useful for medical students

2. CLASSIFICATION
Kingdom: Bacteria
Phylum: Proteobacteriacea
Class: Betaproteobacteria
Order: Neisseriales
Family: Neisseriaceae
Genus: Neisseria
Species: gonorrhoeae
meningitidis
lactamica,etc

3. INTRODUCTION & HISTORY:
Discovered Neisseria
gonorrhoeae (1879)
Albert stain
Mycobacterium
lepraeAlbert Ludwig Sigesmund
Neisser

4. CHARACTERISTICS:
characteristics
Gram
negative/
cocci
Aerobes
Oxidase
positive
diplo
cocc
i

5. CONTAINS TWO IMPORTANT PATHOGENS
 Nesseria meningitidis
 Nesseria gonorrhoeae

6. IMPORTANT DIFFERENCE BETWEEN
N.gonorrhoeae & N. meningitidis
N. gonrrhoeae N.
meningitidis
I have got an
antibiotic resistant
plasmid
I have got a
polysaccharide
capsule

7. NEISSERIA MENINGITIDIS
Gram negative
oval/spherical cocci
0.6 to 0.8 µm in size
Arranged in pairs (adjacent sides flattened)
Bean shaped
Encapsulated
Shape of Neisseria meningitidis
Described and isolated by weichselbaum from spinal
fluid of patient,1887

8. CULTURAL CHARACTERISTICS
Media used:
 non selective media:
 Blood agar
 Chocolate agar
 Mueller-Hinton starch casein hydrolysate agar
 Selective media
 Modified Thayer-Martin Agar
 Colony characteristics
 Color: Bluish grey
 Shape: Round
 Size: About 1mm
 Surface: Smooth
 Elevation: Convex
 Opacity: Transluscent
 Consistency: Butyrous

9. Neisseria meningitidis
growing on chocolate
agar
Neisseria meningitidis
growing on sheep
blood agar

10. BIOCHEMICAL TESTS
• Oxidase positive
• Catalase positive
• Ferments glucose and maltose with acid production
• Nitrate negative
• Colistin resistant
• Doesn’t ferment lactose, sucrose and fructose
• Gamma-glutamyl aminopeptidase positive
• DNAase Positive

11. SEROGROUPS AND SEROTYPES
on the basis of specificity of capsular
polysaccharide antigens
divided into 13 serogroups .
These are A,B,C,D,X,Y,Z,W -135,29-E,H,I,K and
L.
Serogroups A,B,C,X,Y,W 135 : most commonly
associated with meningococcal disease
Group A: epidemics
Group C: localised outbreaks
Group B: both epidemics and outbreaks

12. CONTD…
 Serotypes:
 Based on the outermembrane protein
serogroups further divided into serotypes
 About 20 serotypes have been identified

13. VIRULENCE FACTORS
 Fimbrae (common pili)-
 Lipooligosaccharide:
 Capsule
 Cell membrane proteins
 IgA protease-

14. EPIDEMIOLOGY
Natural
habitat and
reservoir
human nasopharynx
urogenital tract
anal canal
Nasopharyngeal carriers 5-10% adults asymptomatic
carriers
Modes of infection Direct contact or respiratory droplets from
the nose and throat of infected people
Prevelence of meningitis is highest in meningitis belt of Africa
(frequent epidemics occurred there)
In 1996,largest 150000 cases 15000 deaths reported

15. Inhalation of contaminated droplets
Adherence of organism to nasopharyngeal mucosa
Local invasion and spread from nasopharynx to meninges through blood stream (directly along perineural
sheath of olfactory nerve,cribriform plate to subarachnoid space)
In meninges, organsims are internalised into phagocytic cells
They replicate and migrate to subepithelial spaces
Incubation period : 3-4 days
PATHOGENESIS (STEPS)

16. CLINICAL FEATURES
 Febrile illness : Mild and self limiting
 Pyogenic meningitis : High fever, stiff neck,
Kernig’s sign, severe headache, vomiting,
photophobia, chills
 Meningococcemia : acute fever with chills,
malaise, prostation, Waterhouse-
frederichsen syndrome, DIC
 Other Syndrome : Pneumonia, arthritis,
urethritis, respiratory tract infection

