Publications by authors named "Kerry A Hamilton"

The rapid rise of antibiotic-resistant pathogens poses a critical threat to the treatment of infectious diseases. While the spread of antibiotic resistance genes (ARGs) via plasmid conjugation has been extensively studied both in the lab and the clinic, the prevalence and diversity of plasmids in drug-susceptible isolates (e.g.

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Species within the Mycobacterium avium complex (MAC), a subset of nontuberculous mycobacteria (NTM), are of major human health concern and contribute to a significant drinking water burden in the United States (US) and worldwide. The risk increases when MAC levels in environmental media are high, the hosts are susceptible, and exposures to aerosols containing MAC are frequent. MAC is typically not monitored in drinking water; currently, there are no numeric guidelines for NTM or MAC concentrations in distribution networks or building plumbing systems.

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Despite nationally reported metrics that suggest high levels of water security, approximately 12% of the United States of America (US) population is estimated to be water insecure based on the definition in United Nations (UN) SDG 6.1.1.

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The disease burden from Legionella spp. infections has been increasing in many industrialized countries and, despite decades of scientific advances, ranks amongst the highest for waterborne diseases. We review here several key research areas from a multidisciplinary perspective and list critical research needs to address some of the challenges of Legionella spp.

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Modeling Legionella exposure from building water systems is valuable to inform water management plans, but accurate risk estimates require accounting for spatiotemporal variations in concentrations. This comprehensive literature review covers existing mathematical approaches for predicting Legionella fate and transport in building water systems and proposes a framework for advanced modeling considering all mechanisms influencing its presence in water and biofilm during different life-stages (e.g.

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Understanding and predicting the role of waterborne environments in transmitting antimicrobial-resistant (AMR) infections are critical for public health. A population ecology-quantitative microbial risk assessment (QMRA) model is proposed to evaluate urinary tract infection (UTI) development due to recreational waterborne exposures to () and antibiotic-resistant extended-spectrum β-lactamase-producing (ESBL) . The horizontal gene transfer (HGT) mechanism of conjugation and other evolutionary factors were modeled separately in the environment and the gut.

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Livestock are a critical part of our food systems, yet their abundance globally has been cited as a driver of many environmental and human health concerns. Issues such as soil, water, and air pollution, greenhouse gas emissions, aquifer depletion, antimicrobial resistance genes, and zoonotic disease outbreaks have all been linked to livestock operations. While many studies have examined these issues at depth at local scales, it has been difficult to complete studies at regional or national scales due to the dearth of livestock data, hindering pollution mitigation or response time for tracing and monitoring disease outbreaks.

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In public health, risk experts often define acceptable risk targets without community input. We developed a novel method for applying behavioral microeconomics to integrate individuals' risk preferences into risk assessment. To demonstrate this methodology, we explored a risk-risk tradeoff case scenario: increased asthma risk from increased cleaning and disinfection (C&D) and increased infection risk from decreased C&D for healthcare staff.

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Biosolids can provide a nutrient rich soil amendment, particularly for poor soils and semi-arid or drought-prone areas. However, there are concerns that sludge and biosolids could be a source of propagation and exposure to AMR determinants such as antibiotic resistant bacteria (ARB), and antibiotic resistance genes (ARGs). To inform risk assessment efforts, a systematic literature review was performed to build a comprehensive spreadsheet database of ARB and ARG concentrations in biosolids (and some sludges specified as intended for land application), along with 69 other quantitative and qualitative meta-data fields from 68 published studies describing sampling information and processing methods that can be used for modeling purposes.

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Premise plumbing water quality degradation has led to negative health impacts from pathogen outbreaks (e.g., and non-tuberculous mycobacteria), as well as chronic effects from exposure to heavy metals or disinfection by-products (DBP).

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Wastewater treatment plants (WWTPs) provide vital services to the public by removing contaminants from wastewater prior to environmental discharge or reuse for beneficial purposes. WWTP workers occupationally exposed to wastewater can be at risk of respiratory or gastrointestinal diseases. The study objectives were to: (1) quantify pathogens and pathogen indicators in wastewater aerosols near different WWTP processes/unit operations, (2) develop a QMRA model for multi-pathogen and multi-exposure pathway risks, and (3) create a web-based application to perform and communicate risk calculations for wastewater workers.

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Article Synopsis
  • - The COVID-19 pandemic emphasized the importance of using quantitative microbial risk assessment (QMRA) for enhancing public health protection through modeling infectious disease risks.
  • - A recent workshop gathered 41 QMRA experts to outline crucial research priorities such as improving methods, harmonizing environmental monitoring, and integrating different scientific approaches.
  • - Key recommendations include building a collaborative research community, enhancing data collection efforts, and ensuring sustainable funding to support the advancement of QMRA for global health policies.
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Background: Respiratory tract infections are major contributors to the global disease burden. Quantitative microbial risk assessment (QMRA) holds potential as a rapidly deployable framework to understand respiratory pathogen transmission and inform policy on infection control.

