Transcript NEISSERIA
NEISSERIA
Introduction
The
Neisseriae are G-ve diplococci
Pathogens are:- N.meningitidis
N.gonorrhoeae
Exacting growth requirements
Commensals easy to grow on ordinary media
N. gonorrhoeae
Obligate parasite of human urogenital tract.
Morphology: Gram -ve diplococci (bean shaped).
Culture: enriched media (lysed blood or chocolate),
moist aerobic atmosphere +5-10% CO2. Temp.3537oC.
Gram stain of N.gonorrhoea
Selective media
Thayer-Martin medium contains vancomycin,
colistin, nystatin & trimethoprim.
Colonies: 48hrs incubation.
Identification
Oxidase
+ve.
Carbohydrate utilization: N.gonorrhoeae
produces acid from glucose only.
Slide agglutination with specific antisera
(Phadebact test).
Pathogenicity
Causes gonorrhoea
Arthritis,
Septicemia,
Ophthalmia neonatorum.
Gonorrhoea
Acute pyogenic infection of urethra and (in females)
cervix.
Acute purulent urethral , vaginal discharge , dysuria
Asymptomatic in females
Rectum & oropharynx may be involved.
Complications
Prostatitis,
epididymitis , urethral stricture in
males.
Salpingitis , infertility in females
Septicemia
Arthritis
Meningitis (rare).
Diagnosis
Specimen: urethral,cervical smears &swabs
(transport medium).
Gram film: intracellular Gram -ve diplococci
Culture: selective media
Oxidase +ve
acid production from glucose
Latex agglutination
Treatment of gonorrhoea
One curative dose
Sens. Testing
Blind treatment: ceftriaxone, ciprofloxacin
Spectinomycin
Penicillin: resistance common.
N. meningitidis
Habitat: human nasopharynx (10-25%)
Similar to N. gonorrhoea but less exacting ?
Can grow in BA, Chocolate agar without selective
media from CSF ?
Id. CHO utilization: acid from glucose & maltose.
Gram stain of Neisseria meningitis
Haemorrhagic rash
Death from Waterhouse-Friderichsen syndrome
Neck rigidity
Antigenic structure
Polysaccharide antigens
Three
main groups A,B,C
Other groups Y,W135.
Grouping: slide agglutination with specific
antisera
Pathogenicity
Meningococcal meningitis, as a spread from
nasopharynx
blood stream
meninges in
susceptible hosts.
Direct spread to meninges
Rash
Adrenal haemorrhage (Waterhouse-Friderchsen
syndrome)
Meningitis
Clinically: rapid deterioration of flu like illness
Headache, neck stiffness, +ve kerning’s sign,
fever,..…
Diagnosis: CSF + blood culture
CSF: WBC , RBCs
Gram stain: bacteria & cells
Meningitis (Continue)
Culture deposit into blood & chocolate agars and
glucose broth 7 cooked meat media
Incubate in air + 5%CO2
Id : sugar utilization + latex
For partially treated meningitis: detection of bacterial
antigen by: latex agglu, CCIE.. for common
serogroups of meningitis pathogens.
Treatment
Parenteral antimicrobial
Start blind treatment after collection of specimens
by:
Ceftriaxone or cefotaxime
Change later according to sens. Test.
Contacts: rifampicin
Prevention: vaccination (polyvalent)
Commensal Neisseriae
N.pharyngis, N.flava, N.sicca,..
In mucous mem. Of mouth,nose, pharynx, less common in
genital tract.
Differ. From pathogenic one:
grow in ordinary media( no CO2)
at room temp.
rough, pigmented
acid from a number of CHOs
Other causes of meningitis
Bacterial causes:
Three primary pathogens:
N. meningitidis, HI, S.pneumoniae
N.menningitidis
all ages
HI
2m-5y
S.pneumoniae
all ages but more common
in adult with underlying illnesses.
Other causative bacteria (Continue)
E.coli
& other coliforms
Listeria
Strept.group B
Salmonella spp.
Favobacteria..
All common in neonates
Other causative bacteria (Continue
After surgery
or trauma
S.aureus
S.pneumoniae
AFB
chronic meningitis
Spirochaetes
Other Causes
Viral
:enterivirus, Paramyxovirus, Herpes
viruses, adenoviruses, arboviruses.
Fungi: yeasts (Candida, cryptococcus spp.)
Aspergillus spp.
Mucor
Findings in CSF
Normal CSF:
Clear
, colorless
0-5 lymphocytes
Sterile
150-450 mg /l protein
2.8-3.9mmol/l glucose
CSF in bacterial meningitis
Turbid
500-20,000 cells mainly polys,few lymphocytes
Bacteria in Gram stain
Markedly raised protein
Reduced or absent 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 viral meningitis
Clear
or slightly turbid
10-500 cells mainly lymphocytes
Stool culture, or serology +ve
Normal or slightly raised protein
Normal glucose
Cerebral abscess
Clear
or slightly turbid
Bacteria: S. milleri, Bacteroides, S.aureus.
Proteus(Causative bacteria)
0-500 mainly polymorphs
Often no organisms in CSF
Normal or raised protein
Normal glucose
Complication of meningitis
Death ( 30% with pneumococci,10% Hi &
N.meningitidis.
Ventriculitis
hydrocephalus
Paralysis
Cerebral abscess..
Treatment of meningitis
Depends
on age ,causal bacteria
Urgent ,parenteral
Ceftriaxone
Neonates: amp+ gm (or ceftriaxone)
Sens.testing
Anti TB