Question

resistance to penicillin by strains of s. aureus is due to:
thick layer of peptidoglycan
functional pbps
production of beta lactamase
hibition of protein synthesis in the host cell by the organism

Explanation:

Penicillin acts by inhibiting cell - wall synthesis in bacteria. Beta - lactamase (also known as penicillinase) is an enzyme produced by some bacteria (including some strains of S. aureus). This enzyme breaks down the beta - lactam ring of penicillin. The beta - lactam ring is crucial for the antibacterial activity of penicillin. When the ring is broken, penicillin is inactivated.

• A thick layer of peptidoglycan is a characteristic of Gram - positive bacteria (like S. aureus), but it is not the direct cause of penicillin resistance. Penicillin targets the peptidoglycan synthesis process, and a thick layer alone does not confer resistance.
• Functional penicillin - binding proteins (PBPs) are the normal targets of penicillin. Resistance is not due to "functional PBPs" in the sense of normal function; rather, in some resistant bacteria, there may be altered PBPs (e.g., in methicillin - resistant S. aureus or MRSA, there is an altered PBP2a), but the production of beta - lactamase is a more common and direct mechanism for penicillin resistance in non - MRSA S. aureus strains.
• Inhibition of protein synthesis in the host cell by the organism is not a mechanism related to penicillin resistance. Penicillin acts on bacterial cell - wall synthesis, not on host - cell protein synthesis.

Answer:

production of beta lactamase