Antimicrobial susceptibility of Gram-negative organisms isolated from patients hospitalised with pneumonia in US and European hospitals: results from the SENTRY Antimicrobial Surveillance Program, 2009-2012

Int J Antimicrob Agents. 2014 Apr;43(4):328-34. doi: 10.1016/j.ijantimicag.2014.01.007. Epub 2014 Feb 7.


Here we evaluated the frequency of occurrence and antimicrobial susceptibility patterns of Gram-negative bacteria isolated from patients hospitalised with pneumonia in medical centres in the USA (n=28) and Europe and the Mediterranean region (EMR) (n=25) in 2009-2012. Susceptibility testing was performed by reference broth microdilution methods. Overall, 12851 isolates were collected (6873/5978 in USA/EMR). The same top 11 organisms were observed in both geographic regions, but in different rank orders, and Gram-negative organisms represented 61.5/76.1% of strains in USA/EMR. Pseudomonas aeruginosa was the most frequently isolated Gram-negative organism in both regions (20.9/20.9% of cases in USA/EMR) and showed reduced susceptibility to most antimicrobials tested, including ceftazidime (79.6/68.7% susceptibility in USA/EMR), meropenem (76.3/65.8%) and piperacillin/tazobactam (72.9/63.9%). Klebsiella spp. was isolated from 9.7/11.6% of cases and showed extended-spectrum β-lactamase (ESBL) phenotype rates of 19.5/35.1% in USA/EMR. Meropenem and amikacin were active against 62.3/78.7% and 60.8/85.2% of ESBL phenotype Klebsiella spp. from USA/EMR, respectively. Enterobacter spp. ranked fourth in the USA (5.9%) and sixth in EMR (5.5%), whereas Escherichia coli ranked fifth in the USA (5.5%) and third in EMR (11.8%). Acinetobacter spp. and Stenotrophomonas maltophilia combined were isolated from 8.0/10.7% of cases in USA/EMR. A significant increase in P. aeruginosa susceptibility to meropenem and a significant decrease in gentamicin susceptibility among Klebsiella spp. were noted in EMR. These results confirm that very few agents remain broadly active against the most frequently isolated Gram-negative organisms from patients with pneumonia in US and EMR medical centres.

Keywords: Antimicrobial resistance; ESBL; Extended-spectrum β-lactamases; Pseudomonas aeruginosa.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / therapeutic use*
  • Drug Resistance, Multiple, Bacterial*
  • Europe / epidemiology
  • Gram-Negative Bacteria / drug effects*
  • Gram-Negative Bacteria / isolation & purification
  • Gram-Negative Bacterial Infections / drug therapy
  • Gram-Negative Bacterial Infections / epidemiology
  • Gram-Negative Bacterial Infections / microbiology
  • Hospitalization
  • Humans
  • Microbial Sensitivity Tests
  • Pneumonia / drug therapy*
  • Pneumonia / epidemiology*
  • Pneumonia / microbiology
  • United States / epidemiology


  • Anti-Bacterial Agents