Michelle Morginstin
Professor Claudia Marques
BIOL 319
7 May 2018
Gonorrhea
Gonorrhea is one of the most common sexually transmitted illnesses in the United States. It is caused by the Neisseria gonorrhoeae bacterium. According to the Centers for Disease Control and Prevention (CDC) this causative agent of Gonorrhea “infects the mucous membranes of the reproductive tract, including the cervix, uterus, and fallopian tubes in women, and the urethra in women and men” (CDC, 2017). Neisseria gonorrhoeae can also cause an infection of the eyes, throat, mouth, or rectum’s mucus membranes (CDC, 2017). However, this is not an all encompassing description. In order to fully understand this disease, one must acknowledge Gonorrhea’s infectious agent, history, modes of transmission, progression, symptoms, treatment, epidemiology, diagnosis, and prevention tactics.
Infectious Agent
Neisseria gonorrhoeae is the causative agent of a Gonorrhea infection. This bacterium is also known as gonococcus. It is a “gram-negative diplococcus” (Edwards, J. L., Apicella M. A., 2004, p. 965), meaning that N. gonorrhoeae has a thin layer of peptidoglycan in its cell wall and an outer layer that contains Lipopolysaccharide and porins. Gonococcus occurs in pairings of two cocci, or round bacteria. Neisseria gonorrhoeae is an “obligate human-specific pathogen” (Recher, C., Kühlewein, C., Müller, A., Schild, H., Rudel, T., 2007). Furthermore, N. gonorrhoeae employs numerous virulence factors, or mechanisms that allow pathogenesis. These factors “allow this bacterium to successfully adapt to variable microenvironments within its sole human host” (Edwards, J. L., Apicella M. A., 2004, p. 965). Many of these virulence factors “undergo phase and/or antigenic variation, including the pilus, opacity-associated (Opa) outer membrane proteins, and lipooligosaccharide (LOS)” (Edwards, J. L., Apicella M. A., 2004, p. 965). Moreover, N. gonorrhoeae’s porins are “associated with reduction-modifiable protein (Rmp or P.III) and with LOS in the outer gonococcal membrane” (Edwards, J. L., Apicella M. A., 2004, p. 965). This “remarkable variety of adhesins…enable the bacteria to interact with human tissue” (Recher, C., Kühlewein, C., Müller, A., Schild, H., Rudel, T., 2007).
History
Gonorrhea has a long history in the human population. References of this infection date back to “biblical times (Lev. 15:1-15:19), making gonorrhea one of the oldest recorded human diseases” (Edwards, J. L., Apicella M. A., 2004, p. 965). Additionally, implications of gonococcus can be found in ancient Chinese writings (Edwards, J. L., Apicella M. A., 2004). Hippocrates went on to describe “acute gonorrhea as ‘strangury’ obtained from the ‘pleasures of Venus’ in the fourth and fifth centuries B.C.” (Edwards, J. L., Apicella M. A., 2004, p. 966). Moreover, Galen coined the term Gonorrhea, meaning “flow of seed” in A.D. 130, after “mistakenly confus[ing] the purulent discharge associated with gonococcal urethritis with semen” (Edwards, J. L., Apicella M. A., 2004, p. 966). Furthermore, Neisseria gonorrhoeae was first described in 1879 by Albert Ludwig Sigesmund Neisser. In 1882, Leistikow and Löffler “cultivated the gonococcus” (Edwards, J. L., Apicella M. A., 2004, p. 966).
Transmission
According to the CDC, “Gonorrhea is transmitted through sexual contact with the penis, vagina, mouth, or anus of an infected partner” (CDC, 2017). Neisseria gonorrhoeae enters host cells through mucous membranes and attaches to epithelial cells. The following transmission statistics are provided by the CDC:
“Male to female via semen: Approximately 50%-70% per episode of vaginal intercourse.
Female vagina to male urethra: Approximately 20% per episode of vaginal intercourse and
increases to approximately 60%-80% after 4 or more exposures.
Rectal intercourse transmission rates have not been quantified, but rectal intercourse appears to be
an efficient mode of transmission.
Pharyngeal gonorrhea is readily acquired by fellatio but less efficiently acquired by cunnilingus.
