Morphology,pathogenicity,laboratory diagnosis

1.  A Lecture By – Dr. D. W. DESHKAR
 ASSISTANT PROFESSOR DEPT.OF MICROBIOLOGY
 D.Y.PATIL MEDICAL COLLEGE,KOLHAPUR

2. 2
 A 20 year old man presented with urethral discharge &
dysuria for previous two days. H/O unprotected sex
with a commercial sex worker a week back.
 On examination of a smear of pus – Gram negative
diplococci were seen inside polymorphs.
 Culture on Thayer – Martin medium - Positive
 Diagnosis – Gonorrhoea

3. 3
 N.gonorrhoeae causes the
venereal disease
gonorrhoea.
 Gonococcus was first
described in gonorrheal pus
by Neisser in 1879.
 Bumm in 1885 cultured the
coccus & proved its
pathogenicity by inoculating
human volunteers.

4. 4
The name Gonorrhea is derived from
Greek words- Gonos ( seed ) rhoia ( flow ).
Describes a condition in which semen
flowed from the male organ without
erection,

5.  Gram – ve diplococcus.
 With adjacent sides
concave (kidney shaped)
 Predominantly in the
polymorphs ( Intracellular)
 Some cells may contain as
many as 100 cocci.

6.  Gonococci possess pilli on
their surface.
 Pilli facilitate adhesion of the
cocci to mucosal surface &
promote virulence by
inhibiting phagocytosis.
 Gonococci infect non –
cornified epithelium.
 They agglutinate human
RBCs. Haemagglutination not
inhibited by mannose.

7.  Gonococci are non motile. More difficult to grow.
 Are aerobic. But may grow anaerobically also.
 Growth occurring best at pH 7.2 – 7.6 Optimum
temperature for growth – 35 – 36
0
C.
 Essential to provide 5 – 10 % CO2.
 Grow well on CHOCOLATE AGAR & MUELLUR – HINTON
AGAR.
 Selective medium – THAYER – MARTIN medium
(contains Vancomycin + Colistin + Nystatin which
inhibit most of the contaminants).

9.  Are oxidase positive .
 Are Catalase positive
 Rapid Carbohydrate Utilization
test:
Glucose Maltose
N.gonorrhoeae +
(Acid)
-

10.  It is polyphosphate and not
polysaccharide.
 Most evident on freshly isolated
gonococci.
 Is loosely associated with cell
surface.
 It inhibits phagocytosis.
 Are hair like structures extending
from the surface
 Piliated organisms produce altered
appearance of colonies on culture.
 Pilli enhance attachment of organism
to host cells & prevent phagocytosis.
 Act as virulence factor .
 Are made up of pillin proteins.
 Pillin proteins are antigenically
different in almost all strains.
 A single strain can produce several
antigenically distinct pilli.
1. CAPSULE 2. PILLI

11.  There is absence of long O –
antigenic side chains in the
chemical structure of
Lipooligosaccharide (LOS)
which differentiates it from
lipopolysaccharide of Gram – ve
bacilli.
 Toxicity in gonococci is due to
LOS.
 IgA1 protease is produced by
gonococci. It splits and
inactivates IgA which plays a
major role in mucosal defense.
 Two other proteins H8 and Iron
binding protein are also
produced but their role in
pathogenicity is unknown.
3.LIPOOLIGOSACCHARIDE
(LOS)
4.OTHER PROTEINS

12.  5. Proteins – The outer membrane antigens ( proteins ) are the
porins.
i. Protein I (por) – Forms pore on surface. Each strain expresses
one type of protein I. It helps in serotyping of gonococci. Two
variants of protein I – IA & IB. Any one strain carries either IA or IB
but not both. 24 serovers of type IA & 32 serovers of type IB.
ii. Protein II (opa) – One part of protein II is in outer membrane & the
rest is exposed on the surface of bacteria. It takes part in adhesion
of bacterium and its attachment to host cell. Type II protein is
present in those strains which form opaque colonies, so it is also
c/a opacity associated protein.
iii. Protein III – is associated with protein I in the formation of pores
on the cell surface & hence plays a role in the exchange of
molecules across the outer membrane.

13.  Is very delicate organism
 Readily killed by drying, heat &
antiseptics.
 Is a strict parasite & dies in
1 – 2 hrs in exudate outside
the body.
 In culture, the coccus dies in
3 – 4 days but survives in slant
culture at 350
C if kept under
sterile paraffin oil.
 Cultures – preserved for years
if frozen quickly & stored at – -
- 70 0
C.
 Gonococci contains several
cryptic plasmids.
 Two other transmissible
plasmids contain genes that
code for beta lactamase which
causes resistance to penicillin.
RESISTANCE PLASMID

14. N.gonorrhoeae is Human pathogen.
Chimpanzees can be infected artificially
Women may remain Asymptomatic
Gonorrhea infection is generally limited to
superficial mucosal surfaces lined by
columnar epithelium.

