In Vitro Antimicrobial Activity Evaluation of a Novel Fitostimoline® Plus Spray Formulation

Wound contaminants are the main cause of healing delay and infection in both chronic and acute wounds; for this reason, the microbial infection management in wound healing is one of the most important components for an effective standard of care. The wound contaminants are most likely to originate from the environment and from the surrounding skin lesion, and to date, the most frequent bacteria isolated are Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae. In order to counteract and control these contaminants, the standard care includes topical antiseptic agents. The most commonly used include iodine-releasing agents (e.g., povidone-iodine), hydrogen peroxide, and polyhexanide. This study aims to investigate the in vitro antibacterial activity of a novel topical spray (Fitostimoline® Plus spray) based on 0.1% polyhexanide and Rigenase® against S. aureus, P. aeruginosa, K. pneumoniae, and the combination of S. aureus and K. pneumoniae. The in vitro antimicrobial activity of Fitostimoline® Plus spray was evaluated by the agar disk diffusion assay, quantitative suspension test, and quantitative carrier test, demonstrating that Fitostimoline® Plus spray is able to kill 99.9% bacteria. These results support the microbiological characterization of Fitostimoline® Plus spray confirming the antibacterial activity of polyhexanide (PHMB).

Efficacy of relatively low-cost ultraviolet-C light devices against Candida auris

Background: Ultraviolet-C (UV-C) light devices could be useful to reduce environmental contamination with Candida auris. However, variable susceptibility of C. auris strains to UV-C has been reported, and the high cost of many devices limits their use in resource-limited settings. Objective: To evaluate the efficacy of relatively low-cost (<$15,000 purchase price) UV-C devices against C. auris strains from the 4 major phylogenetic clades. Methods: A modification of the American Society for Testing and Materials (ASTM) standard quantitative disk carrier test method (ASTM E 2197) was used to examine and compare the effectiveness of UV-C devices against C. auris, methicillin-resistant Staphylococcus aureus (MRSA), and bacteriophage Phi6. Reductions of 3 log10 were considered effective. UV-C irradiance measurements and colorimetric indicators were used to assess UV-C output. Results: Of 8 relatively low-cost UV-C devices, 6 met the criteria for effective decontamination of C. auris isolates from clades I and II, MRSA, and bacteriophage Phi6, including 3 room decontamination devices and 3 UV-C box devices. Candida auris isolates from clades III and IV were less susceptible to UV-C than clade I and II isolates; 1 relatively low-cost room decontamination device and 2 enclosed box devices met the criteria for effective decontamination of clade III and IV isolates. UV-C irradiance measurements and colorimetric indicator results were consistent with microorganism reductions. Conclusions: Some relatively low-cost UV-C light technologies are effective against C. auris, including isolates from clades III and IV with reduced UV-C susceptibility. Studies are needed to evaluate the effectiveness of UV-C devices in clinical settings.

Hot Carrier Stress Sensing Bulk Current for 28 nm Stacked High-k nMOSFETs

This work primarily focuses on the degradation degree of bulk current (IB) for 28 nm stacked high-k (HK) n-channel metal–oxide–semiconductor field-effect transistors (MOSFETs), sensed and stressed with the channel-hot-carrier test and the drain-avalanche-hot-carrier test, and uses a lifetime model to extract the lifetime of the tested devices. The results show that when IB reaches its maximum, the ratio of VGS/VDS values at this point, in the meanwhile, gradually increases in the tested devices from the long-channel to the short ones, not just located at one-third to one half. The possible ratiocination is due to the ON-current (IDS), in which the short-channel devices provide larger IDS impacting the drain junction and generating more hole carriers at the surface channel near the drain site. In addition, the decrease in IB after hot-carrier stress is not only the increment in threshold voltage VT inducing the decrease in IDS, but also the increment in the recombination rate due to the mechanism of diffusion current. Ultimately, the device lifetime uses Berkley’s model to extract the slope parameter m of the lifetime model. Previous studies have reported m-values ranging from 2.9 to 3.3, but in this case, approximately 1.1. This possibly means that the critical energy of the generated interface state becomes smaller, as is the barrier height of the HK dielectric to the conventional silicon dioxide as the gate oxide.

Comparative evaluation of hydrogen peroxide sporicidal efficacy by different standard test methods

Background and Objectives: There are different sporicidal standard tests with various specifications to deal with products that are claimed for sporicidal activity. The aim of this study was to compare the 7% H O sporicidal efficacy against Bacillus 2 2 subtilis spores using different standard test methods. Materials and Methods: The 7% H O sporicidal efficacy against Bacillus subtilis spores was determined according to the 2 2 AOAC MB-15-04 standard of carrier test and two standard suspension tests (BS EN 13704, AFNOR NF 72-230) in both clean and dirty conditions and by using different interfering substances including bovine serum albumin, yeast extract and skimmed milk. Results: The results of suspension tests with 3 × 105 and 2 × 107 CFU/ml of B. subtilis spore concentration demonstrated that the higher spore counts lead to lower efficacy of 7% H O . Also, the sporicidal activity of 7% H O was reduced in the 2 2 2 2 presence of interfering substances. Bovine serum albumin, yeast, and skimmed milk showed similar interfering effects in suspension test with 3 × 105 CFU/ml. While, in suspension tests with higher initial spore count (2 × 107 CFU/ml) severity of interfering effects were intensified and distinct. Our results indicated that the carrier sporicidal test in comparison with suspension tests required more contact time to kill B. subtilis spores. Conclusion: The results of this study showed that it is reasonable to use interfering substances and inoculated carriers in accordance with actual conditions of product usage in a sporicidal test. Interfering substances may reduce the contact surface between H O and test spores; therefore, the sporicidal efficacy of H O was diminished. So applying suspension test in clean 2 2 2 2 condition to verify the claim of sporicidal activity is strongly discouraged

Germicidal Activity against Carbapenem/Colistin-Resistant Enterobacteriaceae Using a Quantitative Carrier Test Method

ABSTRACT Susceptibility to germicides for carbapenem/colistin-resistant Enterobacteriaceae is poorly described. We investigated the efficacy of multiple germicides against these emerging antibiotic-resistant pathogens using the disc-based quantitative carrier test method that can produce results more similar to those encountered in health care settings than a suspension test. Our study results demonstrated that germicides commonly used in health care facilities likely will be effective against carbapenem/colistin-resistant Enterobacteriaceae when used appropriately in health care facilities.