[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Microbiology](https://durgical.com/en/microbiology/) › [Gram-negative cocci](https://durgical.com/en/microbiology/groups/gram-negative-cocci/) › Neisseria gonorrhoeae [Microbiology](https://durgical.com/en/microbiology/) · [Gram-negative cocci](https://durgical.com/en/microbiology/groups/gram-negative-cocci/) # Neisseria gonorrhoeae - Bacterium - Gram-negative - Exam priority: high A sexually transmitted bacterium that causes gonorrhea; in women it often gives no symptoms and can lead to infertility. Updated 2026-11-01 Also called: gonococcus ## Key points - Intracellular Gram-negative diplococci in a man's urethral discharge: gonorrhea. - Young sexually active woman with a single swollen knee, tenosynovitis and pustules: disseminated gonococcal infection. - Purulent conjunctivitis in the first days of life: gonococcus. - No capsule and shifting pili: reinfection and no vaccine. - Always cover possible Chlamydia co-infection too. ## At a glance **Gram** Gram-negative **Shape** Coffee-bean diplococcus **Oxygen** Aerobic **Family** Neisseriaceae **Stain** Gram: red diplococci inside neutrophils in urethral discharge ## Morphology - Gram-negative diplococci with no capsule - Oxidase-positive; ferments glucose only - Needs enriched media: chocolate agar or Thayer-Martin, in CO2 ## Transmission - Vaginal, oral or anal sex - Mother to newborn during birth (neonatal conjunctivitis) - Repeat infections: no protective immunity **Reservoir:** Humans only ### Isolation precautions What the care team adds to standard precautions. - Standard ## Virulence factors - Pili with antigenic variation: mucosal attachment and antibody escape - Opa and Por proteins: attachment, invasion and blocking of phagocytosis - Lipooligosaccharide (LOS): local inflammation - IgA protease - Readily picks up resistance genes ## Diseases it causes - Urethritis with pus in men; cervicitis, often silent, in women [Gonorrhoea →](https://durgical.com/en/conditions/gonorrhoea/) - Pelvic inflammatory disease, ectopic pregnancy and infertility [Pelvic inflammatory disease →](https://durgical.com/en/conditions/pelvic-inflammatory-disease/) - Disseminated gonococcal infection with septic arthritis (knee, wrist), tenosynovitis and skin pustules [Septic Arthritis of the Knee →](https://durgical.com/en/conditions/septic-arthritis-of-the-knee/) - Epididymitis in men [Epididymitis →](https://durgical.com/en/conditions/epididymitis/) - Purulent conjunctivitis of the newborn (ophthalmia neonatorum), which can cause blindness [Conjunctivitis →](https://durgical.com/en/conditions/conjunctivitis/) ## Clinical picture - Dysuria and thick urethral discharge a few days after exposure - Pharyngitis and proctitis depending on sexual practice - Perihepatitis (Fitz-Hugh-Curtis syndrome) as a complication of pelvic inflammatory disease ## Diagnosis - Nucleic acid amplification tests (NAAT) on urine or swabs: test of choice - Gram stain of male urethral discharge: intracellular Gram-negative diplococci - Culture on Thayer-Martin to test antibiotic susceptibility - Test also for Chlamydia, HIV and syphilis ## Treatment Third-generation cephalosporins: intramuscular ceftriaxone is preferred; oral cefixime only when that is not possible. Chlamydia co-infection and sex partners are treated too. Resistance keeps rising: penicillins, tetracyclines and quinolones no longer work in many regions. Drug class only; doses and regimens are set by the clinician from the current guideline. In Pharmacology: - [Ceftriaxone](https://durgical.com/en/pharmacology/ceftriaxone/) - [Cefixime](https://durgical.com/en/pharmacology/cefixime/) - [Doxycycline](https://durgical.com/en/pharmacology/doxycycline/) ## Prevention - Condoms every time - Screening of people at risk and treatment of partners - Eye prophylaxis for newborns - No vaccine ## In Colombia In Colombia gonorrhea is managed within sexually transmitted infection care; treatment follows local resistance surveillance. ## Memory aid "One sugar, two to treat": the gonococcus ferments a single sugar, but treatment always thinks of two more (Chlamydia and the partner). ## Test yourself Think of the answer, then tap the question to see it. ## Which Gram stain finding in urethral discharge suggests gonorrhea in a man? Gram-negative diplococci inside neutrophils. ## Why can a person get gonorrhea again and again? Its pili change antigen and it has no capsule, so infection leaves no protective immunity. ## Which triad suggests disseminated gonococcal infection? Arthritis (often knee or wrist), tenosynovitis and pustular skin lesions. ## Which antibiotic class is the basis of current treatment? Third-generation cephalosporins, with ceftriaxone as the drug of choice. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/microbiology/neisseria-gonorrhoeae/) ## Related - [Neisseria meningitidis](https://durgical.com/en/microbiology/neisseria-meningitidis/) - [Gardnerella vaginalis](https://durgical.com/en/microbiology/gardnerella-vaginalis/) ## Related conditions - [Gonorrhoea](https://durgical.com/en/conditions/gonorrhoea/) - [Pelvic inflammatory disease](https://durgical.com/en/conditions/pelvic-inflammatory-disease/) - [Septic Arthritis of the Knee](https://durgical.com/en/conditions/septic-arthritis-of-the-knee/) - [Epididymitis](https://durgical.com/en/conditions/epididymitis/) - [Conjunctivitis](https://durgical.com/en/conditions/conjunctivitis/) ## What the colours mean **Gram-positive** Thick peptidoglycan wall: stains purple. **Gram-negative** Thin wall with an outer membrane: stains pink. **Acid-fast** Lipid-rich wall (mycobacteria): Ziehl–Neelsen stain. [← Back to the group: Gram-negative cocci](https://durgical.com/en/microbiology/groups/gram-negative-cocci/) Educational content on microorganisms; not a treatment guide and no substitute for a health professional's advice. No doses are given. Sources: [Gonorrhoea (Neisseria gonorrhoeae infection)](https://www.who.int/news-room/fact-sheets/detail/gonorrhoea-(neisseria-gonorrhoeae-infection)) (WHO, 2025); [Antimicrobial resistance](https://www.who.int/news-room/fact-sheets/detail/antimicrobial-resistance) (WHO, 2026). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/microbiology/neisseria-gonorrhoeae/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/microbiology/neisseria-gonorrhoeae/