Final answer:
The statement that methicillin and dicloxacillin were developed in response to penicillinase-producing Staphylococcus aureus and are penicillin-resistant is true. Methicillin and similar drugs were synthesized to overcome bacterial resistance mechanisms, but the rise of MRSA strains has made treatment of infections challenging.
Step-by-step explanation:
The statement that scientists developed methicillin and dicloxacillin as penicillin-resistant penicillins in response to penicillinase-producing Staphylococcus aureus strains is True. In the 1940s, infections by the bacterium Staphylococcus aureus could be successfully treated with penicillin. However, resistance to penicillin quickly emerged due to bacteria producing an enzyme called penicillinase, which deactivates the antibiotic. As a countermeasure, scientists synthesized penicillin analogs like methicillin and dicloxacillin that are not deactivated by penicillinase.
Methicillin was particularly designed to be resistant to ß-lactamases, which are enzymes that render ß-lactam antibiotics ineffective. Nonetheless, the introduction of methicillin in clinical practice led to the appearance of methicillin-resistant strains of S. aureus (MRSA). Similar concerns have also emerged with dicloxacillin. The resistance in MRSA is a global health concern because these bacteria are not only resistant to methicillin but also to many other available antibiotics, making infections difficult to treat. This is why the development of penicillin-resistant penicillins such as methicillin and dicloxacillin was crucial.