Which of the following is most useful to differentiate Micrococci from Staphylococci: (A) Catalase test, (B) Hugh Leifson test, (C) Oxidase test, (D) All of the above
Answer is B. Micrococci: gram-positive cocci which occur mostly in pairs, tetrads or irregular clusters. They are catalase and modified oxidase positive and aerobic. Non-pathogenic resemble staphylococci but in stained smears, the cells are generally larger and more gram variable than staphylococci and appear in tetrads. A common laboratory method to differentiate between micrococci and staphylococci is Hugh and Leifson's oxidation fermentation test in which micrococci show oxidative and staphylococci show fermentative patterns. Ref: Textbook of Microbiology; Ananthanarayanan and Panicker; 10th Edition; Page No: 209