page_title: Neisseria gonorrhoeae
section_title: Surface molecules
hierarchical_section_title: Neisseria gonorrhoeae / Microbiology / Surface molecules
caption_attribution_description: Eesti&#x3a;&#32; Neisseria gonorrhoeae PHIL 3693 lores.jpg.English&#x3a;&#32; This illustration depicts a urethral exudate containing Neisseria gonorrhoeae from a patient with gonococcal urethritis. This illustration depicts a Gram-stain of a urethral exudate showing typical intracellular gram-negative diplococci, and pleomorphic extracellular gram-negative organisms, which is diagnostic for gonococcal urethritis.Español&#x202f;&#x3a;&#32; Neisseria gonorrhoeae, agente causal de la gonorrea.Euskara&#x3a;&#32; Neisseria gonorrhoeae Gram tindaketarekin; zelula handiak leukozitoak dira.Français&#x202f;&#x3a;&#32; Neutrophiles infectés par Neisseria gonorrhoeae, on retrouve des petits diplocoques gram négatifs caractéristiques.Русский&#x3a;&#32; Возбудитель гонореи в мазке гноя (окраска по Граму).ދިވެހިބަސް&#x3a;&#32; ކިހުނުވުން ޖައްސާ ޖަރާސީމް.
context_page_description: Neisseria gonorrhoeae, also known as gonococcus, or gonococci is a species of Gram-negative diplococci bacteria isolated by Albert Neisser in 1879. It causes the sexually transmitted genitourinary infection gonorrhea as well as other forms of gonococcal disease including disseminated gonococcemia, septic arthritis, and gonococcal ophthalmia neonatorum.
  It is oxidase positive and aerobic, and it survives within neutrophils. Culturing it requires carbon dioxide supplementation and enriched agar with various antimicrobials. It exhibits antigenic variation through recombination of its pili and surface proteins that interact with the immune system.
  Sexual transmission is possible through vaginal, anal, or oral sex. Sexual transmission may be prevented through the use of barrier protection. Perinatal transmission may occur during childbirth, and may be prevented by antibiotic treatment of the mother before birth and the application of antibiotic eye gel on the eyes of the newborn. After an episode of gonococcal infection, infected persons do not develop immunity to future infections.
context_section_description: On its surface, N. gonorrhoeae bears hair-like pili, surface proteins with various functions, and sugars called lipooligosaccharides.  The pili mediate adherence, movement, and DNA exchange. The Opa proteins interact with the immune system, as do the porins. Lipooligosaccharide (LOS) is an endotoxin that provokes an immune response. All are antigenic and all exhibit antigenic variation (see below). The pili exhibit the most variation.  The pili, Opa proteins, porins, and even the LOS have mechanisms to inhibit the immune response, making asymptomatic infection possible.
  
  Dynamic polymeric protein filaments called type IV pili allow N. gonorrhoeae to adhere to and move along surfaces. To enter the host the bacteria uses the pili to adhere to and penetrate mucosal surfaces. The pili are a necessary virulence factor for N. gonorrhoeae; without them, the bacterium is unable to cause infection. To move, individual bacteria use their pili like a grappling hook: first, they are extended from the cell surface and attach to a substrate. Subsequent pilus retraction drags the cell forward. The resulting movement is referred to as twitching motility. N. gonorrhoeae is able to pull 100,000 times its own weight, and the pili used to do so are the amongst the strongest biological motors known to date, exerting one nanonewton. The PilF and PilT ATPase proteins are responsible for powering the extension and retraction of the type IV pilus, respectively. The adhesive functions of the gonococcal pilus play a role in microcolony aggregation and biofilm formation.
  Surface proteins called Opa proteins can be used to bind to receptors on immune cells and prevent an immune response. At least 12 Opa proteins are known and the many permutations of surface proteins make recognizing N. gonorrhoeae  and mounting a defense by immune cells more difficult.
  Lipooligosaccharide (LOS) is a low-weight version of lipopolysaccharide present on the surfaces of most other Gram-negative bacteria. It is a sugar (saccharide) side chain attached to lipid A (thus "lipo-") in the outer membrane coating the cell wall of the bacteria. The root "oligo" refers to the fact that it is a few sugars shorter than the typical lipopolysaccharide. As an endotoxin, LOS provokes inflammation. The shedding of LOS by the bacteria is responsible for local injury in, for example, pelvic inflammatory disease. Although its main function is as an endotoxin, LOS may disguise itself with host sialic acid and block initiation of the complement cascade.
caption: This illustration depicts a Gram stain of a urethral exudate showing typical intracellular Gram-negative diplococci, and pleomorphic extracellular Gram-negative organisms, which is diagnostic for gonococcal urethritis.
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