High -Yield Internal Medicine Board Exam Pearls by Knowmedge - HTML preview

given

 Both the Infectious Disease Society of America (IDSA) and American Thoracic Society

(ATS) advocate obtaining two sets of blood cultures prior to initiating antibiotic therapy

 Coagulase-negative staphylococci is a contaminant in blood cultures about 82% of the

time11

 The difference between blood cultures before the initiation of antibiotics and after the

initiation of antibiotics in identifying a pathogen is 40% versus 18.7%4

 Appropriate blood cultures, allows for prompt identification of the offending organisms

which influences diagnosis, therapy, and prognosis when positive

Pearl #5: Empiric antibiotics for acute uncomplicated cystitis have changed5

 Nitrofurantoin monohydrate/macrocrystals 100mg BID for 5 days is the appropriate

choice for empiric therapy of urinary tract infection

 Trimethoprim-sulfamethoxazole 160/800mg BID for 3 days is an appropriate empiric

choice if local resistance rates of uropathogens do not exceed 20% (expert opinion)

 Fosfomycin trometamol 3g in a single dose is an appropriate empiric choice for urinary

tract infection, but may be inferior efficacy compared to standard short-course regimens

 Pivmecillinam 400mg BID for 3 – 7 days is also an appropriate empiric antimicrobial

agent where available

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 Fluoroquinolones (ofloxacin, ciprofloxacin, and levofloxacin) should be considered

alternative antimicrobials for acute uncomplicated cystitis

 Amoxicillin or ampicillin should not be used for empirical treatment due to resistance to

these agents

Pearl #6: The loading dose of vancomycin is 25 – 30mg/kg based on actual body weight