Publications by authors named "Evan Snitkin"

Pathogen genomic surveillance in healthcare has the potential to enhance patient safety by detecting outbreaks earlier, thereby reducing morbidity and mortality. Despite benefits, there are barriers to adoption, including cost, expertise, and lack of standardized methodologies and incentives. This commentary advocates for 1) investment from healthcare payors, public health, and regulatory bodies and 2) additional research on genomic surveillance for improving patient outcomes and reducing infections.

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Measuring bacterial growth rates is routine, however, determining growth rates during infection in host has been more challenging. Peak-to-trough ratio (PTR) is a technique for studying microbial growth dynamics, calculated using the ratio of replication origin () copies to that of the terminus (), as originally defined by whole genome sequencing (WGS). WGS presents significant challenges in terms of expense and data analysis complexity due to the presence of host DNA in the samples.

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RT027 strains cause infections that vary in severity from asymptomatic to lethal, but the molecular basis for this variability is poorly understood. Through comparative analyses of RT027 clinical isolates, we determined that isolates that exhibit greater variability in their flagellar gene expression exhibit greater virulence . flagellar genes are phase-variably expressed due to the site-specific inversion of the 5'UTR region, which reversibly generates ON vs.

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  • - The study analyzed genomic data from 131 SARS-CoV-2 isolates collected from detainees at Cook County Jail in Chicago between March and May 2020 to understand transmission patterns during the early COVID-19 pandemic.
  • - Researchers found 29 genetic clusters among the detainees, with 17 clusters showing that individuals had overlapped in the jail during potential transmission periods, particularly within two specific buildings.
  • - The results indicate that SARS-CoV-2 was spreading in the jail despite infection control measures, highlighting the need for genomic analysis to enhance infection control strategies in correctional facilities.
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Lack of laboratory capacity hampers consistent national antimicrobial resistance (AMR) surveillance. Chromogenic media may provide a practical screening tool for detection of individuals colonized by extended-spectrum beta-lactamase (ESBL)-producing organisms. CHROMagar ESBL media represent an adequate screening method for the detection of extended-spectrum cephalosporin-resistant (ESCrE), isolated from rectal swabs.

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Background: Preventing transmission is crucial for reducing infections with multidrug-resistant organisms (MDROs) in nursing homes. To identify resident characteristics associated with MDRO spread, we investigated associations between patient characteristics and contamination of their proximate room surfaces with vancomycin-resistant enterococci (VRE).

Methods: In this retrospective observational study, we used demographic and clinical data (including data on comorbidities, physical independence, catheter use within the past 30 days, and antibiotic exposure within the past 30 days) and surveillance cultures of patient body sites and room surfaces at enrolment and during weekly follow-up visits within the first month, and monthly thereafter (up to 6 months), in six US nursing homes collected in a previous clinical trial (September, 2016, to August, 2018).

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Clostridioides difficile produces toxins that damage the colonic epithelium, causing colitis. Variation in disease severity is poorly understood and has been attributed to host factors and virulence differences between C. difficile strains.

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Carbapenem-resistant (CRE) are among the most concerning antibiotic resistance threats due to high rates of multidrug resistance, transmissibility in health care settings, and high mortality rates. We evaluated the potential for regional genomic surveillance to track the spread of -carrying CRE (KPC-CRE) by using isolate collections from health care facilities in three U.S.

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Determining the risk of a phenotypic outcome is a complex balance of variants "for" or "against" the phenotype, which in the context of human genetic diseases have been summarized using polygenic risk scores. In a previously published article (K. T.

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, a leading cause of nosocomial infection, produces toxins that damage the colonic epithelium and results in colitis that varies from mild to fulminant. Variation in disease severity is poorly understood and has been attributed to host factors (age, immune competence and intestinal microbiome composition) and/or virulence differences between strains, with some, such as the epidemic BI/NAP1/027 (MLST1) strain, being associated with greater virulence. We tested 23 MLST1(ST1) clinical isolates for virulence in antibiotic-treated C57BL/6 mice.

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Background: Identifying the source of healthcare personnel (HCP) coronavirus disease 2019 (COVID-19) is important to guide occupational safety efforts. We used a combined whole genome sequencing (WGS) and epidemiologic approach to investigate the source of HCP COVID-19 at a tertiary-care center early in the COVID-19 pandemic.

Methods: Remnant nasopharyngeal swab samples from HCP and patients with polymerase chain reaction-proven COVID-19 from a period with complete sample retention (14 March 2020 to 10 April 2020) at Rush University Medical Center in Chicago, Illinois, underwent viral RNA extraction and WGS.

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We assessed risk factors for colistin resistance among carbapenem-resistant (CRKP) from 375 patients in long-term acute care hospitals. Recent colistin or polymyxin B exposure was associated with increased odds of colistin resistance (adjusted odds ratio = 1.11 per day of exposure, 95% confidence interval = 1.

