Bacterial Sexually Transmitted Disease

Abstract

Sexually transmitted diseases are among the most contagious infections caused by a variety of microorganisms such as viruses, bacteria, fungi, and protozoa. Worldwide, the incidence of bacterial sexually transmitted infections has shown a gradual increase in recent years. Common bacterial sexually transmitted diseases are Chlamydia, gonorrhea, and syphilis. Any person with signs or symptoms suggestive of bacterial sexually transmitted infections should receive a test, even if he or she does not have symptoms or know of a sex partner. Bacterial sexually transmitted diseases can be cured with the right treatment. It is important to take all medications based on the prescription to cure the sexually transmitted infection. Chlamydia is the most common bacterial sexually transmitted infection globally. Gonorrhea strains that are multi-drug resistant have been widely dispersed worldwide. Neisseria gonorrhoeae has a high level of antibiotic resistance, leading to untreatable infections that could one day pose a serious threat to public health and present the greatest obstacles to the prevention and management of sexually transmitted illnesses. Because there is no documented penicillin resistance, penicillin remains the first-line therapy for syphilis.

1. Introduction

Sexually transmitted diseases (STDs), often known as “venereal diseases,” are among the most contagious diseases and are caused by a variety of microorganisms that differ in symptomology, size, life cycle, and treatment susceptibility. Bacteria, viruses, fungi, and protozoa are indeed the pathogens of STDs [1, 2].

These germs can spread from one person to another through blood, sperm, vaginal, and other physiological fluids. As a result, sexually transmitted infections (STIs) are passed from one person to the next by close physical contact, primarily but not solely through sexual intercourse. Ejaculation does not have to occur for STIs to be transmitted from person to person [1, 3].

Nonsexual transmission of these infections happens often from mother to newborn during pregnancy and childbirth, through blood transfusions, and through the sharing of unsterilized needles. Any sexually active individual should discuss his or her risk factors for STIs with health professionals and ask to get a test because anyone may have an STI even without showing any symptoms [1].

Although some infections, including meningitis, can be transmitted through sexual contact, they are not considered STDs because the germs that cause meningitis can already be found in the body or in the environment, and people can get the disease for a variety of reasons [1, 2].

The prevalence of STDs remains high in poor nations, with emerging countries bearing a disproportionate share of the burden. The World Health Organization (WHO) estimates that 374 million new infections with one of four STIs will occur in 2020, which indicates that there are almost 1 million STIs acquired every day. The most prevalent STI is Chlamydia, which accounts for 129 million new infections each year. Gonorrhea has 82 million new infections per year, and syphilis has 42 million new infections annually [3].

Common bacterial STIs may affect the anorectum and perianal skin. Some of these infections are a result of the contiguous spread of sexual intercourse. Worldwide, the incidence of bacterial STIs has shown a gradual increase in recent years. The fast spread of these infections may be due to their varied clinical presentation, which includes pharyngeal, rectal, and urogenital involvement, as well as a significant number of asymptomatic cases [4, 5].

The symptoms of STIs differ between individuals depending on the causative pathogens, and commonly, many people may not experience any symptoms at all. Immediate initiation of STIs treatment is important to minimize the long-term complications of STIs and also prevent the transmission of infections to other people. Common bacterial sexually transmitted diseases are Chlamydia, gonorrhea, and syphilis [1].

2. Chlamydia

Chlamydia is a bacterial STD caused by the organism Chlamydia trachomatis (C. trachomatis), an intracellular organism that produces clinical illness within 1–2 weeks after exposure, which can damage a woman's reproductive organs and cause cervicitis, urethritis, and prostatitis, which occur mostly in young (15–24-year-old) individuals, mostly prevalent in young women [6].

The infection is more likely transmitted during unprotected sexual intercourse through vaginal, anal, or oral sex with someone with the infection, even though semen does not have STI pathogens to transmit the infection from person to person. Women can get Chlamydia in the cervix, rectum, and throat. Men can get Chlamydia in the urethra, rectum, and throat [6, 7, 8]. During childbirth, chlamydial infection is also passed from mother to baby [9, 10].

For behavioral, biological, and cultural reasons, sexually active young individuals are at high risk of getting chlamydial infection. Multiple abnormalities can result from C. trachomatis infection in women including pelvic inflammatory diseases (PIDs), ectopic pregnancy, and infertility. Sometimes women receiving a diagnosis of uncomplicated cervical infection may have asymptomatic upper genital tract infection [6].

