15 Selecting Antimicrobial Regimens W-B Flashcards Preview

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Flashcards in 15 Selecting Antimicrobial Regimens W-B Deck (16):

What is the systemic approach to picking the proper antimicrobial?

Confirming the presence of infection. Identification of the pathogen. Selection of antimicrobial agents. Monitor therapeutic response


What do you look for when confirming the presence of infection?

Fever. WBC with differential. Pain/inflammation. Cough/sputum production


What is a Fever?

Elevation of body temperature above nl range (36-37.8). Hypothalamus - thermal regulatory center. Enhanced leukocyte migration, lymphocyte function and reduced microbial replication. Fever pattern - high spiking vs. sustained fevers


What can cause a "False-Negative" fever?

Overwhelming sepsis (may be hypothermic < 36). Ingestion of antipyretics or corticosteroids (these mask the bodies ability to cause a fever). Partially effective therapy. Localized infections (cystitis, chronic abscesses). Body unable to cause fever usually has worse prognosis


What can cause a "False-Positive" fever?

Autoimmune disease, malignancy. Acute MI, PE, postop atelectasis. Drug-induced: hypersensitivity reaction or antigen-antibody complex resulting in stimulation of macrophages and release of IL-1 (amphotericin B, B-lactams, anticonvulsants, allopurinol, nitrofurantoin). Drug-induced fever usually resolves 48 hrs after drug DC


What is the general information on WBCs?

Normal: 5-10,000. Mildly elevated - elderly, less serious infections. Sepsis: > 50,000. Could be elevated d/t: RA, corticosteroids, lithium, post-major surgery, acute MI. Could be low d/t: leukemia


What is a Differential Count?

Increased neutrophil (PMNs, segs): bacterial infections, nl = 50-70%. Increased bands "left shift": immature cells released in acute infection (normally ~5%). Increased lymphocytes: viral infections (nl: 20-40%). Eosinophilia: parasitic infections (nl = 0-5%), drug allergies. Neutropenia (< 1,000). Lymphopenia (CD4-T helper)


What is Elevated ESR?

Erythrocyte sedimentation rate. Chronic or acute infections: endocarditis, osteomyelitis, intra-abdominal infections. Non-ID: collagen vascular disease. Normal does NOT rule out infection


What is "Colonization"?

Presence of an organism at a body site WITHOUT production of disease in a host, "normal flora"


What is "Infection"?

Presence of an organism within tissues with invasiveness that often results in a response by the host's immune defenses


What are the host factors to think about when selecting an antimicrobial agent?

Drug and allergy history - PCN: rash vs. hives. Concomitant disease states and drugs. Age - increased risk of hepatotoxicity to INH. Pregnancy. Site of infection: CSF vs. bone vs. blood vs. urine


What antibiotics are Pregnancy Category B?

B-lactams, Macrolides, Clindamycin, Nitrofurantoin, Quinupristin/dalfopristin, Daptomycin


Which antibiotics are Pregnancy Category D?

Aminoglycosides, Tetracyclines (Tigecycline)


What are some pharmacologic factors for antimicrobial failure?

Subtherapeutic dosing. Reduced oral absorption. Inadequate duration of therapy. Poor penetration: meningitis, prostatitis, endophthalmitis


What are some host factors for antimicrobial failure?

Immune status: neutropenia, HIV infection. Undrained abscesses, prosthetic materials not removed. Structural abnormalities of various organs. Poor circulation - peripheral vascular disease


What are some microbial factors for antimicrobial failure?

Drug resistance. Superinfection - isolation of a new pathogen resistant to the previous antibiotic regimen