Zoonoses-Haemophilus-Listeria Flashcards
Yersenia pestis gram
negative
Yersenia pestis cause of?
black death
Yersenia pestis source
zoonotic disease/ unsanitary conditions
sylvatic plaque
Yersenia pestis transmitted from rodent to flea and back and forth, usually no severe affects on the rodent
urban plaque
result of rodent flea with Yersenia pestis biting rat and then becoming associated with humans through unsanitary conditions, bites human and causes infection
can lead to bubonic or septicemic plaque
bubonic plague major characteristic
mortaility?
bubo: infected lymph node with pus, NOT CONTAGIOUS
50-75 mortality if not treated promptly
can progress to septicemic plague
speticemic plague can progress to?
pnemonic plague, spread to lungs
HIGHLY CONTAGIOUS WITH AERSOLS AND POSSIBLE HUMAN FLEA
near 100 mortality
vascular shock leads to blackened extremities
Yersenia pestis virulence factors
Pla
yops
F1
LPS
pla of Yersenia pestis
protease, activates plasminogen activator to destroy C3b and C5a
yops of Yersenia pestis
loss of this?
interferes with phago
loss of yops= loss of virulence
F1 of Yersenia pestis
forms anti-phago capsule
LPS endotoxin Yersenia pestis
causes inflammatory symptoms
treatment/ prevention of the black death
antibiotics
vax for short-term protection
avoidance of rodents
Francisella tularensis gram
negative
Francisella tularensis pathgenicity
oppurtunistic zoonosis (animal/tick bites) possible bioterrorism
Francisella tularensis virulnce factors
intracellular growth in macrophages
thin capsule
Francisella tularensis intracell growth
prevent?
can lead to?
prevention of phago lyso fusion, leads to bacteremia
Francisella tularensis thin capsule actions
anti complement and weak LPS endotoxin
Francisella tularensis diseases
“rabbit and tick fever”
ulceroglandular and oculoglandular tularemia
pulmonary tularemia
Brucella gram
negative
Brucella pathogenicity
oppurtunistic zoonosis by B. melitensis
bioterrorism
Brucella disease
undulant fever/ Bang’s disease= systemic bacteremia satrting at LN
waves of symptoms that resolve then recur
Brucella pathogenesis (how it spreads in body)
a
Brucella virulence factors
Ø intracellular growth in macrophages bacteremia
Ø smooth culture (glycocalyx, no capsule)
Ø (weak) LPS endotoxin (no exotoxin)
brucella eradication in US
due to destruction of infected cattle
brucella abortions in animals
In animals, Brucella sp. cause infectious abortion: animal (but not human) placenta has a high
concentration of erythritol (nutrient preferred over glucose) abortion (in lifestock; not in humans)
Haemophilus influenzae gram
negative
Haemophilus influenzae often found where in our flora?
most virulent type?
frequently part of oral flora (carrier rate up to 80%)
6 O-antigen serotypes: a – f: type b is most virulent
Haemophilus influenzae virulence factors
Ø Polyribitol phosphate (PRP) capsule b allows systemic infections T-independent Ag with poor IgM response in young children (without capsule: less virulence; localized infections only) ONLY IN TYPE B
Ø pili
Ø adhesins
Ø IgA protease
Haemophilus influenzae vax
creates what kind of immune response?
does and does not protect against?
Conjugated vaccine against capsule b polysaccharides creates protective IgG, preventing systemic infections
Vaccine does not protect against other encapsulated strains and unencapsulated strains
before the Haemophilus influenzae vax, it was the most common cause of?
bacterial meningitis in young children
Haemophilus influenzae disease seen with vax
Even with vaccination:
by unencapsulated strains:
• otitis media (immunity develops in older children)
• sinusitis, bronchitis, pneumonia
• conjunctivitis pink eye (H.aegyptius strain)
Haemophilus influenzae diseases without vax
sequelae?
Without vaccination: systemic diseases (in children) by encapsulated strains: • meningitis • septicemia, cellulitis, epiglottitis arthritis as a sequelae
Haemophilus influenzae epidemiology
aerosol transmission
respiratory tract in elderly
Legionella pneumophila gram
negative
Legionella pneumophila growth intracellularly
facultatively intracellular (prevents endosome-lysosome fusion; autophagosome-like uptake)
Lives and proliferates in the vacuoles of amoebas and in the endoplasmic reticulum of macrophages
Legionella pneumophila temperatures
up to 46 C
Legionella pneumophila chemical resistance
Relatively resistant to chlorine and other biocides
Legionella pneumophila disease
Legionnaires disease
Legionnaire’s disease transmission
aerosol from water sources (living inside amoeba)
No human-to-human transmission
Legionnaire’s disease presentation
mortality?
severe pneumonia, necrotic abscesses
especially in immune-compromised and elderly; mortality 20%
Legionella pneumophila virulence factors
intracell growth
C3b adhesin
cytotoxins
B lactamase
Legionnaire’s disease treatment
erythromycin and ciporflaxin
Listeria monocytogenes gram
postive
Listeria monocytogenes
acid
temp
salt
• acid-resistant
• cold-resistant (psychrotolerant)
(growth from 1ºC to 45ºC)
• salt-resistant
Listeria monocytogenes
motility
spreads thru?
intracellular?
- motile
- food-borne pathogen (processed meat like hot dogs, dairy like Brie cheese; 4ºC stored)
- facultatively intracellular (enterocytes, macrophages)
Listeriosis rarity? carriers?
Listeriosis is rare (2500 cases/yr) But exposure is common (10% asymptomatic carriers)
Listeria monocytogenes Virulence Factors
- internalins
- listeriolysin O
- 2x phopholipase
- ActA
Listeria monocytogenes internalins
allow entry into enterocytes or Peyer’s patches m cells
Listeria monocytogenes listerolysin O
pore forming toxin
Listeria monocytogenes PLC
lysosome lysis in macrophages/ intracellular growth
ActA Listeria monocytogenes
for actin rocket mobility
Listeria monocytogenes intracellular infections at mucus membrane
just like shigella, evades humoral response when in cells
Cooperation of CD4+ and CD8+ T cell CMI responses with Listeria monocytogenes
mutant vs wildtype
Listeria monocytogenes epidemiology
immune compromised neonates elderly pregnant women contaminated food
Distinguish Gram+ diplo-like cocci: Listeria monocytogenes versus Streptococcus pneumonia
