Effect of linezolid and quinupristin/dalfopristin on formation and disruption of Staphylococcus haemolyticus biofilm in vitro

Abstract number: 1733_120

Juda M., Helon P., Malm A.

Objectives:Staphylococcus haemolyticus belonging to coagulase negative staphylococci is the common commensal of the skin. This strain may cause bacteraemia, especially in hospitalised patients in the presence of indwelling medical devices. The aim of this study was to assess the effect of linezolid and quinupristin/dalfopristin on formation and disruption of S. haemolyticus biofilm structure on polychloride vinyl (PCV) catheter in vitro.

Methods: Four S. haemolyticus strains were isolated from patients with lung cancer during hospitalisation (three from nasopharynx, one from pleural drain). The routine microbiological methods were used for their isolation and identification. Minimal inhibitory concentration (MIC) of linezolid and quinupristin/dalfopristin was determined by E-test according to criteria of Clinical and Laboratory Standards (CLSI). Modified Richard's et al. method was used to assess of ability for adhesion proccess and biofilm formation on the PCV urological Nelaton's catheter in vitro. For evaluation of linezolid and quinupristin/dalfopristin effect on formation and disruption of S. haemolyticus biofilm structure in vitro following antibiotic concentrations were used: 0.125; 0.25; 0.5; 1.0; 2.0; 4.0; 8.0; 16.0×MIC.

Results: All strains possessed strong ability to adhesion and biofilm formation on the PCV catheter in vitro. Linezolid and quinupristin/dalfopristin inhibited adhesion process in concentrations 0.19–0.375 mg/l (0.25–0.5×MIC) and 0.125–0.75 mg/l (1.0–2.0×MIC), respectively. Linezolid effected formation of biofilm in concentrations between 0.5–0.75 mg/l (0.5–1.0×MIC), while quinupristin/dalfopristin – in concentrations between 0.5–3.0 mg/l (2.0–4.0×MIC). Drug concentrations disrupting the mature biofilm structure was higher: 1.5–2.0 mg/l (2.0×MIC) for linezolid and 1.0–6.0 mg/l (8.0–16.0×MIC) for quinupristin/dalfopristin.

Conclusion: Our data indicate that linezolid was more effecive agent, then quinupristin/dalfopristin in prevention of biofilm formation by S. haemolyticus strains on the PCV catheter and disruption of mature biofilm in vitro.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Location: ICC, Munich, Germany
Presentation type:
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