22 Which of the following statements about Staphylococcus aureus is correct? \( \begin{array}{ll}\text { (A) } & \text { It is a mesophilic microorganism. } \\ \text { (B) } \quad \text { Cells will appear pink after Gram staining. } \\ \text { (C) } \quad \text { Enterotoxins produced are easily destroyed by heat. } \\ \text { (D) } \quad \text { It does not thrive well in an oxygen-rich environment. }\end{array} \)

(A) State ONE example of selective media that can be used to isolate [3 marks] EACH of the following microorganisms. (i) Gram positive bacteria. (ii) Staphylococci spp. (iii) Gram negative bacteria.

23 Which one of the following microorganisms moves using flagellum? (A) Amoeba. (B) Euglena. (C) Paramecium. (D) Plasmodium. Which one of the following is NOT a heterotrophic microorganism? \( \begin{array}{ll}\text { (A) } \quad \text { Diatoms. } \\ \text { (B) } \quad \text { Sarcodines. } \\ \text { (C) } \quad \text { Sporozoans. } \\ \text { (D) }\end{array} \)

(A) (i) Describe TWO disadvantages of using Replicate Organism Detection And Counting (RODAC) plate during a surface swab. (ii) Explain TWO purposes of conducting a hand swab test. 12 m

(B) (i) Explain THREE precaution steps during decontamination of biohazard wastes in bag using an autoclave. (ii) Describe TWO materials that will remain undamaged after autoclaving.

Calculate the cfu/cm \( \mathrm{cm}^{2} \) for a tested surface of 4 cm in length and 3 cm in width if the number of colonies on the agar plate is 96 cfu. (A) \( 8 \mathrm{cfu} / \mathrm{cm}^{2} \) (B) \( 12 \mathrm{cmu} / \mathrm{cm}^{2} \). (C) \( 72 \mathrm{cmu} / \mathrm{cm}^{2} \) (D) \( 128 \mathrm{cmu} / \mathrm{cm}^{2} \)