Browsing by Author "Mittelman, M. W."

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Antimicrobial activity of a novel catheter lock solution
(2002-06) Shah, Chirag B.; Mittelman, M. W.; Costerton, J. William; Parenteau, Stephen; Pelak, Michael; Arsenault, Richard; Mermel, Leonard A.
Intravascular catheter-associated bloodstream infections significantly increase rates of morbidity and hospital costs. Microbial colonization and development of biofilms, which are known to be recalcitrant to antibiotic therapy, often lead to the loss of otherwise patent vascular access systems. We evaluated a new taurolidine- and citrate-based catheter lock solution (Neutrolin; Biolink Corporation, Norwell, Mass.) for its activity against planktonic microbes, antimicrobial activity in a catheter model, and biofilm eradication activity. In studies of planktonic microbes, after 24 h of contact, 675 mg of taurolidine-citrate solution per liter caused >99% reductions in the initial counts of Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Entercoccus faecalis. A solution of 13,500 mg/liter was cidal for Candida albicans. Ports and attached catheters inoculated with 50 to 600 CFU of these bloodstream isolates per ml were locked with heparin or the taurolidine-citrate solution. After 72 h, there was no growth in the taurolidine-citrate-treated devices but the heparin-treated devices exhibited growth in the range of 6 x 102 to 5 x 106 CFU/ml. Biofilms were developed on silicone disks in modified Robbins devices with broth containing 6% serum (initial counts, 106 to 108 CFU/cm2). The axenic biofilms were treated for 24 h with taurolidine-citrate or heparin. Taurolidine-citrate exposure resulted in a median reduction of 4.8 logs, whereas heparin treatment resulted in a median reduction of 1.7 logs (P < 0.01). No significant differences in the effects of the two treatments against P. aeruginosa and C. albicans were observed. These findings suggest that aurolidine-citrate is a promising combination agent for the prevention and treatment of intravascular catheter-related infections.
Bacterially derived wood adhesive
(2006-06) Haag, Anthony P.; Geesey, Gill G.; Mittelman, M. W.
Wood adhesives play an essential role in industry, however, many contain significant amounts of toxic components and volatile organic compounds (VOCs) and most are produced from depleting petrochemical resources. We are currently investigating adhesives derived from microbial extracellular polysaccharides for use in the wood products market. Polysaccharides are generally non-toxic, biodegradable, and produced from renewable resources. This study focuses on a new extracellular polysaccharide-based adhesive with performance that may be useful in some wood product applications. The adhesive exhibits improved performance over a previously described bacterial polysaccharide and produces shear strengths on maple substrates of up to 20 MPa at 53% relative humidity and 22 °C. Full strength was achieved in two days with half strength in 2 h. Although shear strength was sensitive to relative humidity, moisture resistance was substantially increased by partial acetylation of the polysaccharide.
Bacterially derived wood adhesive
(2006-06) Haag, Anthony P.; Geesey, Gill G.; Mittelman, M. W.
In an effort to improve AOAC Method 966.04, the Sporicidal Activity of Disinfectants Test, selected modifications to the procedure were evaluated in a collaborative study. Method 966.04 is used to generate efficacy data to support the product registration of sporicides and sterilants. The method is a carrier-based test that provides a qualitative measure of product efficacy against spores of Bacillus subtilis and Clostridium sporogenes. The use of garden soil extract and the lack of standard procedures for the enumeration of spores and neutralization of the test chemicals have been considered problematic for many years. The proposed modifications were limited to the B. subtilis and hard surface carrier (porcelain penicylinder) components of the method. The study included the evaluation of a replacement for soil extract nutrient broth and an establishment of a minimum spore titer per carrier, both considered crucial for the improvement and utilization of the method. Additionally, an alternative hard surface material and a neutralization confirmation procedure were evaluated. To determine the equivalence of the proposed alternatives to the standard method, 3 medium/carrier combinations, (1) soil extract nutrient broth/porcelain carrier (current method), (2) nutrient agar amended with 5 µg/mL manganese sulfate/porcelain carrier, and (3) nutrient agar amended with 5 µg/mL manganese sulfate/stainless steel carrier were analyzed for carrier counts, HCl resistance, efficacy, quantitative efficacy, and spore wash-off. The test chemicals used in the study represent 3 chemical classes and are commercially available antimicrobial liquid products: sodium hypochlorite (bleach), glutaraldehyde, and a combination of peracetic acid and hydrogen peroxide. Four laboratories participated in the study. The results of the spore titer per carrier, HCl resistance, efficacy, and wash-off studies demonstrate that amended nutrient agar in conjunction with the porcelain is comparable to the current method, soil extract nutrient broth/porcelain. The nutrient agar method is simple, inexpensive, reproducible, and provides an ample supply of high quality spores. Due to the current use of porcelain carriers for testing C. sporogenes, it is advisable to retain the use of porcelain carriers until stainless steel can be evaluated as a replacement carrier material for Clostridium. The evaluation of stainless steel for Clostridium has been initiated by the Study Director. Study Director recommendations for First Action revisions are provided in a modified method.
