s. aureus growth under anaerobic conditions, catalase test, growth on selective media

A) S. aureus are facultative anaerobes – here they show good growth on Schaedler agar incubated under anaerobic conditions.

B) Staphylococci (colony on left) are catalase-positive (can degrade hydrogen peroxide into water and hydrogen, creating bubbles). Enterococci and streptococci are catalase negative (nonpigmented E. faecalis colony on right).

C) S. aureus and S. epidermidis grow well on mannitol salt agar showing NaCl tolerance, and ability to ferment mannitol (mannitol fermenting yellow colonies of S. aureus and nonfermenting white colonies of S. epidermidis)

D) S. aureus on Baird-Parker agar. Tellurite tolerance and reduction (due to production of hydrogen sulfide) is shown by black appearance of colonies. Lecithinase and lipase activity is shown by zones of opalescence around the colonies.

Text: Eva van Dijk