Diagnosis is through culture, Gram stain, or nucleic acid tests, such as polymerase chain reaction, of a urine sample, urethral swab, or cervical swab. Chlamydia co-testing and testing for other STIs is recommended due to high rates of co-infection. Microbiology
Neisseria species are fastidious, Gram-negative cocci that require nutrient supplementation to grow in laboratory cultures. Neisseria spp. are facultatively intracellular and typically appear in pairs (diplococci), resembling the shape of coffee beans. Neisseria is non-spore-forming, capable of moving using twitching motility, and an obligate aerobe (requires oxygen to grow). Of the 11 species of Neisseria that colonize humans, only two are pathogens. N. gonorrhoeae is the causative agent of gonorrhea and N. meningitidis is one cause of bacterial meningitis. Culture and identification
N. gonorrhoeae is usually isolated on Thayer–Martin agar (or VPN) agar in an atmosphere enriched with 3-7% carbon dioxide. Thayer–Martin agar is a chocolate agar plate (heated blood agar) containing nutrients and antimicrobials (vancomycin, colistin, nystatin, and trimethoprim). This agar preparation facilitates the growth of Neisseria species while inhibiting the growth of contaminating bacteria and fungi. Martin Lewis and New York City agar are other types of selective chocolate agar commonly used for Neisseria growth. N. gonorrhoeae is oxidase positive (possessing cytochrome c oxidase) and catalase positive (able to convert hydrogen peroxide to oxygen). When incubated with the carbohydrates lactose, maltose, sucrose, and glucose, N. gonorrhoeae will oxidize only the glucose. Surface molecules
On its surface, N. gonorrhoeae bears hair-like pili, surface proteins with various functions, and sugars called lipooligosaccharides.
Prevention
Transmission is reduced by using latex barriers (e.g. condoms or dental dams) during sex and by limiting sexual partners. Condoms and dental dams should be used during oral and anal sex, as well. Spermicides, vaginal foams, and douches are not effective for prevention of transmission. Treatment
The current treatment recommended by the CDC is an injected single dose of ceftriaxone (a third-generation cephalosporin). Sexual partners (defined by the CDC as sexual contact within the past 60 days) should also be notified, tested, and treated. It is important that if symptoms persist after receiving treatment of N. gonorrhoeae infection, a reevaluation should be pursued. Antibiotic resistance
Antibiotic resistance in gonorrhea has been noted beginning in the 1940s. Gonorrhea was treated with penicillin, but doses had to be progressively increased to remain effective. By the 1970s, penicillin- and tetracycline-resistant gonorrhea emerged in the Pacific Basin. These resistant strains then spread to Hawaii, California, the rest of the United States, Australia and Europe. Fluoroquinolones were the next line of defense, but soon resistance to this antibiotic emerged, as well. Since 2007, standard treatment has been third-generation cephalosporins, such as ceftriaxone, which are considered to be our "last line of defense".Recently, a high-level ceftriaxone-resistant strain of gonorrhea called H041 was discovered in Japan. Lab tests found it to be resistant to high concentrations of ceftriaxone, as well as most of the other antibiotics tested. Within N. gonorrhoeae, genes exist that confer resistance to every single antibiotic used to cure gonorrhea, but thus far they do not coexist within a single gonococcus.