export_zoonotic bacteria i Flashcards
Anthrax causative agent
Bacillus anthracis
Bacillus anthracis features
Gram-positive rods in chains
Aerobic
Spore-forming
Bacillus anthracis virulence factors
PROTEIN capsule
Protective Ag
Lethal toxin
Edema toxin
Protective Ag
Operates like a B subunit for an AB toxin
Binds, and allows lethal OR edema toxin to take effect
Lethal toxin
Disrupts normal cell signaling, resulting in apoptosis and inflammation
Edema toxin
Increases cAMP levels, resulting in ion/water efflux and edema
Bacillus anthracis pathogenesis
Spore ingestion/inoculation
Germination and production of toxin
Protective Ag binding, then internalization of LF and/or EF
Bacillus anthracis resevoirs
Cattle, sheep, goats, and soil
Three types of Bacillus anthracis infections
Inoculation
Inhalation
Ingestion
Inoculation anthrax
Most common
Open cuts/wounds
Inhalation anthrax
Uncommon
“Wool-sorters disease”
Ingestion anthrax
GI (rare)
Contaminated meats
Cutaneous anthrax disease
Small red papule -> vesicle -> necrotic ulcer (eschar) with black center
Painless
Inhalation anthrax disease
Spores remain latent
Initially, non-specific (cough, SOB, fatigue)
Second stage (fever, drenching sweat, dyspnea, shock, death)
Fatal if not treated, high mortality rate with treatment
Diagnose anthrax
Clinical signs
Hx of exposure
Gram-stain
Culture
Treatment of cutaneous anthrax
Amoxicillin
Treatment of inhalation or GI anthrax
Three antibiotics
Brucellosis causative agent
Brucella species
Brucella features
Gram-negative coccobacilli
Intracellular pathogens
Which species cause brucellosis in humans?
B. abortis (cattle)
B. suis (swine)
B. melintensis (goats)
Transmission of Brucella
Aerosol
Ingestion (raw milk)
Brucellosis disease
Acute, undulating fever, joint pain, headache, drenching sweat
Can cause spontaneous abortion in pregnant woman
Diagnose brucellosis
Hx
Blood culture, serology, blood PCR
Treat brucellosis
6+ weeks of tetracycline and rifampin
Pasteurellosis causative agent
Pasteurella multocida
Pasteurella multocida features
Gram-negative coccobacilli
Facultative anaerobes
Normal microbiota of many animals
Pasteurella multocida virulence factors
LPS
Polysaccharide capsule
Transmission of pasteurellosis infection
Dog or cat bite/scratch
Pasteurella multocida disease
Redness/swelling around wound
Cellulitis and abscess
Lymphadenopathy
Diagnose pasteurellosis
Hx
Culture/biochemical testing
Treat pasteurellosis
Penicillin
Leptospirosis causative agent
Leptospira interrogans
Leptospira interrogans features
Gram-negative, spiral-shaped, terminal “hooks”
Require dark-field microscopy
Leptospirosis disease
Most cause self-limited, non-specific febrile illness
Two phases of disease
Phase 1 of leptospirosis
Febrile, flu-like
Organism in blood, urine, CSF
Resolution, or progression to phase 2
Phase 2 of leptospirosis
Lasts several weeks
Meningitis, eye inflammation, jaundice, renal failure, petechial rash
Organ failure
Diagnose leptospirosis
Hx
Serology
Treat leptospirosis
Penicillin
Ampicillin
Leptospirosis resevoirs
Rodents
Small mammals
Tularemia causative agent
Francisella tularensis
Francisella tularensis features
Gram-negative coccobacilli
Aerobic
Intracellular (monocyte/macrophage)
Francisella tularensis virulence factors
Prevents phagosome-lysosome fusion
Polysaccharide capsule
LPS
Tularemia disease
Skin = ulceroglandular Eye = oculoglandular
Lungs = pneumonic
Ulceroglandular tularemia disease
Red, painful, swollen papule, becomes purulent, ulcerates
May become bacteremic
Oculoglandular tularemia disease
Painful conjunctivitis with swollen cervical lymph nodes
Pneumonic tularemia disease
Inhalation of infectious aerosol
Pneumonitis, eventual sepsis
High mortality rate
Tularemia treatment
Gentamycin
Tularemia reservoir
Rabbits
Hares
Tularemia vector
Ticks
Deer flies
Plague causative agent
Yersinia pestis
Yersinia pestis features
Gram-negative rod
Yersinia pestis staining
Giemsa stain results in purple, closed safety pin
Yersinia pestis virulence factors
PROTEIN capsule
LPS
Three plasmids (biofilm formation, enhanced resistance to macrophages, resistance to complement)
Yersinia pestic - Bubonic plaque
Transmitted by flea bite
Painful lymphadenopathy results in buboes - can perforate, resulting in bacteremia and septic shock
Gangrene of the extremities
Yesinia pestis - Pneumonic plague
Inhalation of infectious droplets
May be secondary to Bubonic plague
Primary - fever, headache, cough, etc. rapidly progressing to hemoptysis, cardiopulmonary insufficiency, cyanosis, circulatory collapse
Secondary - progresses more slowly
Plague resevoirs
Rodents
Prairie dogs
Plague vectors
Fleas