BackgroundCarbapenem-resistant Enterobacterales (CRE) harboring blaKPC have been endemic in Chica... more BackgroundCarbapenem-resistant Enterobacterales (CRE) harboring blaKPC have been endemic in Chicago-area healthcare networks for more than a decade. During 2016-2019, a series of regional point prevalence surveys identified increasing prevalence of blaNDM-containing CRE in multiple long-term acute care hospitals (LTACHs) and ventilator-capable skilled nursing facilities (vSNFs). We performed a genomic epidemiology investigation of blaNDM-producing CRE to understand their regional emergence and spread.MethodsWe performed whole-genome sequencing on NDM+ CRE isolates from four point-prevalence surveys across 35 facilities (LTACHs, vSNFs, and acute care hospital medical intensive care units) in the Chicago area and investigated the genomic relatedness and transmission dynamics of these isolates over time.ResultsGenomic analyses revealed that the rise of NDM+ CRE was due to the clonal dissemination of an ST147 Klebsiella pneumoniae strain harboring blaNDM-1 on an IncF plasmid. Dated phyl...
Background: Upon admission, 56.8% of patients entering 6 Michigan nursing facilities from regiona... more Background: Upon admission, 56.8% of patients entering 6 Michigan nursing facilities from regional acute-care hospitals (ACHs) were colonized with 1 or more antibiotic-resistant organisms (AROs) (Mody 2018, CID). This observation raises 2 questions critical to regional infection control strategies: (1) Is the high ARO burden entering nursing facilities driven by dominant epidemic lineages or diverse circulating strains? and (2) What are the relative roles of patient characteristics (eg, high-risk patients) and exposure to specific ACHs (eg, high-risk facilities) in determining whether patients are colonized with AROs upon nursing facility admission? Here, we integrated whole-genome sequencing, patient transfer, and clinical data to answer these questions for the 4 most prevalent ARO species in the region: methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecalis (VREfc), Enterococcus faecium (VREfm), and ciprofloxacin-resistant Escherichia coli (...
Background Carbapenem-resistant Enterobacterales (CRE) harboring blaKPC have been endemic in Chic... more Background Carbapenem-resistant Enterobacterales (CRE) harboring blaKPC have been endemic in Chicago-area healthcare networks for more than a decade. During 2016-2019, a series of regional point prevalence surveys identified increasing prevalence of blaNDM-containing CRE in multiple long-term acute care hospitals (LTACHs) and ventilator-capable skilled nursing facilities (vSNFs). We performed a genomic epidemiology investigation of blaNDM-producing CRE to understand their regional emergence and spread. Methods We performed whole-genome sequencing on NDM+ CRE isolates from four point-prevalence surveys across 35 facilities (LTACHs, vSNFs, and acute care hospital medical intensive care units) in the Chicago area and investigated the genomic relatedness and transmission dynamics of these isolates over time. Results Genomic analyses revealed that the rise of NDM+ CRE was due to the clonal dissemination of an ST147 Klebsiella pneumoniae strain harboring blaNDM-1 on an IncF plasmid. Dated...
UropathogenicEscherichia coli(UPEC) is the major causative agent of uncomplicated urinary tract i... more UropathogenicEscherichia coli(UPEC) is the major causative agent of uncomplicated urinary tract infections (UTIs). A common virulence genotype of UPEC strains responsible for UTIs is yet to be defined, due to the large variation of virulence factors observed in UPEC strains. We hypothesized that studying UPEC functional responses in patients might reveal universal UPEC features that enable pathogenesis. Here we identify a transcriptional program shared by genetically diverse UPEC strains isolated from 14 patients during uncomplicated UTIs. Strikingly, thisin vivogene expression program is marked by upregulation of translational machinery, providing a mechanism for the rapid growth within the host. Our analysis indicates that switching to a more specialized catabolism and scavenging lifestyle in the host allows for the increased translational output. Our study identifies a common transcriptional program underlying UTIs and illuminates the molecular underpinnings that likely facilitat...
