Neisseria gonorrhoeae, often called gonococcus, is a bacterium. It causes gonorrhea, a common sexually transmitted infection (STI). Gonorrhea can affect various parts of the body, including the genitals, rectum, and throat. It is a public health concern due to its prevalence and potential for serious complications if untreated.
Understanding Gonococcus
Neisseria gonorrhoeae is classified as a Gram-negative bacterium, distinguished by its cell wall structure. Under a microscope, it typically appears as a diplococcus, forming pairs of sphere-shaped cells, often described as kidney or coffee bean-shaped. It is an obligate human pathogen, meaning it only infects humans and primarily colonizes mucous membranes. It thrives in moist environments within the human body, such as the urogenital tract, throat, and rectum.
The bacterium possesses surface structures like hair-like pili and various surface proteins, including opacity-associated (Opa) proteins. Pili aid in attachment to host cells and contribute to movement, while Opa proteins interact with the immune system. N. gonorrhoeae can adapt and evade the human immune system, partly by altering its surface structures. This ability to modify its appearance helps the bacterium persist in the body, sometimes leading to asymptomatic infections where individuals carry the bacteria without showing signs of illness.
The Infection It Causes: Gonorrhea
Gonorrhea is primarily transmitted through sexual contact, including vaginal, anal, and oral sex. It can also pass from a pregnant individual to their baby during childbirth, potentially causing severe eye infections in newborns. Symptoms, if present, typically appear around two weeks after infection, though onset can vary or never occur. Many infections are asymptomatic, meaning individuals may not know they are infected, which contributes to its spread.
In individuals with penises, common symptoms can include a burning sensation during urination and a white, yellow, or green discharge from the penis. Testicular pain or swelling may also occur, though less commonly. In individuals with vaginas, symptoms are often mild or absent, but can include increased vaginal discharge, painful urination, and vaginal bleeding between periods. Infections in the rectum may cause anal itching, discharge, or pain during bowel movements, while throat infections can lead to a sore throat or swollen lymph nodes. Gonorrhea can also affect the eyes, causing pain, sensitivity to light, and pus-like discharge.
If left untreated, gonorrhea can lead to serious complications. In individuals with vaginas, it can spread to the uterus and fallopian tubes, causing pelvic inflammatory disease (PID). PID can result in chronic pelvic pain, ectopic pregnancy, and infertility due to scarring of the fallopian tubes. For individuals with penises, untreated gonorrhea can lead to epididymitis, an inflammation of the tubes near the testicles, which can cause infertility. In rare instances, the infection can spread through the bloodstream, leading to a disseminated gonococcal infection (DGI) with symptoms like joint pain, skin lesions, and fever.
Detecting Gonococcus: The Role of NAA Tests
Nucleic Acid Amplification (NAA) tests are the preferred method for detecting Neisseria gonorrhoeae. These tests, including techniques such as Polymerase Chain Reaction (PCR) and Transcription-Mediated Amplification (TMA), identify the bacterium’s unique genetic material (DNA or RNA). NAA tests are highly sensitive and specific, meaning they accurately find the bacteria if present and are unlikely to give false positive results. This accuracy is important because N. gonorrhoeae can often be present without noticeable symptoms.
The process involves amplifying tiny amounts of bacterial genetic material in a sample, making it detectable. This amplification allows identification of the infection even when only a few bacterial cells are present. NAA tests can be performed on various samples, making them versatile and less invasive than older diagnostic methods. Common samples include urine, a convenient and non-invasive option for both males and females. Swabs from infection sites like the cervix, vagina, rectum, or throat can also be used.
Using non-invasive samples like urine makes NAA testing particularly beneficial for widespread screening programs. Individuals can often collect samples themselves, improving access to testing. This method is valuable for detecting asymptomatic infections, helping prevent further transmission and serious complications. NAA tests have largely replaced traditional culture methods for routine diagnosis due to their superior sensitivity and faster turnaround times.
Treatment and Prevention
Gonorrhea is treated with antibiotics. The Centers for Disease Control and Prevention (CDC) currently recommends a single intramuscular dose of ceftriaxone for uncomplicated gonorrhea. Prompt treatment is important to prevent complications and reduce the spread of the infection. A challenge in treating gonorrhea is increasing antibiotic resistance, as N. gonorrhoeae has developed resistance to many antibiotics. Healthcare providers monitor resistance patterns to ensure effective treatment.
Due to the frequent co-occurrence of gonorrhea and chlamydia, treatment for chlamydia with doxycycline is often administered concurrently, especially if chlamydia has not been ruled out. After treatment, individuals should abstain from sexual activity for at least seven days and until their symptoms resolve. All recent sexual partners should also be notified, tested, and treated to prevent reinfection and further transmission.
Prevention strategies primarily involve safe sexual practices. Consistent and correct use of condoms during vaginal, anal, and oral sex can significantly reduce the risk of transmission. Regular testing for sexually transmitted infections is a preventive measure, particularly for sexually active individuals and those with risk factors. Testing helps identify infections early, even if asymptomatic, allowing for timely treatment and reducing further spread.