scholarly journals Genomic analysis of Clostridioides difficile in two regions reveals a diversity of strains and limited transmission

2020 ◽  
Vol 41 (S1) ◽  
pp. s237-s238
Author(s):  
Nicole Pecora ◽  
Stacy Holzbauer ◽  
Xiong Wang ◽  
Yu Gu ◽  
Trupti Hatwar ◽  
...  

Background: The epidemic NAP1/027 Clostridioides difficile strain (MLST1, ST1) that emerged in the mid-2000 is on the decline. The current distribution of C. difficile strain types and their transmission dynamics are poorly defined. We performed whole-genome sequencing (WGS) of C. difficile isolates in 2 regions to identify the predominant multilocus sequence types (MLSTs) in community- and healthcare-associated cases and potential transmission between cases using whole-genome single-nucleotide polymorphism (SNP) analysis. Methods: Isolates were collected through the CDC Emerging Infections Program population-based surveillance for C. difficile infections (CDI) for 3 months between 2016 and 2017 in 5 Minnesota counties and 1 New York county. Isolates were limited to incident cases (CDI in a county resident with no positive C. difficile test in the preceding 8 weeks). Cases were classified as healthcare associated (HA-CDI) or community associated (CA-CDI) based on healthcare exposures as previously described. WGS was performed on an Illumina Miseq. The CFSAN (FDA) pipeline was used to compute whole-genome SNPs, SPAdes was used for assembly, and MLST was assigned according to www.pubmlst.org. Results: Of 431 isolates, 269 originated from New York and 162 from Minnesota; 203 cases were classified as CA-CDI and 221 as HA-CDI. The proportion of CA-CDI cases was higher in Minnesota than in New York: 62% vs 38%. The predominant MLSTs across both sites were ST42 (9%), ST8 (8%), and ST2 (8%). MLSTs more frequently encountered in HA-CDI than CA-CDI included ST1 (note that this ST includes PCR Ribotype 027; 76% HA-CDI), ST53 (84% HA-CDI), and ST43 (80% HA-CDI). In contrast, ST110 (63% CA-CDI) and ST3 (67% CA-CDI) were more commonly isolated from CA-CDI cases. ST1 accounted for 7.6% of circulating strains and was more common in New York than Minnesota (10% vs 3%) and was concentrated among New York HA-CDI cases. Also, 412 isolates (1 per patient) were included in the final whole-genome SNP analysis. Of these, only 12 pairs were separated by 0–3 SNPs, indicating potential transmission, and most involved HA-CDI cases. ST1, ST17, and ST46 accounted for 8 of 12 pairs, with ST17 and ST46 potentially forming small clusters. Conclusions: This analysis provides a snapshot of the current genomic epidemiology of C. difficile across 2 geographically and epidemiologically distinct regions of the United States and supports other studies suggesting that the role of direct transmission in the spread of CDI may be limited.Funding: NoneDisclosures: None

2019 ◽  
Vol 6 (2) ◽  
Author(s):  
Bradley T Endres ◽  
Khurshida Begum ◽  
Hua Sun ◽  
Seth T Walk ◽  
Ali Memariani ◽  
...  

Abstract Background The epidemic Clostridioides difficile ribotype 027 strain resulted from the dissemination of 2 separate fluoroquinolone-resistant lineages: FQR1 and FQR2. Both lineages were reported to originate in North America; however, confirmatory large-scale investigations of C difficile ribotype 027 epidemiology using whole genome sequencing has not been undertaken in the United States. Methods Whole genome sequencing and single-nucleotide polymorphism (SNP) analysis was performed on 76 clinical ribotype 027 isolates obtained from hospitalized patients in Texas with C difficile infection and compared with 32 previously sequenced worldwide strains. Maximum-likelihood phylogeny based on a set of core genome SNPs was used to construct phylogenetic trees investigating strain macro- and microevolution. Bayesian phylogenetic and phylogeographic analyses were used to incorporate temporal and geographic variables with the SNP strain analysis. Results Whole genome sequence analysis identified 2841 SNPs including 900 nonsynonymous mutations, 1404 synonymous substitutions, and 537 intergenic changes. Phylogenetic analysis separated the strains into 2 prominent groups, which grossly differed by 28 SNPs: the FQR1 and FQR2 lineages. Five isolates were identified as pre-epidemic strains. Phylogeny demonstrated unique clustering and resistance genes in Texas strains indicating that spatiotemporal bias has defined the microevolution of ribotype 027 genetics. Conclusions Clostridioides difficile ribotype 027 lineages emerged earlier than previously reported, coinciding with increased use of fluoroquinolones. Both FQR1 and FQR2 ribotype 027 epidemic lineages are present in Texas, but they have evolved geographically to represent region-specific public health threats.


