The noun 'bacteria' is plural

Friendly bacteria in the gut helps confer many health benefits.

The above sentence appears in an article of a popular English daily.

It looks like a heading created by a sub-editor/editor of the newspaper.

In the write-up, the word 'bacteria' is used many times - sometimes accompanied by a singular verb and sometimes a plural one.

A reference to an online dictionary reveals that the said word is a plural noun and its singular is 'bacterium'.

Hence, the sentence in the first paragraph above should have been "Friendly bacteria in the gut help confer many health benefits"; and of course, all singular finite verbs used in the article should be replaced by plural ones.