2/4/99

Microbiology II

 

Bacterial Diseases

Staphylococcus and Streptococcus

 

Staph

·        Gram (+) cocci

·        Bunches of grapes

·        Includes:  S. aures, S. epidermidis, S saprophyticus

 

S. saprophyticus

·        No human consequence

·        Found in soil

·        Saprophyte

 

S. epidermidis

·        Used to be known as S. albus

·        Major member of normal flora

·        Abundant on human skin

·        Associated w/ middle ear infections

·        Associated w/ endocarditis and cardiac surgery patients

 

	S. aures	S. saprophyticus	S. epidermiditis
Colonies	Yellow/gold	Muddy	Chalky-white
Coagulase	+	-	-
Mannitol fermentation	+	-	-/variable
Hemolysis	+ (delta)	-	-
Salt tolerance (7%NaCl)	+	-	-
Heat resistance	+	-	-
Pus formation	+	-	-
Penicillinase	+ (90%) b/c has beta lactone ring	-	-
Member of normal flora	Transient	-	+

 

Coagulase--converts fibrinogen to fibrin--responsible for blood coagulation

Heat resistance--endonucleases--non-spore forming organisms are most resistant

Penicillinase-- enzyme which destroys penicillin--member of beta-lactamases

 

S. aureus

·        Responisble for following diseases:

·        Trivial

·        Furuncles

·        Boils

·        Osteomyelitis--young males

·        Empyema--pus in pleural cavity

·        Pericarditis

·        Endocarditis

·        Purulent arthritis

·        Tissue abscess

·        Kidney cortex disease

·        Pneumonia--high mortality

·        Toxic shock syndrome (TSS)

·        Scalded skin syndrome

·        Food posioning

·        More serious

·        Carbuncles

·        TSS

·        Arose in 1980's

·        Seen in 99% of females who were menstrating

·        High fever, shock, death

·        RELY tampons (gone out of business)--injured vaginal wall

·        TSS1, TSS2, TSS3

·        Scalded skin syndrome

·        Kids 0-4 y/o

·        Destruction of granular layer of skin

·        Expose to secondary infections

·        Toxin associated is epidermolytic toxin

·        Peeled skin of babies

·        Ritter's syndrome

·        Food Poisoning

·        Produces heat stable enterotoxin (toxic to GI tract)

·        Can w/stand 120`C for 30 min

·        Main sources:  improperly stored or left over food

 

S. aureus alsoc associated w/ blepharitis--infection of the eyelid

Tx:  penicillin, Methicillin, cephalosporins (1^st generation)

 

I	II	III
G (+) infects	G (+) & G (-)	G (-) infects