690. Exposure to Multiple and Unrelated Antimicrobial Agents is Associated with Bloodstream Infection due to Antibiotic Resistant Bacteria among Hospitalized Children
Session: Poster Abstract Session: They've Been Here a Billion Years! Pediatric Bacterial and Viral Infections
Thursday, October 27, 2016
Room: Poster Hall


Hospital acquired bloodstream infections (BSI) caused by antimicrobial-resistant organisms (ARO) lead to longer hospitalization stays, increased hospital costs, and higher rate of mortality. Risk factors for ARO BSI infection in children are not well described. Our objective was to characterize patients with hospital-acquired ARO and identify clinical, laboratory, and therapeutic factors associated with these infections.


A case-control study of children hospitalized on any inpatient unit from December 2010 to December 2015 was conducted. Cases were defined as patients with a positive blood culture for cefepime and piperacillin-tazobactam resistant Gram-negative bacilli or vancomycin-resistant Enterococcus (VRE). Controls were defined as patients with a positive blood culture with an antibiotic susceptible organism. Antimicrobial exposures within 90 days prior to the culture being drawn were determined for each case.


Of the 227 patients with a Gram-negative BSI, 75 (33%) grew organisms resistant to cefepime or piperacillin-tazobactam. Ciprofloxacin, gentamicin, meropenem, vancomycin, and piperacillin-tazobactam exposure were associated with antibiotic resistance and are presented as box plots displaying the median, interquartile, and total range of days with antimicrobial exposure (Figure 1). Among the 66 BSI due to Enterococcus, 19 (29%) were from VRE. Exposure to ciprofloxacin, linezolid, meropenem, and piperacillin-tazobactam were higher among patients infected with vancomycin-resistant versus susceptible Enterococcus (Figure 2). Patients with BSI due to antimicrobial resistant bacteria had increased exposure to multiple antibiotic classes when compared to patients with BSI from a susceptible organism. Cumulative days of prior antibiotic exposure increased in parallel with increasing resistance and the overall risk of infection.


Overall these results reveal a complex relationship between antibiotic exposure and risk for bloodstream infection with an antimicrobial resistant bacterium. Further studies should investigate antimicrobial-associated effects on commensal microbiota that may contribute to the diverse effects of antibiotics on MDR infection risk.

Erin O'donnell, MD1, Heidi Andersen, MD2, Joshua Courter, PharmD3, Joel Mortensen, Ph.D.4, Lilliam Ambroggio, PhD, MPH5 and David Haslam, MD2, (1)Pediatrics, Cincinnati Children's Medical Hospital Center, Cincinnati, OH, (2)Infectious Disease, Cincinnati Children's Hospital, Cincinnati, OH, (3)Division of Pharmacy, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, (4)Pathology and Laboratory Medicine, Cincinnati Children's Hospital, Cincinnati, OH, (5)Division of Hospital Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH


E. O'donnell, None

H. Andersen, None

J. Courter, None

J. Mortensen, None

L. Ambroggio, None

D. Haslam, None

Findings in the abstracts are embargoed until 12:01 a.m. CDT, Wednesday Oct. 26th with the exception of research findings presented at the IDWeek press conferences.