Parenteral infusions as culture media from a viewpoint of nosocomial bacteremia.

ABSTRACT

OBJECTIVE: To assess the growth patterns of selected organisms in common parenteral solutions, in order to ascertain implications for nosocomial bacteremia. DESIGN: A microbial suspension of approximately 300 CFU/mL was sequentially inoculated into common parenteral infusions from three different manufacturers and incubated at room temperature. Initially, 11 bacterial isolates and one Candida species from clinical specimens were studied. Eight gram-negative rods (GNR) were tested at varying pH's. Species variability was examined by testing an additional 39 isolates. RESULTS: The eight GNR grew in Ringer's lactate (RL) from two manufacturers and only two grew in dextrose 5% in water (D5/W) (Klebsiella pneumoniae and Serratia marcescens). No organism grew in saline or dextrose 5% in saline. The gram-positive cocci and Candida did not grow in any solution. No significant changes in growth were found after modifying the pH of solutions. Significant inter- and intra-species growth variability was noted. CONCLUSIONS: RL is a good culture media for GNR and D5/W is a poor culture media with the exception of some bacteria of the Tribe Klebsielleae. We recommend to follow high standards of nursing practice for administering intravenous infusions and to avoid nutrient-containing solutions for prolonged parenteral use, when possible.