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Gonorrhea
By Calvin Tran
Etiologic agent: Neisseria gonorrhoeae (1).
Transmission/Reservoirs:
N. gonorrhoeae exclusively affects humans and is spread through sexual contact from
person to person. It can affect the eyes, throat, rectum, and genitals (usually urethra in
males & urethra and endocervix in females). It can also be transmitted to a newborn
during childbirth (1).
General characteristics:
N. gonorrhoeae is a Gram-negative cocci. Colonies are typically pinkish-brown. They
typically appear in pairs (diplococcic) and are coffee bean-shaped (5). They are nonspore forming, non-motile, and encapsulated. They are an oxidase positive and lactose
fermenting bacteria (8).
Key tests for identification:
Most tests involve a sample of body fluid or urine. Lab diagnosis involves identifying
characteristics that distinguish N. gonorrhoeae from other Neisseria that are normal
inhabitants of oropharynx and nasopharnx. A Gram-stain is performed to obtain a
presumptive diagnosis that must be confirmed other tests (4). A culture can be performed
on selective media to confirm diagnosis (1). Another popular test is the nucleic acid
hybridization test, in which the DNA of gonorrheal bacteria is mixed with a bodily
sample. Hybridization indicates a positive test.
Signs and symptoms of disease:
The incubation period for gonorrhea is 2-14 days. Many men and most women that have
gonorrhea are asymptomatic. If present, women may experience a white, yellow, or green
discharge from the vagina, pain during intercourse, and lower abdominal pain. For men,
symptoms include discharge, inflammation of the urethra (4). Itching and dysuria may
also be experienced. In some cases, gonorrhea may cause skin lesions and infection of the
joints (1). If left untreated, women can acquire pelvic inflammatory disease (PID), which
may cause serious complications with pregnancy. Untreated gonorrhea can also increase
a person’s risk of acquiring HIV(1).
Historical information:
The first notice of gonorrhea in our recorded history occurs in 1161, when English
parliament passed a law to reduce the spreading of a disease with symptoms consistent
with gonorrhea. The illness used to be treated with the injection of metals, such as
mercury and silver nitrate. Albert Neisser discovered the etiologic agent, Neisseria
gonorrhoeae, in 1879 (3).
Virulence factors:
N. gonorrhoae utilizes pili to attach to nonciliated epithelial cells. Once attached, an outer
membrane protein, P.II, allows for tight binding and attachment to other N. gonorrhoeae
to form a biofilm-like substance. Another outer membrane protein, P.I, allows the
bacteria to survive phagocytosis (4). Also in the outer membrane is lipooligosaccharide
(LOS), which is responsible for most of the symptoms caused by gonorrhea. LOS
activates the complement system, which induces an inflammatory response, lyses
phagocytes, and contributes to gonorrheal discharge (8). Lastly, the LOS allows for
antigenic variation of gonorrhea, causing difficulty for the host immune system to
eliminate the bacteria. N. gonorrhoeae is highly efficient at using transferrin-bound iron
for microbial growth (4).
Control/Treatment/Prevention:
The CDC recommends that gonococcal infections be treated with antibiotics effective
against resistant strains, such as ceftriaxone, cefixime, ciprofloxacin, and oflaxacin (2).
Often times, patients with gonorrhea are also affected with C. tracomatis, so doxycycline
or erythromycin is given in combination (4). Vaccines have been unsuccessful (4).
To prevent contracting gonorrhea, one should properly use a condom, limit sexual
partners, and get tested regularly. To prevent the spread of gonorrhea, limiting sexual
activity is a good idea (1).
Statistics:
In the United States, it is estimated that 820,000 people acquire new gonorrheal
infections, yet less than half of these infections are diagnosed and reported to the CDC. In
2013, only 333,004 cases were reported (2). An outbreak of gonococcal infection was
seen in 2013 in various states, Washington being the major contender, with a 75%
increase in cases. Oregon experienced a 20% increase and California saw a 15% increase
in cases (6).
Globally, the World Health Organization estimated a whopping 106.1 million new cases
of gonorrhea in 2008 (7).
Gonorrhea seems to be on the rise, so prevention methods are necessary now more than
ever.
References:
1. Centers for Disease Control and Prevention. "Gonorrhea - CDC Fact Sheet." Centers
for Disease Control and Prevention. Centers for Disease Control and Prevention, 16 Dec.
2014. Web. 30 Apr. 2015. <http://www.cdc.gov/std/Gonorrhea/STDFactgonorrhea.htm>.
2. Centers for Disease Control and Prevention. "Gonorrhea." Centers for Disease Control
and Prevention. Centers for Disease Control and Prevention, 16 Dec. 2014. Web. 10 May
2015. <http://www.cdc.gov/std/stats13/gonorrhea.htm>.
3. Mandal, Ananya. "Gonorrhea History." News-Medical.net. News-Medical.net, 04 Nov.
2010. Web. 5 May 2015. <http://www.news-medical.net/health/GonorrheaHistory.aspx>.
4. Morse, Stephen A. "Chapter 14: Neisseria, Moraxella, Kingella and
Eikenella." Medical Microbiology. U.S. National Library of Medicine, 1996. Web. 30
Apr. 2015. <http://www.ncbi.nlm.nih.gov/books/NBK7650/#A891>.
5. Newman, Lori, and John Moran. "Update on the Management of Gonorrhea in Adults
in the United States." Clinical Infectious Diseases. Oxford Journals, 2007. Web. 5 May
2015. <http://cid.oxfordjournals.org/content/44/Supplement_3/S84.full>.
6. Steinmetz, Katy. "A Day in the Life of an STD Detective." US A Day in the Life of an
STD Detective Comments. Time, 12 Nov. 2013. Web. 11 May 2015.
<http://nation.time.com/2013/11/12/a-day-in-the-life-of-an-std-detective/>.
7. World Health Organization. "Global Incidence and Prevalence of Selected Curable
Sexually Transmitted Infections." (n.d.): n. pag. 2008. Web.
<http://apps.who.int/iris/bitstream/10665/75181/1/9789241503839_eng.pdf>.
8. Sicat, Maricar. "Neisseria Gonorrhoeae." MicrobeWiki. MicrobeWiki, 2014. Web. 11
May 2015. <https://microbewiki.kenyon.edu/index.php/Neisseria_gonorrhoeae>.