This document discusses the pathogenic Neisseria species Neisseria meningitidis and Neisseria gonorrhoeae. It describes their morphology, cultural characteristics, pathogenicity, and laboratory diagnosis. N. meningitidis can cause meningitis and has an incubation period of 3 days, progressing from asymptomatic carriage to meningococcemia and then meningitis. N. gonorrhoeae causes sexually transmitted infections like urethritis and pelvic inflammatory disease. Laboratory diagnosis for both involves examining CSF or samples from infected sites microscopically and through culture and biochemical tests.

1. RATHEESH
R.L
NEISSERIA

2. GRAM NEGATIVE COCCI
 The medically important species is NEISSERIA

3. THERE ARE TWO IMPORTANT PATHOGENIC
SPECIES
 1. N.MENINGITIDIS (CAUSE OF MENINGITIS)
 2. N. GONORRHOEA ( WHICH CAUSE STD’S)

4. NEISSERIA MENINGITIDIS

5.  Found in nasopharynx in 3-30% of carrier
individuals.
 Cause meningitis (spread through inhalation and
characterized by frontal head ache high grade
fever and stiff neck. )

6. MORPHOLOGY
 It’s aerobic G -ve oval shape diplococci found
intracellular (inside pus cells) and extracellular, non
motile and non spore forms.
 Size varies from 0.6 to 0.8 mm
 Usually occurs as pairs

7. CULTURAL CHARACTERISTICS
 They are aerobic and grow optimum at the temperature
of 37 degree C, and PH 7.4
 The growth will be at peak on 5-10% of atmospheric
carbon dioxide

8. SERUM BROTH
 After 24 hrs , round, convex, bluish gray with
smooth glistening surface colonies will appear

9. BLOOD AGAR MEDIUM
 Colonies are small with 1mm diameter, round, convex,
translucent ( allowing light to pass through it) with
glistening surface and sharp edges

10. THAYER –MARTIN MEDIUM
 TMM with antibiotics facilitates primary isolation
of the organism from the normal mixed flora of
pharynx

11. PATHOGENESIS
 N. meningitidis is the main cause for developing
meningitis of all age more frequently among infants
and chidren.
 Human nasopharynx is the reservoir of infection and is
acquired by droplet spread via infected respiratory
secretions from infected persons.

12.  The incubation period is about three days after
which the following stages will develop.
 1. Asymptomatic stage
 2. Meningococcemia stage
 3. Proper meningitis

13. ASYMPTOMATIC STAGE
 The organism appears in nasopharynx leading to
minor nasopharyngeal infection associated with the
inflammation.

14. MENINGOCOCCEMIA STAGE
 In this stage a small proportion of micro organism will
enter to the blood stream and causing acute fever with
chills, malaise and rashus over bthe skin.
 The thrmbosis of small blood vessals will occur and
leads to disseminated intra vascular coagulation(DIC)

15. PROPER MENINGITIS
 In this stage the organism may spread along the
perineural sheaths of olfactory nerves, reaches to the
sub arachnoid space and leads to sinusitis.
 When reaches to CNS it will cause severe head ache,
stiffness in neck, vomiting, delirium and confusion

16. LABORATORY DIAGNOSIS
It mainly includes
1. hematological investigations and
2. bacteriological investigations

17. HEMATOLOGICAL INVESTIGATIONS
 It shows an increase in the leucocyte count.
 Generally the leucocyte count will be more than
15,000/mm3

18. BACTERIOLOGICAL INVESTIGATIONS
1. EXAMINATION OF CSF
For bacteriological investigation the CSF is
divided into two portions
 One portion of CSF is collected is centrifuged and
observed under a microscope after gram staining.
 The organism will seen as gram negative and
occuring in pairs.

19.  The second portion is inoculated in the blood agar
medium at 37 degree C for 24 hrs in an atmosphere of
5-10% carbon dioxide, round, convex colonies will
appear with 1mm diameter.

20. 2. BIOCHEMICAL TESTS
1. OXIDASE TEST: POSITIVE
The oxidase test is used to identify bacteria that
produce cytochrome c oxidase, an enzyme of the
bacterial electron transport chain
2. SUGAR FEMENTATION TEST: PRODUCE ONLY
ACID, NO GAS

21. 3. CATALASE TEST: POSITIVE
The presence of catalase enzyme in
the bacteria is detected using hydrogen peroxide.
If the bacteria possess catalase (i.e. catalase-
positive)
4. H2S PRODUCTION TEST: NEGATIVE
This test determines whether the microbe
reduces sulfur-containing
compounds to sulfides during the process of
metabolism.

22. 5. NITRATE REDUCTION TEST: NEGATIVE
This test is used for differentiation of
members of Enterobacteriaceae on the basis of
their ability to produce nitrate reductase enzyme
that hydrolyze nitrate (NO3
–) to nitrite (NO2
–).

23. 3.BLOOD CULTURE
 Blood culture will be positive in over 40% of
cases

24. 4. SEROLOGICAL TEST
 In slide agglutination test a drop of saline or a
drop of anti serum is added to the mixture.
 If test is positive the clumps will be produced in
the slide.

