Antibiotics and Anti-infectives Overview

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Questions and Answers

What is the primary action of anti-infective agents?

To increase the growth rate of bacteria

To enhance the immune response

To boost protein synthesis in the body

To selectively target foreign organisms (correct)

Which characteristic is essential for an antibiotic?

Non-selective toxicity

Chemical instability

Rapid biotransformation and elimination

Selective toxicity (correct)

Which of the following best defines bactericidal drugs?

They prevent DNA replication only.

They only inhibit bacterial growth.

They enhance bacterial cell wall synthesis.

They kill bacteria directly. (correct)

What is the most common adverse effect associated with anti-infective therapy?

Nephrotoxicity Signup and view all the answers

What mechanism does an antibiotic use to interfere with bacterial cell function?

Inhibiting the synthesis of the bacterial cell wall Signup and view all the answers

Which of the following macrolides is NOT listed in the content?

Roxithromycin Signup and view all the answers

What is the mechanism of action of chloramphenicols?

Inhibits protein synthesis Signup and view all the answers

Which tetracycline is classified as long-acting?

Doxycycline Signup and view all the answers

Which of the following antibiotics is specifically mentioned as affecting bacterial DNA?

Quinolones Signup and view all the answers

Which of these antibiotics is noted for having a risk of bone marrow toxicity as an adverse effect?

Chloramphenicols Signup and view all the answers

Which of the following antibiotics is classified as a third generation cephalosporin?

Ceftazidime Signup and view all the answers

What is the primary mechanism of action for aminoglycosides?

Disruption of bacterial protein synthesis Signup and view all the answers

Which antibiotic belongs to the fifth generation cephalosporins?

Ceftaroline Signup and view all the answers

Which of the following is a monobactam antibiotic?

Aztreonam Signup and view all the answers

What class of antibiotics does vancomycin belong to?

Polypeptides Signup and view all the answers

Which of the following cephalosporins is commonly associated with parenteral use?

Cefuroxime Signup and view all the answers

Identify the antibiotic that is derived from the genus Streptomyces.

Kanamycin Signup and view all the answers

Which of the following is NOT a first generation cephalosporin?

Cefepime Signup and view all the answers

What is the primary mechanism of action for beta-lactam antibiotics?

Inhibiting cell wall synthesis Signup and view all the answers

Which penicillin is classified as a broad-spectrum aminopenicillin?

Amoxicillin Signup and view all the answers

Which of the following is a beta-lactamase inhibitor?

Clavulanic acid Signup and view all the answers

What characteristic of cephalosporins makes them similar to penicillins?

Mechanism of action and structure Signup and view all the answers

Which of the following is a narrow-spectrum penicillin used against staphylococcal infections?

Oxacillin Signup and view all the answers

What is the role of penicillin-binding proteins (PBPs) in bacterial cells?

Cell wall synthesis Signup and view all the answers

Which group of beta-lactam antibiotics is considered to have the broadest spectrum of activity?

Extended-spectrum penicillins Signup and view all the answers

Which of the following is NOT a type of penicillin?

Cefazolin Signup and view all the answers

Study Notes

Antibiotics - Anti-infectives

Learning outcomes include knowing different therapeutic classifications, gaining knowledge of various drugs, identifying mechanisms of action, and actively participating in identifying market drugs.

Historical Background

Sir Alexander Fleming discovered penicillin in 1929.
Florey and Chain introduced penicillin therapy in 1938.
Antibiosis means "against life".
An antibiotic/antibiotic substance is a substance made by microorganisms that inhibits or destroys other microorganisms.

Anti-infective Agents

Anti-infectives are designed to act selectively on foreign organisms that invade and infect the body.
Anti-infectives range from antibiotics to antifungals, antiprotozoals, anthelmintics, antivirals, and antimycobacterials.

Characteristics of Antibiotics

Antibiotics should possess selective toxicity.
Antibiotics should have chemical stability.
Antibiotics should have a slow rate of biotransformation and elimination.

Spectrum of Activity

Narrow spectrum
Broad spectrum
Bacteriostatic drug
Bactericidal

General Mechanisms of Action of Anti-infective Agents

Some interfere with bacterial cell wall biosynthesis.
Some inhibit protein synthesis.
Some inhibit DNA/RNA synthesis.
Some alter cell membrane permeability.

