In vitro activity of daptomycin and other antimicrobial agents against Staphylococcus coagulase-negative isolated from catheter-related bloodstream infections in intensive care unit patients

Abstract number: P1624

Seral C., Gudé M.J., Pereira A.K., Algarate S., Durán E., Salvo S., Luque P., Rubio C., Castillo F.J.

Objectives: The present study was designed to compare the in vitro activity of daptomycin and other comparator antimicrobial agents against Staphylococcus coagulase-negative (CoNS) isolated from catheter related-bloodstream infections (BSI) in ICU-patients.

Methods: In vitro daptomycin activity was tested by E-test method against 64 CoNS clinical strains (S. epidermidis (n = 49, 76.56%), S. hominis (n = 11, 17.18%), S. haemolyticus (n = 2, 3.12%), S. capitis (n = 1, 1.56%), S. warneri (n = 1, 1.56%) collected during 2008 from 54 patients and isolated from catheter-related infections (33 from blood and 31 from the catheter). MICs were also determined for 5 comparison drugs by E-test: oxazillin, linezolid, tigecycline, vancomycin and teicoplanin and interpreted according to CLSI M100-S18 guidelines.

Results: The prevalence of methicillin resistance was (79.68%). Resistance to aminoglycosides (gentamycin), macrolides and quinolones was strongly associated with methicillin resistance (74.50%, 54.90% and 76.47% of resistance, respectively). 4.68% CoNS were non-susceptible to teicoplanin and 17.18% were non-susceptible to linezolid, but there was no-vancomycin non-susceptibility found. The newer antibiotics, daptomycin and tigecycline, had excellent activity against CoNS.

The rank order of intrinsic activity (MIC90, mg/l) was daptomycin (1) = tigecycline (1) < vancomycin (2) < teicoplanin (4) < linezolid (32).

The most active drugs on the basis of MICs were daptomycin and tigecycline, showing MIC50 and MIC90 values of 0.25/1 and 0.125/1 mg/l and a MIC range, 0.019 to 1.5 and 0.032 to 3 mg/l, respectively. Vancomycin, teicoplanin and linezolid showed a MIC50 and MIC90 values of 1.5/2, 1.5/4 and 0.5/32 mg/l and a MIC range, 0.19 to 3, 0.125 to 24 and 0.019 to >256 mg/l, respectively.

Conclusion: Daptomycin showed an excellent in vitro activity against CoNS clinical strains isolated from catheter related-BSI, irrespective of their resistance to methicillin, aminoglycosides, macrolides and quinolones, making it a useful addition to the therapeutic armamentum for the treatment of Gram-positive catheter related-BSI.

Susceptibility testing of new compounds, as daptomycin and tigecycline, is required to establish those settings where these compounds offer real advantages over established antibiotics as glycopeptides.

Session Details

Date: 16/05/2009
Time: 00:00-00:00
Session name: 19th European Congress of Clinical Microbiology and Infectious Diseases
Location: Helsinki, Finland, 16 - 19 May 2009
Presentation type:
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