25. TREATMENT
 The drug of choice for meningococcal infection
are sulfonamides or chloramphenicol

26. TREATMENT
 The drug of choice for meningococcal infection
are sulfonamides or chloramphenicol

27. NEISSERIA GONORRHOEA

28. MORPHOLOGY
 It’s aerobic G -ve oval shape diplococci found
intracellular (inside pus cells) and extracellular, non
motile and non spore forms.
 Size varies from 0.6 to 1 mm
 Usually occurs as pairs with adjacent sides
concave(bean shaped or kidney shaped)

29. CULTURAL CHARACTERISTICS
 They are aerobic and grow will be optimum in the
media enriched in blood at the temperature of 37
degree C, and PH 7.4
 The growth will be at peak on 5-10% of atmospheric
carbon dioxide

30. SERUM BROTH
 After 24 hrs of incubation at 37 degree C in serum
broth, no turbidity appears which indicating poor
growth.

31. CHOCOLATE AGAR MEDIUM
 Colonies formed after 24 hrs of incubation
are small, i.e 1mm in diameter, round, gray
white, convex, translucent with glistening
surface.

32. THAYER MARTIN MEDIUM
 TMM with antibiotics facilitates primary isolation
of the organism.
 The commonly used antibiotics are vancomycin,
colistin and nystatin.

33. CHACKO NAIR EGG ENRICHED MEDIUM
 It supports efficient growth of organism
from the clinical samples

34. PATHOGENECITY
 The organism is mainly causing the sexually transmitted
diseases.
 Gonorrheal infection is generally limited to superficial
mucosal surfaces lined with columnar epithelium. The areas
most frequently involved are the urethra, cervix, rectum,
pharynx, and conjunctiva.
 Squamous epithelium, which lines the adult vagina, is not
susceptible to infection by the N. gonorrhoeae. However, the
prepubescent vaginal epithelium, which has not been
keratinized under the influence of estrogen, may be infected.
Hence, gonorrhea in young girls may present
as vulvovaginitis.

35.  In females the infection may spread from the
urethra,vagina and cervix to uterus, fallopian tubes,
ovaries and causing pelvic inflammatory disease and
leads to sterility.

36.  In the adult male, an inflammatory and pyogenic infection
of the mucous membranes of the anterior urethra will
occur.
 The most common symptom is a discharge that may range
from a scanty(small amount), clear or cloudy fluid to one
that is abundant and purulent.
 Dysuria (difficulty in urination) is often present.
Inflammation of the urethral tissues results in the
characteristic redness, swelling, heat, and pain in the
region.
 There is intense burning and pain will be present on
urination.

37.  In males the acute urethritis may extend to prostate,
testicles, seminal vesicles and epididymis

38.  Proctitis ( inflammation of rectum) will occur in
both sexes.
 Gonococcal pharyngitis may occur due to oro-
genital contact during sex.
 Ophthalmia neonatorum is a type of gonococcal
infection of the eyes in babies born to infected
women during passage through the infected birth
canal.

39. LABORATORY DIAGNOSIS
It mainly includes
1. hematological investigations and
2. bacteriological investigations

40. HEMATOLOGICAL INVESTIGATIONS
 It shows an increase in the leucocyte count and
polymorphoneuclear cell count.
(polymorphoneuclear cells are a
category of white blood cells characterized by the
presence of granules in their cytoplasm. They are
also called polymorphonuclear leukocytes)

41. BACTERIOLOGICAL INVESTIGATION
 For the bacterial examination different samples are collected
from both males and females
 In females: urethral secretions, vaginal discharges, anal
canal swab, oropharyngeal swabs and blood in gonococcal
septicemia.
 In males: purulent urethral discharge, anal canal swab,
oropharyngeal swabs and blood

42.  1. MICROSCOPY
• Under microscopy after gram staining it
shows gram negative diplo cocci.
• 2. CULTURE
• In Thayer martin medium typical
translucent colonies will appear after 48
hours of incubation at 5-10% of carbon
dioxide.

43. 3. BIOCHEMICAL TEST
• 1. OXIDASE TEST: POSITIVE
• 2. CATALASE TEST: POSITIVE
• 3. SUGAR FEMENTATION TEST:
• PRODUCTION OF
ACID ONLY

44. 4. SEROLOGICAL TESTS
 It includes slide agglutination test, CFT
(Complement Fixation Test), flocculation test,
RIA (Radio Immuno Assay) and ELISA
(Enzyme-linked immunosorbent assay)

45. TREATMENT
 Sulfonamifdes and penicillin are effective against
N.Gonorrhea
 VACCINES
1. GONOCOCCAL PILUS VACCINE
2. GONOCOCCAL LIPOPHYSACCHARIDE
VACCINE
3. GONOCOCCAL PROTEIN-1 VACCINE

46. NOTES
 1. The complement fixation test is an
immunological medical test that can be used to
detect the presence of either specific antibody or
specific antigen in a patient's serum, based on
whether complement fixation occurs..
 2. purpose of flocculation test is to detect serum
antibodies or antibody-like substances that
appear specifically in association with certain
diseases.
 3. Radioimmunoassay (RIA) is a sensitive
method for measuring very small amounts of a
substance in the blood. Radioactive versions of a
substance, or isotopes of the substance, are
mixed with antibodies and inserted in a sample of

47.  4. The enzyme-linked immunosorbent assay
(ELISA) is a common laboratory technique which
is used to measure the concentration of an
analyte (usually antibodies or antigens) in
solution.
 5. In slide agglutination test a drop of saline or a
drop of anti serum is added to the mixture.If test
is positive the clumps will be produced in the
slide.