Gram Positive Bacillus
Erysipelothrix
E. rhusiopathiae
Saprophyte
Nonmotile, nonsporeformer
Microaerophilic
Capsule
Transmission
Fecal contamination
Disease
Maculopapular rash
TX : AB
Listeria
L. monocytogenes
Soil, mammal gut
Noncaspule, nonspore
Motile
F.A.
Transmission
Direct
Vertical
Disease
Skin à bacteremiaàendocarditisànervous
TX: AB
Nocardia
N. asteroids
Saprophyte: soil
Filamentous, branching
Weakly acid fast
Transmission
Susceptible individuals: immunosuppressed
Diseases
Respiratory: resemble TB
Skin: abscesses
TX: AB
Baccillus
B. anthracis
B. cereus
B. anthracis
F.A.
Capsule
Sporeformer
Nonmotile
Reservoir: hoof stock
Diseases:
Cutaneous
Inhalation
Gastrointestinal
Virulence
* capsule
* spore
* exotoxin
* protective antigen
B. cereus
Aerobe
nonencapsulated
Motile
Sporeformer
Diseases
Food poisoning
Catheter sepsis
Ocular
Virulence
*spores
*enterotoxins
*hemolysins
* lecithinase [phospholipase C]
Clostridia
Obligate anaerobes
Motile
Spore former
Various extotoxins
C. tetani
A-B neurotoxin [tetanospasm]: blocks release of inhibitory
Tonic spasms
* Localized
* Cephalic
* Generalized
C. perfringens
Membrane disrupting toxin (phospholipids)
* Gas gangrene
* Food poisoning
C. botulinum
A-B neurotoxin [botulinum toxin]: blocks ACH @ NMJ
Jaw à Limbs à Respiratory m.
* Type A: proteolytic, heat resistant
* Type B: both
* Type E: nonproteolytic, heat labile
C. difficile
Nosocomial Antibiotic induced colitisà diarrhea
Enterotoxin
Cytotoxin
Actinomycosis
Anaerobic
Oral cavity
Location: Jaw, Thoracic, Abd, Pelvic, Generalized
Disease: abscesses, purulent discharge with sulfur granules
Mycobacteriaceae Family
Acid Fast [“G (+) rod”]à mycolic acid in cell wall
Aerobic
Non-spore former
Non-motile
Reservoir: Humans
Transmission: Respiratory Droplet
M. tuberculosis
Slow growing = more virulent
Pulmonary TB: nodular scars, caseous necrosis
Disseminated TB / Extrapulmonary TB:
Brain, kidney, LN, bones, skin, GI
Disease Stages
a) primary
b) latent
c) recrudescent
Virulence Factors
* waxy cell wall: decreased phagocytosis
* catalase
* mycobactin: Iron chelator
DX: organism in fluids, chest X-rays, culture
Tuberculin skin test as a screen
Tx: multidrug therapy
M. leprae
Tuberculoid leprosy
Rash with plaques, possible nerve damage
Lepromatous Leprosy
Erythema nodosum
Neuritis of somatic sensory
Skin appendage loss
Ulceration with secondary infection à bacteremia
Other: nasal,
testes, renal
Corynebacterium diptheriae
Weakly Acid Fast [G (+) bacillus]
Coryne = club ; diptheriae = leather hide
(see family characteristics)
Disease : Diptheriaà Pseudomembrane
^ primarily pharynx and tonsils
^ other mm
nasal à discharge
laryngealà extension or primary
external auditory canalà OM
conjunctival
vulvo-vaginal
Complications due to toxin production:
* edema
* myocarditis
* neuritis (motor nerves)
* Cutaneous (rash)
Virulence Factors
1) Diptheria toxin: A-B exotoxin
inactivates translation of proteins
2) Neuraminidase
3) Protease (Dipthin) : inactivates IgA
DX: Culture on Tellurite media
Schick test
ID toxin
TX: AB
Antitoxins
Prevention: DTP vaccine