antimicrobial therapy Flashcards
(20 cards)
What is the first principle of antimicrobial therapy regarding infection diagnosis?
Accurate diagnosis is essential to identify the causative microorganism and guide antibiotic selection.
What is empirical therapy?
Empirical therapy is initiated without knowing the specific pathogen, using broad-spectrum antibiotics based on symptoms and patient history.
When is definitive therapy used?
After lab tests identify the pathogen, definitive therapy uses targeted, often narrower-spectrum antibiotics to improve efficacy and reduce side effects and resistance.
Why is microbiological testing important before antibiotic treatment?
To accurately identify the pathogen and its antibiotic susceptibility, improving treatment precision.
What is the risk of starting antibiotics without microbiological confirmation?
Increased resistance, disrupted microbiome, and possible inappropriate treatment.
What are common reasons for using combination antibiotic therapy?
Synergy, empirical broad-spectrum coverage, polymicrobial infections, and prevention of resistance.
What is an example of synergistic antibiotic combination?
Ampicillin and gentamicin for Enterococcus, where ampicillin disrupts the wall and gentamicin enters to inhibit protein synthesis.
Why is combination therapy used in TB treatment?
To prevent resistance due to the slow-growing nature of Mycobacterium tuberculosis.
What host characteristics must be considered when prescribing antibiotics?
Immune status, age, kidney/liver function, allergies, pregnancy/lactation, genetic predispositions (e.g. G6PD deficiency).
Why are tetracyclines avoided in children?
They deposit in bones and teeth, causing discoloration and possible growth effects.
What is Clostridium difficile associated with?
Superinfections after broad-spectrum antibiotics disrupt the gut microbiome.
When is oral antibiotic therapy preferred over IV?
When the patient is stable and can absorb the drug orally—it’s cheaper and less invasive.
What are time-dependent antibiotics?
Antibiotics like beta-lactams that need to remain above MIC for most of the dosing interval for efficacy.
What are concentration-dependent antibiotics?
Antibiotics like gentamicin that rely on high peak concentration for killing, followed by low levels to reduce toxicity and resistance.
How is duration of antibiotic therapy determined?
Historically based on practice, but now increasingly guided by clinical trials (e.g. 3 days for uncomplicated UTI, 5 days for CAP).
How is treatment response monitored?
By assessing clinical symptoms (e.g., fever reduction) and microbiological parameters (e.g., culture clearance).
When is prophylactic antibiotic use justified?
Before surgery, in immunocompromised patients, after exposure to outbreaks (e.g. meningitis), and during travel to endemic regions.
What is a good example of inappropriate antibiotic use?
Treating fungal infections without confirmation, or treating asymptomatic bacteriuria without infection evidence.
Why should broad-spectrum antibiotics be de-escalated?
To prevent resistance and microbiota disruption by switching to a more targeted therapy once the pathogen is identified.
What is antimicrobial stewardship?
A strategy to optimize antibiotic use, reduce resistance, and ensure effective treatment by avoiding unnecessary or inappropriate prescriptions.
