Micro - Staphylococci Flashcards
Staphylococcaceae is the _________
Family
Staphylococcus is the _________
Genus
Which species of staphylococcus is coagulase-positive?
Staphylococcus aureus
Which species of staphylococcus, that we specifically learned about, are coagulase-negative?
- *S. epidermidis
- S. saprophyticus
- S. lugdunensis*
Staphylococcus resembles some members of which other genus?
- Micrococcaceae
- *specifically Rothia (Stomatococcus) and Micrococcus
Staphylococcaceae will have what Gram stain morphology?
Gram-positive cocci forming in grape-like clusters
- Staphlyococcus* typically grow under what culture conditions?
- Facultative aerobic
- Facultative anaerobic
- Aerobic
- Anaerobic
Facultative anaerobic
(not picky- O2/CO2/aerobic/anaerobic)
What media will Staphylococcus typically grow on? (4)
- BAP
- CHOC
- CNA
- PEA
TRUE or FALSE
Staphylococcus generally have nutritional requirements
FALSE
generally, Staphylococcus have no nutritional requirements
What Staphylococcus species?
- opaque, smooth colonies
- white-light yellow pigment
- beta hemolytic (usually)
Staphylococcus aureus (AKA SA or S. aureus)
Impetigo, folliculitis, and furuncles are all considered non-invasive diseases caused by which Staphylococcus?
Staphylococcus aureus
What are 3 examples of non-invasive diseases caused by S. aureus?
- Impetigo
- Furuncle
- Folliculitis
Abscesses and osteomyelitis are considered invasive diseases caused by which Staphylococcus species?
S. aureus
What are two invasive diseases caused by S. aureus?
- Abscess
- Osteomyelitis
Food poisoning, scalded skin syndrome, and toxic shock syndrome are diseases that may be caused by which Staphylococcus species?
S. aureus
What are three toxogenic diseases that may be caused by Staphylococcus aureus?
- Toxic shock syndrome
- Scalded skin syndrome
- Food poisoning
What type of species?
- Opaque, smooth colonies
- Grey-white pigment
- Usually Gamma hemolytic
Coagulase Negative Staph (CNS)
S. lugdunensis and S. epidermidis are known to cause which type of infection?
Endocarditis
S. saprophyticus is known to cause which type of infection?
Urinary tract infection
When testing to identify Staphylococci, which test is ONLY used for urine isolates?
Novobiocin
If a Staphylococci species is resistant to novobiocin it can presumptively be called what?
S. saprophyticus
Opaque, smooth, grey-white colonies
Gamma hemolytic
Catalse +
Coagulase =
Novobiocin resistant
Staphylococcus saprophyticus
Opaque, smooth, grey-white colonies
Gamma hemolytic
Catalase +
Coagulase =
Novobiocin susceptible
Ornithine +
Staphylococcus lugdunensis
Ornithine decarboxylase:
When bacteria metabolize amino acids/proteins, what is produced?
Alkaline products
What does a positive ornithine decarboxylase test appear as?
Negative?
Positive = Purple (alkaline)
Negative = Yellow (acid)
Mannitol salt agar (MSA) is considered what type of media?
Selective and differential
Mannitol salt agar inhibits most of what gram-negative organisms and many gram-positive organisms due to what?
High salt concentration (7.5%)
If mannitol is fermented on an MSA agar, what is produced? What does this do to the agar?
Acid is produced when mannitol is fermented causing a pH drop that turns the agar from red to yellow
TRUE or FALSE
S. aureus will grow red colonies with red zones on MSA
FALSE
S. aureus ferments mannitol causing the growth of yellow colonies with yellow zones
Which coagulase negative staphylococcus species is the most commonly isolated species, especially from cases of prosthetic valve endocarditis?
S. epidermidis
Which coagulase negative staphylococcus species is isolated from urinary tract infections, especially in young, sexually active women?
S. saprophyticus
Which coagulase negative staphylococcus species can cause an aggressive form of endocarditis?
S. lugdunensis
This test differentiates staphylococci (+) from streptococci (=)
Catalase
Reagent used for catalase testing
Hydrogen peroxide
H2O2
Which organism will produce a pseudocatalase?
Enterococci
Species that resembles staph except the gram-positive cocci tend to form in tetrads
Micrococcus species
What species?
Creamy, opaque, bright lemon-yellow color
Gamma hemolytic
Micrococcus species
What species:
Creamy, opaque, lemon-yellow gamma hemolytic colonies
GPC in tetrads
Catalase +
Coagulase =
Bacitracin susceptible
Furazolindone resistant
Modified Oxidase +
Micrococcus species
This species is also known as “sticky staph”
Rothia mucilaginosis
What species:
Gram positive cocci in clumps and tetrads
Opaque grey-white, gamma hemolytic, sticky colonies
Catalase =
Rothia mucilaginosus
What type of coagulase is found with the slide test?
Bound coagulase (clumping factor)
What is the catalase reaction for staph?
Positive
Coagulase Slide Test:
What is the ID of the microorganism tested?
Positive - S. aureus
What type of coagulase is found with the tube test?
Free coagulase
