Lectures 13-14-Neisseria gonorrhoea, N. meningitidis

بسم الله الرحمن بسم الله الرحمن الرحيمالرحيم

FAMILY:FAMILY: NEISSERIACEAENEISSERIACEAE

Prof. Khalifa Sifaw GhengheshProf. Khalifa Sifaw Ghenghesh

Genus: Genus: NeisseriaNeisseria

• G-ve, diplococci, kidney shaped

• Oxidase: +ve

Neisseria gonorrhoeaeNeisseria gonorrhoeae

1. 1. N. gonorrhoeaeN. gonorrhoeae

• Gonorrhoea

• Virulence Factors------------------------------------------------------------------------------------Factor Responsible for:------------------------------------------------------------------------------------Pili Attachment to epithelial cellOMP II (PrII)OMP I (PrI) Invasion of epithelial cellsLPS Damage to epithelial cellsIgA protease Destruction of secretory Ab------------------------------------------------------------------------------------

Clinical SignificanceClinical 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 DiagnosisLaboratory Diagnosis• Specimens: Transport media!!!!

– Men: Urethral samples.– Women: Uretheral, cervical and rectal specimens.

• Endocervical swab >>

• 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

TreatmentTreatment

• N. gonorrhoeae-lactamase

• 3rd generation cephalosporins– Ceftriaxone

• Ciprofloxacin:– resistance?

2. 2. N. meningitidisN. meningitidis

• Virulence Factors: > Capsule.

• Serological Classification:– Serogroups A, B, and C.

– Others: X, Y, Z, Z' (29E), and W-135

Gram-stain of Gram-stain of Neisseria meningitidisNeisseria meningitidis Gram-negative diplococciGram-negative diplococci

Clinical SignificanceClinical Significance

• Habitat: Oro- or naso-pharynges of asymptomatic carriers

• Transmission:

• Meningococcemia and/or meningitis >

- rash

- "Waterhouse-Friderchsen syndrome"

• Pneumonia >

Laboratory DiagnosisLaboratory 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 Control • Chemoprophylaxis.• Vaccination.

TreatmentTreatment– PenicillinPenicillin– RifampicinRifampicin– CiprofloxacinCiprofloxacin

• Other Neisseria species:– Moraxella (Branhamella) catarrhalis

Moraxella catarrhalisMoraxella catarrhalis