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For the Chapter in the Schwinghammer, Handbook (not Wells Handbook anymore) please go to Chapter 35, Antimicrobial Regimen Selection.



  • image Every attempt should be made to obtain specimens for culture and sensitivity testing prior to initiating antibiotics.

  • image Empirical antibiotic therapy should be based on knowledge of likely pathogens for the site of infection, information from patient history (eg, recent hospitalizations, work-related exposure, travel, and pets), and local susceptibility.

  • image Patients with delayed dermatologic reactions (ie, rash) to penicillin generally can receive cephalosporins. Patients with type I hypersensitivity reactions (ie, anaphylaxis) to penicillins should not receive cephalosporins. Alternatives to the cephalosporins inveclude aztreonam, quinolones, sulfonamide antibiotics, or vancomycin based on type of coverage indicated.

  • image Creatinine clearance should be estimated for every patient who is to receive antibiotics and the antibiotic dose interval adjusted accordingly. Hepatic function should be considered for drugs eliminated through the hepatobiliary system, such as clindamycin, erythromycin, and metronidazole.

  • image All concomitant drugs and nutritional supplements should be reviewed when an antibiotic is added to a patient’s therapy to ensure drug–drug interactions will be avoided.

  • image Combination antibiotic therapy may be indicated for polymicrobial infections (eg, intra-abdominal and gynecologic infections), to produce synergistic killing (such as β-lactam plus aminoglycoside vs Pseudomonas aeruginosa), or to prevent the emergence of resistance.

  • image All patients receiving antibiotics should be monitored for resolution of infectious signs and symptoms (eg, decreasing temperature and white blood cell count) and adverse drug events.

  • image Antibiotics with the narrowest effective spectrum of activity are preferred. Antibiotic route of administration should be evaluated daily, and conversion from IV to oral therapy should be attempted as signs of infection improve for patients with functioning GI tracts (general exceptions are endocarditis and CNS infections).

  • image Patients not responding to an appropriate antibiotic treatment in 2 to 3 days should be reevaluated to ensure (a) the correct diagnosis, (b) that therapeutic drug concentrations are being achieved, (c) that the patient is not immunosuppressed, (d) that the patient does not have an isolated infection (ie, abscess and foreign body), or (e) that resistance has not developed.

  • image The main goals of antimicrobial stewardship programs (ASPs) are to optimize antimicrobial selection, dosing, duration, and route of administration while minimizing adverse drug events and the emergence of antimicrobial resistance.


Antimicrobials are among the most widely used classes of drugs. In the United States, expenditures for antimicrobial agents exceed $10 billion annually. Approximately 20% to 40% of hospitalized patients receive antibiotics. The use of antibiotics is the main driver in creating selective pressure for the emergence of antimicrobial resistant pathogens; nevertheless, antibiotic overuse remains common. Selecting appropriate antimicrobial agent(s) to treat an infection has proven to be a challenging task.1,2 Although the choice of a single agent or a combination of agents should be individualized for each patient, certain general principles of therapy should ...

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