Impact of selective antimicrobial agents on staphylococcal adherence to biomedical devices.
BACKGROUND
Infection of intravascular or implanted biomedical devices often involves biofilm-forming staphylococci that are recalcitrant to antimicrobial therapy. The present study investigated the activity of 6 antimicrobial agents against biofilm-forming and non-biofilm-forming strains of staphylococci adherent to the surface of selected biomedical devices.


METHODS
Five clinical staphylococcal strains were selected for study in (1) antibiotic-lock model (ALM) and (b) vascular graft model (Dacron and expanded polytetrafluoroethylene [ePFTE]) devices. Test strains were inoculated for 30 minutes to stabilize microbial adherence and then exposed to antibiotic; the impact on bacterial adherence was assessed at 1, 2, 4, 7, and 10 days.


RESULTS
Regarding ALM, daptomycin and rifampin were effective at eradicating staphylococcal adherence by day 4 (P<.01); linezolid and gentamicin by day 7 (P<.01); vancomycin by day 7; and ceftriaxone failed to eradicate staphylococcal adherence in 4 of 5 strains by day 10. Regarding ePTFE, daptomycin and linezolid eradicated staphylococcal adherence by day 2 (P<.01); rifampin by day 4 (P<.01); vancomycin and gentamicin by day 7 (P<.01); and ceftriaxone failed to eliminate staphylococcal adherence in 3 of 5 strains by day 10. Regarding Dacron, daptomycin and rifampin eradicated adherent strains by day 4 (P<.01); linezolid by day 7 (P<.01), and vancomycin, gentamicin, and ceftriaxone decreased staphylococcal adherence by 90%, 95%, and 78%, respectively, by day 10.


CONCLUSIONS
Daptomycin, rifampin, and linezolid demonstrated greater efficacy and speed in eradicating microbial adherence of staphylococcal isolates from selected devices compared with vancomycin, gentamicin, or ceftriaxone (P<.01). Further studies are warranted, however, to validate the clinical efficacy of daptomycin and linezolid in the treatment of biomedical device-associated infections.
Edmiston
Charles E
CE
Division of Vascular Surgery, Medical College of Wisconsin, 9200 West Wisconsin Ave., Milwaukee, WI 53226, USA. edmiston@mcw.edu
Goheen
Michael P
MP
Seabrook
Gary R
GR
Johnson
Christopher P
CP
Lewis
Brian D
BD
Brown
Kellie R
KR
Towne
Jonathan B
JB
D000081:Acetamides / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D001807:Blood Vessel Prosthesis; D002443:Ceftriaxone / Q000494:pharmacology; D017576:Daptomycin / Q000494:pharmacology; D005839:Gentamicins / Q000494:pharmacology; D000069349:Linezolid; D008826:Microbial Sensitivity Tests; D023303:Oxazolidinones / Q000494:pharmacology; D012293:Rifampin / Q000494:pharmacology; D013210:Staphylococcus / Q000187:drug effects* / Q000254:growth & development; D014640:Vancomycin / Q000494:pharmacology
D000081:Acetamides; D000900:Anti-Bacterial Agents; D005839:Gentamicins; D023303:Oxazolidinones; D014640:Vancomycin; D002443:Ceftriaxone; D000069349:Linezolid; D017576:Daptomycin; D012293:Rifampin