Sterility of antibiotic-admixed peritoneal dialysis solution over time

Intraperitoneal antibiotics may be required daily for up to three weeks to treat peritoneal dialysis (PD)-related peritonitis. In some jurisdictions, antibiotic-admixed PD solutions are required to be used within 24 h due to concerns regarding microbial contamination and growth. This requires patients to attend the PD unit daily or alternatively for staff to perform home delivery with associated transport, staffing and cost implications.

The aim of this study was to determine if significant microbial growth occurs in PD solutions following their injection with antibiotic or sterile water.

Twelve PD solution bags were admixed with cefazolin sodium 1 g, diluted in 10 mL sterile water, while a further 12 PD solution bags were admixed with 10 mL sterile water using aseptic technique (AT) under supervision. All bags were stored at room temperature. Three bags from each experimental group were sampled for microbiologic culture at 0-, 24-, 48- and 72-h intervals.

One sterile water admixed bag sampled at 24 h yielded a Corynebacterium spp. after microbiologic culture. A repeat specimen from the same bag at day nine returned a negative culture result. All other sterile water and cefazolin admixed bags returned negative culture results at all time points.

Antibiotic-admixed PD solutions prepared using AT and stored at room temperature remained sterile for up to 72 h. This suggests that patients can be safely issued with a supply of antibiotic-admixed PD bags for up to three days at a time.