title: The microbiology of bacterial peritonitis due to appendicitis in children.
abstract: OBJECTIVE
  The aim of this study was to investigate the microbiology of secondary bacterial peritonitis due to appendicitis and the appropriateness of current antimicrobial practice in one institution.
  
  
  METHODS
  A 14-year retrospective single-centre study of 69 consecutive paediatric patients (age 1-14 years) with appendicitis-related peritonitis and positive peritoneal specimen cultures was conducted. Post-operative outcomes, microbiology and antibiotic susceptibility of peritoneal isolates were analysed in all patients.
  
  
  RESULTS
  Escherichia coli was identified in 56/69 (81 %) peritoneal specimens; four isolates were resistant to amoxicillin-clavulanate, and one other isolate was resistant to gentamicin. Anaerobes were identified in 37/69 (54 %) peritoneal specimens; two anaerobic isolates were resistant to amoxicillin-clavulanate and one isolate was resistant to metronidazole. Pseudomonas aeruginosa was identified in 4/69 (6 %) peritoneal specimens, and all were susceptible to gentamicin. Streptococcal species (two Group F streptococci and three β-haemolytic streptococci) were identified in 5/69 (7 %) specimens, and all were susceptible to amoxicillin-clavulanate. Combination therapy involving amoxicillin-clavulanate and aminoglycoside is appropriate empirical treatment in 68/69 (99 %) patients. Addition of metronidazole to this regime would provide 100 % initial empirical coverage. Inadequate initial empiric antibiotic treatment and the presence of amoxicillin-clavulanate resistant E. coli were independent predictors of the post-operative infectious complications observed in 14/69 (20 %) patients.
  
  
  CONCLUSIONS
  E. coli and mixed anaerobes are the predominant organisms identified in secondary peritonitis from appendicitis in children. Inadequate initial empirical antibiotic and amoxicillin-clavulanate resistant E. coli may contribute to increased post-operative infectious complications. This study provides evidence-based information on choice of combination therapy for paediatric appendicitis-related bacterial peritonitis.
authors.affiliation: Department of Surgery, Portiuncula Hospital, Ballinasloe, Ireland, obinnaobinwa@rcsi.ie.
authors.forename: O
authors.initials: O
authors.lastname: Obinwa
authors.forename: M
authors.initials: M
authors.lastname: Casidy
authors.forename: J
authors.initials: J
authors.lastname: Flynn
mesh_terms: D000293:Adolescent; D000617:Aminoglycosides / Q000627:therapeutic use; D019980:Amoxicillin-Potassium Clavulanate Combination / Q000627:therapeutic use; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D001064:Appendicitis / Q000150:complications* / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D024881:Drug Resistance, Bacterial; D004927:Escherichia coli Infections / Q000150:complications / Q000188:drug therapy*; D005260:Female; D005839:Gentamicins / Q000627:therapeutic use; D006801:Humans; D007223:Infant; D008297:Male; D008795:Metronidazole / Q000627:therapeutic use; D010538:Peritonitis / Q000188:drug therapy / Q000382:microbiology*; D011552:Pseudomonas Infections / Q000150:complications / Q000188:drug therapy*; D011550:Pseudomonas aeruginosa; D012189:Retrospective Studies; D013290:Streptococcal Infections / Q000150:complications / Q000188:drug therapy*; D013292:Streptococcus agalactiae
chemical_list: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D005839:Gentamicins; D008795:Metronidazole; D019980:Amoxicillin-Potassium Clavulanate Combination