Background Patients entering nursing facilities (NFs) are frequently colonized with antibiotic re... more Background Patients entering nursing facilities (NFs) are frequently colonized with antibiotic resistant organisms (AROs). To understand the determinants of ARO colonization on NF admission we applied whole-genome sequencing to track the spread of four ARO species across regional NFs and evaluated patient-level characteristics and transfer acute-care hospitals (ACHs) as risk factors for colonization. Methods 584 patients from six NFs were surveyed for methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecalis/faecium (VREfc/VREfm) and ciprofloxacin-resistant Escherichia coli (CipREc) colonization. Genomic analysis was performed to quantify ARO spread between NFs and compared to patient-transfer networks. The association between admission colonization and patient-level variables and recent ACH exposures was examined using multivariable regression models. Results The majority of ARO isolates across study sites belonged to major healthcare-associated...
While variant identification pipelines are becoming increasingly standardized, less attention has... more While variant identification pipelines are becoming increasingly standardized, less attention has been paid to the pre-processing of variants prior to their use in bacterial genome-wide association studies (bGWAS). Three nuances of variant pre-processing that impact downstream identification of genetic associations include the separation of variants at multiallelic sites, separation of variants in overlapping genes, and referencing of variants relative to ancestral alleles. Here we demonstrate the importance of these variant pre-processing steps on diverse bacterial genomic datasets and present prewas, an R package, that standardizes the pre-processing of multiallelic sites, overlapping genes, and reference alleles before bGWAS. This package facilitates improved reproducibility and interpretability of bGWAS results. Prewas enables users to extract maximal information from bGWAS by implementing multi-line representation for multiallelic sites and variants in overlapping genes. Prewas...
Uropathogenic Escherichia coli (UPEC) is the major causative agent of uncomplicated urinary tract... more Uropathogenic Escherichia coli (UPEC) is the major causative agent of uncomplicated urinary tract infections (UTIs). A common virulence genotype of UPEC strains responsible for UTIs is yet to be defined, due to the large variation of virulence factors observed in UPEC strains. We hypothesized that studying UPEC functional responses in patients might reveal universal UPEC features that enable pathogenesis. Here we identify a transcriptional program shared by genetically diverse UPEC strains isolated from 14 patients during uncomplicated UTIs. Strikingly, this in vivo gene expression program is marked by upregulation of translational machinery, providing a mechanism for the rapid growth within the host. Our analysis indicates that switching to a more specialized catabolism and scavenging lifestyle in the host allows for the increased translational output. Our study identifies a common transcriptional program underlying UTIs and illuminates the molecular underpinnings that likely facil...
Background: Factors that influence vaginal microbiota composition, including its source, are not ... more Background: Factors that influence vaginal microbiota composition, including its source, are not well understood. To determine if vaginal microbiota transmission from mother to daughter at birth influences the human vaginal microbiota composition in adolescence, we investigated the relationship between the vaginal microbiota of 13 mother/daughter pairs and the daughter's birth mode. Results: Based on analysis of bacterial 16S rRNA gene sequences, the vaginal microbiotas of mother/daughter pairs were more similar to each other if the daughter was born by vaginal delivery rather than by C-section. Additionally, genome sequences from an important member of the vaginal microbiota, Lactobacillus crispatus, isolated from one mother/daughter pair in which the daughter was born by vaginal delivery, were highly similar. Conclusions: Both community-level analysis and isolate genome sequence analysis provide evidence of birth-mode dependent transmission and persistence of at least some mem...
As part of the Reproducibility Project: Cancer Biology we published a Registered Report (Eaton et... more As part of the Reproducibility Project: Cancer Biology we published a Registered Report (Eaton et al., 2015) that described how we intended to replicate selected experiments from the paper “Intestinal Inflammation Targets Cancer-Inducing Activity of the Microbiota” (Arthur et al., 2012). Here we report the results. We observed no impact on bacterial growth or colonization capacity when the polyketide synthase (pks) genotoxic island was deleted from E. coli NC101, similar to the original study (Supplementary Figure 7; Arthur et al., 2012). However, for the experiment that compared inflammation, invasion, and neoplasia in azoxymethane (AOM)-treated interleukin-10-deficient mice mono-associated with NC101 or NC101Δ pks the experimental timing of the replication attempt was longer than that of the original study. This difference was because in the original study the methodology was not clearly stated and likely led to the increased mortality and severity of inflammation observed in this...
