title: Rapid adaptation of antibiotic therapy for community-acquired peritonitis using direct cultures on antibiotic agar plates: pilot study.
abstract: BACKGROUND
  Treatment of peritonitis requires prompt surgery and antibiotic therapy. It usually takes two or three days to obtain definitive results of peritoneal cultures and to adapt empirical antibiotic therapy. We assessed the potential time gain associated with direct culture of peritoneal samples on antibiotic agar (AA).
  
  
  METHODS
  Peritoneal samples from 31 consecutive patients undergoing surgery for suspected community-acquired peritonitis were cultured according to the standard method and on AA containing one of the following five regimens: amoxicillin/clavulanic acid + gentamicin, ticarcillin/clavulanic acid + gentamicin, cefotaxime +metronidazole, piperacillin/tazobactam, or ertapenem. We compared the treatment modifications made by physicians aware only of the results of the standard method with the modifications the AA method would have indicated.
  
  
  RESULTS
  Fewer isolates were identified by direct culture on AA than by the standard method (17 vs. 45; p = 0.0001), but definitive results were obtained much more rapidly (median 1 [range 1-3] days vs. 3 [range 2-7] days; p < 0.0001). Antibiotic regimens were changed for 14 patients on the basis of the results of the standard method (broader antibiotic spectrum and narrower spectrum in seven patients each). With the AA method, these changes could have been indicated after a median of 1 (range 1-2) days instead of 4 (range 1-11) days (p = 0.0006). The AA method missed only one resistant bacterial strain and isolated nine strains not detected by the standard method, including an extended-spectrum beta-lactamase-producing Escherichia coli. A complicated outcome was more frequent in patients having isolates found with the AA but not the standard method (86% vs. 21%; p = 0.003).
  
  
  CONCLUSIONS
  Use of the AA method for culture of peritoneal samples from patients with community-acquired peritonitis speeds appropriate adaptation of antibiotic therapy and warrants further investigation.
authors.affiliation: Département d'Anesthésie-Réanimation Chirurgicale, Assistance Publique Hôpitaux de Paris, Paris, France. sigismond@lasocki.com
authors.forename: Sigismond
authors.initials: S
authors.lastname: Lasocki
authors.forename: David
authors.initials: D
authors.lastname: Skurnik
authors.forename: Claudette
authors.initials: C
authors.lastname: Muller-Serieys
authors.forename: Regis
authors.initials: R
authors.lastname: Bronchard
authors.forename: Candice
authors.initials: C
authors.lastname: Marcel
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Marmuse
authors.forename: Philippe
authors.initials: P
authors.lastname: Montravers
authors.forename: Antoine
authors.initials: A
authors.lastname: Andremont
mesh_terms: D000328:Adult; D000362:Agar; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001419:Bacteria / Q000187:drug effects / Q000254:growth & development / Q000302:isolation & purification*; D017714:Community-Acquired Infections / Q000188:drug therapy*; D003470:Culture Media / Q000737:chemistry*; D005260:Female; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests / Q000379:methods*; D008875:Middle Aged; D010538:Peritonitis / Q000188:drug therapy*; D010865:Pilot Projects; D013997:Time Factors; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D003470:Culture Media; D000362:Agar