Chlamydial infection is commonly asymptomatic both in women and men. Health sector institutions frequently rely on screening tests for all sexually active women aged <25 years, and recommended annual screening for high risky individuals (women aged ≥25 years who have more than one sex partner, a new sex partner, or a sex partner who has an STIs) to detect chlamydial infection [2].

Chlamydia is a global public health problem that is the leading bacterial sexually transmitted infection in developed and undeveloped countries. Nonlymphogranuloma venereum (LGV) serovars infection is mostly asymptomatic but can produce aggressive infection manifest by perianal, anal, or rectal ulceration with resulting pain and discharge [11].

Even though evidences are insufficient to recommend routine screening for C. trachomatis among sexually active young men because of different factors (i.e., efficacy, feasibility, and cost-effectiveness), where there are clinical settings with a high prevalence of Chlamydia sexually active young men should be screened. The primary focus of women diagnosed with Chlamydia infection should be to detect and treat the infection, prevent complications, and to treat their partners, whereas men should be screened for Chlamydia only when resources permit and prevalence is high [2].

2.1 Clinical manifestation

Chlamydia trachomatis causes infection of the lower and upper genital tracts of both sexes, thus having a great influence on reproductive health. Chlamydia usually does not cause any symptoms but can still transmit the disease to others. Asymptomatic infection is frequent in women; many women with Chlamydia sampled from the cervix have no signs or symptoms of infection [6, 12].

No genital symptoms are specifically correlated with chlamydial cervical infection. But over 70% of men experience symptoms, such as urethral discharge, penile discomfort, and dysuria, which may cause serious complications that result in irreversible damage, including infertility [13].

Chlamydial infection may cause induced endocervical bleeding and mucopurulent endocervical discharge. The observation of purulent yellow or greenish cervical discharge on a cervical swab is associated with the presence of chlamydial infection [14]. When a woman does not receive treatment; Chlamydia can spread into the uterus or fallopian tubes, causing PIDs, which occur in about 10–15% of women [6, 15, 16]. In young, sexually active men, about 70% of acute epididymitis appears to be attributable to chlamydial infection [17].

2.2 Diagnosis

Since chlamydial infections may not have specific symptoms and are often indistinguishable, laboratory diagnosis is necessary to identify the correct etiology; the cell culture, and nucleic acid amplification tests (NAATs) were the gold standard tests for detection for years. Cell culture is the most sensitive test to use on easy-to-obtain specimens [10, 13].

The other most widely used diagnostic methods are the direct fluorescent antibody (DFA) and enzyme immunoassay (EIA) tests. Polymerase chain reaction (PCR) in the diagnosis of chlamydial infection has also been a gold standard [18]. Chlamydial trachomatis infection can be diagnosed by cervical or vaginal swabs or first-void urine for women, and for men can be diagnosed by testing a urethral swab or first-void urine similar to women [2].

2.3 Treatment

Chlamydia can be cured easily with antibiotic medications. Although medical treatment will cure the infection, the disease will not repair any long-term damage alone. To prevent spreading the infection to sex partners, patients starting single-dose antibiotic therapy should not have sex until the treatment is completed [6]. In some cases, chlamydial infection recurs 3–6 weeks after treatment [19].

• Adolescent and adult chlamydial infection treatment regimen: doxycycline 100 mg orally two times/day for 7 days; alternatively; azithromycin 1 g orally in a single-dose or levofloxacin 500 mg orally once daily for 7 days are recommended.

• Azithromycin 1 g orally in a single dose is recommended for chlamydial infection during pregnancy or amoxicillin 500 mg orally three times per day for 7 days.

• The following is the recommended treatment regimen for neonatal chlamydial infection: Erythromycin base or ethyl succinate 50 mg/kg body weight per day, divided into four doses per day for 14 days

• For pregnant women with chlamydial infection, a single dose of azithromycin 1 g orally is recommended, and alternatively amoxicillin 500 mg orally three times a day for 7 days [2].

3. Additional management considerations

An individual treated for Chlamydia infection should be instructed to abstain from sexual intercourse for 7 days after single-dose therapy to minimize disease transmission to their sexual partners. To minimize the risk of reinfection, an infected person should abstain from sexual intercourse until all of their sex partners have been treated.