Common Adverse Reactions of Anti-infective Therapy

Nephrotoxicity
Gastro-intestinal
CNS toxicity
Hypersensitivity
Superinfections

B-Lactam Antibiotics (Structure/Examples)

Includes Penicillins, Cephalosporins, Carbapenems, and Monobactams
Have a beta-lactam ring structure
Inhibits cell wall synthesis

Penicillins (Examples/Classification)

Narrow/Intermediate spectrum penicillins (Penicillin G, Penicillin V, Amoxicillin, Ampicillin)
Broad spectrum penicillins (Aminopenicillin- Amoxicillin, Ampicillin, Bacampicillin)
Penicillinase-resistant Penicillin /Narrow Spectrum (Cloxacillin, Nafcillin, Methicillin, Dicloxacillin, Oxacillin)
Extended-spectrum penicillins (Carbenicillin, Mezlocillin, Piperacillin, Ticarcillin acid)
Beta-lactamase inhibitors (Clavulanic, Sulbactam, Tazobactam)

Beta-Lactamase Inhibitors

Class I inhibitors (Clavulanic acid, Sulbactam, and tazobactam)
Class II inhibitor (Carbapenem derivative imipenem)

Cephalosporins

Similar to penicillins in mechanism of action, chemical structure, and toxicities.
Target bacterial cell wall transpeptidases and penicillin-binding proteins (PBPs) to cause cell wall lysis.
Varying generations based on discovery time
Oral: Cephalexin, Cephradine, Cefadroxil, Cefaclor, Cefprozil, Loracarbef, Cefuroxime axetil, Cefpodoxime proxetil, Cefixime
Parenteral: Cephalosphorin containing cef; Cephradine, Cefuroxime, and Cefixime (oral and parenteral)

Classification

First Generation (Cefalexin, Cephradine, Cefadroxil, Cephalothin, Cephapirin, Cefazolin)
Second Generation (Cefaclor, Cefmetazole, Cefonicid, Cefotetan, Cefoxitin, Cefuroxime, Cefpodoxime, Cefprozil, Loracarbef, Cefamandole)
Third Generation (Cefixime, Cefoperazone, Cefotaxime, Ceftazidime, Ceftibuten, Ceftizoxime, Ceftriazone)
Fourth Generation (Cefepime, Cefpirome)
Fifth Generation (Ceftaroline, Ceftobiprole)

Monobactams (Examples)

Aztreonam Disodium (Azactam)
Tigemonam

Polypeptides (Examples)

Vancomycin Hydrochloride (Vancocin, Vancoled)
Teicoplanin (Teichomycin A2, Targocid)
Bacitracin

Membrane-Active Agents (-Polymixin, -Gramicidir)

Polymixin
Gramicidir

Agents Affecting Bacterial Protein Synthesis

Aminoglycosides
Macrolides
Lincosamides
Tetracyclines
Chloramphenicols

Aminoglycosides (History/Examples)

Discovered in 1939 from Streptomyces
Kanamycin, Neomycin, Paromomycin, Gentamicin, Tobramycin, Netilmicin
potent broad-spectrum activity
Examples include Gentamicin (Garamycin), Tobramycin, Amikacin (Amikin), Netilmicin (Netromycin), Kanamycin (Kantrex), Streptomycin, Neomycin, Paromomycin, Spectinomycin

Macrolides (Examples)

Clarithromycin (Klaricid, Klaz)
Erythromycin
Diritromycin (Dynabac)
Azithromycin (Zithromax)

Lincosamides (Examples)

Lincomycin Hydrochloride (Lincocin)
Clindamycin Hydrochloride (Dalacin)
Clindamycin Palmitate Hydrochloride (Cleocin Pediatric)
Clindamycin Phosphate (Cleocin Phosphate)

Tetracyclines (Types/Examples)

Short-acting (Tetracycline, Oxytetracycline)
Intermediate acting (Demeclocycline, Methacycline)
Longacting(Doxycycline)
Includes Tetracycline, Oxytetracycline, Demeclocycline, Methacycline, Doxycycline, Minocycline, Rolitetracycline

Chloramphenicols

MOA: Inhibits protein synthesis by binding to 50S subunit of bacterial ribosome.
Broad spectrum
Pharmacokinetic: Orally and IV; metabolized in liver; crosses placenta and blood-brain barrier.
ADR: Bone marrow toxicity

Other Antibiotics (Types/Examples)

Novobiocin Sodium
Quinupristin/Dalfopristin (Synercid)
Mupirocin (Bactroban)
Linezolid (Zyvox)

Agents Affecting Bacterial DNA

Quinolones (Nalidixic acid, Cinoxacin, Norfloxacin, Uritracin, Enoxacin, Ciprofloxacin, Ofloxacin, Lomefloxacin, Sparfloxacin)

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Description

This quiz explores antibiotics and their therapeutic classifications, mechanisms of action, and historical context. You will learn about various anti-infective agents, their characteristics, and the significance of antibiotics in modern medicine. Join us to test your knowledge on these vital substances that combat infections.