15. THE ORGANS & TISSUES INVOLVED
Cervix
Urethra
Rectum
Pharynx
Conjunctiva
Vaginal epithelium – covered with squamous
epithelium not infected
However prepubertal vaginal epithelium is
infected in young girls present with
vulvovaginitis

16.  Gonorrhea is a Venereal disease.
 The disease is acquired by sexual contact.
 In general incubation period is 2 -8 days.
 In men the disease starts as purulent discharge
containing gonococci in large numbers.
 The disease spreads to prostate, seminal vesicle, and
epididymis.
 In men chronic urethritis may lead to stricture formation.
 The infection may spread to the periurethral tissues,
forming abscesses & multiple discharging sinuses --------
----- “ Watercan perineum”.

17. CLINICAL PRESENTATION IN
MALES –
 Majority of males present with
acute urethritis with purulent
discharge
 5% of patients carry bacteria
without distress
 Rectal and Pharyngeal
infections are less often
symptomatic

18. CLINICAL PRESENTATION IN
FEMALES –
 Endocervix infection is the
most common presentation in
women
 Present with vaginal
discharge and Dysuria
 Infection and abscess of
Bartholin and Skene’s glands

19. – OTHER MANIFESTATIONS
 Peritonitis can spread.
 Fitz Hugh Curtis Syndrome ---
Perihepatic inflammation.
 Disseminated gonococcus
infection
 Painful Joints may lead to
Arthritis
 Fever, Few septic lesions on
the extremities
 Meningitis and Endocarditis

20. – GONORRHOEA CAN
MANIFEST AS ORAL
INFECTION -
 Changing sexual practices
and oral sex predisposes the
sex partners with involvement
of oropharengeal regions

21. – DISSEMINATED INFECTION -
 Seen more commonly in
women who may present
with painful joints, fever, and
few septic lesions or the
extremities
 Rarely disseminated
infections may present as
endocarditis or meningitis

22. 1. SPECIMENS -
• Discharge or urethral swab,
Endocervical swab –
- The meatus is cleaned with a gauze
soaked in saline & a sample of the
discharge collected with a platinum
loop for culture, or directly on the slide
for smears.
- Cervical swabs are collected carefully,
using speculum.
- In chronic cases morning drop of
secretion is examined.
- Centrifuged deposits of urine also
demonstrate gonococci.

23. TRANSPORTATION OF SPECIMENS -
• It is preferred in culture, specimens
should be inoculated in prewarmed
plates,immeditely on collection
• If not possible specimen should be
collected on charcoal impregnated
swabs and sent to laboratory in
Stuart’s transport medium.

24. - MICROSCOPY – GRAM STAINING
• Gram’s method of staining is sensitive
in 95% of infections.
• The demonstration of intracellular
Gram negative diplococci in stained
smears provides a presumptive
evidence of gonorrhea in men.
• Diagnosis of gonorrhoea by smear
exam. is unreliable in females.
• Specimens are inoculated onto culture
plates freshly prepared.
• Delay in inoculation of specimens on
culture media reduces the rate of
isolation.

25. - CULTURE -
• Gonococci are aerobic and may grow
aerobically.
• It is essential to provide 5 – 10% CO2.
• They grow well on Chocolate agar and
Mueller – Hinton agar.
• The colonies are small, convex,
translucent, and slightly umbonate
with finely granular surface and lobate
margins.

26. - SELECTIVE CULTURE MEDIUM
-
• The selective medium is
Thayer – Martin medium
containing Vancomycin,
colistin, and Nystatin,
effectively inhibits most
contaminants including non
pathogenic Neisseria

27. - SEROLOGY -
• Complement fixation test
• Precipitation Reaction
• Passive agglutination Using whole cell lysate, pilus protein
• Immunofluorescence & lipopolysaccharide Ags.
• Radioimmunoassay
• Coagglutination
- Biochemical Tests –
• Catalase Test - +ve, Oxidase Test - +ve
• Ferments glucose with acid production. Maltose not fermented.

28. - MOLECULAR METHODS -
• DNA probes can be used
for confirmation, and also
used for the detection of
Gonococci in urethral and
cervical specimens.
• PCR methods are
available in specialized
laboratories

29. - PENICILLIN -
 Was a popularly used antibiotic.
 However resistance has reduced
its utility.
 For a long time the drug
resistance has overcome with
increased dosage.
 Complete resistance to penicillin
has made the drug obsolete in
several parts of the world.

30. - PENICILLIN - GENES CODE
RESISTANCE
 The penicillin resistant strains
possess the gene coding for TEM-
type ß-lactamase commonly found
in Escherichia coli.

31. - OTHER DRUGS USED -
 Ceftriaxone
 Cefixime
 Flouroquinolones
 Ciprofloxin
 Tetracycline
 Co-Amoxi - clav
 Spectinomycin
In Disseminated Gonococcal disease and any complicated infection
treatment for 7-10 days is necessary

32.  The key control measures in gonorrhea are -
1 Rapid diagnosis
2 Use of effective antibiotics
3 Tracing, examination and treatment of
contacts.
4 Inappropriate self medication has contributed
to widespread antimicrobial resistance.

33. 33