Who first discovered bacteria?

Van Leeuwenhoek discovered "protozoa" - the single-celled organisms and he called them "animalcules". He also improved the microscope and laid foundation for microbiology. He is often cited as the first microbiologist to study muscle fibers, bacteria, spermatozoa and blood flow in capillaries. read more

The person credited with first discovering bacteria is Dutch tradesman and scientist Antony van Leeuwenhoek. He greatly improved the microscope, discovered protozoa (which he called animalcules) and set the very foundations of microbiology. read more