7.1 PDF task. Fundamentals of the management of infectious processes with antimicrobial agents (Principles of antimicrobial therapy)

1. The main principles of antimicrobial therapy (7 items, A-G).

Answer: Verification of infection; Proper choice of antimicrobial treatment strategy; Assessment of host (patient) factors; Assessment of the site of infection; Assessment of drug safety and efficacy; Assessment of treatment cost; Monitoring the course of treatment and evaluating outcomes. (Page 11.)

2. What is the term for the persistent inhibition of bacterial growth when the antibiotic concentration falls below the MIC level? a) Bacteriostatic effect b) Postantibiotic effect c) Time-dependent bactericidal effect d) Concentration-dependent bactericidal effect e) Bactericidal effect f) Temperature-dependent bactericidal effect

Answer: b) Postantibiotic effect (PAE) - persistence of growth suppression after brief antibiotic exposure, even when drug concentration falls below MIC (page 17).

3. What key patient-related factors must be evaluated before initiating antimicrobial therapy, and why? (7 items, A-G)

Answer: Age; Immune system and comorbidities with concomitant medications (organ transplantation, diabetes, HIV); Liver and kidney function; Circulation (poor antibiotic penetration to infection site); Pregnancy (placental barrier, teratogenic/embryotoxic risk); Lactation (drug excretion into breast milk); Allergy, genetic factors. (Page 19.)

4. For which patients is the assessment of individual characteristics not particularly important before prescribing antimicrobial therapy? a) Cancer chemotherapy patients b) Renal failure patients c) Elderly patients d) Patients with hypertension e) Liver failure patients

Answer: d) Patients with hypertension. INFERRED by elimination - immune status, renal function, age, and hepatic function are all explicitly listed as needing individual assessment (pages 19-20); hypertension isn't on that list.

5. Indicate the known factors/drivers of antibacterial resistance (AMR) (4 items, A-D).

Answer given: Overuse and misuse of antibiotics; Incorrect dosing or insufficient duration; Broad-spectrum use when narrow-spectrum would suffice; Environmental spread of resistant organisms. FLAG: doesn't map cleanly onto the lecture's driver categories (page 25). Double-check against your professor's expected answer.

6. How can this figure be interpreted? (funeral industry/cadaver AMR spread diagram, cited Pagal Endale H, 2023)

Answer: your interpretation is thorough and reasonable. FULLY EXTERNAL - this figure/citation is from an outside paper, not this lecture deck.

7. What are the origins of antimicrobial resistance (AMR)? (3 items, A-C)

Answer: Intrinsic (natural, inherent properties of bacteria); Acquired (horizontal transfer from another bacteria); Adaptive (triggered by environmental signals). (Pages 26-27.)

8. What are the main routes of antimicrobial resistance gene transfer? Explain them. (3 items, A-C)

Answer: Transduction - bacteriophages transfer DNA between bacteria; Transformation - DNA from a dead bacterium released and taken up by another, incorporated into its chromosome; Conjugation - direct genetic transfer via a sex pilus, plasmid-mediated. (Pages 26-27.)

9. Based on the figure, explain the three main mechanisms of bacterial resistance to antimicrobial agents (A-C).

Answer: A) Reduced antibiotic accumulation - membrane changes, narrowed pores, more active efflux pumps. B) Enzymatic inactivation - beta-lactamases inactivate beta-lactam antibiotics (note: "antibodies" in your sheet is a typo for "antibiotics"). C) Target modifications - alterations of the target site preventing binding. (Page 28.)

10. What changes in antibacterial drug clearance are observed in pregnant patients? Why?

Answer: Faster clearance due to increased blood volume, accelerated GFR, and enhanced liver activity/metabolism (page 20, specifically for penicillins, cephalosporins, aminoglycosides).

11. Into which areas of the human body do antimicrobial agents penetrate with difficulty? (4 items, A-D)

Answer: CNS (due to BBB), Eye (blood-ocular barrier), Bone (poor vasculature), Prostate (acidic environment). CNS/Eye/Bone/Prostate confirmed as difficult sites (pages 21, 23). FLAG: BBB reasoning is lecture-supported (page 21); specific reasons for eye/bone/prostate are added from general pharmacology.

12. What conditions allow the switch from parenteral drug administration to oral administration? (4 items, A-D)

Answer: Overall clinical improvement is seen; Absence of fever for 8-24 hours; Decreased leukocyte count; GI function is intact. (Page 22.) Note: "hemodynamic stability" isn't a separate bullet in the lecture.

13. What possible errors can occur in antimicrobial therapy? (8 items, A-H)

Answer: Inappropriate drug/dose/route of administration; Immunosuppression; Undrained abscesses (+ retained necrotic tissue, foreign bodies); AMR; Poor penetration into infection site (page 23). FLAG: "Incorrect diagnosis" isn't explicitly named as an error category in this lecture.

14. Which drugs or drug classes have their pharmacodynamic dose-bactericidal effect relationship illustrated in the figure (Table III, A-D)?

Answer: A) Beta-lactams - time above MIC (fT>MIC), not Cmax. B) Glycopeptides (vancomycin) - exposure-dependent (fAUC:MIC). C) Fluoroquinolones - exposure + peak dependent, strong PAE. D) Aminoglycosides - concentration-dependent, high Cmax drives killing. FLAG: this exact table isn't reproduced verbatim in the lecture, but the PK/PD concepts are directly taught on pages 16-17.

15. Indicate the mode of action of drugs A and B according to the graph curves (bacterial concentration over time after drug added; A plateaus, B declines).

Answer: A = Bacteriostatic (halts growth without reducing bacterial count - the "drug policeman" concept, page 5). B = Bactericidal (actively reduces bacterial count over time - the "drug killer", pages 5-6). FLAG: this specific graph isn't in the extractable lecture text, but the concept it illustrates is directly covered.

16. Explain the activity curves of bactericidal agents (Tobramycin vs Ticarcillin, log CFU/mL over time at multiples of MIC). What is MIC?

Answer: Tobramycin (aminoglycoside) shows concentration-dependent killing - higher multiples of MIC produce faster, greater killing. Ticarcillin (beta-lactam) shows time-dependent killing - plateaus regardless of concentration; what matters is time above MIC. MIC = the lowest antimicrobial concentration that prevents visible microbial growth after 24 hours of incubation (page 9). FLAG: this classic "Craig curves" figure isn't in this lecture's extractable text, but the concept is taught on pages 16-17.