title: Recommendations for initial antibiotic treatment of extracavitary arterial graft infections.
abstract: BACKGROUND
  Initial antibiotic treatment of extracavitary arterial graft infections is usually empiric or based on Gram's stain findings. Increasing virulence of bacteria causing extracavitary arterial graft infections may render previous choices of antibiotics obsolete. The purposes of this study were to correlate Gram's stain findings of gram-positive bacteria and gram-negative bacteria with wound cultures and provide a microbiologic basis for appropriate initial antibiotic therapy.
  
  
  METHODS
  Between July 1, 1979 and June 30, 1994, specimens obtained on the day of admission from purulent wounds involving 113 extracavitary arterial graft infections were retrospectively reviewed for Gram's stain and culture and sensitivity results.
  
  
  RESULTS
  Gram's stain findings correlated with final cultures on only 28 of 113 cases (25%), including 20 of 48 pure gram-positive, 2 of 24 pure gram-negative, and 6 of 41 mixed bacterial cultures. Staphylococcus aureus was the most common gram-positive bacteria cultured (43 isolates) and Pseudomonas species was the most common gram-negative bacteria (25 isolates). Bacteria were sensitive to a first-generation cephalosporin in only 32% (36 of 113) of infections. A combination of vancomycin and either ticarcillin-clavulanic acid or ceftazidime, which have minimal toxicity and provide excellent coverage against staphylococci, Pseudomonas, and other gram-negative bacteria, would have covered 96% (109) and 95% (107) of cultured organisms, respectively.
  
  
  CONCLUSIONS
  Regardless of Gram's stain findings, current recommendations for initial treatment of extracavitary arterial graft infections should include vancomycin and ceftazidime or ticarcillin-clavulanic acid until final culture and sensitivity results dictate the use of more selective antibiotics.
authors.affiliation: Section of Vascular Surgery, Pennsylvania Hospital, Thomas Jefferson Medical College, Philadelphia, USA.
authors.forename: K D
authors.initials: KD
authors.lastname: Calligaro
authors.forename: F J
authors.initials: FJ
authors.lastname: Veith
authors.forename: M L
authors.initials: ML
authors.lastname: Schwartz
authors.forename: W
authors.initials: W
authors.lastname: Pan
authors.forename: M J
authors.initials: MJ
authors.lastname: Dougherty
authors.forename: D A
authors.initials: DA
authors.lastname: DeLaurentis
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D001158:Arteries / Q000601:surgery*; D001807:Blood Vessel Prosthesis; D002442:Ceftazidime / Q000627:therapeutic use; D002969:Clavulanic Acids / Q000627:therapeutic use; D004359:Drug Therapy, Combination / Q000627:therapeutic use; D006801:Humans; D011552:Pseudomonas Infections / Q000188:drug therapy; D012189:Retrospective Studies; D013203:Staphylococcal Infections / Q000188:drug therapy; D013530:Surgical Wound Infection / Q000188:drug therapy*; D013982:Ticarcillin / Q000627:therapeutic use; D014182:Transplantation, Autologous; D014640:Vancomycin / Q000627:therapeutic use; D014680:Veins / Q000637:transplantation
chemical_list: D000900:Anti-Bacterial Agents; D002969:Clavulanic Acids; D014640:Vancomycin; C043215:ticarcillin-clavulanic acid; D002442:Ceftazidime; D013982:Ticarcillin