Staph is a common abbreviation for staphylococcus, which is a group of bacteria. Staphylococcus aureus is a common organism that lives on human skin and may turn from resident to invader if circumstances are favorable. Frequent sites of infection are the skin, lung, heart, bone and bloodstream. At one time, most staph infections could be successfully treated with penicillin, but recent times have brought the development of resistant strains. Susceptibility testing of the particular organism against available antibiotics is invaluable in choosing appropriate therapy.
Penicillins
Penicillin is one of the first antibiotics developed, but unfortunately it is no longer of use against staph infections. Newer generations of penicillin-type antibiotics such as methicillin, dicloxacillin and nafcillin are still useful for treating non-resistant strains of staph. Combining amoxicillin with the drug clavulanate makes it more effective at treating sensitive forms of the bacteria. Ampicillin plus sulbactam is a combination medicine available for intravenous use that works on the same principle.
Cephalosporins
The first-generation cephalosporin cephalexin is an alternative first line oral antibiotic for treating staphylococcal infections. Cefazolin is an intravenous first-generation drug. Later generations of cephalosporins, such as cefuroxime axetil and cefprozil, are sometimes effective, but the first-generation medicines tend to be better for this infection.
Tetracyclines
Minocycline, doxycycline and the category namesake tetracycline may be effective against staph strains that are resistant to penicillins. Such a resistant strain is referred to as Methicillin-resistant Staphylococcus aureus, or MRSA, and can be quite difficult to treat, especially if it is acquired in the hospital where it has been exposed to numerous antibiotics.
Add-on Drugs
Gentamicin is an antibiotic administered intravenously that improves the performance of other medicines in a synergistic fashion. It is not effective by itself. Rifampin is an oral medicine that is also not useful singularly, but enhances the effects of other antibiotics.
Fluoroquinolones
Ciprofloxacin, and other drugs in this group, may be adequate for non-resistant types of staph.
Miscellaneous
Many antibiotics used to treat staph infections do not fall neatly into a category. Trimethoprim-sulfamethoxazole is a well-established oral medication that is sometimes overlooked as a useful alternative when treating MRSA. Clindamycin is another oral medicine available to treat methicillin-resistant and sensitive organisms. Vancomycin is administered intravenously and has a long track record of success against MRSA, although resistance is increasing. Linezolid is a newer oral antibiotic that is often used in especially tough cases. Daptomycin and quinupristin-dalfopristin are novel intravenous medications usually reserved for use in complicated infections in severely ill hospitalized patients.
References
- Medline Plus: MRSA
- Centers for Diseaes Control: Outpatient Management of Skin and Soft Tissue Infections in the Era of Community Acquired MRSA
- Johns Hopkins Antibiotics Guide
- "The Sanford Guide to Antimicrobial Therapy 2009"; David Gilbert, M.D. et. al.; January 2009
