD and a non-STD, let’s take a look at some bacteria and viruses that can be transmitted sexually, even though they’re not officially categorized as “STDs.”

MRSA: Methicillin-Resistant Staphylococcus aureus

MRSA bursting out of a dead blood cell. Image: Frank DeLeo, NIAID

MRSA bursting out of a dead blood cell. Image: Frank DeLeo, NIAID

You’ve probably heard of MRSA, which is pronounced “mersa” and stands for methicillin-resistant Staphylococcus aureus — a strain of bacteria that is resistant to every antibiotic in the penicillin family, as well as others. S. aureus, or “staph” for short, is the same bacteria responsible for TSS, or toxic shock syndrome, which has most infamously been associated with the use of highly absorbent tampons. But mostly, staph is a common cause of skin infections, which could be deadly in the pre-antibiotic era, but these days usually don’t raise too many eyebrows.

Unfortunately, with the emergence of MRSA, which is difficult to treat with the usual drugs, we might once again have to worry about minor skin infections blossoming into life-threatening conditions. Additionally, MRSA has found a way to hop from person to person via sexual contact, and sexually transmitted MRSA has been documented in both heterosexual and MSM (men who have sex with men) populations. Untreated, it can lead to a form of gangrene in which tissue blackens as it dies. Continue reading

Get Smart About Antibiotics!

This week we celebrate Get Smart About Antibiotics Week. Antibiotics, or antimicrobials as they are also called, cure bacterial infections by killing bacteria or reducing their ability to reproduce so your own body’s immune system can overcome an infection. Penicillin was the first antibiotic, and was discovered in 1924 by Alexander Fleming. Since its widespread use, beginning in the 1940s, countless lives have been saved from devastating bacterial infections. Talk about a wonder drug!


Improper use of antibiotics can have dangerous consequences.


Since then, different types of antibiotics have been developed to combat many different types of infectious bacteria. Classes of antibiotics include penicillins, cephalosporins, macrolides, fluoroquinolones, aminoglycosides, and others. In each of these classes there are lots of different individual medications. (For example, cephalosporins include the drugs cephalexin, ceftriaxone, cefaclor, and others.) Some antibiotics are broad spectrum, which means they work on many different bacteria. Some are more narrow spectrum, used for specific bacteria.

Antibiotics only work for bacterial infections … not viral infections. They are ineffective at killing viruses. Viral infections include colds, flu, runny noses, most coughs and bronchitis, and sore throats unless they are caused by strep. Sexually transmitted viruses include human papillomavirus (HPV), herpes simplex virus, and HIV. Continue reading

STD Awareness: Antibiotic-Resistant Gonorrhea

Under the microscope, Neisseria gonorrhoeae infects larger human cells (click to enlarge). The bacteria resemble tiny pairs of coffee beans. Image: Dr. Norman Jacobs, CDC

Under the microscope, Neisseria gonorrhoeae infects larger human cells (click to enlarge). The bacteria resemble tiny pairs of coffee beans. Image: Dr. Norman Jacobs, CDC

Writing about sexually transmitted diseases (STDs), one must walk the line between warning readers of risks and engaging in full-fledged alarmism. So it’s a bit disconcerting that researchers writing in the New England Journal of Medicine last month declared that it’s “time to sound the alarm”: The emergence of completely antibiotic-resistant gonorrhea is becoming more of a realistic threat and less of a theoretical possibility. The bacteria that cause gonorrhea are evolving faster than we can develop effective antibiotics against them, and a return to the era of untreatable gonorrhea could see a rise in the particularly nasty complications that arise from a long-term gonorrheal infection, such as pelvic inflammatory disease and epididymitis.


There are genes that confer resistance to every single antibiotic we use to cure gonorrhea. If they all combine within one organism, we might have a superbug on our hands.


Neisseria gonorrhoeae is a species of tricky bacteria that cause gonorrhea, which can infect the mouth, throat, rectum, urethra, cervix, and even eyes. These bacteria have vexed us for thousands of years, having evolved many strategies for entrenching themselves in our bodies. They can alter the proteins that adorn their surfaces, rendering our immune systems incapable of recognizing them. They can form colonies in which they work together to manipulate our cell surfaces with their retracting appendages until they’re allowed entry inside, where they can surreptitiously multiply.

You’ve probably heard of MRSA, which is pronounced “mersa” and stands for methicillin-resistant Staphylococcus aureus — a strain of bacteria that has acquired resistance to methicillin, as well as pretty much every other antibiotic to boot. MRSA is an example of evolution by natural selection — what didn’t kill its ancestors made them stronger, spawning a drug-resistant strain.

Why are we talking about MRSA in a post about STDs? It’s not just because MRSA has apparently found a way to be transmitted sexually, but also because it helps make the concept of antibiotic-resistant gonorrhea more accessible. It wasn’t until less than a century ago that we finally developed a magic-bullet treatment for gonorrhea, and for a handful of decades it was quickly and easily treated with a dose of penicillin. Enter evolution by natural selection. Continue reading