Pearls Before Swine by Stephan Pastis for August 30, 2018

Actually. I think Stephan is correct. Some nouns are irregular, for example, “This is a bacterium, a single celled creature that has the ability to move on its own and thus is considered to be in the animal kingdom rather than a plant. This specimen was taken from this particular colony of bacteria in the Petri dish. Bacteria (as a collective category) is the cause of many diseases and illnesses due to unsafe food handling procedures”. Bacterium is singular. The first use of bacteria is a modifier (modifying the ‘colony’, indicating the colony is made of lots of individual “bacteriums” (as opposed to some bacteria, some viruses, a few strings of spaghetti, etc.). In the next sentence bacteria (a plural term) modified the direct object “colony”. In other words, this one bacterium was taken from a group of many individual bacteriums.