Multiple coinfections may happen when a person receives a diagnosis of Chlamydia infection and should be tested for human immunodeficiency virus (HIV), syphilis, and gonorrhea. Test of cure to detect therapeutic failure is not advised for non-pregnant persons treated with the recommended unless therapeutic adherence is in question, reinfection is suspected or symptoms persist. If an individual had sexual contact with chlamydial infected person, the sex partners of the infected person should be referred for evaluation, testing, and presumptive treatment [2].

4. Gonorrhea

Gonorrhea is an STD that is caused by the bacterium Neisseria Gonorrhoeae (N. gonorrhoeae) that can infect all individuals. Gram-negative diplococcus, N. gonorrhoeae, is initially identified in 1879 by Albert Neisser from exudates of urethritis and cervicitis. Humans are the only natural reservoir of N. gonorrhoeae with an incubation period of 1–14 days [5, 20].

It can cause infections in the genitals, rectum, and throat, which affect young people ages 15–24 years. Men who experience symptomatic urethral infections may seek curative therapy, whereas women frequently experience asymptomatic infections caused by N. gonorrhoeae. Asymptomatic infection from N. Gonorrhoeae may affect the women’s urethra, endocervix, rectum, and pharynx, which make up the main reservoir for gonococcal infection [21].

Gonorrhea can spread by having sexual contact with an infected person, and from mother to child during childbirth. Gonorrhea is the second commonly reported bacterial sexually transmitted diseases, and the incidence of new cases of gonorrhea is especially high in developing countries, which can produce symptoms in men that cause them to seek curative treatment to prevent complications [22, 23].

Annual screening for N. Gonorrhoeae infection is recommended for all sexually active women aged <25 years and for older women at increased risk for infection. Risk factors for gonorrheal infection include inconsistent condom use among persons who are not in mutually monogamous relationships, exchanging sex for money, and coexisting STIs [2].

4.1 Clinical manifestation

Gonorrhea may have no symptoms, but some men may have a burning sensation when urinating; white, yellow, or green discharge from the penis; painful or swollen testicles, and some women may often have a painful or burning sensation when urinating; increased vaginal discharge/vaginal bleeding, which may have a risk of developing serious complications [24].

If gonorrhea is not appropriately treated, it can lead to pelvic inflammatory disease, infertility, and ectopic pregnancy. Pregnant women can pass the gonorrheal infection to their babies during childbirth, and the newborn can become blind or have life-threatening infections as a result [21].

Anorectal gonococcal infection shows a thick purulent discharge that is expressed from the anal crypts in response to external anal pressure. Nonspecific findings of mucosal erythema, edema, friability, and pus are noted in infected individuals with proctitis from rectal infection [4].

4.2 Diagnosis

Specific microbiologic diagnosis of N. gonorrhoeae infection should be performed for all persons at risk of having gonorrhea, which can potentially reduce many related complications [2]. Urine can be used to test for ureteral infection of gonorrhea. However, if there is oral and/or anal sex, swabs may be used to collect samples from the throat, rectum, and cervix. Cell culture, nucleic acid hybridization tests (NAHTs), and nucleic acid amplification tests (NAATs) are available for the detection of genitourinary infection with N. gonorrhoeae [20].

The standard diagnostic procedure for men with symptomatic urethritis is the gram stain, because of its high specificity and sensitivity. However, in asymptomatic men or women with genital infections, the Gram stain is less useful because of its lower sensitivity. Gram stain of endocervical specimens, pharyngeal specimens, or rectal specimens is not sufficient to detect infection and therefore is not recommended [25].

The result of cultural diagnosis may be reduced if lubricants with antibacterial agents are used during anoscopy, which makes water a recommended lubricant in this setting. There are no approved nucleic acid amplification tests for rectal infection, while nonculture techniques are gaining acceptance in genital gonococcal infections [26].

Certain NAATs that have been demonstrated to detect Neisseria species might have low specificity when diagnosing oropharyngeal specimens for N. Gonorrhoeae but NAAT sensitivity for identifying N. Gonorrhoeae from nongenital and urogenital sites is superior to culture even though it may vary by NAAT type. Optimal specimen types for gonorrhea screening using NAATs include vaginal swab specimens for women and first-void urine for men [27].

4.3 Treatment

Gonorrhea treatment is complicated by the ability of N. Gonorrhoeae to develop resistance to antimicrobials. There is a high level of antimicrobial resistance in N. Gonorrhoeae, resulting in untreatable infections that in the future may become a significant major public health issue and pose the greatest challenges to the prevention and control of sexually transmitted infections [20].

