Multiple choice Which of the following is not an acid fast structure? Oocysts of Cryptosporidium parvum Actinomycetes Bacterial spores Streptomyces Mycobacteria Reveal answer Fill a bubble to check yourself D Correct answer Explanation Streptomyces are a non-acid fast genera of Actinimycetes. Streptomyces do not have mycolic acid in their cell walls.