Question

You suspect a patient is infected with protozoa. Which procedure are you going to confirm that?

1) Look under a microscope

2) Carry out a negative stain

3) Carry out a gram stain

4) Grow cells on a medium containing penicillin and see whether it grows

5) Carry out an acid-fast stain

Answer 1

1) Look under a microscope

Microorganisms are not visible in microscope clearly without stain specially protozoa.

2) Carry out a negative stain. Is not specific at all

3) Carry out a gram stain: it differentiate into two category based on cell wall thickness

4) Grow cells on a medium containing penicillin and see whether it grows: again being penicillin resistant or not is not specific character of protozoa

5) Carry out an acid-fast stain

Protozoa retains color of carbol fuschin even after treatment with dilute acid and is characteristic of very few class of microorganism so 5th option is right