Survival of Beta-Lactamase-Producing and -Nonproducing Bacteria in Intravenous Solutions

Abstract

The survival of beta-lactamase-producing (β-lac+) and non-beta-lactamase-producing (β-lac-) Bacillus and Staphylococcus spp. has been investigated in dextrose 5% injection, NaCl 0.9%, and dextrose 5% in NaCl 0.9% solutions. Tests were performed under static and turbulent conditions of incubation, with and without antibiotics added to the fluids, and with or without 1% citrated blood. All solutions were inoculated with about 1000 organisms/mL, and sampled for viable bacteria at specific time intervals. Under static conditions, there was no significant decrease in viability (p > 0.01) of the bacilli, except for the staphylococci (p < 0.01). However, when cultures were agitated, all species showed significant decline in viability (p < 0.01). When antibiotics were present, S. aureus (β-lac+) declined gradually throughout 24 hours (p > 0.01). B. cereus (β-lac+) concentrations were static in all solutions. All organisms multiplied rapidly in solutions containing blood. The results suggest that the growth characteristics of both β-lac+ and β-lac- bacteria in intravenous fluids are essentially similar, except in solutions containing beta-lactamase-sensitive antibiotics in which (β-lac+ bacteria tend to survive.