Microbiology and immunology are hands-down my favourite subjects of those included in NPLEX I. Unfortunately they are also some of the toughest areas on the exam so I am including as much as I can to help those about to write or rewrite the exam. As far as bacteria and parasites, here are two quick summaries (bacteria and parasites) I used as a refresher before I walked into the exam. Click the images to download the documents. I used these in conjunction with the USMLE Step 1 and your other notes. Feel free to scribble your own additions and let me know if you see anything that needs to be corrected or updated.
I am in the process of working on more fun stuff for micro, and also for immunology, so check back! Happy studying :)