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Neisseria gonorrhoeae
(gonococcus)

Neisseria gonorrhoeae on agar plate

Neisseria gonorrhoeae on a nonselective medium for pathogenic Neisseria species after 48 hours of cultivation. Gonococci are the most fastidious of the Neisseria species, require complex growth media and are highly susceptible to toxic substnces (e.g., fatty acids). Gonococci are not able to grow on common blood agar. Often are used media resembling chocolate agar in appearance(e.g., modified Thayer-Martin agar(MTM) or Martin-Lewis agar(ML))
Plates are always incubated in a CO2-enriched, humid atmosphere (some gonococci require CO2 for growth, the growth of all species is enhanced by CO2).
Colonies of N.gonorrhoeae vary in diameter from 1 to 4.0 mm after 48 hours owing to the formation of different colony types (designated T1, T2, T3, T4). The colonies are smooth and nonpigmented. Some strains may produce atypical small colonies.

Neisseria gonorrhoeae, also known as Gonococci (plural), or Gonococcus (singular), is a species of Gram-negative coffee bean-shaped diplococci bacteria responsible for the sexually transmitted disease gonorrhea. Neisseria are fastidious Gram-negative cocci, requiring nutrient supplementation to grow in laboratory cultures.

These cocci are facultatively intracellular and typically appear in pairs (diplococci), in the shape of coffee beans. Of the eleven species of Neisseria that colonize humans, only two are pathogens. N. gonorrhoeae is the causative agent of gonorrhoea and is transmitted via sexual contact.

Neisseria is usually isolated on Thayer-Martin agar - an agar plate with three different antibiotics and nutrients which not only facilitate the growth of Neisseria species, but inhibit the growth of Gram-positive organisms and most bacilli and fungi. Further testing to differentiate the species includes testing for oxidase (all Neisseria show a positive reaction) and the carbohydrates maltose, sucrose, and glucose test in which N. gonorrhoeae will only oxidize (that is, utilize) the glucose.

Disease

Symptoms of infection with N. gonorrhoeae differ depending on the site of infection. Infection of the genitals can result in a purulent (or pus-like) discharge from the genitals which may be foul smelling, inflammation, redness, swelling, dysuria and a burning sensation during urination. N. gonorrhoeae can also cause conjunctivitis, pharyngitis, proctitis or urethritis, prostatitis and orchitis. Conjunctivitis is common in neonates and silver nitrate or antibiotics are often applied to their eyes as a preventive measure against gonorrhoea. Neonatal gonorrheal conjunctivitis is contracted when the infant is exposed to N. gonorrhoeae in the birth canal, and can result in corneal scarring or perforation. Disseminated N. gonorrhoeae infections can occur, resulting in endocarditis, meningitis or gonococcal dermatitis-arthritis syndrome. Dermatitis-arthritis syndrome presents with arthralgia, tenosynovitis and painless non-pruritic dermatitis. Infection of the genitals in females with N. gonorrhoeae can result in pelvic inflammatory disease if left untreated, which can result in infertility. Pelvic inflammatory disease results if N. gonorrhoeae travels into the pelvic peritoneum (via the cervix, endometrium and fallopian tubes).

Abbreviated from Wikipedia.

description image
GRAM-NEGATIVE DIPLOCOCCI
NONMOTILE
NONSPOREFORMING
CATALASE: POSITIVE
OXIDASE: POSITIVE
AEROBES

BASIC TESTS
FOR IDENTIFICATION

Growth on blood agar-
Acid production from:
Glucose+
Maltose-
Fructose-
Sucrose-
γ-glutamylaminopeptidase-
Tributyrin hydrolysis-
Polysaccharide synthesis-
ONPG-
Reduction of NO3-
sel media
Thayer-Martin agar
Appearance
Composition
Modified Thayer-Martin agar (MTM agar)
Composition
Martin-Lewis agar (ML agar)
Composition
New York City medium (NYC medium)
Composition
gram negative diplococci drawing

ANTIBIOTIC
TREATMENT

Should be always guided by
in vitro susceptibility
tests!!

CEPHALOSPORINS

Cephalosporins II, III

TETRACYCLINES

Doxycycline

FLUOROQUINOLONES
(high prevalence of resistance in some areas)

MACROLIDES

Spectinomycin

list of anntibiotics

 

 
 

COLONY MORPHOLOGY

Neisseria gonorrhoeae neisseria gonorrhoeae neisseria gonorrhoeae neisseria gonorrhoeae
neisseria gonorrhoeae neisseria gonorrhoeae neisseria gonorrhoeae neisseria gonorrhoeae
neisseria gonorrhoeae neisseria gonorrhoeae neisseria gonorrhoeae neisseria gonorrhoeae
neisseria gonorrhoeae neisseria gonorrhoeae neisseria gonorrhoeae neisseria gonorrhoeae
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