[Do liquid wastes from automated instruments in medical laboratories have their proper microbicide effect?]

Liquid wastes from clinical biology automated systems are currently evacuated in the urban network after chemical treatment to eliminate a possible risk of infection. Since these wastes are ecotoxic because of the presence of numerous chemical reagents, we studied their intrinsic microbicidal power towards a selection of infectious agents widely found in clinical specimens. The objective was to determine if an additional anti-infectious treatment before elimination is necessary. Thus, we evaluated the bactericidal effect of liquid wastes of several automated systems towards four bacterial species (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Enterococcus faecalis) and their virucidal activity against a non-enveloped virus, resistant in the environment (adenovirus). This effect was determined for different exposure times. Our results showed that the antibacterial activity was highly variable depending on the waste-bacteria pair considered (varying from no activity to complete sterilization of a strong bacterial inoculum). The liquid wastes were on the other hand globally inactive towards adenovirus.