Staphylococcus  

 
Staphylococcus cluster                      Staphylococcus (EM)                      Staphylococcus aureus colonies

What you should know:

Staphylococcus is  a catalase-positive Gram-positive coccus that is normally arranged in clusters. It is a facultatively anaerobic chemoheterotroph commonly found on skin and mucous membranes. Important species in this genus include S. aureus (an opportunistic pathogen) and S. epidermidis. Staphylococci are salt-tolerant. S. aureus is a frequent concern in hospitals due to its ability to produce virulence factors such as DNAse, gelatinase, and coagulase, and due to the appearance of methicillin-resistant strains (MRSA).

Classification: 

Domain Bacteria

    Phylum Firmicutes

        Class Bacilli

Bergey's Manual Volume 3: The low G+C Gram-positive Bacteria

Type species

Staphylococcus aureus

Facultative anaerobe, oxidase-negative, catalase-positive, nitrate reduction-positive

Metabolism: respiratory and fermentative (Acid from glucose, lactose, sucrose), 

Hydrolysis: amylase-negative, DNAse-positive, casease-positive

Other: H₂S-negative, indole-negative, citrate-negative, urease-positive, coagulase-positive

Structure: non-motile

Staphylococcus epidermidis

Same as above except: DNAse-negative, casease-negative, nitrate-negative, coagulase-negative