INTRODUCTION AND OBJECTIVES: Uropathogenic Escherichia coli (UPEC) is the major causative agent o... more INTRODUCTION AND OBJECTIVES: Uropathogenic Escherichia coli (UPEC) is the major causative agent of uncomplicated urinary tract infections (UTIs). UPEC strains carry diverse assortments of virulence factors and a common virulence genotype responsible for urinary tract infection is yet to be defined. We hypothesized that studying patterns of gene expression in patients might identify universal bacterial features that enable uropathogenesis. METHODS: Using RNA sequencing technology, we examined UPEC gene expression directly in 14 patients presenting with uncomplicated UTI and compared it to the gene expression of identical strains cultured in vitro to mid-exponential stage in filter-sterilized human urine. RESULTS: Here we identify a common transcriptional program shared by genetically diverse UPEC strains isolated from 14 patients with uncomplicated UTIs. Strikingly, the conserved gene expression program in patients is distinct from one observed during in vitro urine culture of the identical strains. Moreover, regulatory network analysis reveals that drastic downregulation of key metabolic regulons in all 14 UPEC strains facilitates markedly increased expression of translation and replication machinery. CONCLUSIONS: Taken together, our study identifies for the first time a common thread underlying UTI and illuminates the molecular underpinnings that likely facilitate the remarkably fast growth rate of UPEC that has been previously observed in infected patients.
Development of effective strategies to limit the proliferation of multidrug-resistant organisms r... more Development of effective strategies to limit the proliferation of multidrug-resistant organisms requires a thorough understanding of how such organisms spread among health care facilities. We sought to uncover the chains of transmission underlying a 2008 U.S. regional outbreak of carbapenem-resistant by performing an integrated analysis of genomic and interfacility patient-transfer data. Genomic analysis yielded a high-resolution transmission network that assigned directionality to regional transmission events and discriminated between intra- and interfacility transmission when epidemiologic data were ambiguous or misleading. Examining the genomic transmission network in the context of interfacility patient transfers (patient-sharing networks) supported the role of patient transfers in driving the outbreak, with genomic analysis revealing that a small subset of patient-transfer events was sufficient to explain regional spread. Further integration of the genomic and patient-sharing n...
Uropathogenic (UPEC) strains cause most uncomplicated urinary tract infections (UTIs). These stra... more Uropathogenic (UPEC) strains cause most uncomplicated urinary tract infections (UTIs). These strains are a subgroup of extraintestinal pathogenic (ExPEC) strains that infect extraintestinal sites, including urinary tract, meninges, bloodstream, lungs, and surgical sites. Here, we hypothesize that UPEC isolates adapt to and grow more rapidly within the urinary tract than other isolates and survive in that niche. To date, there has not been a reliable method available to measure their growth rate Here we used two methods: segregation of nonreplicating plasmid pGTR902, and peak-to-trough ratio (PTR), a sequencing-based method that enumerates bacterial chromosomal replication forks present during cell division. In the murine model of UTI, UPEC strain growth was robust , matching or exceeding growth rates and only slowing after reaching high CFU counts at 24 and 30 h postinoculation (hpi). In contrast, asymptomatic bacteriuria (ABU) strains tended to maintain high growth rates at 6, 24, ...
Despite insights gained through experimental models, the set of bacterial genes important for hum... more Despite insights gained through experimental models, the set of bacterial genes important for human infection is unclear for many of our most threatening pathogens. Klebsiella pneumoniae is a leading cause of health care-associated infections (HAIs) and commonly colonizes hospitalized patients, but the factors that determine whether a particular isolate causes disease or remains a colonizer are poorly understood. To identify bacterial genes associated with K. pneumoniae infection, a case-control study was performed comparing infected and asymptomatic colonized patients. Comparative bacterial genomics was combined with a conditional logit model that identified patient factors differentiating cases from controls. This method identified five gene loci associated with infection after adjustment for patient factors, including a psicose sugar utilization locus that was validated as a fitness factor during mouse lung infection. These results indicate that bacterial genome-wide association ...
