The document provides an overview of Neisseria meningitidis, a gram-negative bacterium responsible for meningococcal disease, including meningitis and meningococcemia. It details the bacterium's morphology, culture conditions, biochemical reactions, pathogenesis, clinical symptoms, treatment options, and laboratory diagnosis methods. Additionally, the document outlines the epidemiology and prevention strategies associated with this pathogen.

1. VIVEKANANDA ARTS AND SCIENCE
COLLEGE FOR WOMEN
Veerachipalayam 637 303 Sangakiri, Salem dt, Tamilnadu
DEPARTMENT OF MICROBIOLOGY
SUBJUCT :MEDICAL BACTERIOLOGY
TOPIC: NEISSERIA MENINGITIDIS
SUBJUCT INCHARGE: SUBMITTED BY:
Dr. R. Mythili Ravichandran P. Nikoshiya Cyprus
Head of the Department III-Bsc., Microbiology
Department of Microbiology. Department of Microbiology.

2. Neisseria meningitis

3. SYNOPSIS
• Introduction
• Morphology
• Culture
• Biochemical reaction
• Resistance
• Classification
• Pathogenesis
• Clinical disease
• Treatment
• Laboratory diagnosis
• Profile axis

4. Introduction
 Epidermal cerebrospinal meningitis was known early in the
nintheenth century.
 In 1887,weichselbaum isolated the organism from the
spinal fluid of a patient, now called Neisseria meningitidis,
in pure culture and described the organism.
 N. Meningitidis causes acute purulent meningitis, also
known as cerebrospinal meningitis or cerebrospinal fever.

6. Morphology
Gram negative oval cocci.
0.6-8 mm
Occur typically in pairs.
Adjacent sides flattened.
Nonmotile
Piliated
Most of the fresh isolates from blood or spinal fluid are
encapsulated.

7. Culture
 N. Meningitidis is a strict aerobe and no growth occurs anaerobically.
 Optimum temperature 35°-36°C, but it will not grow below 30° C.
 Optimum pH 7.4-7.8.
 CO2 5-10%
 Growth requirement N. Meningitidis –Blood agar, Chocolate agar, Mueller-Hindan starch casein
hydrolysate agar are generally used for isolation of organism.
 Modified Thayer Martin medium contains antibiotic facilitates.
 8-24 hrs incubation – 0.5-1mm colonies formed.
 Incubation continued 24 hrs – 2-3mm Large colonies formed.
 At the margins – smooth and rough type of colonies are seen.

8. Biochemical reactions
Catalase and oxidase positive
It produces acid from maltose and
glucose.
Vaccines- serogroups :A, C, W-135,Y.

9. Resistance
It very delicate organism and highly susceptible
to heat.
Alternation in pH.
Desiccation
To disinfectants.

10. Classification
ANTIGENIC CLASSIFICATION OF N. MENINGITIDIS
 Polysaccharide capsule : serogroups ( 13 groups –A, B, C, D, X, Y, Z,
W 135,29E, H, I, K and L.
 OMP ( Por A and Por B) : serotypes 1,2,.......20.

11. Pathogenesis
 N. Meningitidis is the aetiologic agent of two life – threatening disease
Meningococcal meningitidis
Fulminant meningococcaemia
 Meningococci are strict human parasites.
 Organism – carried – Asymptomatically –in oropharynx and nasopharynx.
 Serogroup –specific antibodies in blood by 7-10 days.
 Rapid multiplication in the blood – stream results in meningococcaemia.

12. Clinical disease
1. Meningitis : cerebrospinal fever (CNS) – suppurative lesion of
meninges – involves- surface of spinal cord and cortex of brain.
Sudden onset – fever, vomiting, chills, myalgias and arthragias.
2. Meningococceamia : Approximately 10-30% - meningococcal
disease – develop – Meningococcemia without clinically apparent
meningitis. Acute fever with chills, malaise, prostation and purpuric
rash. Fulminant meningococcaemia called Waterhouse –
friderichsen syndrome.
3. Other syndrome : caused by N. Meningitidis include pneumonia,
arthritis, and urethritis. Respiratory track infection – precedes –
meningococcal pneumonia.

13. Treatment
Third generation – cephalosporin ( e.g.,
Cefotaxime or ceftriaxone) are administrated.
Alternatively, chloramphenicol can be
administrated.
N. Meningitidis remains susceptible.
Penicillin G – alternative drug

14. Laboratory
diagnosis
1. EXAMINATION OF CSF
2. CULTURE
3. AUTOPSY

15. 1.Examination of CSF
Microscopy
 Gram stain – smear of CSF
deposit commonly – gram
negative intracellular diplococci
 Extracellular also in about 85%
of patients in the early stages.
Biochemical test
 CSF protein is markedly raised

16. 2. Culture
1. CSF : CSF sample add glucose broth- incubation – result
turbidity.
2. Blood : Blood culture positive – 40% cases of meningococcal
meningitidis. Incubate 7 days –Antigens present conforming.
3. Nasopharyngeal swab: This is cultured to detect the carriers.
4. Other culture : skin lesion, joint fluid.

17. 3. Autopsy
 Specimens collecting died body causing
meningococcol infection through –collected
meninges, lateral ventricles, or the surface of the
brain and spinal cord

18. Profile axis
Here is a brief profile axis for Neisseria meningitidis:
 I. Microbiology :Gram-negative diplococcus
 II. Epidemiology_: Global distribution, high-risk groups (adolescents, young
adults, etc.)
 III. Clinical Features_: Meningitis, sepsis, septicemia, rash
 IV. Transmission_: Respiratory droplets, close contact
 V. Pathogenesis_: Adhesion, invasion, immune evasion, inflammation
 VI. Diagnosis_: Culture, PCR, serotyping
 VII. Treatment_: Antibiotics, supportive care
 VIII. Prevention_: Vaccination, chemoprophylaxis, good hygiene.

19. Thank you