Bacterial STDs: Symptoms and Treatment

Between 2013 and 2017 there was a dramatic increase of bacterial STD infections in the US, with a 22% increase in chlamydia, 67% increase in gonorrhea, and a 76% increase in syphilis cases.[1]

Incidences of syphilis had reached a historic low around the year 2000 but have increased every year since then and are now commonly included in STD screenings.[2]

Untreated bacterial STDs can cause long-term pain, increased risk of contracting HIV, and even infertility. Thankfully, there are antibiotic treatments that can cure these infections, but new strains of antibiotic-resistant bacteria are worrying public health officials.[1]

Causes of infection

Bacterial STD infections are spread through unprotected vaginal, anal, or oral sex. Any human contact can spread a bacterial infection, but sex is a particularly efficient transmission method due to the intimate contact of saliva or fluids that contain bacteria.

Specific lifestyle choices put you at a higher risk of contracting an infection, such as multiple or new sex partners, inconsistent or incorrect condom usage, and living in an urban area where STD rates are high. Infection rates differ between gender, race, sexuality, and geographic location.[3]

Certain underlying conditions, like bacterial vaginosis in women, can put you at increased risk of contracting an STD.[4]

Symptoms of infection

Symptoms differ between the sexes, with some bacterial STDs commonly having no symptoms in women.

It's important to be screened for STDs regularly if you are sexually active. If you notice any symptoms shortly after having sex with a new partner, go see a doctor to be tested.

  • Male genitals – Burning while peeing or inflammation of the urethra (urethritis) within days after sex are symptoms of a bacterial infection. You may also have white pus coming out of the tip of the penis, and swelling or tenderness in the testicles.[3][5]
  • Female genitals – Symptoms in women are uncommon, but they may include painful urination, inflammation of the cervix (cervicitis), and bleeding between menstrual periods (intermenstrual), or bleeding after sex (postcoital).[3][5][6]
  • Oral – Symptoms of a throat infection are uncommon, but may include an itchy or sore throat, or trouble swallowing after giving oral sex.[7]
  • Anal – Symptoms of an anorectal infection are uncommon, but they may include rectal pain or irritation, painful defecation, itching, or constipation.[3][5]

Common bacterial infections

The recent spike in STD infections is primarily due to an increase in cases among gay and bisexual men. The southern and western US tend to have higher rates of infection, and reported rates among blacks are higher than all other racial groups.[3][8][9]

  • Chlamydia trachomatis (chlamydia) – Chlamydia can infect the genitals, anus, and throat and is the most common bacterial STD in the US with over 1.7M cases in 2017. Infection rates have been climbing for several decades with no signs of slowing down. The infection is most common in young women aged 15-24 years old, and geographically most common in the southern US. Women have roughly twice the incidence as men and usually have no symptoms. The Centers for Disease Control (CDC) recommends annual chlamydia screening for all sexually active women younger than 25 years old, and for older women at increased risk for infection. Standard treatment of antibiotics is single-dose azithromycin (1000 mg) or a 7-day course of twice-daily doxycycline (100 mg). Some variations of the bacteria (serovars) can cause lymphogranuloma venereum, an infection of the genital lymph nodes.[5][8][10][11]
  • Neisseria gonorrhoeae (gonorrhea) – Gonorrhea infections peaked in the 1970s and then reached historic lows, but have since been increasing and gaining antibiotic-resistance. Doctors are down to only one class of antibiotics left that can reliably treat gonorrhea. Gonorrhea can infect the genitals, anus, and throat and is now the second most common bacterial STD in the US with over 500k cases in 2017. The infection is most common in men aged 20-29 years old, and geographically most common in the southern US. Standard antibiotic treatment recommended by the CDC is with a dual therapy of ceftriaxone injection (250 mg) and azithromycin pill (1000 mg). This course of treatment can also cure chlamydia, so it is recommended in cases where a bacterial STD is suspected but not yet confirmed. Men usually experience inflammation of the urethra (urethritis), and 70% of men have urethritis symptoms within 3 days of exposure. At least 50% of women with genital infections have no symptoms.[1][3][12][13]
  • Treponema pallidum (syphilis) – Syphilis rates were high in the early 1900s but declined rapidly after the introduction of the antibiotic penicillin. Around the year 2000, infection rates were so low in the US that public health authorities declared syphilis eradication a feasible goal. Unfortunately, infection rates have risen every year since then and syphilis is now the third most common bacterial STD with over 100k reported cases in 2017. If left untreated, syphilis progresses in stages that can potentially affect every organ system, and cause serious complication in pregnant women including stillbirth. The infection is most common among men aged 20-29 years old, is 7 times more common in men than women, and geographically most common in the western US. Over half the cases of primary and secondary state syphilis are among gay men. Syphilis is easy to treat in its early stages: a single injection of benzathine penicillin G (2.4M units) will cure it.[2][9][14]

Bacteria being researched

Mycoplasma and ureaplasma species commonly colonize the genital tract in humans, have been associated with symptoms in both sexes, and with adverse outcomes among pregnant women. No diagnostic tests exist that have been cleared by the FDA.

  • Mycoplasma genitalium – Although not yet widely recognized as an STD, this bacteria is estimated to be more common than gonorrhea. It was first identified in the 1980s and has become a recognized cause of urethritis in men, responsible for roughly 20% of urethritis cases that are not due to chlamydia or gonorrhea, and 30% of chronic urethritis cases. Women usually have no symptoms, but the bacteria has been detected in up to 30% of women with cervical inflammation (cervicitis). This bacteria can infect the genitals and anus and should be suspected in cases of persistent or recurrent urethritis. For treatment, researchers have found azithromycin (1000 mg) to be relatively effective, but antibiotic resistance is increasing. A 7-14 day course of moxifloxacin has been successfully used to treat people with previous treatment failures, but it's only been used in a few cases, and the drug has not been tested in clinical trials.[6][15][16]
  • Mycoplasma hominis – There are indications that this bacteria is common among sexually experienced women and also may play a role in inflammation of the female sexual organs: the fetal membranes (chorioamnionitis), fallopian tubes (salpingitis), and inner lining of the uterus (endometritis). A survey in Australia found the rate of prevalence to be 13.7% of women.[17]
  • Ureaplasma urealyticum – This bacteria is associated with sexual activity and is found in 40-80% of women and 20-50% of men without symptoms, and has therefore been difficult for researchers to confirm a causal relationship with any diseases. However, the bacteria has been associated with bacterial overgrowth of the vagina (vaginosis), and inflammation of the fallopian tubes (salpingitis). It is also associated with premature pregnancies and is believed to be more virulent in that regard than mycoplasma hominis. A survey in Australia found the rate of prevalence to be 6.1% of women.[17][18][30]
  • Ureaplasma parvum – This bacteria has been associated with sexual transmission, and also with urethritis and male infertility. Studies suggest men can infect women, and there have been associations with late abortion and early preterm birth. A survey in Australia found the rate of prevalence to be 57% of women.[17][18]
  • Gardnerella vaginalis (gardnerella) – This bacteria is the predominant organism found in women with bacterial vaginosis, which has been associated with preterm birth and increased risk of acquiring HIV. However, this bacteria is also found in roughly 70% of healthy women so its role in the disease is unclear. The bacteria can be found in the urethra of men and is believed to be sexually transmitted, as condom use can decrease the rate of infection.[19][31]

Uncommon infections

These bacteria are either less commonly transmitted sexually or have been nearly eradicated by the use of antibiotics, such as chancroid.

  • Haemophilus ducreyi (chancroid) – Chancroid infections peaked in the 1940s and had a slight resurgence in the 1980s, but have since declined considerably. Symptoms include the appearance of open sores (ulcers) in the genital area. The treatment given for chlamydia or gonorrhea will also cure chancroid: a ceftriaxone injection (250 mg) or azithromycin pill (1000 mg).[20][21]
  • Neisseria meningitidis (meningococcus) – This bacteria is in the same genus as gonorrhea, but less common and only colonizes the nasal cavity (nasopharynx), therefore it can be acquired by receiving oral sex. It's commonly known to cause swelling in the brain (meningitis) but has also been associated with urethritis. In 2015 an increase was seen in the midwest US, with nearly all patients being heterosexual men with symptoms or urethritis who had received oral sex. The CDC recommends the same treatment as gonorrhea.[22]
  • Streptococcus species – Several species of this bacteria, which are commonly known to cause pneumonia and pharyngitis, have been associated with urethritis in men. They can potentially be passed through oral sex and vaginal sex, but are rarely reported.[23][24][25]

Risks from infection

Bacterial STD infections can have serious consequences if left untreated, especially in pregnant women.

