Staph infections are sometimes difficult to treat because some strains of staph are resistant to traditional antibiotics, according to Mayo Clinic. Commonly, doctors prescribe cephalosporins and sulfa drugs for staph infections, but some resistant staph strains only respond to vancomycin delivered intravenously.
Over time, some strains of staph evolve to resist the effects of common antibiotics, explains Mayo Clinic. As of 2015, penicillin, once used widely to treat staph, only works in around 10 percent of staph infections. Strains of staph that are resistant to antibiotics, known as methicillin-resistant Staphylococcus aureus, require alternative antibiotics, some of which have additional side effects not seen in traditional antibiotics. Doctors often test the staph bacteria to determine which antibiotics to prescribe for a particular infection. In addition to antibiotic treatment, draining fluid from sores caused by staph skin infections may be necessary.
Because of the adaptability of the staph bacterium, people with staph infection should finish all of the antibiotics prescribed to them, even if they feel better after taking part of the prescription, notes WebMD. If an individual stops taking the prescribed antibiotics prematurely, some staph bacteria may survive. Surviving bacteria may develop resistance to the antibiotic, making any subsequent infections harder to treat. In addition, the residual bacteria may reinfect the individual or infect someone else.