Copper-binding characteristics of exopolymers from a freshwater-sediment bacterium
(1985-04) Mittelman, M. W.; Geesey, Gill G.
Copper-binding activity by exopolymers from adherent cells of a freshwater-sediment bacterium was demonstrated by a combination of equilibrium dialysis and flameless atomic absorption spectrometry. Crude, cell-free exopolymer preparations containing protein and polysaccharide components bound up to 37 nmol of Cu per mg (dry weight). A highly purified exopolysaccharide preparation bound up to 253 nmol of Cu per mg of carbohydrate. The conditional stability constant for the crude exopolymer-Cu complex was 7.3 x 108. This value was similar to those obtained for Cu complexes formed with humic acids and xanthan, an exopolysaccharide produced by Xanthomonas campestris. Studies conducted at copper concentrations, pHs, and temperatures found in sediments from which the bacterium was isolated indicated that the exopolymers were capable of binding copper under natural conditions.
Effects of environmental conditions on the sessile existence of an estuarine sediment bacterium
(1984) Geesey, Gill G.; Salas, S. D.; Mittelman, M. W.
A submerged glass coverslip technique was developed to determine dissolved organic nutrient uptake by adherent cells of a sediment isolate of Enterobacter cloacae . Cells which colonized the coverslips in swirling culture flasks during anaerobic growth remained firmly attached during manipulations employed to determine uptake of radiolabeled glucose by the adherent population. The attached cells were capable of a more rapid rate of glucose uptake than free cells. Lineweaver-Burk plots demonstrated different glucose uptake kinetics for the 2 cell populations. The data suggest that physiological changes occur in cells soon after they become attached to surfaces. These changes appear to enhance the metabolic activity of the adherent population.
Evaluation of slime-producing bacteria in oil field core flood experiments
(1987-02) Geesey, Gill G.; Mittelman, M. W.; Lieu, V. T.
Epifluorescence microscopy and carbohydrate determinations indicated that the decrease in permeability of oil reservoir sand to reclaimed sewage water was partially the result of biological plugging. Filtration and biocide addition studies demonstrated that the increase in bacterial densities and slime concentrations in flooded oil field cores appeared to be due to both deposition from the reclaimed water and in situ microbial growth and slime production. Although these biological components increased throughout the cores during flooding, the region where the water entered the core exhibited the highest cell densities and slime concentrations. The approach described in this report should be useful in predicting the potential of a water source to induce biological plugging of oil reservoir sand.
Investigation of ciprofloxacin penetration into pseudomonas aeruginosa biofilms
(1994-09) Suci, Peter A.; Mittelman, M. W.; Yu, Feipeng Philip; Geesey, Gill G.
Bacterial infections associated with indwelling medical devices often demonstrate an intrinsic resistance to antimicrobial therapies. In order to explore the possibility of transport limitation to biofilm bacteria as a contributing factor, the penetration of a fluoroquinolone antibiotic, ciprofloxacin, through Pseudomonas aeruginosa biofilms was investigated. Attenuated total reflection Fourier transform infrared (ATR/FT-IR) spectrometry was employed to monitor bacterial colonization of a germanium substratum, transport of ciprofloxacin to the biofilm-substratum interface, and interaction of biofilm components with the antibiotic in a flowing system. Transport of the antibiotic to the biofilm-substratum interface during the 21-min exposure to 100 micrograms/ml was found to be significantly impeded by the biofilm. Significant changes in IR bands of the biofilm in regions of the spectrum associated with RNA and DNA vibrational modes appeared following exposure to the antibiotic, indicating chemical modification of biofilm components. These results suggest that transport limitations may be an important factor in the antimicrobial resistance of biofilm bacteria and that ATR/FT-IR spectrometry may be used to follow the time course of antimicrobial action in biofilms in situ.
Investigation of interactions between antimicrobial agents and bacterial biofilms using attenuated total reflection fourier transform infrared spectroscopy
(1998-03) Suci, Peter A.; Vrany, Julia Dawn; Mittelman, M. W.
Biomaterial-centred infections are often difficult to treat. An impaired immune response, acute inflamatory reactions and the presence of recalcitrant attached microorganisms are all contributing factors. A brief review of the role of attached bacteria in biomaterial-centred infections is presented. Two major hypotheses which may explain the recalcitrance of biofilms to antimicrobial agents are discussed. The analytical capabilities of attenuated total reflection Fourier transform infrared (ATR/FTIR) spectroscopy for providing information on both transport of an antimicrobial agent to bacteria embedded in the biofilm and interactions between an antimicrobial agent and biofilm components are described.
Role of Bacterial Exopolymers in the Deterioration of Metallic Copper Surfaces
(1986) Geesey, Gill G.; Mittelman, M. W.; Iwaoka, Teika; Griffiths, Peter R.