scholarly journals A multisite genomic epidemiology study of Clostridioides difficile infections in the USA supports differential roles of healthcare versus community spread for two common strains

2021 ◽  
Vol 7 (6) ◽  
Author(s):  
Arianna Miles-Jay ◽  
Vincent B. Young ◽  
Eric G. Pamer ◽  
Tor C. Savidge ◽  
Mini Kamboj ◽  
...  

Clostridioides difficile is the leading cause of healthcare-associated infectious diarrhoea. However, it is increasingly appreciated that healthcare-associated infections derive from both community and healthcare environments, 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 USA: sequence type (ST) 1 (associated with ribotype 027) and ST2 (associated with ribotype 014/020). We performed whole-genome sequencing and phylogenetic analyses on 382 ST1 and ST2 C. difficile isolates recovered from stool specimens collected during standard clinical care at 3 geographically distinct US medical centres between 2010 and 2017. 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 two SNVs of another isolate from the same geographical collection site compared to 5.5 % of ST2 isolates (P-value=<0.001). Conversely, ST2 isolates were more likely to have close genetic neighbours across disparate geographical 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 geographical 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.

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.


2015 ◽  
Vol 65 (Pt_1) ◽  
pp. 286-292 ◽  
Author(s):  
Daniel Weller ◽  
Alexis Andrus ◽  
Martin Wiedmann ◽  
Henk C. den Bakker

Sampling of seafood and dairy processing facilities in the north-eastern USA produced 18 isolates of Listeria spp. that could not be identified at the species-level using traditional phenotypic and genotypic identification methods. Results of phenotypic and genotypic analyses suggested that the isolates represent two novel species with an average nucleotide blast identity of less than 92 % with previously described species of the genus Listeria . Phylogenetic analyses based on whole genome sequences, 16S rRNA gene and sigB gene sequences confirmed that the isolates represented by type strain FSL M6-0635T and FSL A5-0209 cluster phylogenetically with Listeria cornellensis . Phylogenetic analyses also showed that the isolates represented by type strain FSL A5-0281T cluster phylogenetically with Listeria riparia . The name Listeria booriae sp. nov. is proposed for the species represented by type strain FSL A5-0281T ( = DSM 28860T = LMG 28311T), and the name Listeria newyorkensis sp. nov. is proposed for the species represented by type strain FSL M6-0635T ( = DSM 28861T = LMG 28310T). Phenotypic and genotypic analyses suggest that neither species is pathogenic.


2019 ◽  
Vol 5 (9) ◽  
Author(s):  
Bastian V. H. Hornung ◽  
Ed J. Kuijper ◽  
Wiep Klaas Smits

The Gram-positive enteropathogen Clostridioides difficile (Clostridium difficile) is the major cause of healthcare-associated diarrhoea and is also an important cause of community-acquired infectious diarrhoea. Considering the burden of the disease, many studies have employed whole-genome sequencing of bacterial isolates to identify factors that contribute to virulence and pathogenesis. Though extrachromosomal elements (ECEs) such as plasmids are important for these processes in other bacteria, the few characterized plasmids of C. difficile have no relevant functions assigned and no systematic identification of plasmids has been carried out to date. Here, we perform an in silico analysis of publicly available sequence data to show that ~13 % of all C. difficile strains contain ECEs, with 1–6 elements per strain. Our approach identifies known plasmids (e.g. pCD6, pCD630 and cloning plasmids) and six novel putative plasmid families. Our study shows that plasmids are abundant and may encode functions that are relevant for C. difficile physiology. The newly identified plasmids may also form the basis for the construction of novel cloning plasmids for C. difficile that are compatible with existing tools.