BackgroundCarbapenem-resistant Enterobacterales (CRE) harboring blaKPC have been endemic in Chica... more BackgroundCarbapenem-resistant Enterobacterales (CRE) harboring blaKPC have been endemic in Chicago-area healthcare networks for more than a decade. During 2016-2019, a series of regional point prevalence surveys identified increasing prevalence of blaNDM-containing CRE in multiple long-term acute care hospitals (LTACHs) and ventilator-capable skilled nursing facilities (vSNFs). We performed a genomic epidemiology investigation of blaNDM-producing CRE to understand their regional emergence and spread.MethodsWe performed whole-genome sequencing on NDM+ CRE isolates from four point-prevalence surveys across 35 facilities (LTACHs, vSNFs, and acute care hospital medical intensive care units) in the Chicago area and investigated the genomic relatedness and transmission dynamics of these isolates over time.ResultsGenomic analyses revealed that the rise of NDM+ CRE was due to the clonal dissemination of an ST147 Klebsiella pneumoniae strain harboring blaNDM-1 on an IncF plasmid. Dated phyl...
Background: Upon admission, 56.8% of patients entering 6 Michigan nursing facilities from regiona... more Background: Upon admission, 56.8% of patients entering 6 Michigan nursing facilities from regional acute-care hospitals (ACHs) were colonized with 1 or more antibiotic-resistant organisms (AROs) (Mody 2018, CID). This observation raises 2 questions critical to regional infection control strategies: (1) Is the high ARO burden entering nursing facilities driven by dominant epidemic lineages or diverse circulating strains? and (2) What are the relative roles of patient characteristics (eg, high-risk patients) and exposure to specific ACHs (eg, high-risk facilities) in determining whether patients are colonized with AROs upon nursing facility admission? Here, we integrated whole-genome sequencing, patient transfer, and clinical data to answer these questions for the 4 most prevalent ARO species in the region: methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecalis (VREfc), Enterococcus faecium (VREfm), and ciprofloxacin-resistant Escherichia coli (...
Background Carbapenem-resistant Enterobacterales (CRE) harboring blaKPC have been endemic in Chic... more Background Carbapenem-resistant Enterobacterales (CRE) harboring blaKPC have been endemic in Chicago-area healthcare networks for more than a decade. During 2016-2019, a series of regional point prevalence surveys identified increasing prevalence of blaNDM-containing CRE in multiple long-term acute care hospitals (LTACHs) and ventilator-capable skilled nursing facilities (vSNFs). We performed a genomic epidemiology investigation of blaNDM-producing CRE to understand their regional emergence and spread. Methods We performed whole-genome sequencing on NDM+ CRE isolates from four point-prevalence surveys across 35 facilities (LTACHs, vSNFs, and acute care hospital medical intensive care units) in the Chicago area and investigated the genomic relatedness and transmission dynamics of these isolates over time. Results Genomic analyses revealed that the rise of NDM+ CRE was due to the clonal dissemination of an ST147 Klebsiella pneumoniae strain harboring blaNDM-1 on an IncF plasmid. Dated...
UropathogenicEscherichia coli(UPEC) is the major causative agent of uncomplicated urinary tract i... more UropathogenicEscherichia coli(UPEC) is the major causative agent of uncomplicated urinary tract infections (UTIs). A common virulence genotype of UPEC strains responsible for UTIs is yet to be defined, due to the large variation of virulence factors observed in UPEC strains. We hypothesized that studying UPEC functional responses in patients might reveal universal UPEC features that enable pathogenesis. Here we identify a transcriptional program shared by genetically diverse UPEC strains isolated from 14 patients during uncomplicated UTIs. Strikingly, thisin vivogene expression program is marked by upregulation of translational machinery, providing a mechanism for the rapid growth within the host. Our analysis indicates that switching to a more specialized catabolism and scavenging lifestyle in the host allows for the increased translational output. Our study identifies a common transcriptional program underlying UTIs and illuminates the molecular underpinnings that likely facilitat...
