- Every attempt should be made to obtain specimens for culture and sensitivity testing prior to initiating antibiotics.
- Empirical antibiotic therapy should be based on knowledge of likely pathogens for the site of infection, information from patient history (e.g., recent hospitalizations, work-related exposure, travel, and pets), and local susceptibility.
- Patients with delayed dermatologic reactions (i.e., rash) to penicillin generally can receive cephalosporins. Patients with type I hypersensitivity reactions (i.e., anaphylaxis) to penicillins should not receive cephalosporins. Alternatives to the cephalosporins include aztreonam, quinolones, sulfonamide antibiotics, or vancomycin based on type of coverage indicated.
- 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.
- 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.
- Combination antibiotic therapy may be indicated for polymicrobial infections (e.g., intra-abdominal, gynecologic infections), to produce synergistic killing (such as β-lactam plus aminoglycoside vs. Pseudomonas aeruginosa), or to prevent the emergence of resistance.
- All patients receiving antibiotics should be monitored for resolution of infectious signs and symptoms (e.g., decreasing temperature and white blood cell count) and adverse drug events.
- 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).
- 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 (i.e., abscess, foreign body), or (e) that resistance has not developed.
On completion of the chapter, the reader will be able to:
Recognize general signs, symptoms, laboratory, and microbiologic findings of a patient with an infection.
Apply susceptibility data from an institution’s antibiogram in choosing presumptive antimicrobial therapy.
Select antimicrobial(s) of choice based on organism and infectious disease.
Design an appropriate antimicrobial regimen for a patient-based allergy profile, age, renal and liver function, concomitant disease states, and infection.
Propose alternative antimicrobial therapy for a patient with a penicillin allergy.
Discuss metabolic and host genetic variations that may affect antimicrobial therapy.
Identify major drug interactions with antimicrobials.
Differentiate adverse drug reactions profiles associated with antimicrobial classes.
Explain key pharmacodynamic relationships to optimize antimicrobial dosing.
Recommend antimicrobial agents based on tissue or fluid penetration and site of infection.
Debate advantages and disadvantages of using combination antimicrobial therapy.
Formulate a monitoring plan to assess therapeutic response after initiation of antimicrobial therapy.
Evaluate issues including drug selection, host factors, and pathogen(s) in a patient lacking clinical response to antimicrobial therapy.
List clinical parameters to consider when switching ...