Agroup of nursing students are reviewing information about penicillins. the students demonstrate understanding of the information when they identify the action of penicillinase as causing bacterial resistance by which mechanism?
a. destruction of the beta-lactam ring of the penicillin
b. destruction of the penicillin cell wall
c. rupture of the penicillin membrane
d. enzymatic inactivation of the penicillin

A. destruction of the beta-lactam ring of the penicillin

Explanation:

Penicillins and other antibiotics in the beta-lactan family usually contain a characteristic four-membered ring of beta-lactam.

A penicillin is capable of killing bacteria by binding β-lactam to DD-transpeptidase (a bacterial enzyme that binds peptidoglycan chains to form rigid moving cell walls), inhibiting its activity and preventing the formation of a new cell wall.

Without a cell wall, bacterial cells become vulnerable to external water and molecular pressures, and thus die quickly.

Bacteria can generate resistance to penicillin by producing beta-lactamase, a bacterial enzyme that destroys the penicillin beta-lactan ring, rendering it ineffective.

An example of penicillin-resistant bacteria is Staphylococcus aureus, which produces high amounts of β-lactamase. This bacterium can cause skin, blood or lung infections.

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