Optimizing Empiric Antibiotic Therapy in Patients with Severe β-lactam Allergy.
Antimicrob Agents Chemother. 2013 Sep 16;
Authors: Koliscak LP, Johnson JW, Beardsley JR, Miller DP, Williamson JC, Luther VP, Ohl CA
Antibiotic selection is challenging in patients with severe β-lactam allergy due to declining reliability of alternate antibiotics. Organisms isolated from these patients may exhibit unique resistance phenotypes. The objective of this study was to determine which alternate antibiotics or combinations provide adequate empiric therapy for patients with β-lactam allergy who develop gram-negative infections at our institution. We further sought to determine the effect of risk factors for drug resistance on empiric adequacy. A retrospective analysis was conducted of adult patients hospitalized from September 2009 to May 2010 who had a severe β-lactam allergy; a urine, blood, or respiratory culture positive for a gram-negative organism; and met pre-defined criteria for infection. Patient characteristics, culture and susceptibility data, and pre-defined risk factors for antibiotic resistance were collected. Adequacy of β-lactam and alternate antibiotics was compared for all infections and selected subsets. The primary outcome was adequacy of each alternate antibiotic or combination for all infections. One hundred sixteen infections (40 pneumonias, 67 urinary tract infections, 9 bacteremias) were identified. Single alternate agents were less frequently adequate compared to β-lactams and compared to combination regimens. Only in cases without risk factors for resistance did single-agent regimens demonstrate acceptable adequacy rates; each factor conferred a doubling of risk for resistance. Resistance risk factors should be considered when selecting empiric antibiotics for gram-negative pathogens in patients unable to take β-lactams due to severe allergy.
PMID: 24041892 [PubMed - as supplied by publisher]