Electron-microscopic description of accretions occurring on tips of infected and non-infected central venous catheters

The purpose of the study was do describe the architecture of accretions occurring on the tips of central venous catheters (CVC). A conservative procedure was used followed by two different techniques of electron microscopy the study included 19 catheters which have been used on intensive cared adults, and which were chosen among those of parallel 300 CVC study. CVC were considered sterile, contaminated, colonized or infected according to microbiological and clinical criteria. CVC were found to remain much cleaner than in past clescriptions. When present, accretions were located on the olive-shaped end, and displayed stratified structures with three types of material: amorphous material, thrombus components and inflammatory cells. Bacteria were not seen, even on culture positive CVC. Candida albicans was found on one CVC in the cytoplasm of ganulocytes, and made xio direct contact with the plastic surface. This technique should contribute to the understanding of the pathobiology of CVC infection and provide information proving or precluding the involvement of microbial adherence to polymers in vivo.