Anti-Infective Agents / Antibiotics – Exam Review Flashcards

These 40 question-and-answer flashcards cover historical milestones, mechanisms of action, resistance, classification, major drug classes, adverse effects, nursing considerations, and patient teaching for anti-infective agents.

Who pioneered the use of synthetic chemicals to target infection-causing cells in the 1920s?

Paul Ehrlich.

Which antibiotic was first discovered in mold samples during the 1920s?

Penicillin.

In what year were sulfonamides introduced as the first widely used anti-infective agents?

1935.

List the five primary mechanisms by which anti-infectives work.

1) Disrupt cell-wall biosynthesis, 2) Interfere with metabolic pathways, 3) Inhibit protein synthesis, 4) Disrupt DNA synthesis, 5) Alter cell-membrane permeability.

Which mechanism of action involves interfering with bacterial cell-wall biosynthesis?

Cell wall disruption.

What term describes drugs that kill bacteria outright?

Bactericidal agents.

How do bacteriostatic drugs differ from bactericidal drugs?

Bacteriostatic agents inhibit bacterial reproduction without directly killing the organisms, whereas bactericidal agents kill them.

What is meant by a narrow-spectrum antibiotic?

An antibiotic effective against only a few specific microorganisms with very particular metabolic pathways or enzymes.

State the primary therapeutic goal of anti-infective treatment.

Reduce the population of invading organisms to a level that the host immune system can eliminate.

Why might complete eradication of a pathogen be undesirable?

Because drug levels needed for total eradication could be toxic to the host.

Name three immune-system components involved in fighting infection.

Chemical mediators, leukocytes/lymphocytes, antibodies (plus locally released enzymes).

What is natural (intrinsic) resistance?

When a microorganism is naturally unaffected by a specific drug because it lacks the drug’s target enzyme system.

Define acquired resistance.

The ability of previously sensitive microorganisms to develop resistance to an antimicrobial over time.

Give two ways bacteria can develop drug resistance.

Producing drug-deactivating enzymes and altering cell-membrane permeability (others include modifying transport systems or binding sites, or producing antagonists).

List three strategies to prevent antimicrobial resistance.

Use antibiotics only for target pathogens, give adequate doses for sufficient duration, and avoid indiscriminate prescribing.

What laboratory procedure grows microorganisms on agar plates to identify a pathogen?

A culture.

Why is sensitivity testing performed?

To determine which drugs can control a specific microorganism.

Why must the correct pathogen be identified before prescribing an antibiotic?

To choose the most effective drug, minimize complications, and reduce resistance development.

State three criteria used when selecting an antimicrobial drug for a patient.

1) Least complications for that patient, 2) Most effective against the identified pathogen, 3) Patient-specific factors such as age, pregnancy, and comorbidities.

Give two benefits of combination antibiotic therapy.

Allows lower individual drug doses and can provide synergistic effects or broader organism coverage.

Which organ is at risk for toxicity—especially with aminoglycosides?

The kidneys (nephrotoxicity).

What gastrointestinal adverse effects are common with many antibiotics?

Nausea, vomiting, diarrhea, and abdominal pain.

Define a superinfection.

A secondary infection that occurs when normal flora are eliminated by an antibiotic regimen.

Name two common prophylactic uses of antibiotics.

Preventing malaria in travelers and preventing infection before GI or GU surgery (also for high-risk cardiac patients).

In Gram staining, how do Gram-positive bacteria appear?

They retain the stain and resist decolorization.

What is the main difference between aerobic and anaerobic bacteria?

Aerobic bacteria require oxygen for survival; anaerobic bacteria do not use oxygen.

What is the mechanism of action of aminoglycosides?

They are bactericidal and inhibit protein synthesis in Gram-negative bacteria.

Which two serious toxicities are associated with aminoglycosides?

Ototoxicity (hearing damage) and nephrotoxicity (kidney damage).

Why must renal function be monitored in patients receiving aminoglycosides?

Because aminoglycosides are excreted unchanged in urine and are nephrotoxic.

What key similarity links cephalosporins and penicillins?

They share a similar beta-lactam structure and mechanism, leading to possible cross-sensitivity in allergies.

Fluoroquinolones act by interfering with which bacterial process?

DNA replication in Gram-negative bacteria.

Give two contraindications for fluoroquinolones.

Pregnancy and lactation (also known drug allergies).

Macrolide antibiotics interfere with what cellular process?

Protein synthesis (they can be bacteriostatic or bactericidal).

Penicillins inhibit the synthesis of which bacterial structure?

The cell wall.

Why are tetracyclines contraindicated in children under 8 years old?

They can cause permanent tooth discoloration and bone growth inhibition.

Which antimycobacterial drug combination is notorious for liver toxicity?

Rifampin combined with isoniazid (INH).

What should the nurse assess before starting any antibiotic therapy?

Drug allergies, renal and hepatic function, and (for aminoglycosides) baseline hearing status.

Why should cultures be obtained before the first antibiotic dose when possible?

To identify the organism accurately and guide effective therapy.

What key teaching point should be stressed about completing antibiotic therapy?

Take the full prescribed course even if symptoms improve to prevent resistance and relapse.