title: Pathogen Prevalence and Antimicrobial Susceptibility Among Enterobacteriaceae Causing Hospital-associated Intra-abdominal Infections in Adults in the United States (2012-2013).
abstract: Selection and prompt initiation of the appropriate empiric antimicrobial therapy are critical to decrease morbidity and mortality and shorten the length of hospitalization among patients with hospital-associated intra-abdominal infections (HA-IAIs). Therapeutic choices for the treatment of patients with HA-IAI require careful consideration. This study was conducted to evaluate the antimicrobial susceptibility of common pathogens collected from adult patients with HA-IAI in the United States.
  
  
  
  Gram-negative bacilli (N = 1285) were collected during 2012-2013 from SMART (Study for Monitoring Antimicrobial Resistance Trends). Isolates were tested at a central laboratory by using Clinical and Laboratory Standards Institute methods and interpretation of susceptibility to 12 antimicrobial agents.
  
  
  
  Most of the isolates (80.8%) were Enterobacteriaceae, and Escherichia coli was the most common species. Susceptibility to frequently used antimicrobial agents for treating IAI showed that ertapenem, imipenem, and amikacin were more active than other agents against Enterobacteriaceae, including multidrug-resistant isolates. More than 92% of E coli, including extended-spectrum β-lactamase (ESBL) producers, and Klebsiella pneumoniae isolates were susceptible to ertapenem, imipenem, and amikacin. Cefepime was the most active (>90% susceptibility) cephalosporin against all species except K pneumoniae (86.6%) but with much reduced activity against isolates with ESBLs. Piperacillin/tazobactam had reduced activity against Enterobacter species (70.4%-76.4% susceptible) and ESBL-producing K pneumoniae (22.5% susceptible). Fluoroquinolones exhibited poor activity against E coli (overall susceptibility <70%).
  
  
  
  Proper empiric antimicrobial treatment, including combining appropriate agents, of HA-IAI requires detailed understanding of the epidemiology of common pathogens and antimicrobial resistance patterns. In light of rising rates of antimicrobial resistance, ongoing surveillance is critical for clinical decision-making.
authors.affiliation: International Health Management Associates, Schaumburg, Illinois.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Zalacain
authors.affiliation: International Health Management Associates, Schaumburg, Illinois. Electronic address: dbiedenbach@ihmainc.com.
authors.forename: Douglas J
authors.initials: DJ
authors.lastname: Biedenbach
authors.affiliation: International Health Management Associates, Schaumburg, Illinois.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Badal
authors.affiliation: Merck & Co, Inc, Kenilworth, New Jersey.
authors.forename: Katherine
authors.initials: K
authors.lastname: Young
authors.affiliation: Merck & Co, Inc, Kenilworth, New Jersey.
authors.forename: Mary
authors.initials: M
authors.lastname: Motyl
authors.affiliation: International Health Management Associates, Schaumburg, Illinois.
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Sahm
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D003428:Cross Infection / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D004755:Enterobacteriaceae / Q000187:drug effects* / Q000201:enzymology / Q000302:isolation & purification*; D004756:Enterobacteriaceae Infections / Q000382:microbiology*; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology / Q000302:isolation & purification; D006801:Humans; D059413:Intraabdominal Infections / Q000382:microbiology*; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D014481:United States; D001618:beta-Lactamases / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001618:beta-Lactamases
keywords: United States; adult patients; antimicrobial resistance; intra-abdominal infection; surveillance