Examining the potential impacts of a coastal renourishment project on the presence and abundance of Escherichia coli.

Erosion poses a significant threat to oceanic beaches worldwide. To combat this threat, management agencies often utilize renourishment, which supplements eroded beaches with offsite sand. This process can alter the physical characteristics of the beach and can influence the presence and abundance of microbial communities. In this study, we examined how an oceanic beach renourishment project may have impacted the presence and abundance of Escherichia coli (E. coli), a common bacteria species, and sand grain size, a sediment characteristic that can influence bacterial persistence. Using an observational field approach, we quantified the presence and abundance of E. coli in sand (from sub-tidal, intertidal, and dune zones on the beach) and water samples at study sites in both renourished and non-renourished sections of Folly Beach, South Carolina, USA in 2014 and 2015. In addition, we also measured how renourishment may have impacted sand grain size by quantifying the relative frequency of grain sizes (from sub-tidal, intertidal, and dune zones on the beach) at both renourished and non-renourished sites. Using this approach, we found that E. coli was present in sand samples in all zones of the beach and at each of our study sites in both years of sampling but never in water samples. Additionally, we found that in comparison to non-renourished sections, renourished sites had significantly higher abundances of E. coli and coarser sand grains in the intertidal zone, which is where renourished sand is typically placed. However, these differences were only present in 2014 and were not detected when we resampled the study sites in 2015. Collectively, our findings show that E. coli can be commonly found in this sandy beach microbial community. In addition, our results suggest that renourishment has the potential to alter both the physical structure of the beach and the microbial community but that these impacts may be short-lived.

Complete genome sequences of Mycobacterium smegmatis phages Ashballer and Bombitas.

We report the discovery of two mycobacteriophages isolated from soil in Rock Hill, South Carolina. Ashballer has a genome sequence length of 52,231 bp, while Bombitas is relatively larger at 110,129 bp. Both have siphovirus morphologies and have temperate lifecycles.

Nanosilver: An Old Antibacterial Agent with Great Promise in the Fight against Antibiotic Resistance.

Antibiotic resistance in bacteria is a major problem worldwide that costs 55 billion USD annually for extended hospitalization, resource utilization, and additional treatment expenditures in the United States. This review examines the roles and forms of silver (e.g., bulk Ag, silver salts (AgNO3), and colloidal Ag) from antiquity to the present, and its eventual incorporation as silver nanoparticles (AgNPs) in numerous antibacterial consumer products and biomedical applications. The AgNP fabrication methods, physicochemical properties, and antibacterial mechanisms in Gram-positive and Gram-negative bacterial models are covered. The emphasis is on the problematic ESKAPE pathogens and the antibiotic-resistant pathogens of the greatest human health concern according to the World Health Organization. This review delineates the differences between each bacterial model, the role of the physicochemical properties of AgNPs in the interaction with pathogens, and the subsequent damage of AgNPs and Ag+ released by AgNPs on structural cellular components. In closing, the processes of antibiotic resistance attainment and how novel AgNP-antibiotic conjugates may synergistically reduce the growth of antibiotic-resistant pathogens are presented in light of promising examples, where antibiotic efficacy alone is decreased.

Complete Genome Sequences of Mycobacterium smegmatis Phages MelsMeow, Yorick, Virgeve, and Mikro.

Mycobacterium phages Mikro, Yorick, Virgeve, and MelsMeow were isolated from soil in Rock Hill, South Carolina. Mikro is a myovirus with a comparatively large genome of 157,166 bp. The remainder are siphoviruses with genome lengths ranging from 59,227 bp to 68,563 bp. All phages were isolated on Mycobacterium smegmatis.

Sourcing Antibiotic-Resistant Escherichia coli in Aquatic Ecosystems: A Combined Laboratory and Field Module.

The emergence of antibiotic-resistant bacteria represents a growing threat in aquatic ecosystems. In this combined field and laboratory activity, students will determine whether Escherichia coli, an indicator bacteria species commonly found in aquatic ecosystems, shows signs of resistance to common antibiotics. In addition, students will use molecular biology techniques to identify whether Escherichia coli cells sourced from different hosts (i.e., phylogroups) show different patterns of antibiotic resistance. This activity will help students to gain experience in environmental microbiology, environmental science, molecular biology, and public health. This module is also designed to provide instructors with flexibility to pick and choose activities that best meet the needs of their class or research program.

Complete Genome Sequences of Microbacterium liquefaciens Phages Mercedes, Leafus, Nebulous, and Ixel.

Microbacterium phages Mercedes, Leafus, Nebulous, and Ixel were isolated from soil in Rock Hill, SC. All are lytic phages with Siphoviridae morphotypes and similar genome sequence lengths that range from 40,200 bp to 42,000 bp. The four bacteriophages were isolated using the host Microbacterium liquefaciens.