title: Development of a combination antibiogram for Pseudomonas aeruginosa bacteremia in an oncology population.
abstract: OBJECTIVE
  Development of a combination antibiogram to identify combinations of antibiotics that have the highest likelihood of attaining one active agent in the empiric management of presumed Pseudomonas aeruginosa bacteremia.
  
  
  METHODS
  Patients with cancer and P. aeruginosa bacteremia from January 1 to December 31, 2012 were included in this analysis. The primary outcome was identification of effective combinations of beta-lactam and non-betalactam agents. An effective combination was defined as one which achieved in-vitro activity to greater than or equal to 85% of isolates collected. Furthermore, the addition of the non-beta-lactam agent was required to increase the in-vitro activity by at least 5% over beta-lactam monotherapy. Multiple secondary outcomes were evaluated.
  
  
  RESULTS
  One hundred and twenty-three P. aeruginosa isolates were included from 99 patients. Single agent beta-lactam sensitivities ranged from 72.4 to 79.7%. Combination regimen sensitivities ranged from 73.5 to 96.7%. All combination regimens that included a beta-lactam plus an aminoglycoside were found to be effective per the study definition. Independent risk factors for MDR P. aeruginosa were receipt of intravenous (IV) antibiotics within 90 days and hospital length of stay (LOS) greater than or equal to five days. Increasing the number of antibiotics received was associated with a decrease in survival to hospital discharge.
  
  
  CONCLUSIONS
  Effective combination regimens included all beta-lactam aminoglycoside regimens. Receipt of IV antibiotics within 90 days and hospital LOS greater than or equal to five days were independent risk factors for MDR isolates.
authors.affiliation: Department of Pharmacy Services, Henry Ford Hospital, Detroit, MI, USA zsmith1@hfhs.org.
authors.forename: Zachary R
authors.initials: ZR
authors.lastname: Smith
authors.affiliation: Division of Pharmacy, Pharmacy Clinical Programs, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: Sharla K
authors.initials: SK
authors.lastname: Tajchman
authors.affiliation: Division of Pharmacy, Pharmacy Clinical Programs, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: Brian M
authors.initials: BM
authors.lastname: Dee
authors.affiliation: Division of Pharmacy, Pharmacy Clinical Programs, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Bruno
authors.affiliation: Division of Quantitative Sciences, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Qiao
authors.affiliation: Division of Pharmacy, Pharmacy Clinical Programs, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: Frank P
authors.initials: FP
authors.lastname: Tverdek
mesh_terms: D061605:Administration, Intravenous; D000368:Aged; D000617:Aminoglycosides / Q000008:administration & dosage; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D016470:Bacteremia / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology; D015331:Cohort Studies; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D008297:Male; D008495:Medical Oncology / Q000379:methods / Q000639:trends; D008826:Microbial Sensitivity Tests / Q000379:methods / Q000639:trends; D008875:Middle Aged; D009369:Neoplasms / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology; D011552:Pseudomonas Infections / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000302:isolation & purification; D012189:Retrospective Studies; D047090:beta-Lactams / Q000008:administration & dosage
chemical_list: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D047090:beta-Lactams
keywords: anti-bacterial agents; bacteremia; cancer population; combination; drug therapy; pseudomonas aeruginosa