Perinatal transmission (mother to infant) can occur during vaginal delivery.” (CDC, 2013)
Progression
A gonococcal infection does not have distinct stages; however, the time between initial infection and the presentation of symptoms varies between genders and the sites of infection. In male urethritis, the incubation period is “usually 1-14 days for symptomatic disease. Most become symptomatic in 2-5 days after exposure” (CDC, 2013). In cervicitis, the “incubation period unclear, but symptoms may occur within 10 days of infection” (CDC, 2013). Overall, the incubation period for gonorrhea is 2-5 days. However, some symptoms may not present until 30 days after exposure to N. gonorrhoeae.
Additionally, if not diagnosed or treated, gonorrhea can progress to or cause other health issues. According to the CDC, “in women, gonorrhea can spread into the uterus or fallopian tubes and cause pelvic inflammatory disease (PID). The symptoms may be quite mild or can be very severe and can include abdominal pain and fever” (CDC, 2017). Pelvic inflammatory disease can cause chronic pelvic pain or internal abscesses. “PID can also damage the fallopian tubes enough to cause infertility or increase the risk of ectopic pregnancy” (CDC, 2017). In rare cases, gonococcus can cause infertility in men through complications with the epididymis. “If left untreated, gonorrhea can also spread to the blood and cause disseminated gonococcal infection (DGI). DGI is usually characterized by arthritis, tenosynovitis, and/or dermatitis. This condition can be life threatening” (CDC, 2017).
Symptoms
In men, gonorrhea can cause urethritis or epididymitis. Symptoms of urethritis, or inflammation of the urethra, include “typically purulent or mucopurulent urethral discharge often accompanied by dysuria” (CDC, 2013). Common symptoms of epididymitis, or inflammation of the epididymis, include “unilateral testicular pain and swelling” (CDC, 2013). “Uncommon complications include inguinal lymphadenitis, penile edema, periurethral abscess or fistula, accessory gland infection (Tyson's glands), balanitis, urethral stricture, and perhaps prostatitis” (CDC, 2013).
In women, a gonococcal infection is asymptomatic in at least 50% of cases (CDC, 2013). However, common manifestations of this disease are cervicitis and urethritis. Symptoms of cervicitis, or inflammation of the cervix, “may be nonspecific such as abnormal vaginal discharge, intermenstrual bleeding, dysuria, lower abdominal pain, or dyspareunia” (CDC, 2013). A symptom of urethritis in women is “dysuria, however, most women are asymptomatic” (CDC, 2013).
Both men and women can be infected with gonococcus in the rectum, pharynx, and conjunctiva. “Symptoms of rectal infection…may include discharge, anal itching, soreness, bleeding, or painful bowel movements. Rectal infection also may be asymptomatic. Pharyngeal infection may cause a sore throat, but usually is asymptomatic” (CDC, 2017). Conjunctivitis in adults is usually the result of “autoinoculation”. Symptoms include “eye irritation with purulent conjunctival exudate” (CDC, 2013). Additionally, conjunctivitis can be passed from mother to child during childbirth (CDC, 2017).
Treatment
According to the CDC, gonorrhea “can be cured with the right treatment” (CDC, 2017). This treatment includes the utilization of “dual therapy – a single dose of 250mg of intramuscular ceftriaxone AND 1g of oral azithromycin” (CDC, 2017). These medications can stop the underlying gonococcal infection, but cannot reverse any permanent damage caused during the course of the disease. However, before these treatment options were available, penicillin was employed, and before that were sulfonamides (CDC, 2013). Moreover, antibiotic resistance is becoming a concern with the treatment of gonorrhea, as in many other bacterial infections.
Epidemiology
Gonococcal infection is “the second most commonly reported notifiable disease in the United States” (CDC, 2017). Sexual behavior and “community prevalence”, combined, can “increase the risk of acquiring gonorrhea” (CDC, 2015). According to the CDC, “in 2016, a total of 468,514 cases of gonorrhea were reported in the United States, yielding a rate of 145.8 cases per 100,000 population. During 2015–2016, the rate of reported gonorrhea cases increased 18.5%, and increased 48.6% since the historic low in 2009” (CDC, 2017). In the U.S., the South has the highest number of reported cases, followed by the West, Midwest, and Northeast, respectively. Additionally, there is a much larger incidence rate among the African American population, compared to caucasians. “The rate among Blacks was 8.6 times the rate among Whites (55.7 cases per 100,000 population)” (CDC, 2017). Moreover, there is an increased incidence rate in men compared to women. “During 2012–2016, the rate among males increased 62.6% (105.0 to 170.7 cases per 100,000 males) and the rate among females increased 12.1% (107.9 to 121.0 cases per 100,000 females)” (CDC, 2017). In 2016, most reported gonorrhea cases were among adolescents and young adults. “Persons aged 15–44 years accounted for 91.9% of reported gonorrhea cases with known age” (CDC, 2017). However, “the number of reported cases is suspected to underestimate incidence by approximately 50%” (CDC, 2013).
