Anti-Infective Agents Lecture Review

Flashcards covering the classification, mechanism of action, therapeutic uses, and side effects of major antibiotic classes including Penicillins, Cephalosporins, Tetracyclines, Aminoglycosides, Macrolides, Quinolones, and Sulfonamides.

Empiric therapy

Treatment of an infection before a specific culture has been reported or obtained.

Prophylaxis

Treatment for people at increased risk of infection, such as peri-operative prevention of surgical site infections, short-term meningitis contacts, or long-term conditions like asplenia and immunodeficiency.

Bactericidal

Antibiotics that kill bacteria, such as penicillin.

Bacteriostatic

Antibiotics that inhibit the growth of susceptible bacteria rather than killing them immediately, eventually leading to bacterial death in the presence of good immunity (e.g., tetracycline).

Quinolones (Mechanism)

Antibiotics that inhibit DNA replication.

Rifamycin (Mechanism)

Antibiotics that inhibit transcription.

Inhibition of cell wall synthesis

Mechanism of action for penicillin, cephalosporin, and vancomycin.

Sulfonilamide (Mechanism)

Antibiotics that inhibit metabolism.

Inhibition of translation

Mechanism of action for tetracycline, erythromycin, streptomycin, and chloramphenicol.

Polymyxin (Mechanism)

Antibiotics that cause disruption of cell membrane function.

Natural penicillins

A class of penicillins including penicillin G and penicillin V.

Penicillinase-resistant penicillins

Penicillins such as cloxacillin, dicloxacillin, methicillin, nafcillin, and oxacillin.

Aminopenicillins

Penicillins such as amoxicillin and ampicillin, effective for gram-negative bacilli used for typhoid fever, UTI, and shigellosis.

Extended-spectrum penicillins

Penicillins such as piperacillin, ticarcillin, and carbenicillin.

Beta-lactamase inhibitors

Chemicals including clavulanic acid, tazobactam, and sulbactam that bind with the beta-lactamase enzyme to prevent it from breaking down penicillin.

Penicillin-binding protein

The target inside bacteria that penicillins bind to, leading to the disruption of cell wall synthesis and cell lysis.

Penicillin (Adverse Effects)

Allergic reactions occurring in $0.7\%$ to $8\%$ of treatments, including urticaria, pruritus, and angioedema; $10\%$ of reactions are life-threatening and $10\%$ of those are fatal.

First Generation Cephalosporins

Agents like cefadroxil, cephalexin, and cefazolin that provide good gram-positive coverage but poor gram-negative coverage.

Second Generation Cephalosporins

Agents like cefaclor, cefoxitin, and cefuroxime that provide good gram-positive coverage and better gram-negative coverage than the first generation.

Ceftriaxone (Rocephin)

A third-generation cephalosporin with a long half-life and once-a-day dosing that easily passes meninges into the CSF to treat CNS infections.

Ceftazidime

A third-generation cephalosporin with excellent gram-negative coverage used for Pseudomonas spp. and eliminated renally.

Cefepime (Maxipime)

A fourth-generation cephalosporin with a broader spectrum of antibacterial activity than the third generation, especially against gram-positive bacteria.

Doxycycline

A tetracycline partially excreted by bile, making it suitable for patients with impaired renal function.

Tetracyclines (Interactions)

Agents that bind to $Ca^{2+}$, $Mg^{2+}$, and $Al^{3+}$ ions to form insoluble complexes, reducing absorption when taken with dairy products, antacids, or iron salts.

Tetracyclines (Oral Side Effects)

Strong affinity for calcium leads to discoloration of permanent teeth and enamel in children and may retard fetal skeletal development.

Pseudomembranous colitis

A potential result of alteration in intestinal flora caused by tetracyclines.

Pseudo tumor cerebri

An adverse effect of tetracyclines characterized by increased intracranial pressure.

Aminoglycosides

Potent bactericidal antibiotics produced from Streptomyces, such as gentamicin and amikacin, which have poor oral absorption and serious toxicities.

Aminoglycoside Toxicities

Nephrotoxicity (renal failure) and Ototoxicity involving auditory impairment and the vestibular (eighth cranial) nerve.

Macrolides

Antibiotics including erythromycin, azithromycin, and clarithromycin used for Strep infections, URI, Syphilis, and H. pylori.

Articulopathy

A potential side effect of Quinolones in children due to effects on articular cartilage.

Sulfonamides (Mechanism)

Bacteriostatic agents that prevent folic acid synthesis by inhibiting the enzyme that converts PABA to DHF.

Bactrim

A bactericidal combination of sulfamethoxazole and trimethoprim (which inhibits dihydrofolate reductase) used to treat UTIs and Pneumocystis carinii pneumonia.