Many of the previously recommended therapies are no longer effective, which makes treatment opportunities for N. Gonorrhoeae limited. Therefore, new dual antimicrobial treatment regimens are urgently needed [20, 28]. Zoliflodacin is the new recommended oral antibiotic that successfully treats most cases of uncomplicated gonorrhea [21].

• Recommendation regimen for gonorrheal infection of the pharynx, cervix, urethra, or rectum that is not complicated. If chlamydial infection has not been ruled out, treat for 7 days with doxycycline 100 mg orally twice a day.

• Alternative regimens if ceftriaxone is not available; gentamicin 240 mg IM in a single-dose, plus azithromycin 2 g orally in a single dose, or cefixime 800 mg orally in a single-dose [2].

5. Antimicrobial-resistant N. gonorrhoeae

Gonorrhea treatment may be complicated by the ability of N. gonorrhoeae specious to develop resistance to antimicrobials drugs. Due to the emerging antimicrobial resistance dual therapy for gonorrhea with a cephalosporin plus either azithromycin or doxycycline, even if NAAT for C. trachomatis was negative at the time of treatment recommended by the center for disease control in 2010. Azithromycin might predispose to resistance due to its prolonged half-life [27].

6. Syphilis

Syphilis is one of the most prevalent bacterial STDs caused by the Treponema pallidum T. pallidum) bacterium. It infects the genital area, lips, mouth, or anus of both men and women. Syphilis is transmitted between people by direct contact with a syphilis sore during vaginal, anal, or oral sex and can spread from a mother with syphilis to her unborn baby during pregnancy and childbirth. It is not transmitted through the use of the same toilet; wearing the patient's clothes, or even using food utensils [12].

It is a contagious disease that can cause serious health problems, such as arthritis, brain damage, dementia, and blindness, and may lead to death if left untreated. Syphilis is often difficult to diagnose, and the patient may not have any symptoms for years [1].

T. pallidum can infect the central nervous system at any stage of syphilis that result in neurosyphilis. Early neurologic clinical manifestations of syphilitic meningitis are usually present within the first few months of infection. Late neurologic manifestations occur 10 to >30 years after infection. Ocular syphilis and otosyphilis can occur at any stage of syphilis but are commonly identified during the early stages and can occur with or without central nervous system (CNS) involvement [2].

6.1 Stages of Syphilis

Syphilis infection is divided into four stages with different symptoms that appear in the patient. The symptoms and signs associated with each stage may overlap each other, and symptoms may not appear in order. Some patients have not had any symptoms for years. After the initial infection, the bacterium T. pallidum can remain inactive in the body before becoming active many times, and it needs 21 days to show the first symptom after the acquisition of a syphilis infection [5, 29].

Primary syphilis: During the primary stage of syphilis, a single sore or multiple sores may be noticed, which usually lasts 3–6 weeks and heals regardless of taking the treatment. The primary stage of anorectal syphilis that comes through anal intercourse appears within 2–10 weeks of exposure. The anal chancre is a small indurated papule that eventually upgraded to anal ulcers; located on the perianal skin or in the anal canal; may be single or multiple; are associated with painless but prominent inguinal lymphadenopathy but heals without treatment in 2–4 weeks. Anal ulcers contrasts with genital ulcers are frequently painful [30, 31]. Even after the sore goes away, continuing the treatment is recommended; this will stop the infection from moving to the secondary stage [29].

Secondary syphilis: Four to ten weeks after primary syphilis appears, the spreading of hematogenous untreated syphilis infection leads to secondary stage syphilis [4]. During the secondary stage, the patient may have skin rashes and/or mucous membrane lesions. The rash can appear 2–8 weeks after the chancre develops and sometimes before it heals. The rash may look like rough, red, or reddish-brown spots on the bottoms of the feet and the palms of the hands. This rash does not usually cause itching, but it may be accompanied by wart-like sores in the mouth and sexual areas [29].

The infection is highly contagious during this stage. The symptoms at this stage will go away when the treatment is initiated. Without the right treatment, the infection will move to the latent and tertiary stages of syphilis [1, 5, 29]. The majority of untreated symptoms of syphilis spontaneously resolve after 12 weeks. One-fourth of these untreated patients will experience early latent syphilis [4].

