A rapid ELISA for the diagnosis of intravascular catheter related sepsis caused by coagulase negative staphylococci

Aim: To develop and evaluate a rapid enzyme linked immunosorbent assay (ELISA) for the diagnosis of intravascular catheter related sepsis caused by coagulase negative staphylococci. Methods: Forty patients with a clinical and microbiological diagnosis of intravascular catheter related sepsis and positive blood cultures, caused by coagulase negative staphylococci, and 40 control patients requiring a central venous catheter as part of their clinical management were recruited into the study. Serum IgG responses to a previously undetected exocellular antigen produced by coagulase negative staphylococci, termed lipid S, were determined in the patient groups by a rapid ELISA. Results: There was a significant difference (p = < 0.0001) in serum IgG to lipid S between patients with catheter related sepsis and controls. The mean antibody titre in patients with sepsis caused by coagulase negative staphylococci was 10 429 (range, no detectable serum IgG antibody to 99 939), whereas serum IgG was not detected in the control group of patients. Conclusions: The rapid ELISA offers a simple, economical, and rapid diagnostic test for suspected intravascular catheter related sepsis caused by coagulase negative staphylococci, which can be difficult to diagnose clinically. This may facilitate treatment with appropriate antimicrobials and may help prevent the unnecessary removal of intravascular catheters.

"Nucleosome debris" provokes coagulation and inflammation

Editorial

Antimicrobial activity of a chlorhexidine intravascular catheter site gel dressing

Objectives: The antimicrobial efficacy of a chlorhexidine gluconate (CHG) intravascular catheter gel dressing was evaluated against methicillin-resistant Staphylococcus aureus (MRSA) and an extended-spectrum β-lactamase (ESBL)-producing Escherichia coli. Chlorhexidine deposition on the skin surface and release from the gel were determined. Methods: The antimicrobial efficacy was evaluated in in vitro studies following microbial inoculation of the dressing and application of the dressing on the inoculated surface of a silicone membrane and donor skin [with and without a catheter segment and/or 10% (v/v) serum] on diffusion cells. Antimicrobial activity was evaluated for up to 7 days. Chlorhexidine skin surface deposition and release were also determined. Results: MRSA and E. coli were not detectable within 5 min following direct inoculation onto the CHG gel dressing. On the silicone membrane, 3 log and 6 log inocula of MRSA were eradicated within 5 min and 1 h, respectively. Time to kill was prolonged in the presence of serum and a catheter segment. Following inoculation of donor skin with 6 log cfu of MRSA, none was detected after 24 h. Chlorhexidine was released from the gel after a lag time of 30 min and increasing amounts were detected on the donor skin surface over the 48 h test period. The CHG gel dressing retained its antimicrobial activity on the artificial skin for 7 days. Conclusions: The CHG intravascular catheter site gel dressing had detectable antimicrobial activity for up to 7 days, which should suppress bacterial growth on the skin at the catheter insertion site, thereby reducing the risk of infection. © The Author 2011. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved.