Final answer:
In the treatment of infections caused by penicillinase-producing staphylococci, the three methicillin derivatives commonly used are nafcillin, oxacillin, and dicloxacillin, which are active against many staphylococcal strains, including those that are not MRSA.
Step-by-step explanation:
In the United States, three medications used to treat infections caused by penicillinase-producing strains of Staphylococcus are:
- Nafcillin: A methicillin derivative which is particularly effective against penicillinase-producing bacteria and is commonly used for staphylococcal infections.
- Oxacillin: Another methicillin analog that is resistant to destruction by Staphylococcus aureus enzymes, making it useful for treating infections by these resistant strains.
- Dicloxacillin: This is also a methicillin derivative with similar properties to nafcillin and oxacillin, often prescribed for similar types of infections.
These antibiotics are part of the beta-lactam class and were specifically developed to combat strains of bacteria that produce penicillinase, an enzyme that breaks down penicillins like methicillin. The emergence of MRSA (Methicillin-Resistant Staphylococcus aureus) has made the use of these drugs even more significant. While MRSA strains are resistant to all beta-lactam antibiotics, these three remain effective against many non-MRSA penicillinase-producing S. aureus.