College of Engineering
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The College of Engineering at Montana State University will serve the State of Montana and the nation by fostering lifelong learning, integrating learning and discovery, developing and sharing technical expertise, and empowering students to be tomorrow's leaders.
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Item Evaluation and remediation of bulk soap dispensers for biofilm(2012-01) Lorenz, Lindsey A.; Ramsay, Bradley D.; Goeres, Darla M.; Fields, Matthew W.; Zapka, Carrie A.; Macinga, David R.Recent studies evaluating bulk soap in public restroom soap dispensers have demonstrated up to 25% of open refillable bulk-soap dispensers were contaminated with ~6 log10(CFU ml-1) heterotrophic bacteria. In this study, plastic counter-mounted, plastic wall-mounted and stainless steel wall-mounted dispensers were analyzed for suspended and biofilm bacteria using total cell and viable plate counts. Independent of dispenser type or construction material, the bulk soap was contaminated with 4–7 log10(CFU ml-1) bacteria, while 4–6 log10(CFU cm-2) biofilm bacteria were isolated from the inside surfaces of the dispensers (n=6). Dispenser remediation studies, including a 10 min soak with 5000 mg 1-1 sodium hypochlorite, were then conducted to determine the efficacy of cleaning and disinfectant procedures against established biofilms. The testing showed that contamination of the bulk soap returned to pre-test levels within 7–14 days. These results demonstrate biofilm is present in contaminated bulk-soap dispensers and remediation studies to clean and sanitize the dispensers are temporary.Item Treated recreational water venues(2012-12) Goeres, Darla M.; Hartemann, P.; Dadswell, J. V.Swimming is an activity enjoyed by people of all ages and abilities in all parts of the world. Swimming promotes known health benfits. The water provides support for the body, making it an ideal activity for people with joint pain or who are recovering from an injury. In addition to exercise, soaking in hot tubs or hot springs promotes relaxation and soothes sore muscles. With the notable healthy benefits and enjoyment associated with simming, it is important that the water and facility do not become a source of disease and/or injury. Swimming may be thought of as communal bathing. Bathers introduce varying amounts of organics into the water including sweat, urine, dead skin, hair, oils, lotions and microorganisms every time they enter. The type and concentration of organics introduced by the bather is a function of the individual and the facility they are using. A small child in swim diapers in a splash pool is very different to an adult competitive swimmer practicing in a lap pool. Regardless, it is the responsibility of the facility operator to maintain healthy water quality.Four factors contribute to maintaining a healthy water quality in a recreational water facility: engineering design, water chemistry, disinfection and facility management. All factors must be operating properly for a facility to maintain a healthy bathing environment. For instance, if a facility operator does not adhere to their policies in remediating a fecal accident in the pool water, then even if the facility has a disinfectant residual when the event occurred, they have still placed the other bathers at risk. This chapter will present a holistic approach for the maintenance of recreational water. This includes a discussion on the engineering aspects that define the different facilities, a general discussion on maintaining balanced water chemisty, the use and evaluation of disinfectants and a general discussion at the end on the importance of well-trained facility managers. An overview of the various illnesses that are associated with recreational water which is not maintained correctly are presented as a cautionary note. Finally, like any industry, recreational water is subject to trends, which will be addressed in the appropriate sections.Item Systematic exploration of natural and synthetic flavonoids for the inhibition of Staphylococcus aureus biofilms(2013-09) Manner, Suvi; Skogman, Malena; Goeres, Darla M.; Vuorela, Pia; Fallarero, AdyaryWhen single-cell (or suspended) bacteria switch into the biofilm lifestyle, they become less susceptible to antimicrobials, imposing the need for anti-biofilms research. Flavonoids are among the most extensively studied natural compounds with an unprecedented amount of bioactivity claims. Most studies focus on the antibacterial effects against suspended cells; fewer reports have researched their anti-biofilm properties. Here, a high throughput phenotypic platform was utilized to screen for the inhibitory activity of 500 flavonoids, including natural and synthetic derivatives, against Staphylococcus aureus biofilms. Since discrepancies among results from earlier antibacterial studies on flavonoids had been noted, the current study aimed to minimize sources of variations. After the first screen, flavonoids were classified as inactive (443), moderately active (47) or highly active (10). Further, exclusion criteria combining bioactivity and selectivity identified two synthetic flavans as the most promising. The body of data reported here serves three main purposes. First, it offers an improved methodological workflow for anti-biofilm screens of chemical libraries taking into account the (many times ignored) connections between anti-biofilm and antibacterial properties. This is particularly relevant for the study of flavonoids and other natural products. Second, it provides a large and freely available anti-biofilm bioactivity dataset that expands the knowledge on flavonoids and paves the way for future structure-activity relationship studies and structural optimizations. Finally, it identifies two new flavans that can successfully act on biofilms, as well as on suspendedbacteria and represent more feasible antibacterial candidates.Item Ruggedness and reproducibility of the MBEC biofilm disinfectant efficacy test(2014-07) Parker, Albert E.; Walker, Diane K.; Goeres, Darla M.; Allan, N.; Olson, M. E.; Omar, A.The MBEC™ Physiology & Genetics Assay recently became the first approved ASTM standardized biofilm disinfectant efficacy test method. This report summarizes the results of the standardization process using Pseudomonas aeruginosa biofilms. Initial ruggedness testing of the MBEC method suggests that the assay is rugged (i.e., insensitive) to small changes to the protocol with respect to 4 factors: incubation time of the bacteria (when varied from 16 to 18 h), treatment temperature (20–24 °C), sonication duration (25–35 min), and sonication power (130–480 W). In order to assess the repeatability of MBEC results across multiple tests in the same laboratory and the reproducibility across multiple labs, an 8-lab study was conducted in which 8 concentrations of each of 3 disinfectants (a non-chlorine oxidizer, a phenolic, and a quaternary ammonium compound) were applied to biofilms using the MBEC method. The repeatability and reproducibility of the untreated control biofilms were acceptable, as indicated by small repeatability and reproducibility standard deviations (SD) (0.33 and 0.67 log10(CFU/mm2), respectively). The repeatability SDs of the biofilm log reductions after application of the 24 concentration and disinfectant combinations ranged from 0.22 to 1.61, and the reproducibility SDs ranged from 0.27 to 1.70. In addition, for each of the 3 disinfectant types considered, the assay was statistically significantly responsive to the increasing treatment concentrations.