2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S830-S830 ◽  
Author(s):  
Ashley Paulick ◽  
Michelle Adamczyk ◽  
Lauren C Korhonen ◽  
Alice Guh ◽  
Amy Gargis ◽  
...  

Abstract Background In 2009, the Centers for Disease Control and Prevention (CDC) implemented Clostridioides difficile infection (CDI) surveillance through the Emerging Infections Program (EIP) to monitor the incidence and evolving epidemiology of CDI in the United States. Since 2012, ribotypes (RTs) 027, 106, 002, 014, and 020 have constituted the top five strain types among both US community- and healthcare-associated isolates. Here we describe the changes in molecular epidemiology of C. difficile isolates collected in the United States in 2017. Methods In 2017, CDI surveillance was conducted at 10 EIP sites (CA, CO, CT, GA, MD, MN, NM, NY, OR, and TN). A convenience sample of clinical laboratories across EIP sites submitted C. difficile-positive stool specimens to the MN Department of Health Public Health Laboratory and Hines VA Hospital (IL) for culture. Isolates were forwarded to CDC and characterized by capillary-based PCR-ribotyping and PCR detection of tcdA, tcdB, cdtA, cdtB, and deletions in tcdC. Results In 2017, 1,051 C. difficile isolates were submitted; the total number of isolates received from each site ranged from 11 to 286 with a median of 85.5. In total, 143 RTs were observed, with the majority of isolates harboring toxin genes tcdA and tcdB (95%) and a wild-type tcdC sequence (71%). Among 556 healthcare-associated isolates, RT 027 was the most prevalent and the top RT at 5 sites (CA, GA, MD, NM, TN). Ribotype 106 was the most prevalent among 495 community-associated CA isolates and the top RT at 6 sites (CO, CT, GA, MD, MN, TN). Ribotype 027 significantly decreased from 2012 to 2017 among both healthcare-associated (21% vs 15%; p = 0.02) and community-associated isolates (17% vs 6%; P < 0.0001). Among healthcare-associated isolates, RT 076, which was observed in 8 EIP sites, increased from 2% in 2016 to 5% in 2017 (p = 0.05) and replaced RT 020 as one of the top 5 healthcare-associated RTs in 2017. Conclusion Despite an overall decline since 2012, RT 027 remained the most prevalent RT among healthcare-associated isolates submitted in 2017. The increased frequency of RT 076 among healthcare-associated isolates submitted in 2017 highlights the evolving molecular epidemiology of C. difficile and the need for continued surveillance to monitor potential emerging strains. Disclosures All authors: No reported disclosures.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Bryan Angelo P. Roxas ◽  
Jennifer Lising Roxas ◽  
Rachel Claus-Walker ◽  
Anusha Harishankar ◽  
Asad Mansoor ◽  
...  

