title: Impact of ertapenem on antimicrobial resistance in a sentinel group of Gram-negative bacilli: a 6 year antimicrobial resistance surveillance study.
abstract: OBJECTIVE
  To determine the association between ertapenem and resistance of Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii-calcoaceticus complex to different antimicrobials while adjusting for relevant hospital factors.
  
  
  METHODS
  This was a retrospective time-series study conducted at a tertiary care centre from September 2002 to August 2008. The specific impact of ertapenem on the resistance of these Gram-negative bacilli (GNB) was assessed by multiple linear regression analysis, adjusting for the average length of stay, rate of hospital-acquired infections and use of 10 other antimicrobials, including type 2 carbapenems.
  
  
  RESULTS
  Unadjusted analyses revealed significant increases over the duration of the study in the number of GNB resistant to meropenem/imipenem among 1000 isolates each of E. coli (0.46 ± 0.22, P < 0.05), P. aeruginosa (6.26 ± 2.26, P < 0.05), K. pneumoniae (8.06 ± 1.50, P < 0.0005) and A. baumannii-calcoaceticus complex (25.39 ± 6.81, P < 0.0005). Increased resistance to cefepime (and other extended-spectrum cephalosporins) was observed in E. coli (9.55 ± 1.45, P < 0.0005) and K. pneumoniae (15.21 ± 2.42, P < 0.0005). A. baumannii-calcoaceticus complex showed increased resistance to all antimicrobials except amikacin. After controlling for confounders, ertapenem was not significantly associated (P > 0.05) with changes in resistance for any pathogen/antimicrobial combination.
  
  
  CONCLUSIONS
  After controlling for confounders, ertapenem was not associated with changes in resistance in a group of sentinel GNB, although significant variations in resistance to different antimicrobials were observed in the unadjusted analyses. These results emphasize the importance of implementation of local resistance surveillance platforms and stewardship programmes to combat the global emergence and spread of antimicrobial resistance.
authors.affiliation: Department of Critical Care Medicine, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México City, México.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Rodriguez-Osorio
authors.affiliation: Laboratory of Clinical Microbiology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México City, México.
authors.forename: Cesar O
authors.initials: CO
authors.lastname: Sanchez-Martinez
authors.affiliation: Department of Infectious Diseases, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México City, México.
authors.forename: Javier
authors.initials: J
authors.lastname: Araujo-Melendez
authors.affiliation: Department of Pharmacy, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México City, México.
authors.forename: Elia
authors.initials: E
authors.lastname: Criollo
authors.affiliation: Department of Hospital Epidemiology and Infection Control, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México City, México.
authors.forename: Alejandro E
authors.initials: AE
authors.lastname: Macias-Hernandez
authors.affiliation: Laboratory of Clinical Microbiology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México City, México.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Ponce-de-Leon
authors.affiliation: Clinical Epidemiology Unit, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México City, México.
authors.forename: Sergio
authors.initials: S
authors.lastname: Ponce-de-Leon
authors.affiliation: Department of Medicine, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México City, México sifuentesosornio@gmail.com.
authors.forename: Jose
authors.initials: J
authors.lastname: Sifuentes-Osornio
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D024881:Drug Resistance, Bacterial; D000077727:Ertapenem; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D016905:Gram-Negative Bacterial Infections / Q000188:drug therapy / Q000382:microbiology*; D006801:Humans; D008826:Microbial Sensitivity Tests; D012189:Retrospective Studies; D018571:Sentinel Surveillance; D062606:Tertiary Care Centers; D047090:beta-Lactams / Q000627:therapeutic use*
chemical_list: D000900:Anti-Bacterial Agents; D047090:beta-Lactams; D000077727:Ertapenem
keywords: carbapenems; hospital formulary; susceptibility