Convergent adaptation of Saccharomyces uvarum to sulfite, an antimicrobial preservative widely used in human-driven fermentations

Different species can find convergent solutions to adapt their genome to the same evolutionary constraints, although functional convergence promoted by chromosomal rearrangements in different species has not previously been found. In this work, we discovered that two domesticated yeast species, Saccharomyces cerevisiae, and Saccharomyces uvarum, acquired chromosomal rearrangements to convergently adapt to the presence of sulfite in fermentation environments. We found two new heterologous chromosomal translocations in fermentative strains of S. uvarum at the SSU1 locus, involved in sulfite resistance, an antimicrobial additive widely used in food production. These are convergent events that share similarities with other SSU1 locus chromosomal translocations previously described in domesticated S. cerevisiae strains. In S. uvarum, the newly described VIIXVI and XIXVI chromosomal translocation generate an overexpression of the SSU1 gene and confer increased sulfite resistance. This study highlights the relevance of chromosomal rearrangements to promote the adaptation of yeast to anthropic environments.

Antimicrobial Effect of Additive Silver Nanoparticles to Paints for Reducing the Risk of Cross-Contamination

Paints are mainly used to protect metal structures from rusting and object from adverse effects of weather and sun, in addition to decoration. Most paints are either oil-based or water-based and both have distinct advantages. It can be applied as a solid, a gaseous suspension (aerosol) or a liquid. The increasing demand for new antimicrobial paints is rising recently due to the important need to avoid the spreading of infections mainly caused by harmful microorganisms. The antimicrobial additive can be defined as the additive compound that can resist or prevents the growth of harmful microbes. In this connection, a number of critical factors should be considered in selecting the additive antimicrobials to paints. These factors include safe from adverse impacts on human health and environment, antimicrobial efficiency, achieve a broad spectrum of microbial control, low percentage of the antimicrobial additive, ease of handling, fast and long-acting, migration capability, chemical stability, cost-effective and maintaining the properties of the product and its components. In the case of edible coatings which provide a unique opportunity to control microbial and oxidative changes in human ready-to-use food products, suitable safe materials and active agents for different cases should be applied. To make the traditional paints resistant to pathogenic microorganisms, it is of importance to include several antimicrobial additives, such as silver and zinc ions during the manufacturing process. Silver is a widely used technology in the world, especially in its nano-particle form due to its suitability for deployment in a broad range of materials and applications and its broad spectrum performance. This durable treatment will provide to a large extent effective protection against harmful fungi, bacteria, viruses and consequently helping to minimize staining and material degradation on any surface it is applied to. These antimicrobial paints (APs) can be used in places that harbor pathogenic microorganisms such as hospitals, schools, care homes, kitchen areas, dental and veterinary practices and food production factories. In these places, APs can be applied to contact surfaces within these environments, such as door handles, light switches, flooring, elevator buttons, and bathroom in order to reduce the risk of cross-contamination.

Influence of the Ultrasonic Treatment on the Properties of Polybutylene Adipate Terephthalate, Modified by Antimicrobial Additive

Particular attention is paid to biodegradable materials from the environmental point of view and antimicrobial materials that ensure the microbiological safety of packaged products. The aim of the work was to study the properties of the composition, based on biodegradable polybutylene adipate terephthalate (PBAT) and the antimicrobial additive—birch bark extract (BBE). Test samples of materials were obtained on the laboratory extruder by extrusion with ultrasonic treatment of the melt. The concentration of the antimicrobial additive in the polymer matrix was 1 wt %. A complex research was carried out to study the structural, physico–mechanical characteristics, antimicrobial properties and biodegradability of the modified PBAT. Comparative assessment of the physico–mechanical characteristics of samples based on PBAT showed that the strength and elongation at break indices slightly decrease when the ultrasonic treatment of the melt is introduced. It was found out, that the antimicrobial additive in the composition of the polymer matrix at the concentration of 1 wt % has a static effect on the development of microorganisms on the surface of the studied modified films. Studies of the biodegradability of modified PBAT by composting for 4 months have shown that the decomposition period of modified materials increased, compared to pure PBAT. The developed modified polymer material can be recommended as an alternative replacement for materials based on polyethylene for food packaging.

