A new strategy to control the proliferation of microorganisms in solid hospital waste and the diffusion of nosocomial infections.

A possible tool to reduce nosocomial infections is to identify unknown sources of contamination and then to provide a measure for controlling the related infections. In this study, solid hospital waste was considered a potential source of contamination, and a strategy to reduce the potential risk of pathogen contamination was tested. This paper describes a novel technique for waste management in healthcare settings with a view to facilitating infection prevention and control. We explored the innovative use of sodium dichloroisocyanurate (NaDCC) by investigating the microbicidal activity of chlorine, which derives from the hydrolysis of NaDCC mediated by humidity, and by testing its effect on the inhibition of microorganism growth. NaDCC was inserted in a solid hospital waste bin containing also Lauria-Bertani agar plates, with different dilutions of a known titre of three different microorganisms, namely Escherichia coli, Staphylococcus aureus and Aspergillus brasiliensis. The plates were incubated in the container with or without the antimicrobial agent (control, CNT) at room temperature for 5 days. The number of colony-forming units (CFUs) present on each plate was then counted. Microorganisms capable of proliferating in the CNT waste bin were not able to grow in the presence of NaDCC. Furthermore, the molecular chlorine which developed and was released in the waste bin under the experimental conditions (T=20°C, t=5 days) was quantified using iodometric titration. NaDCC hydrolysis, mediated by humidity, has a strong and long-lasting microbicide effect. The proliferation of tested bacteria and fungi is totally inhibited. These results demonstrate the effectiveness of NaDCC in controlling and/or inhibiting microbial proliferation and support its possible use in the treatment of hospital waste to control the spread of nosocomial contamination.