Touch contamination of connection devices in peritoneal dialysis--a quantitative microbiologic analysis

To determine the level of bacterial contamination associated with touch contact of a connector set during peritoneal dialysis (PD).

The experiment utilized a laboratory-based simulation of a bag exchange procedure. Deliberate touch contamination of the connector set spike was followed by quantitative recovery of micro-organisms from the connector and, in some cases, the dialysis bag.

Patients undergoing PD were used as the "test" group. Departmental secretarial and laboratory staff served as the comparative control group.

The patients were voluntary subjects from a PD outpatients unit and were tested in their own homes.

The numbers of micro-organisms contaminating a connector set and entering the dialysis bag during a touch-contamination event were determined. Additionally we identified hand hygiene and, in particular, the care taken to dry the hands after washing as being highly relevant to microbial touch-contamination levels. Patient hand disinfection, as practised in most PD units, effectively reduced touch contamination to low levels.

Touch contamination of a connector set with unprepared hands led to fewer than 100 micro-organisms translocating from fingers to the spike. If the hands were washed but not dried before touch contact was made, up to 4500 micro-organisms translocated to the connector set spike. Air-towel drying of washed hands before touch contact reduced the translocating numbers by 95%-99%. Hand disinfection, as routinely practiced by PD patients, reduced the bacterial numbers reaching the peritoneal cavity after touch contamination to <5. The range of micro-organisms isolated from the fingers of PD patients using hand disinfectants on a regular basis showed considerably more diversity than the control group.

Hand care prior to bag exchange has a major effect on touch-contamination levels. Accidental touch contact of connecting devices by unprepared hands using a PD-bag exchange procedure leads to the translocation of 500 micro-organisms or fewer to the connector device. If the hands are wet at the time of contact the number translocating can be as high as 4500. Hand drying with an air towel before touch contact reduces the numbers translocating by 95%-99%. Hand disinfection procedures carried out prior to bag exchange minimizes touch-contamination levels.