# What is common to all Staphylococci?
A. All are gram positive
B. Common in nosocomial infections
C. All inhibited by penicillin G
D. All of the above
The correct answer is A. All are gram positive.
Staphylococcus is a genus of Gram-positive bacteria in the family Staphylococcaceae from the order Bacillales. Under the microscope, they appear spherical (cocci), and form in grape-like clusters. Staphylococcus species are facultative anaerobic organisms (capable of growth both aerobically and anaerobically).
Staphylococcus can cause a wide variety of diseases in humans and animals through either toxin production or penetration. Staphylococcal toxins are a common cause of food poisoning, for they can be produced by bacteria growing in improperly stored food items. The most common sialadenitis is caused by staphylococci, as bacterial infections.Staphylococci break down leucine into isovaleric acid, the main odor of foot odor.
The widespread incidence of antibiotic resistance across various strains of S. aureus, or across different species of Staphylococcus has been attributed to horizontal gene transfer of genes encoding antibiotic/metal resistance and virulence. A recent study demonstrated the extent of horizontal gene transfer among Staphylococcus to be much greater than previously expected, and encompasses genes with functions beyond antibiotic resistance and virulence, and beyond genes residing within the mobile genetic elements.