Evaluation of the long-term protection conferred by an organosilicon-based disinfectant formulation against bacterial contamination of surfaces.

AIMS: The aim of this work was to evaluate the efficacy of an organosilicon-based, commercially available antimicrobial formulation in the My-shield® product line against bacterial surface contamination. METHODS AND RESULTS: The antimicrobial product was tested in vitro for its long-term persistence on surfaces and effectiveness against Staphylococcus aureus biofilms in comparison to 70% ethanol and 0.1% or 0.6% sodium hypochlorite. Field testing was also conducted over 6 weeks at a university athletic facility. In vitro studies demonstrated the log reductions achieved by the test product, 70% ethanol, and 0.1% sodium hypochlorite were 3.6, 3.1, and 3.2, respectively. The test product persisted on surfaces after washing and scrubbing, and pre-treatment with this product prevented S. aureus surface colonization for up to 30 days. In comparison, pre-treatment with 70% ethanol or 0.6% sodium hypochlorite was not protective against S. aureus biofilm formation after seven days. The field test demonstrated that weekly applications of the test product were more effective at reducing surface bacterial load than daily applications of a control product. CONCLUSIONS: The test product conferred greater long-term protection against bacterial growth and biofilm formation by S. aureus than ethanol and sodium hypochlorite. Even with less frequent applications, the test product maintained a high level of antimicrobial activity.

Environmental and health outcomes of single-use versus reusable duodenoscopes.

BACKGROUND AND AIMS: The large-scale effects of duodenoscopes on the environment and public health have not been quantified. Our aim was to perform an exploratory life cycle assessment comparing environmental and human health effects of single-use duodenoscopes (SDs) and reusable duodenoscopes (RDs). METHODS: We evaluated 3 duodenoscopes: conventional RDs, RDs with disposable endcaps, and SDs. The primary outcomes were impacts on climate change and human health, complemented by multiple environmental impacts. RESULTS: Performing ERCP with SDs releases between 36.3 and 71.5 kg of CO2 equivalent, which is 24 to 47 times greater than using an RD (1.53 kg CO2) or an RD with disposable endcaps (1.54 kg CO2). Most of the impact of SDs comes from its manufacturing, which accounts for 91% to 96% of its greenhouse gas emission. The human health impact of RDs becomes comparable with the SD lower bound if disposable endcaps or other design modifications can reduce serious infection rates below a target rate of 23 cases per year (.0046%). CONCLUSIONS: Although SDs may provide incremental public health benefit compared with RDs, it comes at a substantially higher cost to the environment. As infection rates continue to decrease from more regimented cleaning protocols and enhanced designs such as disposable endcaps to facilitate cleaning, the negative impact to human health from contaminated RDs could be comparable with SDs.

Ring Expansion of Alkylidenecarbenes Derived from Lactams, Lactones, and Thiolactones into Strained Heterocyclic Alkynes: A Theoretical Study.

Strained cycloalkynes are of considerable interest to theoreticians and experimentalists, and possess much synthetic value as well. Herein, a series of cyclic alkylidenecarbenes-formally obtained by replacing the carbonyl oxygen of four-, five-, and six-membered lactams, lactones, and thiolactones with a divalent carbon-were modeled at the CCSD(T)/cc-pVTZ//B3LYP/6-311+G** and CCSD(T)/cc-pVTZ//CCSD/6-311+G** levels of theory. The singlet carbenes were found to be more stable than the triplets. The strained heterocyclic alkynes formed by ring expansion of these singlet carbenes were also modeled. Interestingly, the C≡C bonds in the five-membered heterocycles, obtained from the rearrangement of ß-lactam- and ß-lactone-derived alkylidenecarbenes, displayed lengths intermediate between formal double and triple bonds. Furthermore, 2-(1-azacyclobutylidene)carbene was found to be nearly isoenergetic with its ring-expanded isomer, and 1-oxacyclopent-2-yne was notably higher in energy than its precursor carbene. In all other cases, the cycloalkynes were lower in energy than the corresponding carbenes. The transition states for ring-expansion were always lower for the 1,2-carbon shifts than for 1,2-nitrogen or oxygen shifts, but higher than for the 1,2-sulfur shifts. These predictions should be verifiable using carbenes bearing appropriate isotopic labels. Computed vibrational spectra for the carbenes, and their ring-expanded isomers, are presented and could be of value to matrix isolation experiments.