Re: e coli in lungs
While e.coli is a gastro bacteria, it can get into the lungs via hand to mouth/nose. It doesn't necessarily mean it was from your mom, but from someone else depositing it where your mom has touched and then passed it on to herself.
If it's in her mouth, it could be breathed in, same with in her nose. If it's ingested, it could be aspirated into her lungs from reflux and colonised there.
If your mom is bedridden or in the hospital, it's easy for things to settle nicely when one's movement or immune system is compromised.
The first treatment would be antibiotics....a few initially the docs try such as doxycycline, Bactrim or both together from what I read.
If it's not responding, then another is used such as ciprofloxicin, or levofloxicin.
If your mom's breathing is affected and she has pneumonia, she would have respiratory support (inhalers/oxygen) and different meds such as third-generation cephalosporins or fluoroquinolones.
Have the doctors done a stool sample to check that she doesn't have it in her gastro tract?
I would suggest thet she also be on very good quality probiotics to help prevent gastro problems/further colonisation of bacterial infection from the antibiotics (c.difficile).
Do the homework....ask the doc lots of questions and know why she's on which meds, etc.
It's all a matter of perspective!