Listeriosis is a disease caused by infection with the bacterium Listeria monocytogenes, and it is most often contracted after eating contaminated foods or liquids. Listeriosis most commonly affects newborns, the elderly, pregnant women, and those individuals with a poorly functioning immune system (immunocompromised).
I have been on Plaquenil and can tell you my diarrhea started within days of starting the med. My doctor warned me that diarrhea and weight loss were side effects. I said, Well, I am usually very constipated and could stand to lose 10 pounds so this could be a good thing.. haha.
This medicine only treats bacterial infections. It won't work for the common cold, the flu, or any other viral infections. Antibiotics such as metronidazole can cause diarrhea, which could be a sign of a new infection. Call your healthcare provider right away if you have diarrhea that's severe, watery, or bloody. Be sure to take metronidazole for the full length of time that your doctor prescribes.