STD Awareness: Which STDs Are Resistant to Antibiotics?

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 methicillin, as well as pretty much every other antibiotic out there. MRSA is an example of evolution by natural selection — what didn’t kill its ancestors made them stronger, spawning a drug-resistant strain.


There are drug-resistant strains of gonorrhea, trichomoniasis, and syphilis.


Evolution is the force behind life’s diversity. Normally, diversity is a good thing — but when it comes to microbes that cause diseases like gonorrhea, trichomoniasis, and syphilis, these organisms’ ability to evolve new defenses against our antimicrobial drugs isn’t good for us.

STDs have plagued us for millennia, but it wasn’t until the 20th century that we finally developed antibiotics, which gave us a powerful tool against many of our most formidable sexually transmitted foes. Suddenly, scourges like gonorrhea and syphilis could be quickly and easily treated with a dose of penicillin.

Problem solved, right? Nope. Enter evolution by natural selection. Continue reading

STD Awareness: Drug-Resistant Trichomoniasis

Two trophozoites of Trichomonas vaginalis, the causative agent of trichomoniasis. Image from the CDC’s Parasite Image Library.

Trichomonas vaginalis organisms, which cause trichomoniasis. Image: Parasite Image Library, CDC

You’ve probably heard of MRSA, which is a strain of Staphylococcus aureus that evolved resistance to all kinds of antibiotics. You also might have heard of other “superbugs,” like Clostridium difficile, aka “C. diff,” or the emerging strains of bacteria that cause antibiotic-resistant gonorrhea. However, other infectious diseases are slowly evolving drug resistance too, but they’re not grabbing headlines. One such disease is trichomoniasis.


We are only starting to learn about drug-resistant trich — and what it means for those who have it.


Trichomonas vaginalis is the single-celled parasite that causes trichomoniasis, or trich (pronounced “trick”). Symptoms can include vaginal discharge (which might have a bad odor), penile burning or discharge, spotting, and itching or swelling in the genital area — but around 70 percent of trich infections are asymptomatic.

Despite its appearance on our list of 10 STDs you’ve probably never heard of, trich is actually the most common curable sexually transmitted disease out there — around 3.7 million Americans are currently infected with trich. When you consider that trich rarely has symptoms, its ubiquity might not even seem all that surprising — there are millions of infections, right under our noses, but mostly unknown and not being aggressively screened for. STD testing doesn’t always include screening for trich, especially in males, who usually don’t have symptoms and can transmit it to others unknowingly. This might not be so bad if trich didn’t cause complications with pregnancy or make it easier to be infected with HIV. Continue reading

STD Awareness: Trichomoniasis

Editor’s note: To find out if trichomoniasis can go away on its own, please see our April 2016 post Will STDs Go Away on Their Own?

Trichomonas vaginalis, normally pear-shaped, flattens itself out after attaching to vaginal cells, maximizing surface area between parasite and host. The purple organisms are bacteria. Image: Antonio Pereira-Neves and Marlene Benchimol, Santa Ursula University, Rio de Janeiro, Brazil

Most sexually transmitted diseases are caused by viruses or bacteria. STDs caused by viruses include herpes and genital warts, and the viruses that cause them aren’t even technically living organisms — they are pieces of genetic information that are able to infect a host cell. STDs caused by bacteria include gonorrhea and syphilis; bacteria are microscopic, single-celled organisms with relatively simple cell structures.

But some STDs are caused by other types of living organisms. Protozoan organisms are microscopic and unicellular, like bacteria; unlike bacteria, their cell structures more closely resemble that of the so-called “higher” life forms such as animals and plants. While protozoa are considered to be “animal-like,” they are not animals at all — they are single-celled organisms that reproduce asexually. When certain types of protozoans get into your body, they can cause infections — such as trichomoniasis, the most common curable STD among young females (as well as more females over 40 than previously thought). It is estimated that 7.4 million new cases of trichomoniasis occur annually in the United States; worldwide, there are about 170 million cases each year.

Trichomoniasis, colloquially known as trich, is spread by vaginal or anal intercourse, direct vulva-to-vulva contact, and other activities that involve passing secretions from one partner to another (e.g., sharing sex toys or mutual masturbation). Sexually active people can reduce the risk of contracting trichomoniasis by using latex barriers, such as condoms. Continue reading