17. Hemorrhage in the adrenal
glands in Waterhouse-
Fridericksen syndrome
Meningococcal disease is favoured by defieciency of the
terminal complement components (C5-C9)

18. PROPHYLAXIS
a. Chemoprophylaxis :
 Rifampicin
 Minocycline
 Ciprofloxacin
b. Vaccination:
 A vaccine containing capsular polysaccharide of
serotypes A and C : for infants below 2 years
 A quadrivalent vaacine constituted by
polysaccharides of serotypes A,C,Y and W-135 :
for children and adults
 conjugate vaccine:
polysaccharide antigen is conjugated to diptheria
toxoid

19. LABORATORY DIAGNOSIS
1. Specimen:
 CSF
 Blood
2. Examination of CSF:
 Increased Pressure
 Turbid
 The collected CSF is divided into 3 portions (for
microscopy, for biochemical tests and for culture)

20.  Microscopy:
 Gram stained smear of CSF deposit commonly shows
Gram negative intracellular diplococci.
 White cell count increases to several thousand per cubic
mm with 90-99% PMNs.
 Biochemical tests:
 Glucose is markedly diminished
 CSF protein is markedly raised CSF:
 Culture:
 Inoculated into chocloate agar
 Incubated at 37c in 5-10% Carbondioxide and high humidity
 After 24 hours bacterial colonies appear
 The organism is tested for biochemical and agglutination reaction

21. Normal CSF:
Clear ,
colorless
0-5
lymphocytes
Sterile
150-450 mg /l
protein
2.8-3.9mmol/l
glucose
CSF in viral meningitis
Clear or slightly turbid
10-500 cells mainly
lymphocytes
Stool culture, or
serology +ve
Normal or slightly raised
protein
Normal glucose
CSF in TB
meningitis:
Clear or slightly turbid
10-500 cells,mainly
lymphocytes( polys early)
AFB in Z-N stain
Grow in LJ medium
Moderately raised
protein
Sugar reduced
CSF in bacterial
meningitis:
Turbid
500-20,000
cells,few
lymphocytes
Bacteria in Gram
stain
Markedly raised
protein
Reduced or
absent glucose
CSF IN DIFFERENT
MENINGITIS

22. 3.Blood culture:
 Blood culture is positive in over 40% cases of
meningiococcal meningitis
4.Other Cultures:
 Nasopharyngeal swab
 Skin lesions
 Joint fluid
 Tracheal aspirate
 Urethral discharge
 Serology
 Petechial lesions

23. d) Detection of antigen:
 For Detection of Meningiococcal DNA
 Polymerase Chain Reaction (PCR)
 For detection of soluble polysaccharide antigen
 Counter current immunoelectrophoresis (CIEP)
 Latex agglutination test

24. Neisseria gonorrhoeae (Gonococcus)
 N. gonorrhoeae causes the sexually
transmitted disease gonorrhoea.
 first described by Neisser in 1879 in
gonorrheal pus.
 resembles meningococci very closely in many
properties.

25. MORPHOLOGY:
Gram negative
oval/spherical cocci
usually found with in the polymorphs
Arranged in pairs (adjacent sides concave)
Kidney shaped
possess pili on their surface

26. CULTURE & CULTURAL CHARACTERISTICS:
 fastidious organisms do not grow on ordinary culture
media.
 aerobic but may grow anaerobically also
 The optimum temperature for growth is 35-36°C &
optimum pH is 7.2-7.6.
 It is essential to provide 5-10% CO2.

27. Media used:
a) Non selective media: Chocolate agar,
Mueller-Hinton agar
Modified New York City
medium
b) Selective media: Thayer Martin medium
with antibiotics (Vancomycin, Colistin &
Nystatin)

28. Colony morphology: Colonies are
small
round
translucent
convex or slightly umbonate
finely granular surface
lobate margins.

