The effect of disinfectants on bottle trap biofilms

Abstract

Multi-Drug Resistant Gram-Negative (MDR-GN) bacteria are resistant to several different antibiotic groups. Sinks in hospitals can become colonised by these organisms and then spread the resistant microbes when the tap is opened. In a previous local study, it has been found that hospital sinks in Mater Dei Hospital (MDH) are often colonised by numerous resistant colonies of microorganisms which may result in nosocomial infections. This study was able to identify the effect of a proprietary product (Clinell Peracetic Acid Drain Disinfectant) in reducing counts of MDR-GN bacteria colonising hospital sink bottle traps. A total of 50 sinks from two wards, 25 sinks in Intensive Therapy Unit (ITU) and 25 sinks in Surgical Ward 3 (S3) were sampled before disinfectant was applied and any present colonies were grown on appropriate culture media. The sinks found to be positive for MDRGN organisms were disinfected using Clinell Peracetic Acid Wipes and Drain Disinfectants. A set of new samples was taken for the disinfected sinks after the course of disinfection in order to analyse any growth that still occurred. The growth that occurred before disinfection was compared to the growth that occurred after disinfection and the significant difference in growths was calculated using sampling distribution of two proportions. As a result, the effectiveness of the product to decolonise MDR-GN bacteria was determined. In ITU, 11 sinks resulted positive which decreased to 3 sinks after disinfection. In S3, 9 sinks resulted positive which decreased to 2 sinks after disinfection. This reduction in positivity was found to be significant due to the calculated p-value being less than the 0.05 level of significance. Therefore, Clinell Peracetic Acid Wipes and Drain Disinfectants proved effective in reducing MDR-GN colonies in MDH.