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بسم الله الرحمن الرحيم. FAMILY: NEISSERIACEAE Prof. Khalifa Sifaw Ghenghesh. Genus: Neisseria. G-ve, diplococci, kidney shaped Oxidase: +ve. Neisseria gonorrhoeae. 1. N. gonorrhoeae. Gonorrhoea Virulence Factors
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بسم الله الرحمن الرحيم FAMILY: NEISSERIACEAE Prof. Khalifa Sifaw Ghenghesh
Genus: Neisseria • G-ve,diplococci, kidney shaped • Oxidase: +ve
1. N. gonorrhoeae • Gonorrhoea • Virulence Factors ------------------------------------------------------------------------------------ Factor Responsible for: ------------------------------------------------------------------------------------ Pili Attachment to epithelial cell OMP II (PrII) OMP I (PrI) Invasion of epithelial cells LPS Damage to epithelial cells IgA protease Destruction of secretory Ab ------------------------------------------------------------------------------------
Clinical Significance • Transmitted by direct, close, usually sexual contact between individuals. • Uncomplicated gonorrhoea: • In men:acute urethritis >purulent discharge • in women (endocervix):vaginal discharge • asymptomatic: • ii. Conjunctivitis (ophthalmia neonatorum): • iii. Pelvic inflamatory disease (PID): • iv. Disseminated gonococcal infection (DGI):
Laboratory Diagnosis • Specimens: Transport media!!!! • Men:Urethral samples. • Women:Uretheral, cervical and rectal specimens. • Endocervicalswab >> • In DGI: • Blood, swabs from skin lesions, or pus aspirated from a joint. • In neonatal ophthalmia:Conjunctival material. • Urine specimen:
Gram stain • Thayer-Martin Media: • Oxidase test • Carbohydrate utilization
Gram-stain of urethral discharge from an infected individual, showing Gram-negative diplococci.
Neisseria gonorrhoeaeUrethral smear with gram negative intracellular diplococci
Treatment • N. gonorrhoeae > b-lactamase • 3rd generation cephalosporins • Ceftriaxone • Ciprofloxacin: • resistance?
2. N. meningitidis • Virulence Factors:> Capsule. • Serological Classification: • Serogroups A, B, and C. • Others: X, Y, Z, Z' (29E), and W-135
Gram-stain of Neisseria meningitidis Gram-negative diplococci
Clinical Significance • Habitat:Oro- or naso-pharynges of asymptomatic carriers • Transmission: • Meningococcemia and/or meningitis> - rash - "Waterhouse-Friderchsen syndrome" • Pneumonia >
Laboratory Diagnosis Specimens:>>Transport media !!!!! • CSF, blood, aspirate from skin lesions or pus from an infected joint. • Carriers: • Gram stain & Blood agar/ TM medium • Grouping:Specific antisera. • CSF:can be examined for meningococcal polysaccharide antigen by latex agglutination, coagglutination, etc...
Control • Chemoprophylaxis. • Vaccination. Treatment • Penicillin • Rifampicin • Ciprofloxacin
Other Neisseria species: • Moraxella (Branhamella) catarrhalis