Preparation and Application of a Xylan-Based Antibacterial Additive Agent against Escherichia Coli Bacteria

In this work, a xylan-based antimicrobial additive agent was prepared and aimed for uses in paper products against Escherichia coli bacteria. The derived Cationic-Xylan-grafted-PHGH (CX-g-PHGH) was successfully synthesized by graft copolymerization of cationic-xylan with guanidine polymer (PHGH) using ceric ammonium nitrate as initiator. The obtained CX-g-PHGH had maximum PHGH grafting ratio of 18.45% and efficiency of 58.45%, and showed good viscosity and thermal stability. Furthermore, the paper samples prepared in this work were reinforced obviously with the addition of CX-g-PHGH by improved mechanical properties. Compared to the reference paper without any of the xylan-derivatives, the index of tensile, tear, burst and folding endurance of the paper had increases up to 20.07%, 25.31%, 30.20% and 77.78%, respectively. Moreover, the prepared CX-g-PHGH paper exhibited an efficient antimicrobial activity against E. coli bacterial, by which a lot of applications based on the new xylan-derived additive agent obtained in this work could be found, especially in field of antimicrobial paper products against E. Coli bacteria from contaminated food.

Stability of a 50 mg/mL Ceftazidime Eye-Drops Formulation

Background Microbial keratitis are severe infectionsgenerally linked to risk factors. High-doses antibiotic eye-drops could be required to avoid severe complications. In such cases, hospital pharmacists are in charge of their production given the lack of such formulations on the market. The stability of these antibiotic eye-drops is generally limited to a couple of days and publications generally do not describe addition of microbial preservatives even though it is a European Pharmacopeia requirement. The aim of this study was to describe a new ceftazidime eye-drops formulation at 50 mg/mL with a antimicrobial additive, benzalkonium chloride at 0.04 mg/mL. Methods Physico-chemical studies of this new formulation were performed by a stability indicating HPLC-UV method validated according to ICH standards, osmolality measurements, pH monitoring and visual examinations. Antimicrobial preservative efficacy was evaluated according to the method from the European Pharmacopeia. Results After 75 days at −20 °C followed by 7 days at 4 °C, or after 7 days at 4 °C, the eye-drops were stable. A degradation trend was finally observed at day 14 at 4 °C. Conclusions A new ceftazidime eye-drops formulation is proposed with a stability of 7 days. Outpatients do not need to return to the hospital pharmacy for repeat dispensing, thus possibly improving treatment compliance.

Patterns of triclosan resistance in Vibrionaceae

The antimicrobial additive triclosan has been used in personal care products widely across the globe for decades. Triclosan resistance has been noted amongVibriospp., but reports have been anecdotal and the extent of phenotypic triclosan resistance across the Vibrionaceae family has not been established.Here, triclosan resistance was determined for Vibrionaceae strains across nine distinct clades. Minimum inhibitory concentrations (MIC) were determined for 70 isolates from clinical (n = 6) and environmental sources (n = 64); only two were susceptible to triclosan. The mean MIC for all resistant Vibrionaceae was 53 µg mL−1(range 3.1–550 µg mL−1), but was significantly different between clades (p < 0.001). The highest mean triclosan MIC was observed in the Splendidus clade (200 µg mL−1;n = 3). Triclosan mean MICs were 68.8 µg mL−1in the Damselae clade and 45.3 µg mL−1in the Harveyi clade. The lowest mean MIC was observed in the Cholerae clade with 14.4 µg mL−1, which was primarily represented by clinical strains. There were no significant differences in triclosan MIC among individual species or among environmental strains isolated from different locations. Overall, phenotypic triclosan resistance appears to be widespread across multiple clades of Vibrionaceae.