2015 ◽  
Vol 65 (Pt_2) ◽  
pp. 516-521 ◽  
Author(s):  
Gaiyun Zhang ◽  
Yubian Zhang ◽  
Xijie Yin ◽  
Shuang Wang

A Gram-staining-positive, aerobic, motile and non-spore-forming actinobacteria, designated strain F10T, was isolated from a deep-sea sediment of the western Pacific Ocean. Phylogenetic and phenotypic properties of the organism supported that it belonged to the genus Nesterenkonia . Strain F10T shared highest 16S rRNA gene sequence similarity of 96.8 % with Nesterenkonia aethiopica DSM 17733T, followed by Nesterenkonia xinjiangensis YIM 70097T (96.7 %) and Nesterenkonia alba CAAS 252T (96.6 %). The organism grew at 4–50 °C, at pH 7.0–12.0 and in the presence of 0–12 % (w/v) NaCl, with optimal growth occurring at 40 °C, at pH 9.0 and in the presence of 1 % (w/v) NaCl. The peptidoglycan type was A4(alpha), l-Lys–Gly–l-Glu. The polar lipid profile of strain F10T consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, two unknown glycolipids and two unknown lipids. The isolate contained MK-9 (92 %) and MK-8 (5.8 %) as the major components of the menaquinone system, and anteiso-C17 : 0 (50.9 %) and anteiso-C15 : 0 (29.8 %) as the predominant fatty acids. The G+C content of the genomic DNA of strain F10T was 66.2 mol%. Based on phenotypic, genotypic and phylogenetic analyses, strain F10T represents a novel species of the genus Nesterenkonia for which the name Nesterenkonia alkaliphila sp. nov. is proposed. The type strain is F10T ( = LMG 28112T = CGMCC 1.12781T = JCM 19766T = MCCC 1A09946T).


2013 ◽  
Vol 63 (Pt_3) ◽  
pp. 934-938 ◽  
Author(s):  
Wen-Ming Chen ◽  
Rey-Chang Chang ◽  
Chih-Yu Cheng ◽  
Yu-Wen Shiau ◽  
Shih-Yi Sheu

A novel bacterium, designated strain JchiT, was isolated from soil in Taiwan and characterized using a polyphasic approach. Cells of strain JchiT were aerobic, Gram-stain-negative, motile and rod-shaped. They contained poly-β-hydroxybutyrate granules and formed dark-yellow colonies. Growth occurred at 20–37 °C (optimum between 25 and 30 °C), at pH 6.0–8.0 (optimum between pH 7.0 and pH 8.0) and with 0–2 % NaCl (optimum between 0 and 1 %). Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain JchiT belonged to the genus Jeongeupia and that its closest neighbour was Jeongeupia naejangsanensis BIO-TAS4-2T (98.0 % sequence similarity). The major fatty acids (>10 %) of strain JchiT were summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c), C16 : 0 and C18 : 1ω7c. The major cellular hydroxy fatty acid was C12 : 0 3-OH. The isoprenoid quinone was Q-8 and the genomic DNA G+C content was 66.1 mol%. The polar lipid profile consisted of a mixture of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylserine and two unidentified phospholipids. The DNA–DNA relatedness value between strain JchiT and J. naejangsanensis BIO-TAS4-2T was about 41.0 %. On the basis of the genotypic and phenotypic data, strain JchiT represents a novel species in the genus Jeongeupia , for which the name Jeongeupia chitinilytica sp. nov. is proposed. The type strain is JchiT ( = BCRC 80367T  = KCTC 23701T).


Author(s):  
Fenfa Li ◽  
Qingyi Xie ◽  
Shuangqing Zhou ◽  
Fandong Kong ◽  
Yun Xu ◽  
...  

Strain HNM0947T, representing a novel actinobacterium, was isolated from the coral Galaxea astreata collected from the coast of Wenchang, Hainan, China. The strain was found to have morphological and chemotaxonomic characteristics consistent with the genus Nocardiopsis . The organism formed abundant fragmented substrate mycelia and aerial mycelia which differentiated into non-motile, rod-shaped spores. Whole-cell hydrolysates contained meso-diaminopimelic acid and no diagnostic sugars. The major menaquinones were MK-10(H8), MK-10(H6) and MK-10(H4). The major phospholipids were phosphatidylcholine, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannosides. The major fatty acids were iso-C16:0, anteiso-C17:0, C18:0, C18:0 10-methyl (TBSA) and anteiso-C15:0. The G+C content was 71.3 mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain HNM0947T belonged to the genus Nocardiopsis and shared highest sequence similarity to Nocardiopsis salina YIM 90010T (98.8%), Nocardiopsis xinjiangensis YIM 90004T(98.5%) and Nocardiopsis kunsanensis DSM 44524T (98.3%). The strain HNM0947T was distinguished from its closest type strain by low average nucleotide identity (90.8%) and dDDH values (60.4%) respectively. Based on genotypic, chemotaxonomic and phenotypic characteristics, it was concluded that strain HNM0947T represents a novel species of the genus Nocardiopsis whose name was proposed as Nocardiopsis coralli sp. nov. The type strain was HNM0947T (=CCTCC AA 2020015 T=KCTC 49525 T).