Background Patients entering nursing facilities (NFs) are frequently colonized with antibiotic re... more Background Patients entering nursing facilities (NFs) are frequently colonized with antibiotic resistant organisms (AROs). To understand the determinants of ARO colonization on NF admission we applied whole-genome sequencing to track the spread of four ARO species across regional NFs and evaluated patient-level characteristics and transfer acute-care hospitals (ACHs) as risk factors for colonization. Methods 584 patients from six NFs were surveyed for methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecalis/faecium (VREfc/VREfm) and ciprofloxacin-resistant Escherichia coli (CipREc) colonization. Genomic analysis was performed to quantify ARO spread between NFs and compared to patient-transfer networks. The association between admission colonization and patient-level variables and recent ACH exposures was examined using multivariable regression models. Results The majority of ARO isolates across study sites belonged to major healthcare-associated...
While variant identification pipelines are becoming increasingly standardized, less attention has... more While variant identification pipelines are becoming increasingly standardized, less attention has been paid to the pre-processing of variants prior to their use in bacterial genome-wide association studies (bGWAS). Three nuances of variant pre-processing that impact downstream identification of genetic associations include the separation of variants at multiallelic sites, separation of variants in overlapping genes, and referencing of variants relative to ancestral alleles. Here we demonstrate the importance of these variant pre-processing steps on diverse bacterial genomic datasets and present prewas, an R package, that standardizes the pre-processing of multiallelic sites, overlapping genes, and reference alleles before bGWAS. This package facilitates improved reproducibility and interpretability of bGWAS results. Prewas enables users to extract maximal information from bGWAS by implementing multi-line representation for multiallelic sites and variants in overlapping genes. Prewas...
Uropathogenic Escherichia coli (UPEC) is the major causative agent of uncomplicated urinary tract... more Uropathogenic Escherichia coli (UPEC) is the major causative agent of uncomplicated urinary tract infections (UTIs). A common virulence genotype of UPEC strains responsible for UTIs is yet to be defined, due to the large variation of virulence factors observed in UPEC strains. We hypothesized that studying UPEC functional responses in patients might reveal universal UPEC features that enable pathogenesis. Here we identify a transcriptional program shared by genetically diverse UPEC strains isolated from 14 patients during uncomplicated UTIs. Strikingly, this in vivo gene expression program is marked by upregulation of translational machinery, providing a mechanism for the rapid growth within the host. Our analysis indicates that switching to a more specialized catabolism and scavenging lifestyle in the host allows for the increased translational output. Our study identifies a common transcriptional program underlying UTIs and illuminates the molecular underpinnings that likely facil...
Background: Factors that influence vaginal microbiota composition, including its source, are not ... more Background: Factors that influence vaginal microbiota composition, including its source, are not well understood. To determine if vaginal microbiota transmission from mother to daughter at birth influences the human vaginal microbiota composition in adolescence, we investigated the relationship between the vaginal microbiota of 13 mother/daughter pairs and the daughter's birth mode. Results: Based on analysis of bacterial 16S rRNA gene sequences, the vaginal microbiotas of mother/daughter pairs were more similar to each other if the daughter was born by vaginal delivery rather than by C-section. Additionally, genome sequences from an important member of the vaginal microbiota, Lactobacillus crispatus, isolated from one mother/daughter pair in which the daughter was born by vaginal delivery, were highly similar. Conclusions: Both community-level analysis and isolate genome sequence analysis provide evidence of birth-mode dependent transmission and persistence of at least some mem...
As part of the Reproducibility Project: Cancer Biology we published a Registered Report (Eaton et... more As part of the Reproducibility Project: Cancer Biology we published a Registered Report (Eaton et al., 2015) that described how we intended to replicate selected experiments from the paper “Intestinal Inflammation Targets Cancer-Inducing Activity of the Microbiota” (Arthur et al., 2012). Here we report the results. We observed no impact on bacterial growth or colonization capacity when the polyketide synthase (pks) genotoxic island was deleted from E. coli NC101, similar to the original study (Supplementary Figure 7; Arthur et al., 2012). However, for the experiment that compared inflammation, invasion, and neoplasia in azoxymethane (AOM)-treated interleukin-10-deficient mice mono-associated with NC101 or NC101Δ pks the experimental timing of the replication attempt was longer than that of the original study. This difference was because in the original study the methodology was not clearly stated and likely led to the increased mortality and severity of inflammation observed in this...
