Post on 16-Jan-2016
NEISSERIANEISSERIA
IntroductionIntroduction The Neisseriae are G-ve diplococci Pathogens are:- N.meningitidis N.gonorrhoeae Exacting growth requirements Commensals easy to grow on ordinary media
N. gonorrhoeaeN. 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.35-37oC.
Gram stain of N.gonorrhoea
Selective mediaSelective media
Thayer-Martin medium contains vancomycin, colistin, nystatin & trimethoprim.
Colonies: 48hrs incubation.
IdentificationIdentification
Oxidase +ve. Carbohydrate utilization: N.gonorrhoeae
produces acid from glucose only. Slide agglutination with specific antisera
(Phadebact test).
PathogenicityPathogenicity
Causes gonorrhoea Arthritis, Septicemia, Ophthalmia neonatorum.
GonorrhoeaGonorrhoea
Acute pyogenic infection of urethra and (in females) cervix.
Acute purulent urethral , vaginal discharge , dysuria Asymptomatic in females Rectum & oropharynx may be involved.
ComplicationsComplications
Prostatitis, epididymitis , urethral stricture in males.
Salpingitis , infertility in females Septicemia Arthritis Meningitis (rare).
DiagnosisDiagnosis
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 gonorrhoeaTreatment of gonorrhoea
One curative dose Sens. Testing Blind treatment: ceftriaxone, ciprofloxacin Spectinomycin Penicillin: resistance common.
N. meningitidisN. 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 structureAntigenic structure
Polysaccharide antigens Three main groups A,B,C Other groups Y,W135. Grouping: slide agglutination with specific
antisera
PathogenicityPathogenicity
Meningococcal meningitis, as a spread from nasopharynx blood stream meninges in susceptible hosts.
Direct spread to meninges Rash Adrenal haemorrhage (Waterhouse-Friderchsen
syndrome)
MeningitisMeningitis
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)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.
TreatmentTreatment
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 NeisseriaeCommensal 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 meningitisOther 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)Other causative bacteria (Continue)
E.coli & other coliforms Listeria Strept.group B Salmonella spp. Favobacteria.. All common in neonates
After surgery or trauma S.aureus S.pneumoniae AFB chronic meningitis Spirochaetes
Other causative bacteria (ContinueOther causative bacteria (Continue
Other CausesOther Causes
Viral :enterivirus, Paramyxovirus, Herpes
viruses, adenoviruses, arboviruses. Fungi: yeasts (Candida, cryptococcus spp.) Aspergillus spp. Mucor
Findings in CSFFindings in CSF
Normal CSF:
Clear , colorless 0-5 lymphocytes Sterile 150-450 mg /l protein 2.8-3.9mmol/l glucose
CSF in bacterial meningitisCSF 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 meningitisCSF 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 meningitisCSF 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 abscessCerebral 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 meningitisComplication of meningitis
Death ( 30% with pneumococci,10% Hi & N.meningitidis.
Ventriculitis hydrocephalus Paralysis Cerebral abscess..
Treatment of meningitisTreatment of meningitis
Depends on age ,causal bacteria Urgent ,parenteral Ceftriaxone Neonates: amp+ gm (or ceftriaxone) Sens.testing Anti TB