Biocide Options to Control the Transmission of Pathogens

Download or read book Biocide Options to Control the Transmission of Pathogens written by Shilpa Saseendran Nair and published by . This book was released on 2020 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hospitals act as an environment for the spread of human pathogens. Recontamination of hospital surfaces exacerbates the problem of pathogen transmission. The potential solution for the problem is using long-term active surface anchoring-based biocides to reduce hospital acquired infections (HAI). The main aim of the study is to establish an assay of the antimicrobial potency of biocidal surfaces. To do this, I used a well-documented biocide, surface anchoring quaternary ammonium-based biocides (SAQAS) which are claimed to retain the activity for 30 days after application. The presence of biocide after application on the surface was detected using Fourier Transform Infrared Spectroscopy (FTIR) and Atomic Force Microscopy (AFM). Assay establishment started with the model organisms Escherichia coli and Staphylococcus aureus, using a modified JIS Z 2801:2000 method using glass and LDPE as surfaces in both wet and dry conditions. Further, the test was expanded with antibioticresistant pathogens (MRSA and ESBL E. coli) and endospores (Bacillus cereus). Both wet and dry fomite tests showed the active killing of gram-positive and gram-negative organisms, including antibiotic-resistant bacteria, but not endospores, on both surfaces. The study was expanded to check the antimicrobial activity of SAQAS biocide for 30 days as per the manufacturer's claim on different surfaces in a Microbiology laboratory. The real-world test failed to show any significant difference between microbial burdens on laboratory surfaces pre and post-intervention of biocides up to 30 days. The loss of activity was assessed by checking the stability of biocide on the surface in real-world conditions to determine whether the surface is active to kill environmental organisms or laboratory-grown S. aureus. The results showed the surface was active to kill 106 CFU S. aureus for up to 30 days, while not killing the environmental organism, which could be the result of bacteria associating with dust particles, and not contacting the biocide. Further, the manufacturer's claim of biocidal surface durability after the cleaning was assessed by washing the biocidal surface with disinfectants prior to challenge with S. aureus. The biological activity was substantially reduced after washing, and explained by the removal of the biocidal layer by FTIR and AFM analysis. Finally, the assay established was used to check the antimicrobial potency of photocatalytic titanium dioxide (TiO2) containing paints, where the results showed that the painted surfaces were active only in the presence of UV light and not in white light. Surface chemistry analysis of painted coupons using XPS and FE-ESEM-EDX identified the presence of silver (Ag) improved the antimicrobial potency. In short, the SAQAS biocide and the TiO2 containing paint tested require improvement before they can be recommended for use to prevent fomite mediated transmission. However, these assays established will be useful to determine the antimicrobial potency, real-world application, stability and durability of new antimicrobial surfaces before commercialization.