Staphylococcus, Micrococcus & Similar Organisms Flashcards
S. aureus colonial morphology
Pinhead, medium-sized, raised, creamy, gold yellow pigment
What test differentiates among Staphylococcus spp?
Coagulase
Staphylococcus result to Lysostaphin
Susceptible
Staphylococcus result to Bacitracin
Resistant
Micrococcus result to Furazolidone
Resistant
Enterotoxin also known as Toxic Shock Syndrome Toxin-1 or Pyrogenic Exotoxin C
Enterotoxin F
Toxin causing Ritter-Lyell Disease
Exfoliative toxin
Cytolytic toxin which causes severe cutaneous infections and necrotizing pneumonia; makes Staphylococcus more invasive
Panton-Valentine Leukocidin (PVL)
Large pustules surrounded by a small zone of erythema
Bullous impetigo
Drug-induced hypersensitivity reaction; steroid administration
Toxic Epidermal Necrolysis
Causative agent of prosthetic valve endocarditis and stitch abscess
S. epidermidis
Causative agent of UTIs in young women (2nd most common cause of UTI)
S. saprophyticus
Causative agent of aggressive endocarditis; has the mecA gene
S. lugdunensis
B-hemolytic Staphylococcus
S. aureus & S. epidermidis
S. epidermidis on MSA:
Pink (NMF)
What is the biochemical test used to differentiate Staphylococcus and Micrococcus from Streptococcus?
Catalase test
What is the reagent used in Oxidase test?
6% tetramethylphenylenediamine HCl in dimethyl sulfoxide (DMSO)
Confirmatory coagulase test; test for free coagulase
Tube coagulase
Positive result in slide coagulase test
Clumping
What is the biochemical test used to differentiate among coagulase(+) and (-) Staph?
Voges-Proskauer
What is the reagent used in PYR test?
p-dimethylaminocinnamaldehyde
Only coagulase(+) Staphylococcus negative for PYR test
S. aureus
Most useful test for S. lugdunensis
Ornithine Decarboxylase (ODC)
