This document provides information about the genus Neisseria, including its two most medically important species - N. meningitidis and N. gonorrhoeae. It covers the general characteristics of Neisseria, pathogenesis and diseases caused by the two species, laboratory diagnosis methods, and treatment and prevention strategies. Learning objectives include understanding properties, species, pathogenesis, diagnosis, and drugs of choice for Neisseria, as well as differentiating between Neisseria species.

1. Genus Neisseria
Almugadam B Saad
Lecturer of medical microbiology Full nameLecturer of medical microbiology
Faculty of medical laboratory sciences
University of El Imam El Mahadi
Kosti-Sudan
MSc University of Khartoum
BSc University of El Imam El Mahadi
Full name
Babiker Saad Almugadam Yousif

2. Genus Neisseria
With the end of this topic , You should
know the following:
Learning
objectives
1-Important properties , M.Important
species , Pathogenesis , Lab diagnosis
,and drugs of choice for neisseria
2-How to differentiate between the
species of neisseria

3. Scientific classification
Kingdom: Bacteria
Phylum: Proteobacteria
Class: Betaproteobacteria
Order: Neisseriales
Family: Neisseriaceae
Genus: Neisseria
Medical Important Species
1-N.meningitidis (Meningococci)
2-N.gonorrheae (Gonococci)

4. - Aerobic , Gram-ve
diplococci with flattened
edges , Non motile ,
General Characters of
Neisseria
edges , Non motile ,
Non sporing , intracellular
or extracellular , oxidase
positive, , Catalase positive
, Some species are
capsulated.

5. Pathogenesis
1-N.meningitidis
-Fastidious , 13 serogroup base on
capsule Ag .
infection cause mainly by group
A,B,C,Y,X and W (commonly
by A,C and less commonly with B).
Has 3 outer membrane protein(OMP).
-Virulence Factors :-Virulence Factors :
Capsule , endotoxin , and IgA protease
-Diseases : meningitis ,meningococcemia
2-N.gonorrheae
-Fastidious , more than 100 serotypes base on pillus Ag , and Has 3 OMP
-Virulence Factors :
Pilli , endotoxin , and IgA protease , some produce B.lactamase ,OMPII
-Diseases :
Gonorrhea , pelvic inflammatory disease (PID) , disseminated gonococcal
infection , purulent conjunctivitis(Ophthalma neonatorum)

6. Laboratory diagnosis
- Specimen: depend on the type and site of infection
- Microscopy : Gram-ve diplococci with flattened edges , both
intracellular (in side PMN).

7. Culture: Done in many culture media according to type and site of
infection , both are fastidious.Their growth inhibited by toxic trace of
metals and fatty acid found in certain media like Blood agar.
Growth of N.meningitidis enhance by presence of 5-10% CO2
Growth of N.gonorrheae occur under absolute require of 5-10% CO2
On Chocolate agar:On Chocolate agar:
1-N.meningitidis : Transparent or
grey , shiny
2-N.gonorrheae: raise , colorless
colonies
Example of Selective Media:
MNYC , Thayer martin medium

8. - Identification : Base on
- Colonial Morphology and staining reaction ?
- Biochemical reaction and Antibiotic susceptibility
Manual :
CHO utilizationGAPDNAse /ONBGSpecies
SMLG
-ve+ve-ve+ve+ve-veN.meningitidis
-ve-ve-ve-ve-ve-veN.gonorrheae
Tube method
-CHO utilization ??????
-Animal pathogencity (Gonococci)

9. - Molecular : as PCR , Sequencing
Several slide latex agglutination test kits
are available to identify neisseria based
on detection of Ag.
Quelling reaction use to meningococcal
infection and to serogruop meningococci.
- Serology :
- Molecular : as PCR , Sequencing
-Typing of Neisseria :
As Auxotyping and serotyping of N.gonorrheae

10. Treatment and prevention
-N.meningitidis sensitive to penicillin G , Has vaccine compose of
capsular polysaccharide Ag
-N.gonorrheae sensitive to ceftriaxone , PID treated with
cefoxitin+doxycycline
PPNG
TRNG
CMRNG
Antibiotics resistant
N.gonorrheae strains
Antibiotics resistant N.gonorrheae strains Detection???/?