INTRODUCTION AND OBJECTIVES: Uropathogenic Escherichia coli (UPEC) is the major causative agent o... more INTRODUCTION AND OBJECTIVES: Uropathogenic Escherichia coli (UPEC) is the major causative agent of uncomplicated urinary tract infections (UTIs). UPEC strains carry diverse assortments of virulence factors and a common virulence genotype responsible for urinary tract infection is yet to be defined. We hypothesized that studying patterns of gene expression in patients might identify universal bacterial features that enable uropathogenesis. METHODS: Using RNA sequencing technology, we examined UPEC gene expression directly in 14 patients presenting with uncomplicated UTI and compared it to the gene expression of identical strains cultured in vitro to mid-exponential stage in filter-sterilized human urine. RESULTS: Here we identify a common transcriptional program shared by genetically diverse UPEC strains isolated from 14 patients with uncomplicated UTIs. Strikingly, the conserved gene expression program in patients is distinct from one observed during in vitro urine culture of the identical strains. Moreover, regulatory network analysis reveals that drastic downregulation of key metabolic regulons in all 14 UPEC strains facilitates markedly increased expression of translation and replication machinery. CONCLUSIONS: Taken together, our study identifies for the first time a common thread underlying UTI and illuminates the molecular underpinnings that likely facilitate the remarkably fast growth rate of UPEC that has been previously observed in infected patients.
Development of effective strategies to limit the proliferation of multidrug-resistant organisms r... more Development of effective strategies to limit the proliferation of multidrug-resistant organisms requires a thorough understanding of how such organisms spread among health care facilities. We sought to uncover the chains of transmission underlying a 2008 U.S. regional outbreak of carbapenem-resistant by performing an integrated analysis of genomic and interfacility patient-transfer data. Genomic analysis yielded a high-resolution transmission network that assigned directionality to regional transmission events and discriminated between intra- and interfacility transmission when epidemiologic data were ambiguous or misleading. Examining the genomic transmission network in the context of interfacility patient transfers (patient-sharing networks) supported the role of patient transfers in driving the outbreak, with genomic analysis revealing that a small subset of patient-transfer events was sufficient to explain regional spread. Further integration of the genomic and patient-sharing n...
Uropathogenic (UPEC) strains cause most uncomplicated urinary tract infections (UTIs). These stra... more Uropathogenic (UPEC) strains cause most uncomplicated urinary tract infections (UTIs). These strains are a subgroup of extraintestinal pathogenic (ExPEC) strains that infect extraintestinal sites, including urinary tract, meninges, bloodstream, lungs, and surgical sites. Here, we hypothesize that UPEC isolates adapt to and grow more rapidly within the urinary tract than other isolates and survive in that niche. To date, there has not been a reliable method available to measure their growth rate Here we used two methods: segregation of nonreplicating plasmid pGTR902, and peak-to-trough ratio (PTR), a sequencing-based method that enumerates bacterial chromosomal replication forks present during cell division. In the murine model of UTI, UPEC strain growth was robust , matching or exceeding growth rates and only slowing after reaching high CFU counts at 24 and 30 h postinoculation (hpi). In contrast, asymptomatic bacteriuria (ABU) strains tended to maintain high growth rates at 6, 24, ...
Despite insights gained through experimental models, the set of bacterial genes important for hum... more Despite insights gained through experimental models, the set of bacterial genes important for human infection is unclear for many of our most threatening pathogens. Klebsiella pneumoniae is a leading cause of health care-associated infections (HAIs) and commonly colonizes hospitalized patients, but the factors that determine whether a particular isolate causes disease or remains a colonizer are poorly understood. To identify bacterial genes associated with K. pneumoniae infection, a case-control study was performed comparing infected and asymptomatic colonized patients. Comparative bacterial genomics was combined with a conditional logit model that identified patient factors differentiating cases from controls. This method identified five gene loci associated with infection after adjustment for patient factors, including a psicose sugar utilization locus that was validated as a fitness factor during mouse lung infection. These results indicate that bacterial genome-wide association ...
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