Bacteriophage treatment before chemical disinfection can enhance removal of plastic surface-associated; Pseudomonas aeruginosa

Opportunistic pathogens can linger on surfaces in hospital and building plumbing environments, leading to infections in at-risk populations. Further, biofilm-associated bacteria are protected from removal and inactivation protocols, such as disinfection. Bacteriophages show promise as tools to treat antibiotic resistant infections. As such, phages may also be useful in environmental applications to prevent newly acquired infections. In the current study, the potential of synergies between bacteriophage and chemical disinfection of the opportunistic pathogen Pseudomonas aeruginosa was assessed under various conditions. Specifically, surface-associated P. aeruginosa was treated with various concentrations of phages (P1 or JG004), chemical disinfectant (sodium hypochlorite or benzalkonium chloride), or combined sequential treatments under three distinct attachment models (spot inoculations, dry biofilms, and wet biofilms). Phages were very effective at removing bacteria in spot inoculation (>3.2 log10 removal) and wet biofilms (up to 2.6 log10 removal), while phages prevented regrowth of dry biofilms in the application time. In addition, phage treatment followed by chemical disinfection inactivated more P. aeruginosa under wet biofilm conditions better than either treatment alone. This effect was hindered when chemical disinfection was applied first, followed by phage treatment, suggesting additive benefits of combination treatments are lost when phage is applied last. Further, we confirm prior evidence of greater phage tolerance to benzalkonium chloride relative to sodium hypochlorite, informing choices for combination phage-disinfectant approaches. Overall, this paper further supports the potential of using combination phage and chemical disinfectant treatments to improve inactivation of surface-associated P. aeruginosa. Importance Phages are already utilized in the healthcare industry to treat antibiotic resistant infections, such as on implant-associated biofilms and in compassionate care cases. Phage treatment could also be a promising new tool to control pathogens in the built environment, preventing infections from occurring. This study shows that phage can be combined effectively with chemical disinfectants to improve removal of wet biofilms and bacteria spotted onto surfaces while preventing regrowth in dry biofilms. This has the potential to improve pathogen containment within the built environment and drinking water infrastructure to prevent infections of opportunistic pathogens

Development and evaluation of a novel human-specific fecal source tracking marker

Enteric viruses pose a significant health risk to the public through exposure to contaminated environmental waters, costing society billions of dollars to treat millions of excess illnesses annually. Current available methods to monitor human fecal pollution in impacted waters either do not correlate with viral pathogen presence and risk, cross-react with other animal sources, or are not abundant enough in environmental waters to be reliably detected. This dissertation investigates a novel target for a human-specific indicator of fecal pollution, the bacteriophage “crAssphage”. First, a metagenomic evaluation was conducted as an initial step to evaluate the potential of the crAssphage genome for assay development. Results indicated that crAssphage is enriched in sewage and more abundant than other viruses and bacteriophages in sewage, suggesting its high potential as a target for human-specific marker development. Next, end-point PCR primers were designed along the length of the crAssphage genome and screened against human sewage samples and non-human animal fecal samples to assess which genomic regions may be the most useful as source tracking markers. The two best performing primer pairs were adapted to TaqMan qPCR assays. These assays were evaluated head-to-head against two bacterial qPCR human source tracking markers to evaluate their performance. The assays were widespread in geographically diverse human sources and as abundant or more abundant in sewage and impaired environmental water than the bacterial-based assays. Moreover, the assays displayed high human-association. Finally, an initial environmental evaluation was conducted to correlate the crAssphage-based assays to pollution events, culturable bacterial and phage indicators, and molecular bacterial and viral indicators. This study demonstrated the usefulness of the crAssphage assays in a real-world system, validating their high abundance and correlation with pollution events and other indicators of fecal pollution. Ultimately, the research in this dissertation contributes two novel viral-based technologies for detection of human fecal pollution that will enhance management of environmental waters and protect public health through the development of an abundant viral fecal source-tracking marker

Utility of Two-Stage Laryngotracheal Reconstruction in the Management of Subglottic Stenosis in Adults

No abstract.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/83473/1/21521_ftp.pd

Potential probiotic approaches to control Legionella in engineered aquatic ecosystems

Opportunistic pathogens belonging to the genus Legionella are among the most reported waterborne-associated pathogens in industrialized countries. Legionella colonize a variety of engineered aquatic ecosystems and persist in biofilms where they interact with a multitude of other resident microorganisms. In this review, we assess how some of these interactions could be used to develop a biological-driven "probiotic" control approach against Legionella. We focus on: (i) mechanisms limiting the ability of Legionella to establish and replicate within some of their natural protozoan hosts; (ii) exploitative and interference competitive interactions between Legionella and other microorganisms; and (iii) the potential of predatory bacteria and phages against Legionella. This field is still emergent, and we therefore specifically highlight research for future investigations, and propose perspectives on the feasibility and public acceptance of a potential probiotic approach. Keywords: Legionella; antagonism; biofilm; competition; pathogen–host interaction; predation; probiotics; protozoa

