Neisseria Summary


Neisseria gonorrhoeae (see WebLinked image; see WebLinked image; see WebLinked image; see WebLinked image)

Capacity to invade intact mucus membranes or skin with abrasions

Most common sites of inoculation are the vagina or cervix in the female and the penis in the male

Only piliated cells (formerly, colony types T1 and T2) are virulent by attaching to intact mucus membranes, penetrating into and passing through mucosal cells, and establishing infection in the sub-epithelial layer

Seriously underreported, sexually transmitted disease found only in humans with strikingly different epidemiological presentations for females and males

Major reservoir is asymptomatic carriage in females

Microscopy reveals encapsulated, small, gram-negative diplococci inside polymorphonuclear leukocytes (PMN's) in urethral purulent discharge

Penicillin is no longer the drug of choice because MIC has steadily increased, and plasmid-mediated enzymatic hydrolysis and chromosomally-mediated resistance has risen to >10% of all strains

Ceftriazxone, cefixime, or a fluoroquinolone for uncomplicated cases and in combination with doxycycline or azithromycin for dual infections with other STD's


Neisseria meningitidis

Pili-mediated, receptor-specific colonization of nonciliated cells of nasopharynx

Antiphagocytic polysaccharide capsule allows systemic spread

Toxic effects mediated by hyperproduction of lipooligosaccharide (LOS) lacking O-side chain

Meningitis, meningococcemia, pneumonia, arthritis, urethritis following dissemination of virulent organisms from the nasopharynx

Large numbers (>10e7 organisms/ml) of encapsulated, small, gram-negative diplococci in the presence of polymorphonuclear leukocytes (PMN's) in cerebrospinal fluid (CSF)

Serogroups A, B, C, Y, W135

Transparent, non-pigmented, oxidase-positive, nonhemolytic colonies on chocolate blood agar with enhanced growth in moist atmosphere with 5% CO2

Although patients with systemic disease generally are bacteremic, commercial blood culture bottles contain toxic additives that may inhibit growth

Differentiated from other species in the genus by acid production from glucose and maltose, but not sucrose or lactose


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