Study on a New Ultraviolet Sterilizer to the Surface Disinfection of the Ultrasound Probe

We studied the disinfection effect of a new ultraviolet （UV） sterilizer and its utilization on ultrasound probe surfaces. Carrier quantitative germicidal tests, simulated on-the-spot trials, and organic substance influence tests were used to carry out experimental observation. Artificially infected probes were disinfected using the sterilizer or a germicidal lamp for comparison. The total number and types of bacteria were determined and identified. Our results demonstrated the sterilizer had the best disinfection effect among three different disinfection methods in hospital. The sterilizer has been used in a hospital setting for 2 years with no notable damage to the ultrasound probe instrument. It has the advantages of fast disinfection, high disinfection effect, and good compatibility with the ultrasound instrument, worthy of being a promoted application in medical institutions.

Effects of Multiple Cleaning and Disinfection Interventions on Infectious Diseases in Children: A Group Randomized Trial in China

Objective To assess the effectiveness of multiple cleaning and disinfection interventions in the homes and kindergartens, in reducing gastrointestinal and respiratory illnesses of children. Methods From October 2010 to September 2011, we performed a prospective, controlled study in China. 408 children under 5 years old were recruited and group randomized into intervention and control groups. Families and kindergartens in the intervention group were provided with antibacterial products for hand hygiene and surface cleaning or disinfection for one year. Each child＇s illness symptoms and sick leave were recorded every day. Results A total of 393 children completed the study, with similar baseline demographics in each of the 2 groups. Except for abdominal pain, the odds of symptoms （fever, cough and expectoration, runny nose and nasal congestion, diarrhea）, illness （acute respiratory illness and gastrointestinal illness）, and sick leave per person each month were significantly reduced by interventions. The rates of fever, diarrhea, acute respiratory illness, gastrointestinal illness and sick leave per person per year were significantly decreased as well. Conclusion Not only the acute respiratory children were significantly reduced by multiple and gastrointestinal illness but the sick leave rate in interventions.

Rapid and accurate evaluation of vaporized hydrogen peroxide on the efficiency of disinfection, using a sensitive dual-channel laser scanning cytometer

Vaporized hydrogen peroxide(VHP)is a highly active disinfectant,and VHP decontamination systems have been widely applied in hospitals,microbiological laboratories,and pharmaceutical industries.However,the decomposition of VHP into non-toxic by-products is essential.Evaluation of the disinfection efficacy of VHP is crucial to ensuring the reliability of VHP disinfection and controlling microbial contamination.In this study,a rapid and sensitive strategy is proposed to evaluate the efficacy of VHP in surface disinfection by detecting the survived and killed bacteria from VHP-exposed biological indicators(BIs).A dual-channel solid-phase cytometer is designed,and fluorescent dyes are used as indicators to automatically and accurately distinguish live cells from dead cells in themixtures of bacteria.To verify the availability and effectiveness of the laser scanning cytometry,experiments on its application in estimating the efficacy of VHP disinfection practice have been carried out in this study,and its estimation effect compared with that of the traditional plate counting method.Results show that the proposed assay might distinctly identify live or killed cells labeled by green and red fluorescent dyes and examined the disinfection efficacy in 30 min by calculating the bactericidal rate.Compared with the plate counting method,the proposed approach is accurate and practical,with an average detection efficiency of 98.47%±1.55%.Moreover,an excellent correlation between the concentrations of B.subtilis var niger(ATCC 9372)measured by the proposed detection system and by the plate counting method is noticed(R2=0.9971),indicating that this approach had advantages in the detection of trace microorganisms.To summarize,the proposed strategy appears practical and significant in many fields in which microbial counting and identification are required.

Feasibility of bubble surface modification for natural organic matter removal from river water using dissolved air flotation

A novel, functionalized bubble surface can be obtained in dissolved air flotation （DAF） by dosing chemicals in the saturator. In this study, different cationic chemicals were used as bubble surface modifiers, and their effects on natural organic matter （NOM） removal from river water were investigated. NOM in the samples was fractionated based on molecular weight and hydrophobicity. The disinfection byproduct formation potentials of each fraction and their removal efficiencies were also evaluated. The results showed that chitosan was the most promising bubble modifier compared with a surfactant and a synthetic polymer. Tiny bubbles in the OAF pump system facilitated the adsorption of chitosan onto microbubble surfaces. The hydrophobic NOM fraction was preferentially removed by chitosan-modified bubbles. Decreasing the recycle water pH from 7.0 to 5.5 improved the removal of hydrophilic NOM with low molecular weight. Likewise, hydrophilic organic compounds gave high dihaloacetic acid yields in raw water. An enhanced reduction of haloacetic acid precursors was obtained with recycle water at pH values of 5.5 and 4.0. The experimental results indicate that NOM fractions may interact with bubbles through different mechanisms. Positive bubble modification provides an alternative approach for OAF to enhance NOM removal.