Rapid reduction of Legionella pneumophila on stainless steel with zeolite coatings containing silver and zinc ions

2003 ◽  
Vol 36 (2) ◽  
pp. 69-72 ◽  
Author(s):  
P. Rusin ◽  
K. Bright ◽  
C. Gerba
Keyword(s):  
Stainless Steel ◽  
Legionella Pneumophila ◽  
Zinc Ions ◽  
Rapid Reduction ◽  
Zeolite Coatings

scholarly journals Chlorine Disinfection of Legionella spp., L. pneumophila, and Acanthamoeba under Warm Water Premise Plumbing Conditions

2020 ◽  
Vol 8 (9) ◽  
pp. 1452 ◽  
Author(s):  
Rebekah L. Martin ◽  
Kara Harrison ◽  
Caitlin R. Proctor ◽  
Amanda Martin ◽  
Krista Williams ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Disease Outbreaks ◽  
Opportunistic Pathogen ◽  
Gene Copy ◽  
Rrna Gene ◽  
Rapid Reduction ◽  
Water Heaters ◽  
Copy Numbers ◽  
Premise Plumbing ◽  
Magnesium Anode

Premise plumbing conditions can contribute to low chlorine or chloramine disinfectant residuals and reactions that encourage opportunistic pathogen growth and create risk of Legionnaires’ Disease outbreaks. This bench-scale study investigated the growth of Legionella spp. and Acanthamoeba in direct contact with premise plumbing materials—glass-only control, cross-linked polyethylene (PEX) pipe, magnesium anode rods, iron pipe, iron oxide, pH 10, or a combination of factors. Simulated glass water heaters (SGWHs) were colonized by Legionella pneumophila and exposed to a sequence of 0, 0.1, 0.25, and 0.5 mg/L chlorine or chloramine, at two levels of total organic carbon (TOC), over 8 weeks. Legionella pneumophila thrived in the presence of the magnesium anode by itself and or combination with other factors. In most cases, 0.5 mg/L Cl2 caused a significant rapid reduction of L. pneumophila, Legionella spp., or total bacteria (16S rRNA) gene copy numbers, but at higher TOC (>1.0 mg C/L), a chlorine residual of 0.5 mg/L Cl2 was not effective. Notably, Acanthamoeba was not significantly reduced by the 0.5 mg/L chlorine dose.

scholarly journals Preventing Healthcare-Associated Legionellosis with Rapid Reduction of High Concentrations of Legionella Using Mechanical Removal of Blind Ends and Intensive Hot Water Flushing

2021 ◽  
Vol 41 (1) ◽  
pp. 3-7
Author(s):  
Alan Medić ◽  
Ljilja Balorda ◽  
Ivanka Matas ◽  
Ines Leto ◽  
Dinko Puntarić ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Distribution Systems ◽  
Water Distribution ◽  
Hot Water ◽  
Rapid Reduction ◽  
Mechanical Removal ◽  
Two Measures ◽  
High Concentrations ◽  
Healthcare Associated ◽  
Emergency Measures

Background: The aim of this paper was to present the effectiveness of the mechanical removal of blind ends and flushing of hot water systems at outlets as the only possible emergency measures to reduce the concentration of Legionella spp in hot water. Methods: Two measures have been undertaken: mechanical removal of blind ends and intensive hot water flushing when the water has not been used for more than 7 days. Results: We detected Legionella pneumophila serogroup 1 in concentration of 1.000- 55.000 CFU/L at all samples sites. In the control sampling, after three weeks, we found seven sampling sites negative for Legionella and only two sampling sites positive. All nine sampling sites were negative after ten weeks. Conclusion: Establishing good water flow throughout the hospital seems to be the most important measure, in order to make the multiplication of Legionella in the hot water distribution systems unlikely.

Effects of culture conditions and biofilm formation on the iodine susceptibility of Legionella pneumophila

1992 ◽  
Vol 38 (5) ◽  
pp. 423-429 ◽  
Author(s):  
Kari L. Cargill ◽  
Barry H. Pyle ◽  
Richard L. Sauer ◽  
Gordon A. McFeters
Keyword(s):  
Stainless Steel ◽  
Key Words ◽  
Legionella Pneumophila ◽  
Biofilm Formation ◽  
Growth Conditions ◽  
Culture Conditions ◽  
Well Water ◽  
Agar Media ◽  
Steel Surfaces ◽  
T Values

