Ma. Livesley et al., USE OF PULSED-FIELD GEL-ELECTROPHORESIS TO DETERMINE THE SOURCE OF MICROBIAL-CONTAMINATION OF CENTRAL VENOUS CATHETERS, European journal of clinical microbiology & infectious diseases, 17(2), 1998, pp. 108-112
Microorganisms detected in situ on the distal tip of central venous ca
theters (CVC) within 90 min of insertion were investigated using pulse
d-field gel electrophoresis to analyse genomic fragments obtained with
the SmaI restriction enzyme. Thirty patients received a triple lumen
CVC, which was inserted directly through the skin using the Seldinger
technique, In a further 30 patients a triple lumen CVC was inserted th
rough a Swan sheath, thereby avoiding direct contact of the CVC with t
he skin. Staphylococci were isolated from the distal tips of the cathe
ters in 6 patients (5 who had the CVC inserted directly through the sk
in and 1 who had the CVC inserted via a Swan sheath.) Twenty-three sta
phylococcal isolates were also isolated from the insertion equipment a
nd the skin swabs surrounding the insertion site of these six patients
. All the isolates were genotyped. In one of the patients the organism
s isolated from the skin were identical to those on the CVC tip. In tw
o further patients similar organisms were isolated from the insertion
equipment and the patients' skin. These results, in addition to the re
duced colonisation rates observed when catheters were introduced throu
gh a Swan sheath, support the hypothesis that microorganisms from the
skin are impacted onto the CVC tip and the CVC insertion equipment at
catheter insertion.