Biology and management of horseweed

"This publication discusses some of the biological characteristics that make horseweed particularly troublesome to control in agronomic crops. Then it provides management strategies, using technologies now available, that will allow growers to control herbicide-resistant horseweed and hopefully slow the spread of glyphosate resistance."--Extension website, viewed October 31, 2022.Reviewed by Kevin Bradley (Division of Plant Sciences), Mark Loux (Ohio State University), Jeff Stachler (Ohio State University), Bill Johnson (Purdue University), Glenn Nice (Purdue University), Vince Davis (Purdue University), Dawn Nordby (University of Illinois)Reviewed 10/22Includes bibliographical reference

Orthogonal Reference Surrogate Fuels for Operability Testing

The approval and evaluation process for sustainable aviation fuels (SAF) via ASTM D4054 is both cost- and volume-intensive, namely due to engine operability testing under severe conditions. Engine operability tests of combustor under figures of merit (FOM) limit phenomena are the fuel effects on lean blowout, high-altitude relight, and cold-start ignition. One method to increase confidence and reduce volume in tiered testing is to use surrogate fuels for manipulation of properties. Key fuel performance properties (surface tension, viscosity, density) for cold-start ignition was determined prior to this study. Prior work regarding this FOM has not considered the combination of these properties. A surface tension blending rule was validated and incorporated into the jet fuel blend optimizer (JudO). A generalized surrogate calculator for N-dimensional surrogate components and features was developed. Jet fuel surrogates developed in this study were a mixture of conventional and sustainable aviation fuels instead of pure components. These surrogates suggested to be tested in this study could illuminate near worst-case effects for sustainable aviation fuel in a given configuration/rig. With those scenarios tested, we can further understand the influence on the key properties relative to cold-start ignition. This work and supporting experimental evidence could potentially lower the barrier for SAF approval processes. Document type: Articl

High tolerance to self-targeting of the genome by the endogenous CRISPR-Cas system in an archaeon

CRISPR-Cas systems allow bacteria and archaea to acquire sequence-specific immunity against selfish genetic elements such as viruses and plasmids, by specific degradation of invader DNA or RNA. However, this involves the risk of autoimmunity if immune memory against host DNA is mistakenly acquired. Such autoimmunity has been shown to be highly toxic in several bacteria and is believed to be one of the major costs of maintaining these defense systems. Here we generated an experimental system in which a non-essential gene, required for pigment production and the reddish colony color, is targeted by the CRISPR-Cas I-B system of the halophilic archaeon Haloferax volcanii. We show that under native conditions, where both the self-targeting and native crRNAs are expressed, self-targeting by CRISPR-Cas causes no reduction in transformation efficiency of the plasmid encoding the self-targeting crRNA. Furthermore, under such conditions, no effect on organismal growth rate or loss of the reddish colony phenotype due to mutations in the targeted region could be observed. In contrast, in cells deleted for the pre-crRNA processing gene cas6, where only the self-targeting crRNA exists as mature crRNA, self-targeting leads to moderate toxicity and the emergence of deletion mutants. Sequencing of the deletions caused by CRISPR-Cas self targeting indicated DNA repair via microhomology-mediated end joining

Biology and management of giant ragweed

"This publication discusses the biological characteristics that make giant ragweed troublesome, and provides management guidelines that will minimize yield losses and slow the development of glyphosate-resistant biotypes."--Extension website, viewed October, 31, 2022.Reviewed by Kevin Bradley (Division of Plant Sciences), Bill Johnson (Purdue University), Mark Loux (Ohio State University), Dawn Nordby (University of Illinois), Christy Sprague (Michigan State University), Glenn Nice (Purdue University), Andy Westhoven (Purdue University), Jeff Stachler (Ohio State University)Reviewed 10/22Includes bibliographical reference

MDM2 expression in the progression of Barrett’s oesophagus

Barrett's oesophagus (BO) is the main precursor for oesophageal adenocarcinoma (OAC), and dysplasia arising within it is the standard marker used to predict risk of malignant progression. However, dysplasia diagnosis is subject to a significant amount of interobserver variation. Biomarkers may aid the diagnosis of dysplasia and may help predict the risk of progression to OAC. Abnormal expression of p53 can be reproducibly detected by immunohistochemistry (IHC) and it is an effective marker of risk of OAC1. There is however still a need for additional early stage markers