Bug and Bacteria

Bug noun - A person with a strong and habitual liking for something.

Bacteria and bug are semantically related in germ topic. In some cases you can use "Bacteria" instead a noun "Bug", when it comes to topics like micro-organism.

Bacteria noun - (microbiology) single-celled or noncellular spherical or spiral or rod-shaped organisms lacking chlorophyll that reproduce by fission; important as pathogens and for biochemical properties; taxonomy is difficult; often considered to be plants.

Bug and bacteria are semantically related in germ topic. You can use "Bug" instead a noun "Bacteria", if it concerns topics such as micro-organism.