Principles of Antimicrobial Use Flashcards
(45 cards)
Septic shock
Profound hemodynamic and metabolic abnormalities
TW
normal 4-10x10^9/L
neutrophils
45-75% normal range (relative to total WBC, most significantly phagocytose bacteria)
CRP
normal <10mg/L, infection >40mg/L
Procalcitonin
< 0.5ug/L
What does increase in lymphtocyte mostly indicate?
TB/ viral infectiom
Which is the most specific biomarker of infection (objective evidence)?
procalcitonin helps decide to start/stop abx
Usual sterile sites
kidney, bladder, cns, cvs, lower respiratory tract, bone, joint
Most common sites of infection
respiratory tract, urinary tract, skin and soft tissue, intra abdominal
Types of combination therapy
indifference (most of the time), synergy, antagonism
Benefits of combination therapy
- Extend spectrum of activity
- Achieve synergistic bactericidal effect
- Prevent development of resistance
Hospital-acquired pneumonia (combi therapy)
Empirical or definitive therapy of polymicrobial infections: piper/tazo + vanco
- extend spectrum of activity
Ventilator associated pneumonia (combi therapy)
Empirical therapy to cover all resistant strains of the same org: piper/tazo + cipro, cover Pseudomonas aeruginosa
- extend spectrum of activity
Enterococcus endocarditis (combi therapy)
Ampicillin + gentamicin or ampicillin + ceftriaxone
- achieve synergistic bactericidal effect
Why are trimethoprim and sulfamethoxazole combined to be used as co-trimoxazole?
Achieve synergistic bactericidal effect
Eg. of combi therapy used for prevention of development of resistance?
antimicrobial combinations against M. tuberculosis, HIV
Disadvantages of combination therapy
- Increased risk of toxicity and allergic reactions
- Increased risk of drug interactions
- Increased cost
- Selection of MDR bacteria
- Increased risk of superinfections (2nd infection imposed on earlier one by a different microorg)
- Concern for antagonistic effect - more of an issue for antifungals
host factors (9)
age, g6pd, pregnancy and lactation, severity of illness, status of host immune function, renal or hepatic impairment, history of allergy and adr, HA-assoc risk factors, recent antimicrobial use
Cross-reactivity present in ADR?
Nope
Cross-reactivity present in allergy?
Yes
Cross reactivity between penicillins and cephalosporins or carbapenems is due to?
Allergic reaction to abx with similar side chain, not a class effect
Shared side chain R1 (clinically relevant cross sensitivity)
amoxicillin, ampicillin, cephalexin
ceftriaxone, ceftazidime, cefepime, aztreonam
Which cephalosporin has no share side chain R1 with pencillins?
cefazolin
Empiric antimicrobial therapy based on
clinical presentation of likely site of infection, likely organisms causing infection at that site and likely susceptibility from antibiogram
