In this slide, I will teach you about gram-negative cocci which Neisseria Meningitidis. I will tell you about its diseases, transmission, pathogenesis, characteristics, lab diagnosis, treatment, and prevention in a short and easy way.

2. NEISSERIA MENINGITIDIS
Meningococcus

3. GRAM NEGATIVE COCCI
•Neisseria meningitides ( Meningococcus)
•Neisseria gonorrhoeae ( Gonococcus)

4. DISEASES
• Meningitis (Inflamation of the meninges)
• Meningococcemia
• Petechial hemorrhages small, purpuric lesions on leg (discolouration of the skin
or mucous membranes due to haemorrhage from small blood vessels )
• Disseminated intravascular coagulation (DIC) blood clots form throughout
• the body, blocking small blood vessels.
• Water friderichsen syndrome
• High fever,shock,widespread pupura,disseminated intravascular coagulation,
thrombocytopenia and adrenal insufficiency.

6. HABITAT AND TRANSMISSION
• Habitat
• Upper respiratory tract (Nose to Upper part of vocal card)
• Transmission
• Respiratory droplets, (Small aqueous droplet produced by
exhalation)
• Respiratory secretions

7. PATHOGENESIS VIRULENCE FACTORS
• Colonize the upper respiratory tract.(Nasopharyx)
• Via blood stream reach meninges.
• Pyogenic
• Polysaccharide capsule resist phagocytosis to polymorphonuclear
leukocytes (PMNs)
• IgA (Immunoglobulin A) protease produce
• Factor H binding proteins (FHBP) inhibitor of complement factor c3b
reduce opsonization.
• Endotoxin contains lipooligo polysaccharide (LOS) in cell wall cause
septic shock seen in meningiococcemia.

8. PROPERTIES OF POLYSACCHARIDE CAPSULE
• Enhances virulence by antiphagocytic action
• Serological groups defines as a Antigen
• Detected in spinal fluid as a Antigen in patient of
meningitis
• Vaccine. As a antigen

9. PREDISPOSING FACTORS
• Defeciency in late complement components
predispose to recurrent meningococcal infections.(C5
to C9 risk of high infections)
• Splenic and anemic patient are high risk.

10. CHARACTERICTICS
• Gram negative diplococci
• Encapsulated pyogenic bacteria (H. influenzae,
S.pneumonia)
• Kidney bean shaped
• Pilli, antigenic variations i.e chromosomal
rearrangement
• More than 100 serotypes

11. LABORATORY DIAGNOSIS
• Gram stained smear and culture (Crystal violet)
• Catalase positive (H2O2 into H20 and O2)
• Oxidase positive colonies on chocolate agar
• Drop of oxidase agent on filter paper, colony of bacteria is rubbed on
it, purple color indicates positive test
• Ferments maltose (glucose)
• Thayer-Martin agar 5% chocolate sheep blood and antibiotics
• VPN agar (Vancomycin, Polymixin, Nystatin)

13. TREATMENT
•Pencillin G
•(No significant ressitance)
•Ceftriaxone
•(3rd generation cephalosporin)

14. PREVENTION
• Group A cause epidemics of meningitis
• Vaccines against group A,C,Y and W-135 menigococci contain polysaccharide capsule as
immunogen.
• Vaccine against group B meningococci contains factor H-binding protein, NadA neisserial
adhesion A, NHBA neisserial heparin binding protein, OMV oute membrane vesicle contain Por
A antigen or as immunogen
• Polysaccharide vaccine exist in two forms
• Conjugate vaccine contain polysaccharide coupled to carrier protein such as diptheria toxoid
• C, Y plus Haemophilus influenzae coupled with tetanus toxoid.
• Non conjugate vaccine contain only polysaccharide.
• Rifampin or ciprofloxacin to close contact to decrease oropharyngeal carriage.

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