AbstractClostridioides difficile infection (CDI) is a major healthcare-associated diarrheal disease. Consistent with trends across the United States, C. difficile RT106 was the second-most prevalent molecular type in our surveillance in Arizona from 2015 to 2018. A representative RT106 strain displayed robust virulence and 100% lethality in the hamster model of acute CDI. We identified a unique 46 KB genomic island (GI1) in all RT106 strains sequenced to date, including those in public databases. GI1 was not found in its entirety in any other C. difficile clade, or indeed, in any other microbial genome; however, smaller segments were detected in Enterococcus faecium strains. Molecular clock analyses suggested that GI1 was horizontally acquired and sequentially assembled over time. GI1 encodes homologs of VanZ and a SrtB-anchored collagen-binding adhesin, and correspondingly, all tested RT106 strains had increased teicoplanin resistance, and a majority displayed collagen-dependent biofilm formation. Two additional genomic islands (GI2 and GI3) were also present in a subset of RT106 strains. All three islands are predicted to encode mobile genetic elements as well as virulence factors. Emergent phenotypes associated with these genetic islands may have contributed to the relatively rapid expansion of RT106 in US healthcare and community settings.


2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S809-S809
Author(s):  
Ioannis Zacharioudakis ◽  
Fainareti Zervou ◽  
Michael Phillips ◽  
Maria E Aguero-Rosenfeld

Abstract Background It is common practice among microbiology laboratories in the United States to blind the BioFire FilmArray GI Panel results for Clostridioides (Clostridium) difficile (C. difficile) in fear of over-diagnosis of C. difficile infection (CDI). Methods We conducted a retrospective cohort study in 2 tertiary academic centers in New York to examine the rate of missed CDI diagnosis and the associated adverse outcomes from blinding the BioFire FilmArray GI Panel results for C. difficile. Of note, in one of the two included hospitals the list of daily positives is reviewed by an Infectious Diseases attending to determine whether cases have been tested for CDI and if not if they meet criteria for CDI. Adult patients with FilmArray GI Panel positive for C. difficile on admission to the hospital who lacked dedicated testing for C. difficile were included in the analysis and were stratified as possible, probable and definite cases of missed CDI diagnosis. Results Among the 144 adult patients with a FilmArray GI Panel test positive for C. difficile within 48 hours of hospital admission, 18 did not have a concurrent dedicated C. difficile testing. Eight patients were categorized as possible cases of missed CDI diagnosis, 5 as probable and 4 as definite, for a total of 17 cases of at least possibly missed CDI diagnosis. One case was considered to represent C. difficile colonization rather than infection for a rate of 6.9% of CDI over-diagnosis based on the FilmArray GI Panel results. Missed CDI diagnoses were associated with a delay in initiation of appropriate therapy, admission to the intensive care unit, hospital re-admission, colorectal surgery and death/discharge to hospice. Five out of 17 cases of missed CDI diagnosis (29.4%) lacked traditional risk factors for CDI. Conclusion In conclusion, the practice of concealing FilmArray GI Panel results for C. difficile may lead to a higher rate of missed CDI diagnosis than over-diagnosis and might need to be re-considered at least in patients with community-onset colitis of unknown etiology on presentation to the hospital. Disclosures All authors: No reported disclosures.


2017 ◽  
Vol 30 (1) ◽  
pp. 42-55 ◽  
Author(s):  
Karen J. LeCount ◽  
Linda K. Schlater ◽  
Tod Stuber ◽  
Suelee Robbe Austerman ◽  
Timothy S. Frana ◽  
...  

The gel diffusion precipitin test (GDPT) and restriction endonuclease analysis (REA) have commonly been used in the serotyping and genotyping of Pasteurella multocida. Whole genome sequencing (WGS) and single nucleotide polymorphism (SNP) analysis has become the gold standard for other organisms, offering higher resolution than previously available methods. We compared WGS to REA and GDPT on 163 isolates of P. multocida to determine if WGS produced more precise results. The isolates used represented the 16 reference serovars, isolates with REA profiles matching an attenuated fowl cholera vaccine strain, and isolates from 10 different animal species. Isolates originated from across the United States and from Chile. Identical REA profiles clustered together in the phylogenetic tree. REA profiles that differed by only a few bands had fewer SNP differences than REA profiles with more differences, as expected. The GDPT results were diverse but it was common to see a single serovar show up repeatedly within clusters. Several errors were found when examining the REA profiles. WGS was able to confirm these errors and compensate for the subjectivity in analysis of REA. Also, results of WGS and SNP analysis correlated more closely with the epidemiologic data than GDPT. In silico results were also compared to a lipopolysaccharide rapid multiplex PCR test. From the data produced in our study, WGS and SNP analysis was superior to REA and GDPT and highlighted some of the issues with the older tests.


