Transcript Listeria and Erysipelothrix Nov 2009

Listeria
and Erysipelothrix
Ali Somily MD
Classification
– Genus listeria
– Soil , water, and vegetation
– Many species?
• L.ivanovia ( animal)
• L.innocua ( food)
• L.monocytogen
–Pathogenic to human
Microbiology
• Specimen
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Blood
CSF
Amniotic fluid
Non sterile site
• Vagina
• Stool spp not swab
– 1-5% carrier
• Media
– BAP
– CHO
• Temp
– Cold enrichment for
several days
Microbiology
• Smear
– Aerobic non spore
forming short G+ve B or
coccobacilli
– Rounded end , singly or
short chain
• In CSF might mimic
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Enterococcus
S.pneumoniae
Corynebacterium
Haemophilus
• Culture
– Catalase +ve
– H2S –ve
Listeria monocytogenes
Clinical syndromes
• Epidemiology
– Summer month
– Epidemic& sporadic
– Dairy product & meat
• Predisposing factors
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Newborn
Elderly
Pregnancy
Cell mediated Abn.
• AIDS
• Lymphoma
• Transplant
• Diseases
• Septcemia
• CNS (meningitis,
encephalitis)
• AmnionitisPreg.
Termination
Life Cycle
Treatment
• Ampicillin not cefotaxime
Erysipelothrixs rhusiopathiae
• Genus Erysipelothrixs
– Two spp
• E. rhusiopathiae (only
pathogen)
• E.tonsillarum
Microbiology
• Smear
– Gram positive nonspore
forming short baccilli,
– Rounded end singly or
short chain
– Slender and long
filaments
Microbiology
• All -ve
– Catalase
– Oxidase
• H2S +ve
E. rhusiopathiae
• Carried by animal (fish, Swine)
• Cutaneous infection Erysipeloid
– Skin abrasion, injury bite from infected animal.
– Hand of veterinarians butchers and fish handlers
– Generalized rare
– I’C (bacteremia and endocarditis)
Erysipeloid
Corynebacterium
Coryneform
• Aerobic non spore forming
gram positive bacilli
• Coryne=
clubcoynebacterium
• >40 spp devided into 3
groups
– Group I human and animal
– Group II plant
– Group III nonpathogenic
• C.dipthteriae
• Archanobacterium
• Gardnerella
Microbiology
• Smear
– Vary from coccoid to rod .Clubbed stain unevenly Arrange
in V-shape Chinese letter .Rod in parallel or palisade
formation
• C.diphtheria
– Nasopharyngeal swab
– BAP
– Selective media
• Tellurite medium( black colonies)
– Tinsdale
– Cystine –tellurite BAP
– Sensitive to K tellurite may not grow
– Loeffler’ s media not as primary mediametachromatic
granules
• Identification
– Catalase +VE
– APICoryne
– RapID CB plus
• Toxigenicity
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Elek test reference lab
Antisera on strep under special media
Neg and pos control in addition to the patientsample
Incubate 37d
45o line of precipitation
Reincubate 72 hr if negative
C. diphtheriae
VARIENT OF C.DIPHTHERIA:
1. GRAVIS
2. MITIS
3. INTERMEDIUS
COLONIAL MORPHOLOGY
TINSDAL MEDIA
TINSDAL MEDIA
(i) C. diphtheriae biotype gravis colonies on a Tinsdale
agar plate
Recovery of Miscellaneous Pathogens From Throat
Cultures
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Pseudomembrane of the pharynx
Occasionally of the skin.
Toxigenic strains of Corynebacterium.
To confirm a clinical diagnosis of diphtheria,
the strain isolated diphtheriae.
• The disease is characterized must be shown
to produce toxin.
Clinical infections
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Respiratory and cutaneous
Uncommon in North America and Western Europe.
Humans are the only natural hosts for C. diphtheriae.
Carried in the upper respiratory tract
Spread by droplet infection or hand-tomouth contact.
IP 2 to 5 days.
Low-grade fever, malaise, and a mild sore throat.
Tonsils or pharynx.
• Rapidly multiply on the epithelial cells and trigger an
inflammatory reaction.
• The infecting toxigenic strain of C. diphtheriae
produces toxin locally
• Tissue necrosis and exudate formation.
• Cell necrosis and exudate forms a very tough gray to
white pseudomembrane, which attaches to the
tissues.
• Spread downward into the larynx and trachea.
• Suffocation if the membrane spreads
• Blocks the air passage or if it is dislodged
• The toxin also is absorbed and produces a variety of
systemic effects.
– Kidneys, heart, and nervous system
• Death often is a result of cardiac failure.
• Another effect of the toxin is a demyelinating
peripheral neuritis paralysis following the acute
illness
• Mortality of 5-10%, highest in very young and old.
• Erythromycin is the drug used for penicillin-sensitive
individuals.
Antitoxin
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Produced in horses.
Hypersensitivity to horse serum precludes its administration.
10% allergic reaction to the horse serum.
Antibiotics have no effect on toxin
Eliminate the focus of infection as well as prevent the spread
of the organism.
• The drug of choice is penicillin.
• Nonrespiratory sites
– Cutaneous
• Systemically, but systemic complications are less
common than from upper respiratory infections.
The routine immunization
• Diphtheria, pertussis, tetanus, polio :
– 2,4,6,18 months, 4 yrs
• Routine immunization since 1950's - one or two
cases a year, classic diptheria rare
• Since 1990, thousands of cases in former Soviet
Union (mortality 3-23%)
Diptheria-vaccine
• Toxoid; cell-free detoxified diphtheria toxin
protects against the systemic effects of toxin
but not against local infection/colonization
Diphtheria toxin/Zoonotic
• C.ulceran
– Bovine mastitis
• C.pseudotuberculosis
– Animal(sheep) LNs