OK. To me, this looks like another badly written textbook question. (We see a lot of them here) Both answers seem fine to me.In fact, it's a mutiple-choice question :
"Before Alexander Fleming discover penicillin, many people die....
A. infected with simple bacteria B. from simple bacterial infections " At first I chose B but my teacher said it was wrong and the answer must be A .
I see .Thank u ThomasI'm with Parla here. People died from simple bacterial infections is idiomatic.
People died infected with simple bacteria is strange because:
1. What are simple bacteria?
2. The causal link isn't very clearly established by the adjectival infected with simple bacteria.
3. It raises questions about which bacteria infect us, and which live peaceably in symbiosis with us.
Life can be hard for teachers, but I'd say this one got this wrong. Treat the issue tactfully, Charminglibra.