29. Biochemical reactions:
1) Oxidase test: Positive
2) Ferments only glucose
but not maltose.

30. PATHOGENICITY:
Source of infection:
1. Asymptomatic carriers
2. Patients
Mode of infection:
1. Venereal infection (sexual contact)
2. Nonvenereal infection

31. Antigenic structure & virulence factors:
1. Pili
2. Lipooligosaccharide: Endotoxic.
3. Outer membrane proteins: 3 types
a) Protein I (por)- it is a porin & helps in adherence.
b) Protein II (opa)- helps in adherence.
c) Protein III (rmp)- it is associated with protein I.
4. IgA1 protease: Splits & inactivates IgA.

32. Antigenic structure & virulence factors

33. Mechanism of pathogenesis:
Gonococci adhere to epithelial cells of urethra or
other mucosal surface through pili
penetrate through the intercellular space
reach the sub epithelial connective tissue &
causes inflammation
Leads to clinical manifestations
Incubation period: 2-8 days.

34. Disease:
A) In men:
The disease starts as an acute urethritis with a
mucopurulent discharge
extends to the prostate, seminal
vesicles & epididymis
In some it may become chronic urethritis leading to
stricture formation
The infection may spread to the periurethral tissues,
causing abscesses & multiple discharging sinuses
(Watercan perineum)

35. B) In women:
The initial infection is urethritis & cervicitis but vaginitis
does not occur in adult female (vulvovaginitis can
occur in prepubertal girls)
The infection may extend to Bartholin’s glands,
endometrium & fallopian tubes causing
Pelvic Inflammatory Disease (PID)
Rarely peritonitis may develop with perihepatic
inflammation (Fitz-Hugh-Curtis syndrome)

36. C) In both the sexes:
Proctitis, pharyngitis,
conjunctivitis, bacteraemia which may lead to
metastatic infection such as arthritis,
endocarditis, meningitis, pyemia & skin rashes.
D) In neonates:
Opthalmia neonatorum (a
nonvenereal gonococcal conjunctivitis in the
newborn) results from direct infection during
passage through birth canal.

37. 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
B) In women:
i) Urethral discharge
ii) Cervical swabs

38. C) In both the sexes: Blood, CSF, synovial fluid,
throat swab, rectal swab & material from skin
rashes.
Transport: If there is delay in processing than the
specimens should be sent in “ Stuart’s medium”.

39. 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.

40. 2. Immunofluorescence:

41. B) Culture:
Media used:
Colony morphology:
Gram’s smear:
Reveals Gram negative
cocci in pairs with
adjacent sides concave.
Biochemical reactions:

42. C) Serology:
 Complement fixation test,
 Precipitation,
 Passive agglutination,
 Immunofluorescence,
 Radioimmunoassay.(uses whole-cell
lysate,pilus protein and lipopolysaccharide
antigen)

43. TREATMENT:
 Previously Penicillin was drug of choice but
resistance developed rapidly.
 Penicillin resistant is due to production of
penicillinase enzyme & the strains are called
as penicillinase producing Neisseria
gonorrhoeae (PPNG).
 Now Ceftriaxone or Ciprofloxacin plus
Doxycycline or Erythromycin is useful.

44. EPIDEMIOLOGY:
 Gonorrhoea is an exclusively human disease.
 The only source of infection is a human
carrier or less often a patient.
 Asymptomatic carriage in women makes them
a reservoir to spread infection among their
male contact.
 Gonorrhoea is an venereal disease (STD).

45. PROPHYLAXIS:
 Early detection of cases,
 Tracing of contacts,
 Health education,
 General measures,
 Vaccination has no role in prophylaxis.

46. NONGONOCOCCAL (NONSPECIFIC) URETHRITIS
 Urethritis due to causative agents other than
gonococcus.
 Etiology:
a) Bacteria- Chlamydia trachomatis
Mycoplasma urealyticum
Ureaplasma urealyticum
b) Parasites- Trichomonas vaginalis
c) Viruses- Herpes simplex
Cytomegalovirus
d) Fungi- Candida
 NGU can be a part of Reiter’s syndrome- a clinical
condition characterized by urethritis, arthritis &
conjunctivitis.

47. COMMENSAL NEISSERIAE
N. lactamica
N.pharyngis
N. polysaccreae
N. cinerea
N. flavescens
N. mucosa
Commensal
neisseriae