2019 ◽  
Vol 69 (10) ◽  
pp. 1801-1804 ◽  
Author(s):  
Melany Gonzalez-Orta ◽  
Carlos Saldana ◽  
Yilen Ng-Wong ◽  
Jennifer Cadnum ◽  
Annette Jencson ◽  
...  

Abstract In a cohort of 480 patients admitted to an acute care hospital, 68 (14%) had positive perirectal cultures for toxigenic Clostridioides difficile on admission. Of the 11 patients (2%) diagnosed with healthcare-associated C. difficile infections, 3 (27%) had genetically related admission and infection isolates, based on whole-genome sequencing.


2020 ◽  
Author(s):  
Arianna Miles-Jay ◽  
Vincent B. Young ◽  
Eric G. Pamer ◽  
Tor C. Savidge ◽  
Mini Kamboj ◽  
...  

ABSTRACTClostridioides difficile is the leading cause of healthcare-associated infectious diarrhea. However, it is increasingly appreciated that healthcare-associated infections derive from both community and healthcare transmission, and that the primary sites of C. difficile transmission may be strain dependent. We conducted a multisite genomic epidemiology study to assess differential genomic evidence of healthcare vs. community spread for two of the most common C. difficile strains in the U.S.: sequence type (ST) 1 (associated with Ribotype 027) and ST2 (associated with Ribotype 014/020). Isolates recovered from stool specimens collected during standard clinical care at three geographically distinct U.S. medical centers between 2010 and 2018 underwent whole genome sequencing and phylogenetic analyses. ST1 and ST2 isolates both displayed some evidence of phylogenetic clustering by study site, but clustering was stronger and more apparent in ST1, consistent with our healthcare-based study more comprehensively sampling local transmission of ST1 compared to ST2 strains. Analyses of pairwise single nucleotide variant (SNV) distance distributions were also consistent with more evidence of healthcare transmission of ST1 compared to ST2, with 44% of ST1 isolates being within 2 SNVs of another isolate from the same geographic collection site compared to 5.5% of ST2 isolates (p-value = <0.001). Conversely, ST2 isolates were more likely to have close genetic neighbors across disparate geographic sites compared to ST1 isolates, further supporting non-healthcare routes of spread for ST2 and highlighting the potential for misattributing genomic similarity among ST2 isolates to recent healthcare transmission. Finally, we estimated a lower evolutionary rate for the ST2 lineage compared to the ST1 lineage using Bayesian timed phylogenomic analyses, and hypothesize that this may contribute to observed differences in geographic concordance among closely related isolates. Together, these findings suggest that ST1 and ST2, while both common causes of C. difficile infection in hospitals, show differential reliance on community and hospital spread. This conclusion supports the need for strain-specific criteria for interpreting genomic linkages and emphasizes the importance of considering differences in the epidemiology of circulating strains when devising interventions to reduce the burden of C. difficile infections.DATA SUMMARYAll whole genome sequence data was uploaded to the National Center for Biotechnology Information (NCBI) Sequence Read Archive (SRA) under Bioproject accessions PRJNA595724, PRJNA561087, and PRJNA594943. Metadata that comply with patient privacy rules are included in the Supplementary Materials.