Diagnosis
Gonorrhea is diagnosed by collecting specimens and utilizing a Nucleic Acid Amplification Test (NAAT). This technique allows lab technicians to multiply the amount of bacteria in the specimen, through PCR, SDA, or TMA, and to observe its genetic material to make a diagnosis. This allows for early detection because other tests look for the presence of antigens. The production of these cellular markers takes a longer period of time. According to the CDC,
“urogenital gonorrhea can be diagnosed by testing urine, urethral (for men), or endocervical or
vaginal (for women) specimens using…NAAT. It can also be diagnosed using gonorrhea culture,
which requires endocervical or urethral swab specimens. If a person has had oral and/or anal sex,
pharyngeal and/or rectal swab specimens should be collected either for culture or for NAAT (if the
local laboratory has validated the use of NAAT for extra-genital specimens)” (CDC, 2017).
Additionally, alternative methods can be utilized, including DNA probe, gram-stained smear, or Enzyme-Linked Immunosorbent Assay (ELISA) (CDC, 2013).
Prevention
The only way to entirely prevent the transmission of gonorrhea is to abstain from vaginal, oral, or anal sex. The CDC also recommends being in “a long-term mutually monogamous relationship with a partner who has been tested and is known to be uninfected” (CDC, 2017). However, the use of latex condoms can reduce the risk of transmission. It is also suggested that sexually active individuals receive annual screening for gonorrhea, among other STDs. Moreover, although a vaccine for this disease does not yet exist, researchers continue to work to accomplish this feat.
Conclusion
Although gonorrhea is the “second most commonly reported notifiable disease” (CDC, 2017) in the U.S., it is also treatable and preventable. However, this is contingent on the assumption that patients have access to education, barrier methods of birth control, and medical care and treatment. Increasing access to these entities could help hinder the current increased rates of gonococcal infection in the United States and, therefore, enable the population make better choices and stay healthy.
References
Centers for Disease Control and Prevention. (2013). Gonorrhea Module. STD Curriculum for Clinical
Educators. Retrieved from https://www.cdc.gov/std/ready-to-use/gonorrhea/gonorrhea-notes-
April-2013.pdf
Centers for Disease Control and Prevention. (2015). Gonorrhea. 2016 Sexually Transmitted Diseases
Surveillance. Retrieved from https://www.cdc.gov/std/stats14/gonorrhea.htm
Centers for Disease Control and Prevention. (2017). Gonorrhea. 2016 Sexually Transmitted Diseases
Surveillance. Retrieved from https://www.cdc.gov/std/stats16/Gonorrhea.htm
Centers for Disease Control and Prevention. (2017). Gonorrhea – CDC Fact Sheet (Detailed Version).
Sexually Transmitted Diseases (STDs). Retrieved from https://www.cdc.gov/std/gonorrhea/stdfact
-gonorrhea-detailed.htm
Centers for Disease Control and Prevention. (2017). Gonorrhea Treatment and Care. Sexually Transmitted
Diseases (STDs). Retrieved from https://www.cdc.gov/std/gonorrhea/treatment.htm
Edwards, J. L., Apicella M. A. (2004). The Molecular Mechanisms Used by Neisseria gonorrhoeae To
Initiate Infection Differ between Men and Women. Clinical Microbiology Reviews, 17 (4). 965-981.
Recher, C., Kühlewein, C., Müller, A., Schild, H., Rudel, T. (2007). Host Glycoprotein Gp96 and Scavenger
Receptor SREC Interact with PorB of Disseminating Neisseria gonorrhoeae in an Epithelial Invasion
Pathway. Cell Host & Microbe, 2. 393-403.