Biology 216 - Lect 17B
Pasteurella
Organism that should be suspect in animal bite wound.
A. Bacteriology
	Small Gm- coccobacilli; bipolar; usually capsule.
	Won't grow on MacConkey (not enteric)
	H2S with lead acetate (low levels) - 
		Penicillin sensitive (helpful)
	Antiphagocytic capsule and outer 
		membrane proteins.
B. Pathos and Clinical - strains vary widely 
		in virulence.
	1. Reservoir - mouth & GI commensal of dog 
			and cat, most avirulent
		Opportunistic in these animals.
		Fowl cholera - hemorrhagic septicemia ->
			 shock, heart muscle petechia
	2. Introduced through bite or scratch 
			(cats more often than from dogs).
		Transmitted by cat licking previous wound.
		Sutured wounds.
		Zoonosis (animal disease transferred to
			 humans) and reservoirs (carriers)
		Other infections if predisposed 
			(superinfection of lung.....)
	3. Rapid onset: 24 hour, cellulitis, blood in tissue, 
			edema, painful, 
		Deeper - synovial, bone, lymphadenitis.
		Rarely systemic, usually local.
		Slow resolution, should be treated
C. Diagnosis
	1. History - bite, red swelling, pain in hours, 
		abscess in 24 hours.
	2. Culture - Usually mixed; BAP (must
		 mushroom smell); MacConkey no growth.
	3. ID - Gm-, bipolar, Ox+, Cat+, NO3+, Sucrose+, 
		Indole+, Lead acetate (PbS)+
		Pen sensitive helps presumptive ID 
		(most gm negative are resistant)
D. Prevention and Treatment - Clean wound;
		drain; antibiotics.