2021 ◽  
Vol 14 ◽  
pp. 175628482110481
Author(s):  
Adam Ressler ◽  
Joyce Wang ◽  
Krishna Rao

In the United States, Clostridioides difficile infection (CDI) is the leading cause of healthcare-associated infection, affecting nearly half a million people and resulting in more than 20,000 in-hospital deaths every year. It is therefore imperative to better characterize the intricate interplay between C. difficile microbial factors, host immunologic signatures, and clinical features that are associated with adverse outcomes of severe CDI. In this narrative review, we discuss the implications of C. difficile genetics and virulence factors in the molecular epidemiology of CDI, and the utility of early biomarkers in predicting the clinical trajectory of patients at risk of developing severe CDI. Furthermore, we identify associations between host immune factors and CDI outcomes in both animal models and human studies. Next, we highlight clinical factors including renal dysfunction, aging, blood biomarkers, level of care, and chronic illnesses that can affect severe CDI diagnosis and outcome. Finally, we present our perspectives on two specific treatments pertinent to patient outcomes: metronidazole administration and surgery. Together, this review explores the various venues of CDI research and highlights the importance of integrating microbial, host, and clinical data to help clinicians make optimal treatment decisions based on accurate prediction of disease progression.


2020 ◽  
Author(s):  
Joyce Wang ◽  
Betsy Foxman ◽  
Ali Pirani ◽  
Zena Lapp ◽  
Lona Mody ◽  
...  

ABSTRACTBackgroundPatients 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.Methods584 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.ResultsThe majority of ARO isolates across study sites belonged to major healthcare-associated lineages: MRSA (ST5;N=89/117); VREfc (ST6;N=68/75); CipREc (ST131; N=58/64), and VREfm (clade A; N=129/129). While the genomic similarity of strains between NF pairs was associated with overlap in their feeder ACHs (Spearman’s rho=0.44-0.75, p<0.05 for MRSA, VREfc and CipREc), limited phylogenetic clustering by either ACH or NF supported regional endemicity. Significant predictors for ARO colonization on NF admission included lower functional status (adjusted odds ratio [aOR]>1 for all four AROs) and recent exposure to glycopeptides (aOR>2 for VREfm, VREfc and MRSA) or 3rd/4th-generation cephalosporins (aOR>2 for MRSA and VREfm). Transfer from specific ACHs was an independent risk factor for only one ARO/ACH pair (VREfm/ACH19, aOR=2.48[1.06-5.83]).ConclusionIn this region, healthcare-associated ARO lineages are endemic among connected NFs and ACHs, making patient characteristics more informative of NF admission colonization risk than exposure to specific ACHs.SummaryUsing a combination of whole-genome sequencing, patient transfer and clinical data, we discerned the dissemination of four high-priority antibiotic-resistant organisms (ARO) in the regional healthcare network, and epidemiolocal drivers underlying the high ARO importation rate into regional nursing facilities.


2015 ◽  
Vol 81 (18) ◽  
pp. 6200-6209 ◽  
Author(s):  
Will Van Treuren ◽  
Loganathan Ponnusamy ◽  
R. Jory Brinkerhoff ◽  
Antonio Gonzalez ◽  
Christian M. Parobek ◽  
...  

ABSTRACTIxodes scapularisis the principal vector of Lyme disease on the East Coast and in the upper Midwest regions of the United States, yet the tick is also present in the Southeast, where Lyme disease is absent or rare. A closely related species,I. affinis, also carries the pathogen in the South but does not seem to transmit it to humans. In order to better understand the geographic diversity of the tick, we analyzed the microbiota of 104 adultI. scapularisand 13 adultI. affinisticks captured in 19 locations in South Carolina, North Carolina, Virginia, Connecticut, and New York. Initially, ticks from 4 sites were analyzed by 454 pyrosequencing. Subsequently, ticks from these sites plus 15 others were analyzed by sequencing with an Illumina MiSeq machine. By both analyses, the microbiomes of female ticks were significantly less diverse than those of male ticks. The dissimilarity between tick microbiomes increased with distance between sites, and the state in which a tick was collected could be inferred from its microbiota. The genusRickettsiawas prominent in all locations.Borreliawas also present in most locations and was present at especially high levels in one site in western Virginia. In contrast, members of the familyEnterobacteriaceaewere very common in North CarolinaI. scapularisticks but uncommon inI. scapularisticks from other sites and in North CarolinaI. affinisticks. These data suggest substantial variations in theIxodesmicrobiota in association with geography, species, and sex.


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