Controlling Microbial Growth in the Body: Antimicrobial Drugs

These flashcards summarize key concepts from the lecture on antimicrobial drugs, their mechanisms of action, and considerations related to antimicrobial therapy.

Who contributed to the development of antimicrobials alongside Paul Ehrlich?

Alexander Fleming and Gerhard Domagk.

What is the principle of selective toxicity?

An effective microbial agent must be more toxic to pathogens than to the host.

What defines semisynthetic antimicrobials?

Semisynthetics are chemically altered antibiotics that are more effective, longer lasting, or easier to administer than naturally occurring antibiotics.

What is the action of β-lactam antibiotics?

They irreversibly bind to enzymes that cross-link NAM subunits in bacterial cell walls.

What does mupirocin specifically inhibit?

It selectively binds to isoleucyl-tRNA synthetase, preventing the loading of isoleucine only in Gram-positive bacteria.

How are broad-spectrum drugs different from narrow-spectrum drugs?

Broad-spectrum drugs are effective against a wide range of organisms, while narrow-spectrum drugs target specific types of bacteria.

What are the main categories of side effects of antimicrobial therapy?

Toxicity, allergies, and disruption of normal microbiota.

Define therapeutic index.

The ratio of the dose of a drug that can be tolerated to the drug's effective dose; a higher TI indicates a safer drug.

What causes the development of resistant microbial populations?

New mutations of chromosomal genes and acquisition of R plasmids.

List one way to retard the development of antimicrobial resistance.

Maintain a high concentration of the drug in the patient for a sufficient time to inhibit the pathogen.

What is the role of penicillinase in antibiotic resistance?

Penicillinase (β-lactamase) breaks down the beta-lactam ring structure of penicillins, rendering them inactive.

How do antiviral drugs affect viral metabolism?

They target unique aspects of viral metabolism to inhibit viral replication.

What is the function of nucleoside analogs in antimicrobial action?

They interfere with the function of nucleic acids and distort shapes, preventing replication, transcription, or translation.

What is the difference between new mutations and the acquisition of R plasmids in conferring drug resistance?

New mutations involve changes in the organism's own DNA, while acquisition of R plasmids occurs through mechanisms like transformation, transduction, and conjugation.

Explain the role of synergism in antimicrobial therapy.

Synergism occurs when one drug enhances the effect of a second drug, making the treatment more effective.