Gram negative cocci, Neisseriae, NEISSERIAE MENINGITIDIS, DISEASES, IMPORTANT PROPERTIES , PATHOGENESIS & EPIDEMOLOGY , CLINICAL FINDINGS, TREATMENT , PREVENTION, NEISSERIAE GONORRHOEAE

2. Presented by SYEDA MARYAM

3.  Gram negative cocci
 Shape of paired kidney beans
 Inhibited by toxic trace metals
fatty acid found in certain culture media
 Cultured on chocolate agar
contain blood heated to 80C
inactivates the inhibitors
 Is oxidase positive contain enzyme CYTOCHROME C
important laboratory diagnostic test
PHENYLENEDIAMINE turns purple/black
as a result of oxidation of reagent by enzyme

5. Also known as MENINGIOCOCCI

6.  MENINGITIS
 MENINGOCOCCEMIA

7.  Prominent polysaccharide capsule
antiphagocytic
enhances virulence
immunogen in vaccine induces protective antibody
 Divided into 13 serologic groups
based on antigenicity of their capsular polysaccharide
most common cause of meningitis /meningococcemia
group A, B, C, Y, W-135
group A leading cause of epidemic meningitis
group B not immunogenic in human
not part of vaccine that contain capsular polysaccharide

8.  Human is only natural host of N. meningitides
 Transmitted by air borne droplet
 Colonizers of nasopharynx
become part of transient flora of upper respiratory tract
 Carriers are usually asymptomatic
 Enter blood stream from nasopharynx
spread to specific site MENINGES & JOINTS
disseminated through out the body MENINGIOCOCCEMIA
 5% people become chronic carrier
source of infections for others
 Meningitis in infants older than 2 months
strep. Pneumonia
N. meningitides group A epidemic meningitis
group B meningitis in developed countries

9.  4 impotant virulence factors
POLYSACCHRIDE CAPSULE
enable organism to resists phagocytosis
is immunogen used in several vaccines
ENDOTOXINS
causes fever, shock and pathophysiologic changes
IMMUNOGLOBULIN IgA PROTEASE
help bacteria to attach to membrane of upper respiratory tract
cleaves secretory IgA
FACTOR H BINDING PROTEIN (FHBP)
bind factor H inhibitors of complement C3b
it’s presence on the surface of meningococci reduces
opsonization

10.  Immunity is group specific
immunity against on group yet susceptible to infection by another
group
 Resistance to disease correlates to the presence of antibody to the
capsular polysaccharide
 Most carriers develop antibody titter against it within 2 weeks of
colonization
 Complement deficiency i.e. LATE ACTING COMPLEMENT (C6-C9)
Increases the rate of meningococcal bacteremia

11.  2 most important manifestations are
MENINGITIS
MENINGOCOCCEMIA
 WATERHOUSE- FRIDERICHSEN SYNGROME
Is a life threatening form of meningococcemia
is characterized by high fever
shock
widespread purpura
DIC
thrombocytopenia
adrenal insufficiency
 Bacteremia results in seeding of many organs i.e. meninges
symptoms are increased level of PMN in spinal fluid
fever, headache, stiff neck

12.  Smear and culture of blood and spinal fluid samples
 Presumptive diagnosis can be made if Gram negative cocci is seen in the CSF of
spinal fluid
 Grow best on chocolate agar incubated at 37C and 5% CO2 atmosphere
 Differentiation between N. meningitides and N. gonorrhea
N. meningitides ferments MALTOSE
N. gonorrhea don’t ferment MALTOSE
while both ferments GLUCOSE
 Also identified by immunofluorescence
 Procedure of rapid diagnosis LATEX AGGULTINATION TEST
detects capsular polysaccharide in spinal fluid

13.  Drug of choice for meningococci Ceftriaxone / penicillin G
 Strains resistant to penicillin G rarely emerges
 Strains resistant to SULFONAMIDE common

14.  CHEMOPROPHYLAXIS
 Immunization
 For prophylaxis RIFAMPIN + CIPROFLOXACIN

15. Also known as GONOCOCCUS

16.  Gonorrhea
 Neonatal conjunctivitis (ophthalmic neonatorum)
 Pelvic inflammatory disease PID

17.  Cause disease only in human
 Usually transmitted sexually
 Newborn is infected during birth
 Symptomatic in men and asymptomatic in women
 Pili most imp. Virulence factor
mediate attachment to mucosal cell surface
antiphagocytic
 Have no capsule
 Main host defense against gonococci are IgA, IgG, complement & neutrophil

18.  Cause localized infection in genital tract
disseminated with seeding of various organs via blood stream
 GONORRHEA
in men causes urethritis
dysuria
purulent discharge
epididymitis may occur
in women infection in endocervix
purulent vaginal discharge
intermenstrual bleeding (cervicitis)
ascending infection to uterine tube SALPINGITIS , PID
result in sterility or ectopic pregnancy

19.  DGIs
arthritis
tenosynovitis
pustules in skin
common cause of septic arthritis in
sexually active adults
 Other infected sites includes
anorectal area
throat pharyngitis
eyes purulent conjunctivitis

20.  Diagnosis of urogenital infections depend upon
growth staining
culture of discharge
nucleic acid amplification
test

21.  CEFTRIAXONE in uncomplicated gonococcal infection
 GENTAMYCIN + AZITHROMYCIN if patient is allergic to penicillin G or
cephalosporin

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