"Respiratory" Bacteria (Legionella, Haemophilus, Pseudomonas) Flashcards
Legionnaire’s disease: classic S/S?
severe atypical (unilateral/lobar) pneumonia; rigors; dry non-productive cough; hyponatremia; GI/CNS symptoms
incubation period of Legionnaire’s disease
2-10d
incubation period of Pontiac Fever
1-2d
S/S Pontiac Fever
mild flu-like
habitat of Legionella
environmental water supplies (lakes, hot water tanks, ACs)
pathogenesis of Legionella
- invades alveolar Macrophages via the C3b receptor; – - - inhibits lysosome binding, replicates;
- releases degradative enzymes to kill the macrophages at time of release
habitat of Pseudomonas aeroginosa
ubiquitous in moist areas (sinks, soap bars, cut flowers, respiratory/dialysis equipment)
transmission of Legionella
aerosols from the environmental water source (NOT person to person)
detection of Legionella
urine antigen (warm 1st AM urine)
treatment of Legionella
macrolides, quinolones
pathogenesis of P.aeroginosa
pili adhere to respiratory epithelia, capsule adheres to tracheal => biofilm formation, toxins released
5 toxins of P. aeroginosa
Phospholipase C (degrades cell membranes) Endotoxin (fever, shock) Exotoxin A (ADP-ribosylation of eEF-2) Endotoxin exoenzyme S (prevents phagocytosis) Pigments (pyocyanin, pyoverdine: color + ROS)
P. aeroginosa morphology (4 easy-to-remember points)
1-3 flagella;
grape candy odor;
greenish-blue colonies (pyocyanins);
aerobic
10 manifestations of P. aeroginosa
SKIN: burn wound infections, hot tub folliculitis, ecthyma gangrenosum
EAR: otitis externa, malignant external otitis
EYE: keratitis
LUNGS: CF/COPD bronchopneumonia
NOSOCOMIAL: UTIs in cath’d patients
BONES: Osteomyelitis
DIFFUSE: sepsis
Ecthyma gangrenosum (P. aeroginosa)
P. aeroginosa. Rapidly progressing necrotic cutaneous lesions. Common in i-comp, especially leukemia/neutropenia/hematologic malignancies.
Hot tub folliculitis (P. aeroginosa)
P. aeroginosa. Infection of the apocrine sweat glands (nipples, areolas, external ear)
Malignant otitis externa (P. aeroginosa)
When otitis externa gets out of control. EAC pussy discharge, pain, swelling. Can lead to CNS damage or sepsis. Often mistaken for mastoiditis
Osteomyelitis (P. aeroginosa)
Clasically, puncture wound in sweaty sneakers
Pneumonia (P. aeroginosa)
Diffuse bilateral bronchopneumonia, classic infection in CF patients (biofilm!)