  • More likely to get HIV - Chlamydia and gonorrhea are associated with increased susceptibility to HIV, and also increase transmission in men because urethritis increases HIV shedding.[3][8]
  • Pelvic inflammatory disease (PID) – This disease comprises a spectrum of inflammatory disorders of the upper female genital tract, and is a major source of infertility. Chlamydia, gonorrhea, streptococcus species, gardnerella vaginalis, mycoplasmas, and ureaplasmas have all been associated with PID.[3][8][15][26]
  • Infertility – Untreated chlamydia and gonorrhea can cause infertility. Mycoplasma species are also being studied.[3][15]
  • Chronic pelvic pain – Chlamydia and gonorrhea can cause long-term pelvic pain.[3][8]
  • Periurethral fistula – Rarely, chlamydia and gonorrhea can cause urethral scarring and abnormal connections between organs (fistulas) in men.[3][5]

Pregnancy risks

  • Ectopic pregnancy – Chlamydia and gonorrhea can increase the likelihood of a fertilized egg implanting outside the uterus, often as a consequence of PID.[3][8]
  • Stillbirth – If syphilis is acquired and untreated during the four years before birth, it can lead to infection of the fetus in up to 80% of cases and may result in stillbirth or death of the infant in up to 40% of cases.[2]
  • Preterm birth – Mycoplasmas and ureaplasmas have been associated with inflammatory reactions that lead to preterm delivery.[6][17]
  • Infant bronchopulmonary dysplasia – Ureaplasmas have been associated with chronic lung disease that affects newborns and infants.[17]
  • Passing STD to infant – STDs can be passed to the baby during birth, such as chlamydia, which can potentially lead to blindness and pneumonia, and gonorrhea, which can lead to conjunctivitis.[3][8]

Detection and treatment

Bacteria have different incubation periods in the body so they may not be detectable right away. Regardless, it's recommended to get tested right away if you have symptoms, and you can be started on an antibiotic treatment even before you get an exact diagnosis.

In the case where a bacterial STD is suspected, but not necessarily confirmed, the CDC recommends the stronger dual-therapy for gonorrhea since it will also cure a chlamydia infection if that's what it turns out to be.

  • Dual antibiotic therapy – Used for gonorrhea and can be used empirically without confirmation for chlamydia. It involves an intramuscular injection of ceftriaxone (250 mg) and an oral dose azithromycin (1000 mg). It can also be used to treat a genital N. meningitidis infection or chancroid.[12]
  • Single dose azithromycin (1000 mg) – Used for confirmed infections of chlamydia. Can also be used for M. genitalium, however if the treatment fails then the person often has an antibiotic-resistant strain.[5][15]
  • Benzathine penicillin G (2.4M units) – Used to treat syphilis, administered intramuscularly.[14]
  • 7-day course of twice-daily doxycycline (100 mg) – Alternative treatment for a confirmed infection of chlamydia.[5]
  • 7-day course of moxifloxacin (400 mg) – Alternative treatment for antibiotic-resistant M. genitalium. Treatments of 7, 10 or 14 days have been successfully used to treat people with previous treatment failures, but it's only been used in only a few cases, and the drug has not been tested in clinical trials. This class of antibiotics (fluoroquinolones) poses higher risks than others.[15]

Risks of antibiotics

Antibiotics work in different ways: some prevent the bacteria from building a cell wall, or burst its membrane, or damage its DNA. The body is full of healthy bacteria, so taking antibiotics can disrupt the natural balance in the body and cause diarrhea and other gastrointestinal symptoms.

An emerging field of science is the study of this collection of healthy bacteria and organisms in our body known as the microbiome. The microbiome has been linked to mental health, immunity, obesity, heart disease, and cancer.

Antibiotics cause a depletion of our normal healthy bacteria and an increased proportion of the remaining antibiotic-resistant microbes, which can lead to changes in our immune system.[27][28]

Unfortunately, there are no effective natural therapies against STDs and antibiotics are the only surefire way to cure the infection. In general, long-term exposure to some classes of antibiotics is considered safe.[29]

Final thoughts

It used to be the case that bacterial STDs led to long-term suffering and even death. Nowadays, we have treatments that can easily cure a bacterial infection, but antibiotics have risks of their own and there aren't any good alternatives.

The best option is clearly to avoid infection in the first place so you don't put yourself at risk. If possible, stay in a monogamous relationship with a partner who reciprocates. Always practice safe sex and get tested regularly.