title: Incidence rate of fluoroquinolone-resistant gram-negative rod bacteremia among allogeneic hematopoietic cell transplantation patients during an era of levofloxacin prophylaxis.
abstract: There are concerns that emerging resistance to fluoroquinolones (FQ) may be leading to increasing rates of gram-negative rod (GNR) bacteremia in hematopoietic cell transplant (HCT) recipients. We set out to describe time trends in the incidence rates of GNR bacteremia and FQ-resistant GNR bacteremia in HCT recipients during an era of levofloxacin prophylaxis. We conducted a longitudinal retrospective study of adults undergoing allogeneic HCT between 2003 and 2012 at the Seattle Cancer Care Alliance (SCCA). Annual trends in the incidence rates of GNR bacteremia and FQ-resistant GNR bacteremia through 100 days after transplantation were assessed using Poisson regression. Cox proportional hazards regression was used to compare 30-day mortality between patients with FQ-resistant and those with FQ-sensitive GNR bacteremia. Of the 2306 patients included in this cohort, 280 (12.1%) had GNR bacteremia. The incidence rates of GNR bacteremia and FQ-resistant GNR bacteremia increased from 2003 to 2009 and decreased afterwards; however, the overall annual trends were not significant (incidence rate ratio [IRR], 1.01; 95% confidence interval [CI], .98 to 1.05; IRR, 1.01; 95% CI, .95 to 1.08, respectively). FQ-resistant GNR bacteremia was associated with increased mortality compared with FQ-sensitive GNR bacteremia, even after adjustment for underlying disease severity, conditioning regimen, and age at transplantation (hazard ratio, 2.11; 95% CI, 1.06 to 4.23). On average, rates of FQ-resistant GNR bacteremia have not significantly changed over 10 years of FQ prophylaxis, although FQ-resistant GNR bacteremia is associated with increased mortality compared with FQ-sensitive GNR bacteremia.
authors.affiliation: Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington; Department of Epidemiology, University of Washington School of Public Health, Seattle, Washington.
authors.forename: Arianna
authors.initials: A
authors.lastname: Miles-Jay
authors.affiliation: Department of Laboratory Medicine, University of Washington, Seattle, Washington.
authors.forename: Susan
authors.initials: S
authors.lastname: Butler-Wu
authors.affiliation: Department of Epidemiology, University of Washington School of Public Health, Seattle, Washington.
authors.forename: Ali
authors.initials: A
authors.lastname: Rowhani-Rahbar
authors.affiliation: Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington; Infection Prevention, Seattle Cancer Care Alliance, Seattle, Washington; Department of Medicine, University of Washington, Seattle, Washington. Electronic address: spergam@fhcrc.org.
authors.forename: Steven A
authors.initials: SA
authors.lastname: Pergam
mesh_terms: D000328:Adult; D000368:Aged; D064591:Allografts; D000900:Anti-Bacterial Agents; D016470:Bacteremia / Q000453:epidemiology*; D024881:Drug Resistance, Bacterial; D005260:Female; D016965:Gram-Negative Anaerobic Straight, Curved, and Helical Rods; D016905:Gram-Negative Bacterial Infections / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D064704:Levofloxacin; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D064704:Levofloxacin
keywords: Fluoroquinolone resistance; Gram-negative; Hematopoietic cell transplantation