1676, Levin Hook first discovered bacteria in the oral cavity, which was called "microorganism" at that time.

186 1 year, Pasteur's experiment with his famous gooseneck proved that there were bacteria in the air.

Levin Hook was the first person to observe bacteria, but he didn't solve the mystery of bacteria. Pasteur's experiment denied the theory of natural occurrence of bacteria, and according to his own research on fermentation, he pointed out that there are many kinds of bacteria in the air, and their life activities can cause the fermentation of organic matter and produce various useful products, and some products can also ferment for other bacteria to produce unexpected products. In addition, Pasteur also created the pasteurization method in 1886, and developed vaccines for chicken cholera, anthrax and erysipelas around 1880. So personally, the first person to uncover the mystery of bacteria should be Pasteur.

What needs to be added is that R.Hook and Antoni van Leeuwenhoek are two people.