Reduction In Number Of Microorganisms Research Articles

Laboratory evaluation of Drawtex Hydroconductive Dressing with LevaFiber technology

The aim of this study was to assess absorption, sequestration and retention of microorganisms by Drawtex Hydroconductive dressing with LevaFiberTM technology. The absorption over time and the ability to sequester and retain bacteria were assessed in the laboratory using an in vitro model where known amounts of fluid and microorganisms were allowed to absorb and sequester over a 24 hour period. The reduction in numbers of microorganisms following sequestration was determined using standard plate counting methods. Retention of the organisms was visualised by scanning electron microscopy. Drawtex was shown to absorb eight times its own weight in fluid over time and it showed a 90% reduction in bacterial numbers over a 24 hour period in sequestration experiments. Direct observation by scanning electron microscopy demonstrated bacterial retention in the dressing fibres. Drawtex is a recent addition to the formulary for absorbent dressings available in the UK. It demonstrates excellent absorption properties, while maintaining integrity. In addition, it sequesters and retains microorganisms, which will help with removal of exudate and bioburden from the wound bed to help facilitate wound healing. This study was funded by an educational grant from Martindale Pharma, UK. The authors have no conflicts of interest to declare with regard to the manuscript or its content.

Antibacterial copper–nickel bilayers and multilayer coatings by pulsed laser deposition on titanium

Biofouling, especially microfouling, is a major concern with the use of titanium (Ti) in the marine environment as a condenser material in cooling water systems. Earlier, copper–nickel (Cu/Ni) alloys were extensively used in marine environments due to their high corrosion and biofouling resistance. However, the choice of condenser material for the new fast breeder reactor in Kalpakkam is Ti to avoid steam side corrosion problems, which may pose a threat to steam generator parts having sodium as the secondary coolant. This study evaluates the surface modification of Ti using nano films of copper (Cu) and nickel (Ni) to utilize the antibacterial property of copper ions in reducing microfouling. The surface modification of Ti was carried out by the deposition of a Cu/Ni bilayer and (Cu/Ni)10 multilayer films using a pulsed laser deposition technique. Various surface characterization studies revealed that the deposited Cu/Ni films were thin and nanocrystalline in nature. The antibacterial properties were evaluated using total viable count and epifluorescence microscopic techniques. The results showed an apparent decrease in bacterial attachment on multilayered and bilayered Cu/Ni thin films on Ti surfaces. Comparative studies between the two types of films showed a bigger reduction in numbers of microorganisms on the multilayers.

Photocatalytic inactivation of Clostridium perfringens and coliphages in water

This study presents results of the photocatalytic inactivation of two groups of microorganisms: spores of the anaerobic bacterium Clostridium perfringens and coliphage. A cylindrical reactor impregnated with titanium dioxide and irradiated with ultraviolet light (15 W) was used. Parameters such as color, turbidity, hydraulic detention time (HDT) and initial concentration of microorganisms were evaluated in relation to the efficiency of the inactivation process. According to the experiments with the bacterium C. perfringens, the reduction in number of microorganisms was higher than 98% after an irradiation time of 152 seconds, independent of color and turbidity. For solutions with low turbidities efficiency of the coliphage inactivation reached approximately 100% between 89 and 104 HDT, while this value was 98% for solutions with higher turbidities.

Effect of Electrical Stimulation on Meat Microflora: Observations on Agar Media, in Suspensions and on Beef Carcasses

Electrical stimulation of beef carcasses did not cause a significant reduction in surface microbial population at three different sampling positions immediately following slaughter. However, significant microbial reduction (P<0.05) was found at position 2 (muscle above aitch bone) but not at position 1 (inside of neck) or position 3 (fat on outside of round) after 72 h of chilling storage. Nine bacterial species from eight different genera commonly associated with meat were inoculated on three different agar media which varied in electrical conductivity. Electrical stimulation of these media caused a reduction in numbers of microorganisms under various voltage and time treatments. Spore-forming bacteria were the most resistant to the electrical treatments. Among the non-spore formers, gram-negative bacteria were more resistant to electrical treatment than gram-positive bacteria. Also, microorganisms inoculated on the lowest resistance medium A revealed greater reduction in numbers than that of the other media with higher resistance. A five log cycle reduction in Escherichia coli, Pseudomonas putrefaciens and Pseudomonas fragi was found in 0.85% saline solution and phosphate buffered saline solution after a 30-V, 5-min treatment, but little change in count was detected in 0 . 1% aqueous peptone or 2.5 M sucrose solution.

Immediate and Residual (Substantive) Efficacy of Germicidal Hand Wash Agents

A range of commercial hand wash agents was compared against 4% chlorhexidine gluconate (Hibitane) for immediate and residual (substantive) germicidal effect in hygienic hand disinfection. Chlorhexidine gluconate (4%) liquid detergent gave an immediate and residual reduction in number of microorganisms released from finger tips after a short exposure (15-s) hand wash. An iodophor product containing 0.75% available iodine gave comparable results for the immediate reduction of microorganisms released, but it did not give a residual effect. Other products, including those containing Irgasan DP 300, para-chlorometa-xylenol (PCMX), or low concentration iodophor (0.005% available iodine) as the active ingredient, did not give an immediate or a residual reduction in microorganisms released from finger tips.