The susceptibility of Legionella pneumophila to iodination was studied with cultures grown in well water, on rich agar media, and attached to stainless-steel surfaces. Legionella pneumophila grown in water cultures in association with other microorganisms were less sensitive to disinfection by chlorine and iodine than were agar-passaged cultures. Differences in sensitivity to disinfection between water-cultured and agar-grown legionellae were determined by comparing C × T values (concentration in milligrams per litre multiplied by time in minutes to achieve 99% decrease in viability)and CM × T values (concentration in molarity). Iodine (1500×) gave a greater difference in CM × T values than did chlorine (68×). Iodine was 50 times more effective than chlorine when used with agar-grown cultures but was only twice as effective when tested against water-grown Legionella cultures. C × T × S values (C × T multiplied by percent survivors), which take into consideration the percent surviving bacteria, were used to compare sensitivities in very resistant populations, such as those in biofilms. Water cultures of legionellae associated with stainless-steel surfaces were 135 times more resistant to iodination than were unattached legionellae, and they were 210 000 times more resistant than were agar-grown cultures. These results indicate that the conditions under which legionellae are grown can dramatically affect their susceptibility to some disinfectants and must be considered when evaluating the efficacy of a disinfecting agent. Key words: Legionella pneumophila, iodine, disinfection, growth conditions, biofilms, water.

NiAl precipitation in Fe-12w/o Cr-5w/o Ni-4w/o Al

1983 ◽  
Vol 41 ◽  
pp. 202-203
Author(s):  
L.E. Murr ◽  
J.S. Dunning ◽  
S. Shankar
Keyword(s):  
Solid Solution ◽  
Stainless Steel ◽  
Stainless Steels ◽  
Alloy Composition ◽  
Chromium Content ◽  
Scale Up ◽  
Optical Metallography ◽  
Property Evaluation ◽  
310 Stainless Steel ◽  
Microstructural Studies

Aluminum additions to conventional 18Cr-8Ni austenitic stainless steel compositions impart excellent resistance to high sulfur environments. However, problems are typically encountered with aluminum additions above about 1% due to embrittlement caused by aluminum in solid solution and the precipitation of NiAl. Consequently, little use has been made of aluminum alloy additions to stainless steels for use in sulfur or H2S environments in the chemical industry, energy conversion or generation, and mineral processing, for example.A research program at the Albany Research Center has concentrated on the development of a wrought alloy composition with as low a chromium content as possible, with the idea of developing a low-chromium substitute for 310 stainless steel (25Cr-20Ni) which is often used in high-sulfur environments. On the basis of workability and microstructural studies involving optical metallography on 100g button ingots soaked at 700°C and air-cooled, a low-alloy composition Fe-12Cr-5Ni-4Al (in wt %) was selected for scale up and property evaluation.

Comparison of Recovery and Recrystallization in Stainless Steel Following Plane-Wave Shock Loading and Explosive Forming

1970 ◽  
Vol 28 ◽  
pp. 428-429 ◽  
Author(s):  
J. A. Korbonski ◽  
L. E. Murr
Keyword(s):  
Stainless Steel ◽  
Shock Loading ◽  
Pressure Pulse ◽  
Shock Pressure ◽  
304 Stainless Steel ◽  
Strain Rates ◽  
Two Dimensional ◽  
Aisi 304 Stainless Steel ◽  
Aisi 304 ◽  
Explosive Forming

Comparison of recovery rates in materials deformed by a unidimensional and two dimensional strains at strain rates in excess of 104 sec.−1 was performed on AISI 304 Stainless Steel. A number of unidirectionally strained foil samples were deformed by shock waves at graduated pressure levels as described by Murr and Grace. The two dimensionally strained foil samples were obtained from radially expanded cylinders by a constant shock pressure pulse and graduated strain as described by Foitz, et al.

Use of SEM, X-ray analysis and TEM to localize Fe3+ reduction in roots

1988 ◽  
Vol 46 ◽  
pp. 392-393 ◽  
Author(s):  
William P. Wergin ◽  
P. F. Bell ◽  
Rufus L. Chaney
Keyword(s):  
Electron Microscopy ◽  
Root Hairs ◽  
Rapid Reduction ◽  
X Ray ◽  
Physical Evidence ◽  
Transmission Electron ◽  
Young Root ◽  
Insoluble Precipitate ◽  
Uptake And Transport ◽  
Scanning Electron

In dicotyledons, Fe3+ must be reduced to Fe2+ before uptake and transport of this essential macronutrient can occur. Ambler et al demonstrated that reduction along the root could be observed by the formation of a stain, Prussian blue (PB), Fe4 [Fe(CN)6]3 n H2O (where n = 14-16). This stain, which is an insoluble precipitate, forms at the reduction site when the nutrient solution contains Fe3+ and ferricyanide. In 1972, Chaney et al proposed a model which suggested that the Fe3+ reduction site occurred outside the cell membrane; however, no physical evidence to support the model was presented at that time. A more recent study using the PB stain indicates that rapid reduction of Fe3+ occurs in a region of the root containing young root hairs. Furthermore the most pronounced activity occurs in plants that are deficient in Fe. To more precisely localize the site of Fe3+ reduction, scanning electron microscopy (SEM), x-ray analysis, and transmission electron microscopy (TEM) were utilized to examine the distribution of the PB precipitate that was induced to form in roots.

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