Mechanisms of ceftriaxone prophylaxis against late bacteremic vascular graft infection caused by Staphylococcus aureus in a dog model.
Possible mechanisms of the prophylactic effect of ceftriaxone against late bacteremic vascular graft infection in dogs were investigated. Dogs bearing an expanded polytetrafluoroethylene graft implanted as thoracoabdominal aortic bypass for one month were exposed to transient bacteremia produced by intravenous injection of 2.6 +/- 1.8 x 10(8) colony forming units Staphylococcus aureus 209P-R. To assess the effect of the antibiotic on bacteria already adherent onto the grafts, we compared the results from six untreated dogs used as controls and six dogs receiving ceftriaxone (0.5 g, intramuscularly) 90 minutes after the bacteremic challenge. The grafts were removed one week after the bacteremic challenge and cut into 10 to 15 fragments, each submitted to viable bacterial counts. The number of grafts and the number of fragments yielding bacterial growth were the same in the two groups. However, the median density of bacteria was lower (p less than 0.01) in the dogs given ceftriaxone, 64 colony forming units/cm (range: 3-8,700), than in the control dogs, 585 colony forming units/cm (range: 12-64,000), suggesting that ceftriaxone had an effect on the postadherence phase of the development of infection. To assess the effect of ceftriaxone on the adherence phase we compared the results from seven untreated dogs and seven dogs receiving ceftriaxone (0.5 g intramuscularly) 90 minutes before the bacteremic challenge. The grafts were removed two hours after the bacteremic challenge. Though all the seven grafts were colonized in each group, the number of fragments yielding bacterial growth was lower (p less than 0.05) in the dogs given ceftriaxone (59/70) than in the control dogs (90/91).(ABSTRACT TRUNCATED AT 250 WORDS)
Leport
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C
Department of Infectious and Tropical Diseases, Claude Bernard Hospital, Paris, France.
Goëau-Brissonnière
O
O
Lebrault
C
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Vildé
J L
JL
Pechére
J C
JC
D000818:Animals; D001012:Aorta, Abdominal; D001013:Aorta, Thoracic; D016470:Bacteremia / Q000517:prevention & control*; D001422:Bacterial Adhesion / Q000187:drug effects; D001807:Blood Vessel Prosthesis / Q000009:adverse effects; D002443:Ceftriaxone / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology / Q000627:therapeutic use*; D015169:Colony Count, Microbial; D004285:Dogs; D007273:Injections, Intramuscular; D011138:Polytetrafluoroethylene; D016459:Prosthesis-Related Infections / Q000517:prevention & control*; D013203:Staphylococcal Infections / Q000517:prevention & control*; D013211:Staphylococcus aureus / Q000302:isolation & purification / Q000502:physiology; D013997:Time Factors
D002443:Ceftriaxone; D011138:Polytetrafluoroethylene