Latent syphilis: The latent stage of syphilis is a period when there are no visible signs or symptoms. Without treatment, the infected person continues to have syphilis in his/her body for years. The infection is contagious in the early part of the latent stage and may continue its transmission even without showing symptoms [1, 29].

Tertiary/Late syphilis: This is the most destructive stage, in which complications of syphilis appear in patients who have not undergone the required treatment. Tertiary syphilis is very serious and would occur 10–30 years after the infection began. In tertiary syphilis, the disease damages the internal organs, which results in death [1, 4, 29].

6.2 Diagnosis

Dark field microscopic examinations and molecular tests for detecting T. Pallidum directly from lesion exudate are methods for diagnosing early syphilis and congenital syphilis. Another method for diagnosis is the demonstration of spirochetes in biopsy specimens stained with Warthin-Starry Silver. Alternatively, a direct fluorescent antibody test for T. Pallidum is performed by some laboratories (11,25).

A nontreponemal test (i.e., venereal disease research laboratory [VDRL] or rapid plasma reagin [RPR] test) and a treponemal test (Treponema pallidum passive particle agglutination [TP-PA] assay), chemiluminescence immunoassays [CIAs] and immunoblots, or rapid treponemal assays are the diagnostic methods of syphilis [4, 29].

6.3 Treatment

• For adults and adolescents with primary, secondary, or early latent syphilis; benzathine penicillin (G 2.4 million units) is administered intramuscularly in a single dose.

• For adults and adolescents with late latent syphilis or latent syphilis of unknown duration; benzathine penicillin G 7.2 million units total, administered as three doses of 2.4 million units each administered intramuscularly at weekly intervals.

• For neurosyphilis, ocular syphilis, or otosyphilis; aqueous crystalline penicillin G 18–24 million units per day, administered as 3–4 million units intravenously every 4 hours or continuous infusion for 10–14 days [2, 32].

7. Additional management options

All individuals who have primary and secondary syphilis are encouraged to take an HIV test at the time of diagnosis and treatment and recommended to offered HIV PrEP for negative HIV test results. Persons who have symptomatic neurologic syphilis disease should have an evaluation that includes cerebral spinal fluid analysis and individuals with syphilis who have symptoms of ocular syphilis should have cranial nerve and ophthalmologic examinations [2].

8. Follow-Up

Clinical and serologic investigations should be needed within 12 months of treatment; if conditions for follow-up are uncertain more frequent evaluation might be prudent. Assessing serologic response to treatment can be difficult, and definitive criteria for evaluating treatment outcomes by serologic criteria have not been well established [33].

In addition, nontreponemal test titers might decrease more slowly for persons previously treated for syphilis. Among individuals with neurologic findings without any reported sexual exposure during the previous 3–6 months indicating that treatment failure might be possible, a cerebral spinal fluid examination is recommended, and should also be reevaluated for HIV infection [34].

9. Prevention of bacterial STDs

Abstain: When there is no open discussion about a sexual partner’s past sexual health history, abstaining from sexual activity is the most efficient strategy to avoid STIs.

Communicate and double-check: Always discuss safe sex prior participating in just about any substantial sexual contact. Because sexually transmitted illnesses do not often show symptoms, it is possible to be infected without realizing it. So, avoid vaginal and anal intercourse before checking for STDs. Oral sex was not without risks, but it is less dangerous. To avoid direct touch, use a latex condom or a dental dam.

Use condoms and dental dams consistently: If abstinence is not the first choice, use latex condoms to decrease the possibility of getting infected with sexually transmitted illnesses. When using a latex condom or dental dam, avoid using petroleum lubricants like petroleum jelly. Furthermore, condoms composed of natural membranes are ineffective at preventing STDs.

Avoid excessive alcohol or drugs: People who are prone to consuming excessive alcohol or drugs are more likely to take sexual risks [5].

Conflict of interest

The authors declare no conflict of interest.

CNS	Central Nervous System
CIAs	Chemiluminescence Immunoassays
DFA	Direct Fluorescent Antibody
EIA	Enzyme Immunoassay
LGV	Nonlymphogranuloma Venereum
NAATs	Nucleic acid amplification tests
RPR	Rapid Plasma Regain
STDs	Sexually Transmitted Diseases
STIs	Sexually Transmitted Infections
TP-PA	Treponema Pallidum Passive Particle Agglutination
VDRL	Venereal Disease Research Laboratory
WHO	World Health Organization