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Article Synopsis
  • The study investigates how certain genes in Klebsiella pneumoniae are linked to the transition from gut colonization to infection, highlighting the genetic differences between strains.
  • Researchers compared cases of infection (N=85) with asymptomatic carriers (N=160) to find 37 genes associated with infection risk, many related to stress and antibiotic resistance rather than traditional virulence factors.
  • Five of these genes were further validated in a separate group, suggesting their role in understanding infection progression in patients carrying Klebsiella bacteria.
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We assessed susceptibility patterns to newer antimicrobial agents among clinical carbapenem-resistant (CRKP) isolates from patients in long-term acute-care hospitals (LTACHs) from 2014 to 2015. Meropenem-vaborbactam and imipenem-relebactam nonsusceptibility were observed among 9.9% and 9.

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Background: A crucial barrier to the routine application of whole-genome sequencing (WGS) for infection prevention is the insufficient criteria for determining whether a genomic linkage is consistent with transmission within the facility. We evaluated the use of single-nucleotide variant (SNV) thresholds, as well as a novel threshold-free approach, for inferring transmission linkages in a high-transmission setting.

Methods: We did a retrospective genomic epidemiology analysis of samples previously collected in the context of an intervention study at a long-term acute care hospital in the USA.

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Clinical disease from Clostridioides difficile infection can be mediated by two toxins and their neighboring regulatory genes located within the five-gene pathogenicity locus (PaLoc). We provide several lines of evidence that the cytotoxicity of C. difficile may be modulated by genomic variants outside the PaLoc.

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More than half of women will experience a urinary tract infection (UTI), with uropathogenic Escherichia coli (UPEC) causing ~80% of uncomplicated cases. Iron acquisition systems are essential for uropathogenesis, and UPEC strains encode highly diverse iron acquisition systems, underlining their importance. However, a recent UPEC clinical isolate, HM7, lacks this diversity and instead encodes the synthesis pathway for a sole siderophore, enterobactin.

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  • A study conducted at Cook County Jail examined the prevalence of MRSA colonization among incarcerated females, enrolling 250 women shortly after intake.
  • The research found that 20% of participants were colonized with MRSA, with significant associations to high-risk behaviors such as drug use, unstable housing, and sexual activity.
  • The findings challenge previous beliefs about lower MRSA risk in women, indicating that targeted interventions may be needed for high-risk populations.
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Symbiotic bacteria are responsible for the majority of complex carbohydrate digestion in the human colon. Since the identities and amounts of dietary polysaccharides directly impact the gut microbiota, determining which microorganisms consume specific nutrients is central for defining the relationship between diet and gut microbial ecology. Using a custom phenotyping array, we determined carbohydrate utilization profiles for 354 members of the , a dominant saccharolytic phylum.

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Increasing evidence of regional pathogen transmission networks highlights the importance of investigating the dissemination of multidrug-resistant organisms (MDROs) across a region to identify where transmission is occurring and how pathogens move across regions. We developed a framework for investigating MDRO regional transmission dynamics using whole-genome sequencing data and created regentrans, an easy-to-use, open source R package that implements these methods (https://github.com/Snitkin-Lab-Umich/regentrans).

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Machine learning (ML) for classification and prediction based on a set of features is used to make decisions in healthcare, economics, criminal justice and more. However, implementing an ML pipeline including preprocessing, model selection, and evaluation can be time-consuming, confusing, and difficult. Here, we present mikropml (prononced "meek-ROPE em el"), an easy-to-use R package that implements ML pipelines using regression, support vector machines, decision trees, random forest, or gradient-boosted trees.

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  • MRSA is a major cause of both healthcare and community infections, with USA300 being the community strain and USA100 being the healthcare strain.
  • Researchers used whole-genome sequencing (WGS) to refine an antibiotic prediction rule that distinguishes between these strains based on their resistance patterns, collecting MRSA isolates from 2007 to 2017.
  • The study found that lower resistance (≤2 antibiotic classes) predicted USA300 with good accuracy, and higher resistance was linked to individuals with a history of incarceration, indicating a more resistant strain circulating in at-risk communities.
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  • Bloodstream infections (BSI) represent a significant public health challenge due to their high mortality rates and rising antibiotic resistance, particularly among Gram-negative bacteria.
  • The study focused on six common pathogens (E. coli, S. marcescens, K. pneumoniae, E. hormaechei, C. freundii, and A. baumannii) to analyze their infection dynamics and replication rates in a mouse model.
  • Findings revealed that while some bacteria like K. pneumoniae and S. marcescens grew rapidly in specific organs, others were gradually cleared, indicating varying abilities to establish and maintain infections in the host.
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