Objectives: The goal of this paper was to evaluate, motivate, and inform further development of the use of QMRA as a rapid tool to understand the transmission of respiratory pathogens and improve the evidence base for infection control policies.

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This study establishes site-specific risk-based threshold (RBT) concentrations for sewage-associated markers, including Bacteroides HF183 (HF183), Lachnospiraceae Lachno3 (Lachno3), cross-assembly phage (CrAssphage), and pepper mild mottle virus (PMMoV), utilizing quantitative microbial risk assessment (QMRA) for recreational estuarine waters (EW). The QMRA model calculates a RBT concentration corresponding to a selected target illness risk for ingestion of EW contaminated with untreated sewage. RBT concentrations were estimated considering site-specific decay rates and concentrations of markers and reference pathogen (human norovirus; HNoV), aiding in the identification of high-risk days during the swimming season.

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Valley Fever is a respiratory disease caused by inhalation of arthroconidia, a type of spore produced by fungi within the genus Coccidioides spp. which are found in dry, hot ecosystems of the Western Hemisphere. A quantitative microbial risk assessment (QMRA) for the disease has not yet been performed due to a lack of dose-response models and a scarcity of quantitative occurrence data from environmental samples.

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Scarcity of freshwater for agriculture has led to increased utilization of treated wastewater (TWW), establishing it as a significant and reliable source of irrigation water. However, years of research indicate that if not managed adequately, TWW may deleteriously affect soil functioning and plant productivity, and pose a hazard to human and environmental health. This review leverages the experience of researchers, stakeholders, and policymakers from Israel, the United-States, and Europe to present a holistic, multidisciplinary perspective on maximizing the benefits from municipal TWW use for irrigation.

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Article Synopsis
  • Using aerosol tracers helps assess the risk of airborne infections in building designs, particularly against viruses like SARS-CoV-2 and influenza.
  • A method is proposed to enhance a quantitative microbial risk assessment (QMRA) model by using synthetic DNA tracer concentrations to understand aerosol emissions from coughing or sneezing.
  • The tracer-scaled QMRA model evaluates various risk reduction strategies, such as ventilation and air filtration, providing a simple way to assess the effectiveness of interventions in reducing infection risks in indoor spaces.
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The aeromicrobiological transmission pathway of enteric pathogens in places with unsafe sanitation services is poorly understood. In an attempt to partly fill this knowledge gap, we assessed the potential public health impact of bioaerosols near open waste canals (OWCs) using Quantitative Microbial Risk Assessment (QMRA). We used data acquired in La Paz, Bolivia to characterize the risk of disease that aerosolized enteric pathogens may pose through food, fomites and inhalation (all followed by ingestion).

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In recent years, drinking water-associated pathogens that can cause infections in immunocompromised or otherwise susceptible individuals (henceforth referred to as DWPI), sometimes referred to as opportunistic pathogens or opportunistic premise plumbing pathogens, have received considerable attention. DWPI research has largely been conducted by experts focusing on specific microorganisms or within silos of expertise. The resulting mitigation approaches optimized for a single microorganism may have unintended consequences and trade-offs for other DWPI or other interests (e.

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Human noroviruses are a leading cause of food- and water-borne disease, which has led to an interest in quantifying norovirus health risks using quantitative microbial risk assessment (QMRA). Given the limited availability of quantitative norovirus data to input to QMRA models, some studies have applied a conversion factor to estimate norovirus exposure based on measured fecal indicator bacteria (FIB) concentrations. We conducted a review of peer-reviewed publications to identify the concentrations of noroviruses and FIB in raw, secondary-treated, and disinfected wastewater.

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Wastewater surveillance for pathogens using reverse transcription-polymerase chain reaction (RT-PCR) is an effective and resource-efficient tool for gathering community-level public health information, including the incidence of coronavirus disease-19 (COVID-19). Surveillance of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) in wastewater can potentially provide an early warning signal of COVID-19 infections in a community. The capacity of the world's environmental microbiology and virology laboratories for SARS-CoV-2 RNA characterization in wastewater is increasing rapidly.

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The annual risks of colonization, skin infection, bloodstream infection (BSI), and disease burden from exposures to antibiotic-resistant and susceptible () were estimated using quantitative microbial risk assessment (QMRA). We estimated the probability of nasal colonization after immersion in wastewater (WW) or greywater (GW) treated across a range of treatment alternatives and subsequent infection. Horizontal gene transfer was incorporated into the treatment model but had little effect on the predicted risk.

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Risk assessment is critical for identifying target concentrations of antibiotic resistant pathogens necessary for mitigating potential harmful exposures associated with water reuse. However, there is currently limited available data characterizing the concentrations of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in recycled water to support robust efforts at risk assessment. The objective of this systematic review was to identify and synthesize the existing literature documenting the presence and abundance of ARB and ARGs in recycled water.

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