Hello, Mere mentioning STAPHYLOCOCCAL INFECTIONS is not sufficient for the treatment point of view because you mentioned that you are having serious abdominal pain. Staphylococcus aureus is the most virulent of many staphylococcal species and this causes minor skin infection to soft tissue infection to life-threatening systemic infections. Other form of staphylococcal is collectively called as coagulase negative staphylococci . However there are so many drugs but MULTIPLE DRUG RESISTANT is also for staphylococcal infections. So get in blood culture for drug sensitivity test . Sensitive to penicillin=======Penicillin G . Sensitive to methicillin======Nafcilin or oxacillin ( alternative cefazolin , vancomycin). If resistant to methicillin=====Vancomycin 1gm. So these are few drugs , you can try . When abdominal infection present due to staphylococcus it may produces vomiting , diarrhea , pain abdomen , intestinal infection. Hope this information will be helpful for you.