title: Epidemiology and susceptibility of Gram-negative appendicitis pathogens: SMART 2008-2010.
abstract: BACKGROUND
  The Study for Monitoring Antimicrobial Resistance Trends (SMART) has tracked the in vitro activity of ertapenem and comparators against aerobic gram-negative bacteria from intra-abdominal infections since 2002. This report describes the epidemiology and susceptibility for clinical isolates associated with appendicitis, collected from 2008 to 2010.
  
  
  METHODS
  A total of 1,720 gram-negative bacilli were collected from patients with appendicitis in 122 hospitals in 39 countries worldwide; of these, 23% of isolates were from pediatric patients (≤ 17 years old). Minimum inhibitory concentrations (MICs) and extended-spectrum β-lactamase (ESBL) phenotypes were determined by broth microdilution and interpreted using Clinical and Laboratory Standards Institute guidelines.
  
  
  RESULTS
  The global ESBL-positive rate was 16.3%, ranging from 2.2% for Proteus mirabilis to 16.6% for Escherichia coli and 20.1% for Klebsiella pneumoniae. The ESBL-positive rates differed by age group (17.7% in adults vs. 11.4% in children) and by geographic region, with significantly higher rates in Asia/Pacific (28.0%) and significantly lower rates in North America (9.1%), Africa/Middle East (4.8%), and Europe (4.4%). Amikacin, imipenem-cilastatin, piperacillin-tazobactam, and ertapenem were the most active of the tested agents against aerobic gram-negative appendicitis pathogens across pediatric and adult age groups and across geographic regions, including ESBL-positive isolates. Cefepime and ceftazidime were active against ≥ 90% of global pediatric isolates. E. coli, by far the most frequently isolated species (68% in adults and 75% in pediatric patients), was significantly less susceptible in adults than in pediatric patients (p<0.05; Fisher exact test) to all tested agents except amikacin, ertapenem, imipenem-cilastatin, piperacillin-tazobactam, and ampicillin-sulbactam (with the latter showing low activity in both age groups).
  
  
  CONCLUSIONS
  These in vitro data suggest that amikacin, imipenem-cilastatin, piperacillin-tazobactam, and ertapenem would perform well against aerobic gram-negative bacilli associated with appendicitis in both adults and children, especially in regions with high rates of ESBL-positive E. coli.
authors.affiliation: International Health Management Associates, Inc, Schaumburg, Illinois 60173, USA. shlob@ihmainc.com
authors.forename: Sibylle H
authors.initials: SH
authors.lastname: Lob
authors.forename: Robert E
authors.initials: RE
authors.lastname: Badal
authors.forename: Samuel K
authors.initials: SK
authors.lastname: Bouchillon
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Hawser
authors.forename: Meredith A
authors.initials: MA
authors.lastname: Hackel
authors.forename: Daryl J
authors.initials: DJ
authors.lastname: Hoban
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001064:Appendicitis / Q000453:epidemiology* / Q000382:microbiology*; D002648:Child; D015331:Cohort Studies; D024881:Drug Resistance, Bacterial; D062665:Epidemiological Monitoring; D014943:Global Health; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000302:isolation & purification; D016905:Gram-Negative Bacterial Infections / Q000453:epidemiology* / Q000382:microbiology*; D006801:Humans; D008826:Microbial Sensitivity Tests; D062486:Public Health Surveillance / Q000379:methods
chemical_list: D000900:Anti-Bacterial Agents