I was treated for h influenza bacteria in my sinuses. now i have non mrsa staph in my sinuses. how did i get staph when already on antibiotics?

Where was culture?: It is not possible to know if the culture was taken from the sinuses, unless you had an operative procedure. The only entrance to the sinuses is in the lateral wall of the nose. Was the culture taken from the nose. What antibiotic were you taking? Even the nostril possesses S. aureus. Also the antibiotic may not have been effective against S. aureus. Need to know more.