Narrow Results

The present work describes the use of a magnetic porphyin (5-(4-carboxy-phenyl)-10,15,20-triphenyl-21H, 23H-porphyrin TPP) nanoconjugate (SPION-TPP) for destroying pathogenic bacteria followed by the recovery of the magnetic photosensitizer. SPION-TPP was tested for its activity against two different gram-positive bacterial strains (Staphylococcus aureus and Steptoccoccus mutans). It is observed that SPION-TPP at a very low concentration of 0.5 $\mu$M is effective in destroying gram-positive bacteria (10${}^{\mathrm{\text{7}}}$–10${}^{\mathrm{\text{8}}}$ CFU ml${}^{\mathrm{\text{-1}}})$S. aureus with several orders reduction and few orders in S. mutans. The aim of this work is to combine photoactivity against microorganisms imparted by the photosensitizer with the possibility of recovering the nanoconstruct with magnets for disposal/reuse.

This study sought to determine the minimum bactericidal concentrations (MBCs) of didecyldimethylammonium chloride (DDAC), povidone iodine (PI), and chlorhexidine and the differences in these values among coagulase-negative staphylococci (CNSs) that harbor or do not harbor biofilm-related genes (eno, bap, and ica). Using the limiting dilution technique, the MBCs against three different disinfectants were estimated and compared using statistical methods. The results showed that the biofilm-gene-positive CNS isolates exhibited higher tolerance ($p=0.02$, upper-tailed test) to 2mgL${}^{-1}$ DDAC and 10mgL${}^{-1}$ povidone iodine ($p=0.03$, upper-tailed test). Different resistance capacities were found among these three biofilm formation-related genes. The isolates that contained the bap gene exhibited a higher tolerance level. This observation was confirmed by logistic regression models, which revealed that the bap (odds ratio $=5.17$) and eno (odds ratio $=3.56$) genes significantly affected the survival capacity. This study demonstrated that biofilm-gene-positive CNS isolates exhibited increased survival in the presence of higher concentrations of all three disinfectants and that both the bap and eno genes could affect the survival capacity. Among the three genes, the bap gene had the strongest effect on the survival capacity of CNSs in the presence of all three disinfectants. The appropriate use of disinfectants can control these biofilm-gene embedded CNSs more efficiently.

Healthcare-Associated Infections (HAIs) are a significant cause of morbidity and mortality and occur in many healthcare facilities including hospitals, surgery centers and long-term care facilities. It is well known that some pathogens can persist on healthcare surfaces for weeks to months and spread readily to new surfaces. It is current practice to disinfect or clean surfaces routinely in order to reduce the risk of HAIs. However, routine cleaning can damage the surface chemically or mechanically, which may actually increase the surface contamination. Fundamental knowledge is therefore needed to understand the influence of cleaning and disinfection on healthcare surfaces in order to mitigate pathogen persistence. In this study, materials and objects found in healthcare facilities were selected and exposed to disinfection procedures including wiping and soaking with readily available chemical disinfectants. A variety of chemical disinfectants were selected which contain hydrogen peroxide, quaternary ammonia, and chlorine, respectively. Optical microscopy, contact angle measurement, atomic force microscopy (AFM), Fourier Transform Infrared (FTIR) spectroscopy and nanoindentation are used to analyze surface characteristics before and after disinfection in order to study the effect of disinfection on material properties. Disinfection procedures are found to cause changes to surface properties of materials and objects which can be detected and observed or quantified by the approaches used in this study. The methods should become regular practice in the studies of healthcare surfaces and their role in HAIs. Each method in this study may not be reliably applied to every object or disinfection scenario. Sample geometry and features may influence response during measurement and affect results. The combination of the approaches is able to sufficiently characterize chemical, mechanical, and topological changes to the surface.

Creating an ecologically safe and economically effective integrated electrolysis unit (IEU) which generates anode liquor (containing Cl2) and liquid ferrates (Na2FeO4) from the brine and the wastes of anode liquor electrolytic production (NaOH), is a new approach to water treatment. Thus, the anode liquor and the ferrates can be used on site - the anode liquor for drinking, industrial water for disinfection and the ferrates for industrial wastewater treatment. The membrane electrolysis was chosen as a prospective method to obtain both the chlorine-containing anode liquor for drinking, the industrial water for disinfection and the sodium ferrate for wastewater treatment. The proposed IEU is environmentally friendly and economically efficient and allows the combination of two electrolysis processes in one unit using an adaptive automated control system. The scoped approach helps to avoid violating water treatment laws and standards, and increases the quality as well as the energy efficiency of the overall process.

Despite the treatment processes that a typical wastewater is subjected to, microorganisms present in the wastewater are not effectively removed. These pathogenic organisms play important roles in the spread of waterborne diseases. Important treatment process employed to destroy or inactivate these pathogenic microorganisms is called disinfection. Disinfection is an important application under chemical treatment process ofwastewater, which includes the use of chemical agents, such as compounds of chlorine, and/or nonchemical agents, such as heat, UV light, radiation, and mechanical means.