Wet lab Flashcards
Gram positive, Cat pos organisms
- GPC
- Catalase positive
- aerobes and facultative anaerobes
- only Staph aureus is clinically significant
- humans are the natural reservoir
S. Aureus
GPC , Cat pos
- have many virulent factors: Catalase, Coagulase, DNAse, hyaluronisase…
- usually skin and soft tissue infections
- can cause bactermemia, sepsis, ostomylitis
Coag Negative staph
- coag and DNAse negative
- Epidermitis Saprohyticus, Lugdunensis
- form biofilms
- saprophyticus is resistant to novobiocin
Catalase test
use hydrogen peroxide to determine if the organism has catalase
Coagulase
is used to differentiate S. Aureus from other coag negative staph.
- Staph produces free and bound coagulase
- mix with rabbit plasma to observe clumping
-
Mannitol Salt agar
is selective and differential media
- used for the isolation and presumptive ID of S. Aureus
- SA is able to ferement mannitol turns media to yellow
- has lots of salt
Novobiocin
make a .5 mcfarland standard
- streak a lawn and place a novo. disc one the media
- Saprophyticus is resistant
A Disc
Bactracin
- streak for lawn
- add disc
- S. Pyogenes susceptible
CAMP
Streak S. Aureus down the center then close in the opposite directions streak other things
- if postive the hemolysis will be arrow shaped
- Group B strep
Optochin disc
P disc
- used to determine S. Pnuemonia
- > than 14mm for susceptible
Klebsiella
Lactose Ferm on MAC
encapsulated so mucoid colonies
- Pneumo - neg, Oxytoca- Pos
Proteus
swarmer
- non lac ferm
- mirabilas- neg, virgalis - pos
- phenolalanine deaminase pos
MAC plate
- uses bile salts and crystal violet in the medium to encourage growth of GNR
MRVP
1st part: add methyl red to indicate acid end products fermentation glucose
- VP: detects neutral end products of glucose fermentation
Oxsidase
swab colony
- add oxidase reagent blue is positive
- pseudomonas: positive
- E. Coli negative