Gonorrhea Or Gonococcal Infection
Neisseria gonorrhoeae causes gonorrhea, a sexually transmitted disease that affects women, men and children. Every year approximately 1 million cases are reported, while at least the same number are not reported. Medical and social consequences are significant. The infection can cause infertility in women and is a major risk factor for HIV infection. On average, a man is infected every 4th intercourse with an infected woman while a woman is infected every 2nd intercourse with infected man.
Neisseria gonorrhoeae infection mechanism is different for men and women. A remarkable feature of this organism as researchers discovered is the extraordinary ability to survive in his only host, the human body and also gonorrhea infects men and women using different pathogenetic mechanisms.
Mechanism of infection
N. gonorrhoeae is an exclusively human pathogen that has no other host, besides the human mucosa, especially the genital mucosa. The microorganism developed remarkable mechanisms that avoid the host immune system attack (congenital and adapted). In particular, the bacteria surface has a coating of red cell antigens, antigenic structure identical to human red cells.
Through a unique mechanism, and apparently random, variable imporntant virulence factors are expresse, allowing N. gonorrhoeae to be ubiquitous in some people, in different environmental conditions. Adhesion factors, called pili, have a wide variable antigenicity. This is due to a unique genetic mechanism, by which, large portions of the structure are encoded in some boxes that can be accidentally moved inside or outside the gene expressed. The mechanism is similar to the variable portion of immunoglobulins in mammals. The result is that a single microorganism has the ability to produce over 1 million distinct antigenic pili, thereby allowing it to overcome the host’s immune system attack.
A remarkable feature is the ability of N. gonorrhoeae to infect men and women by different pathogenetic mechanisms. Both mechanisms are highly efficient and take advantage of the environmental conditions and the expression of cell surface receptors. These mechanisms have been studied for the first time in the departments of microbiology, urology and obstetrics / gynecology, University of Iowa, USA.
Studies have shown that epithelial cells lining the distal two-thirds of the male urethra are susceptible to infection with gonorrhea. Experimental human infections have shown that for 40 hours after infection, gonorrhea can not be cultivated in the urethral exudate or urine, because gonorrhea penetrates mucosal cells immediately after infection and can be cultivated only after it has replicated (duplicated) in these cells that will be “shelters”.
Their penetration into epithelial cells is not a random event. Pili, surface structures that allow gonorrhea to avoid immune attack of the host, set on the epithelial cell surface receptors from the urethra (urethral mucous forming). Meanwhile, gonococcal components enter the epithelial cells to prevent apoptosis (programmed cell death). This is prolonged cell life, while gonococci multiply within them. Eventually, when the number of gonococcal cells is very high, nutrients are depleted and the cells die.
In the tissue where the infection was initiated cytokines are produced by epithelial cells and are released into the bloodstream to recruit inflammatory cells at the infection site (neutrophils, which are usually found in the analysis of urethral exudates in men)
In women, gonococcal infection involves an interaction of different, more complex factors between host and N. gonorrhoeae. Initial targets of gonorrhea are ecto and endocervical tissues. These cells are remarkable in several respects. They produce and secrete all components of the complement alternative pathway and express surface type 3 (CR3) receptors of complement. Alternative pathway complement components interact with gonorrhea, resulting in assembling ligands for CR3 on the surface of N. gonorrhoeae . In addition, gonococcal pili, the main factor through which the bacteria attaches on host cells, and a channel of nutrients called porina and can interact with cells as such, without the need for other mechanisms to facilitate attachment. Cooperative interaction with CR3 results in altered plasma membrane (composed of epithelial cells mentioned above), and the formation of inclusions. Inclusions are protrusions (penetrations inside the membrane). Also, bacteria has the ability to secrete substances that facilitate their vacuolation. Once the epithelial cells were infected the bacteria begins to secrete various proteins. One of these proteins is the enzyme called phospholipase D (FD). It seems that phospholipase D accelerates epithelial cell surface CR3 position, thus facilitating invasion of new healthy cells by N. gonorrhoeae
Symptoms of gonorrhea usually appear after a period of 2 days to 3 weeks after exposure to infection. Some women and men are asymptomatic until severe complications.
Symptoms in women:
- Dysuria (burning sensation when urinating and painful)
- Yellow vaginal discharge
- Vascular fragility (bleeding very easily)
- Dyspareunia (painful intercourse).
Symptoms in men:
- White-yellow milky discharge ureteric
- Dysuria (burning sensation when urinating and painful)
- Redness and swelling of the opening of the urethra in the penis
- Lower abdominal pain
- Pain and edemas (swelling) in the testes.
Gonococcal infection is transmitted through vaginal, anal or oral sex. Children are infected at birth if their mothers are infected.
Detection of symptoms is difficult in many cases so most people do not know they are infected for a long period of time. Most of asymptomatic individuals will find they are infected when their partner is diagnosed. The only sure way to detect infection is to test (culture of urethral or vaginal secretions) for gonococcal infection. Diagnosis is based on vaginal or urethral cultures. For harvesting these secretions a cotton swab is used that is then sent to the laboratory for testing. Results are available in about 3 days. Harvesting is not painful and can be made even in asymptomatic individuals.
Gonococcal infection is dangerous, even if asymptomatic. Untreated gonococcal infection can lead to the following complications:
- Gonococcal eye (eye infection)
- Irreversible damage to the reproductive organs
- Infertility (difficulty in getting pregnant).
- Sterility (inability to have children), as a result of acute salpingitis caused by the gonococcal infection
- Tubal ectopic pregnancy, a complication that can be fatal to the pregnant woman
Although it may have serious complications if left untreated, gonorrhea can be cured. Treatment consists of antibiotics (usually penicillin, erythromycin, tetracycline ofloxacin, cefixine, and ceftriaxine). It is very important that treatment is completed correctly to be effective. Unfortunately, antibiotics can not treat gonococcal infection complications.
Recommendations for prevention of gonococcal infection are identical to those for preventing other sexually transmitted diseases.
The best way to prevent gonococcal infection is abstinence (no sex) or sexual intercourse with one uninfected partner, which in turn has no other sexual partner. Another recommendation is to use protection during intercourse. Condoms, used properly from the beginning to the end of each sexual contact is the best protection option. Diaphragms and spermicides foams or gels are less effective and should not replace condoms, but can be used with it.
After unprotected intercourse with an infected partner sex, a specialist must be consulted. The sexual partner must be treated as well. It is very important to avoid sexual activity until the infection is treated. Otherwise, the partner is infected and can reinfect you. Also anterior partner/partners should be screened earlier and treated promptly in case of infection to prevent the spread of disease. 3-6 weeks after completion of antibiotic therapy, individuals are retested. This is very important to ensure that treatment was adequate and properly followed and the infection was cured.