3. • Two most important gram negative cocci which are Pathogens
belong to genus Neisseria.
• This genus contains two gram negative cocci
• Neisseria meningitidis and
• Neisseria gonorrhoeae.
• Name gram negative cocci which are pathogenic to human being?
5. Properties of Genus Neisseria
This is the Only genus of Gram-negative cocci that regularly
causes diseases in humans
• often arranged as diplococci
* Distinguished from many other Gram-negative pathogens by
being oxidase positive, catalase positive
11. Cultural characters
Gonococci are fastidious organisms do not grow on ordinary
• These require rich media
• They are aerobic but may grow anaerobically also.
• It is essential to provide 5-10% CO₂.
12. Gonococcal Virulence Factors
1. Pili: .
2. Lip oligosaccharide:
3. IgA1 protease:
5, Outer membrane proteins: a) Protein I (por)
b) Protein II (opa)
c) Protein III (rmp)
*Fimbriae enable them to attach to human cells
*Polysaccharide capsules protect the bacteria from the lytic
enzymes within phagocyte
* Lipooligosaccharide: composed of lipid A (endotoxin) and
17. Transmission of gonorrhea
Transmit by sexual contact
Greater efficiency of transmission from male to female
Male to female: 50 - 90%
Female to male: 20 - 80%
Vaginal & anal intercourse more efficient
18. Transmission of gonorrhea
Can be acquired from asymptomatic partner
Increases transmission and susceptibility to HIV 2-5 fold
Infects mucous membranes
Incubation period ~ 1 – 14 days
19. Common sites of infection
• Men: Urethra, Pharynx
A) In men:
1. The disease starts as an acute urethritis with a mucopurulent
2. The infection extends to the prostate, seminal vesicles &
A) In men:
3. In few cases it may become chronic urethritis leading to stricture
4. The infection may spread to the periurethral tissues, causing
abscesses & multiple discharging sinuses
22. B) In women:
1. The initially there is urethritis & cervicitis
2. The infection may extend to Bartholin’s glands,
endometrium & fallopian tubes causing Pelvic Inflammatory
3. Rarely peritonitis may develop with perihepatic
34. What is Meningitis?
It is inflammation of meninges
Meningitis can be caused by many different organisms including
viruses and bacteria.
Meningitis, caused by a bacteria, is life threatening and requires
urgent medical attention and treatment with antibiotics.
35. What is Meningitis?
It is inflammation of meninges
Meningitis caused by a virus is very rarely life threatening but
can cause the body to become very weak.
When bacteria invade the body they can cause meningitis,
septicaemia or meningitis and septicaemia together
36. Causes of Meningitis
- Haemophilus influenzae
- Group A Streptococcus
- Group B Streptococcus
- Mumps Virus
- Influenza Virus
- West Nile Virus
- Also entero viraus
37. Bacteria of meningitis
Three primary pathogens:
N. meningitidis, all ages
Haemophilus influenzae 2---5 years children
S.pneumoniae all ages but more common in
adult with underlying illnesses.
40. Symptoms can be the same for Viral and Bacterial
• Fever and chills
• Mental status changes
• Nausea and vomiting
• Sensitivity to light (photophobia)
• Severe headache
• Stiff neck
41. Laboratory Diagnosis:
• Examine direct smear from CSF for intra &
extra cellular g - dc
• Other body sites include nasopharyngeal
swabs, sputum, and urogenital specimens
Gram-stained smear of CSF
showing the extra cellular and
43. Findings in CSF
Clear , colorless
0-5 lymphocytes/cu mm
15 -45 mg /100ml protein
44. What are difference between N. meningitidis and N. gonorrhoeae?
• N. meningitidis (meningococcus) has a prominent polysaccharide
capsule whereas N. gonorrhoeae (gonococcus) has no
• N. meningitidis is maltose positive whereas N. gonorrhoeae is
45. What are difference between N. meningitidis and N. gonorrhoeae?
• N. meningitidis causes meningitidis whereas N. gonorrhoeae
• N. meningitidis is not transmitted sexually whereas N.
gonorrhoeae is transmitted sexually.
46. What are the properties of N. meningitidis capsule?
• (1) Enhances virulence by its anti-phagocytic action
• (2) It is the antigen that defines the serologic groups.
• (3) It is the antigen detected in the spinal fluid of patients with
• (4) It is the antigen in the vaccine
47. What are signs and symptom of meningococcemia and
• Signs and symptom of meningococcemia
• The most severe form of meningococcemia is the life-threatening
and causes Waterhouse-Frederickson syndrome, which is
• High fever,
48. What are signs and symptom of meningococcemia and
• Widespread purpura,
• Disseminated intravascular coagulation,
• Thrombocytopenia, and
• Adrenal insufficiency.