1. Gram negative cocci

2. After gram staining
Bacteria
Gram stain
Gram-Positive Gram-negative

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?

4. NEISSERIA

5. Properties of Genus Neisseria
This is the Only genus of Gram-negative cocci that regularly
causes diseases in humans
• Nonmotile,
• often arranged as diplococci
* Distinguished from many other Gram-negative pathogens by
being oxidase positive, catalase positive

6. NEISSERIA
Neisseria gonorrhoeae
Neisseria meningitidis

7. Neisseria gonorrhoeae

8. NEISSERIA GONORRHOEA
[GONOCOCCUS]

9. Morphology :
• Gram negative diplococci means are arranged in pairs with
adjacent side concave - kidney shaped.
• Capsulated
• Motile

10. Structure
• Fimbriae extend several
micrometers from cell surface

11. Cultural characters
Gonococci are fastidious organisms do not grow on ordinary
culture media
• 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:
4.capsule
5, Outer membrane proteins: a) Protein I (por)
b) Protein II (opa)
c) Protein III (rmp)

14. PATHOGENESIS
*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
sugar molecules

15. PATHOGENESIS
* IgA protease produced by the bacteria cleaves secretory IgA in
mucous
* Can easily change its surface antigens

16. DISEASES
* 1. Ophthalmia neonatorum
2. Gonorrhea

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
Rectum
•Women: Endocervix,
Pharynx and
Rectum
Neonates: conjunctiva

20. Symptoms
A) In men:
1. The disease starts as an acute urethritis with a mucopurulent
discharge
2. The infection extends to the prostate, seminal vesicles &
epididymis

21. Symptoms
A) In men:
3. In few cases it may become chronic urethritis leading to stricture
formation
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
Disease (PID)
3. Rarely peritonitis may develop with perihepatic
inflammation

23. OPHTHALMIA NEONATORUM

24. LABORATORY DIAGNOSIS:
Specimens collected:
A) In men:
a) Acute infection- Urethral discharge
b) Chronic infection-
i) Morning drop
ii) Discharge collected after prostatic massage
iii) Centrifuged deposit of urine

25. LABORATORY DIAGNOSIS:
Specimens collected:
B) In women:
i) Urethral discharge
ii) Cervical swabs

26. Transport:
If there is delay in processing than the
specimens should be sent in “ Stuart’s medium”.

27. Methods of examination:
A) Direct microscopy:
1. Gram staining:
Smear provides a presumptive
evidence of gonorrhea in men.
Gram negative diplococci are found.
But it is unreliable in women.

28. B) Culture:
Media used: Thayer martin
Gram’s smear:
Reveals Gram negative cocci in pairs
Biochemical reactions:
Oxidase + maltose -
Catalase+ glucose +

29. NEISSERIA
Neisseria gonorrhoeae
Neisseria meningitidis

30. Neisseria meningitidis

31. Neisseria meningitidis
Characteristics
 Aerobic,
 Diplococci
 Nonmotile
 Oxidase positive
 Catalase positive
 Fastidious, capnophilic

32. Virulence Factors:
Neisseria meningitidis
• Pili
• Polysaccharide capsule
• Cellular membrane proteins
• Lipooligosaccharide/endotoxin

33. Disease caused by Neisseria meningitidis
• Meningitidis

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
• Bacterial
- Haemophilus influenzae
- Meningococcus
- Pneumococcus
- Group A Streptococcus
- Group B Streptococcus
• Viral
- Mumps Virus
- Influenza Virus
- West Nile Virus
- Also entero viraus

37. Bacteria of meningitis
Bacterial causes:
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.

38. The Meninges and Cerebrospinal Fluid
Fig 22.2

39. Pathogenicity
Meningococcal meningitis, organisms spread from
nasopharynx blood stream meninges
Direct spread to meninges

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:
Neisseria meningitidis
• Identification
• 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
intracellular gram-negative
diplococci

42. Laboratory Diagnosis:
Neisseria meningitidis
• Oxidase-test positive
• Conventional carbohydrates for biochemical identification (glucose+
and maltose+)
• Maltose +

43. Findings in CSF
Normal CSF:
Clear , colorless
0-5 lymphocytes/cu mm
Sterile
15 -45 mg /100ml protein
2.8-3.9mmol/l glucose

44. What are difference between N. meningitidis and N. gonorrhoeae?
• N. meningitidis (meningococcus) has a prominent polysaccharide
capsule whereas N. gonorrhoeae (gonococcus) has no
polysaccharide capsule.
• 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
causes gonorrhoeae.
• N. meningitidis is not transmitted sexually whereas N.
gonorrhoeae is transmitted sexually.

46. What are the properties of N. meningitidis capsule?
• Answer
• (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
meningitis
• (4) It is the antigen in the vaccine

47. What are signs and symptom of meningococcemia and
meningitis?
• Signs and symptom of meningococcemia
• The most severe form of meningococcemia is the life-threatening
and causes Waterhouse-Frederickson syndrome, which is
characterized by
• High fever,

48. What are signs and symptom of meningococcemia and
meningitis?
• Shock,
• Widespread purpura,
• Disseminated intravascular coagulation,
• Thrombocytopenia, and
• Adrenal insufficiency.

49. •Thanks