Week 2 - Staphylococcus Flashcards
Staphylococcus is a gram ______ cocci arranged in _____-_____ clusters.
positive, grape-like
Staphylococcus
Staphylococcus is a _________ anaerobe.
facultative
Do not require oxygen
Staphylococcus is _____-motile (______-_________).
non, non-flagellated
Staphylococcus is ______-spore forming.
non
Staphylococcus is _______ positive (detoxify ______).
catalase, H2O2
Normally MQ and neutrophils release reactive oxygen species such as hydrogen peroxide. Bacteria have a bullet? against HP = catalase which destroys ROS.
Staphylococcus grows on media containing?
Give an example media.
High salt (>or= to 6.5-10%).
Mannitol SALT agar.
What are the two widely used culture media for growth?
Mannitol salt agar containing high salt (NaCl) concentration (6.5-10%) & Blood agar
Beta
alpha
Gamma
Mannitol salt agar
Mannitol salt agar selectively supports growth of which Gram-positive bacteria?
- Staphlococcus
- Enterococcus
- Listeria
- Micrococcaceae
Mannitol salt agar inhibits the growth of most?
- Gram-negative bacteria
- Streptococcus (gram positive)
S. aureus ferments mannitol and changes the agar color from red to yellow.
S. epidermidis does not ferment manitol and no agar color color change (remains red).
Purple agar base containing 1% of maltose:
1. S. intermedius (left)
2. S. aureus (right; yellow)
3. S. hyicus (bottom)
Staphylococcal spp. classification using unique pigment production on mannitol salt agar and purple agar base with 1% maltose.
Blood agar allows determination of the _____ of _______ toxin produced by the isolates.
type, hemolysin
In addition to growing in the blood media, they are destroying the RBCs.
Alpha = incomplete
Hemolysis = green
Beta = complete
Hemolysis = clear
Gamma = no
Hemolysis = no change in media
Describe what is occurring in the top arrow of this image.
Yellow/golden colony due to a golden
colored carotenoid pigment
staphyloxanthin (it is antioxidant)
any staph with staphy = highly pathogenic
Describe what is going on in the bottom right of this image
Non-hemolysis (gamma) by Staph. epidermidis