Hi, Welcome to Health care magic forum.
There are several bacteria,and any bacteria can cause any infection, except some specific infections.
Minocycline is a broad sprectrum antibiotic,as you said, your daughter will be having ssecondary infection with bacteria,over the viral infection, so can be cured with the minocycline.
If no relief is found in few days, i advise you to consult a physician for diagnosis and treatment.
I usually prescribe to my patient with such symptoms of viral origin,besides minocycline,
phenylephrine hydrochloride,paracetampl,and antihystamine.
Wishing for a quick and complete recovery. Thank you.