Antibacterial efficacy, mode of action, and safety of a novel nano-antibiotic against antibiotic-resistant Escherichia coli strains.

Globally rising antibiotic-resistant (AR) and multi-drug resistant (MDR) bacterial infections are of public health concern due to treatment failure with current antibiotics. Enterobacteria, particularly Escherichia coli, cause infections of surgical wound, bloodstream, and urinary tract, including pneumonia and sepsis. Herein, we tested in vitro antibacterial efficacy, mode of action (MoA), and safety of novel amino-functionalized silver nanoparticles (NH2-AgNP) against the AR bacteria. Two AR E. coli strains (i.e., ampicillin- and kanamycin-resistant E. coli), including a susceptible strain of E. coli DH5α, were tested for susceptibility to NH2-AgNP using Kirby-Bauer disk diffusion and standard growth assays. Dynamic light scattering (DLS) was used to determine cell debris and relative conductance was used as a measure of cell leakage, and results were confirmed with transmission electron microscopy (TEM). Multiple oxidative stress assays were used for in vitro safety evaluation of NH2-AgNP in human lung epithelial cells. Results showed that ampicillin and kanamycin did not inhibit growth in either AR bacterial strain with doses up to 160 µg/mL tested. NH2-AgNP exhibited broad-spectrum bactericidal activity, inhibiting the growth of all three bacterial strains at doses ≥1 µg/mL. DLS and TEM revealed cell debris formation and cell leakage upon NH2-AgNP treatment, suggesting two possible MoAs: electrostatic interactions followed by cell wall damage. Safety evaluation revealed NH2-AgNP as noncytotoxic and antioxidative to human lung epithelial cells. Taken together, these results suggest that NH2-AgNP may serve as an effective and safer bactericidal therapy against AR bacterial infections compared to common antibiotics.

Asthma May Not be a Potential Risk Factor for Severe COVID-19 Illness: A Scoping Review.

The coronavirus disease 2019 (COVID-19) is a respiratory disease caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), but whether the asthmatic patients are at increased risk for severe COVID-19 illness than non-asthmatic patients has remained unclear. This scoping review aimed to assess the available evidence to determine if asthmatic patients are at a higher risk for severe COVID-19 illness. Searching several electronic databases and adhering to the PRISMA guidelines, we conducted a scoping review of 70 articles and using defined inclusion-exclusion criteria, 21 articles were analyzed in-depth and included in this scoping review. The findings of this scoping review point to a lack of relationship between asthma and severe COVID-19 illness. While a limited number of studies (n = 4) identified asthma as a risk factor, most studies (n = 17) found no independent association between asthma and severe COVID-19 illness. We, thus, conclude that asthma may not be a potential risk factor for severe COVID-19 illness. Owing to limited evidence, we recommend large-scale prospective cohort studies with standardized methodologies to decipher potential role of asthma in COVID-19 severity. Further, understanding the impact of specific asthma medications, genetic factors, and other comorbidities on COVID-19 outcomes may help inform clinical practice guidelines for effective patient health management.

A scoping review on the effects of Varroa mite (Varroa destructor) on global honey bee decline.

Arguably the most ecologically and economically valuable pollinators worldwide, honey bees play a significant role in food production and enrich biodiversity through pollination. Varroa destructor is an invasive ectoparasitic mite that attacks and feeds on European honey bee, Apis mellifera. Because literature on the effectiveness and sustainability of various treatment modalities available for Varroa mite control in honey bee colonies are scattered, this scoping review was conducted to serve as a guiding document with a focus on: (1) identifying the detrimental impact Varroa mites have on the European honey bee; (2) determining current methods for Varroa mite control and their limitations; (3) examining current market landscape and key players in the pesticide market; and (4) identifying opportunities for more sustainable Varroa mite control methods. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, 397 articles published between 1998 and 2022 were screened; of which 65 articles were retained using inclusion/exclusion criteria, which were systematically analyzed in-depth, information extracted, and included in this scoping review. The results suggest that Varroa mites are one of the predominant causes of global honey bee decline as they lack natural resistance to Varroa mites, thereby negatively affecting honey bee reproduction and immunity, killing broods, and transmitting pathogenic viruses to colonies. Further, our findings suggest that: apiarists have many options for Varroa control, but no method has proven to be effective, safe and nonpersistent in the environment; adoption of nano-pesticides and development of sustainable alternatives to traditional pesticides are key drivers for growing pesticide market; and nano-pesticides may have potential to serve as an effective, safe and non-ecopersistent pesticide for Varroa mite and associated virus control. In conclusion, this review highlights an unmet need for effective and sustainable control strategies and tools for Varroa mite and virus control.

Comprehensive Phytotoxicity Assessment Protocol for Engineered Nanomaterials.

In order for nanotechnology to be sustainably applied in agriculture, emphasis should be on comprehensive assessment of multiple endpoints, including biouptake and localization of engineered nanomaterials (ENMs), potential effects on food nutrient quality, oxidative stress responses, and crop yield, before ENMs are routinely applied in consumer and agronomic products. This chapter succinctly outlines a protocol for conducting nanophytotoxicity studies focusing on nanoparticle purification and characterization, arbuscular mycorrhizal fungi (AMF)/symbiont inoculation, biouptake and translocation/localization, varied endpoints of oxidative stress responses, and crop yield.