Author(s):  
Shan Jiang ◽  
Feng-Bai Lian ◽  
You-Yang Sun ◽  
Xiao-Kui Zhang ◽  
Zong-Jun Du

A Gram-stain-negative, rod-shaped and facultatively aerobic bacterial strain, designated F7430T, was isolated from coastal sediment collected at Jingzi Wharf in Weihai, PR China. Cells of strain F7430T were 0.3–0.4 µm wide, 2.0–2.6 µm long, non-flagellated, non-motile and formed pale-beige colonies. Growth was observed at 4–40 °C (optimum, 30 °C), pH 6.0–9.0 (optimum, pH 7.5–8.0) and at NaCl concentrations of 1.0–10.0 % (w/v; optimum, 1.0 %). The sole respiratory quinone of strain F7430T was ubiquinone 8 and the predominant cellular fatty acids were summed feature 8 (C18 : 1  ω7c / C18 : 1  ω6c; 60.7 %), summed feature 3 (C16 : 1  ω7c/C16 : 1  ω6c; 30.2 %) and C15 : 0 iso (13.9 %). The polar lipids of strain F7430T consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, one unidentified phospholipid and three unidentified lipids. Results of 16S rRNA gene sequences analyses indicated that this strain belonged to the family Halieaceae and had high sequence similarities to Parahaliea aestuarii JCM 51547T (95.3 %) and Halioglobus pacificus DSM 27932T (95.2 %) followed by 92.9–95.0 % sequence similarities to other type species within the aforementioned family. The rpoB gene sequences analyses indicated that the novel strain had the highest sequence similarities to Parahaliea aestuarii JCM 51547T (82.2 %) and Parahaliea mediterranea DSM 21924T (82.2 %) followed by 75.2–80.5 % sequence similarities to other type species within this family. Phylogenetic analyses showed that strain F7430T constituted a monophyletic branch clearly separated from the other genera of family Halieaceae . Whole-genome sequencing of strain F7430T revealed a 3.3 Mbp genome size with a DNA G+C content of 52.6 mol%. The genome encoded diverse metabolic pathways including the Entner–Doudoroff pathway, assimilatory sulphate reduction and biosynthesis of dTDP-l-rhamnose. Based on results from the current polyphasic study, strain F7430T is proposed to represent a novel species of a new genus within the family Halieaceae , for which the name Sediminihaliea albiluteola gen. nov., sp. nov. is proposed. The type strain of the type species is F7430T (=KCTC 72873T=MCCC 1H00420T).


Author(s):  
Silvio Hering ◽  
Moritz K. Jansson ◽  
Michael E. J. Buhl

A novel species within the genus Eikenella is described, based on the phenotypical, biochemical and genetic characterization of a strain of a facultatively anaerobic, Gram-negative rod-shaped bacterium. Strain S3360T was isolated from the throat swab of a patient sampled during routine care at a hospital. Phylogenetic analyses (full-length 16S rRNA gene and whole-genome sequences) placed the strain in the genus Eikenella , separate from all recognized species but with the closest relationship to Eikenella longinqua (NML 02-A-017T). Eikenella is one of the genera in the HACEK group known to be responsible for rare cases of endocarditis in humans. Until the recent descriptions of Eikenella exigua , Eikenella halliae and Eikenella longinqua , Eikenella corrodens had been the only validly published species in this genus since its description as Bacteroides corrodens in 1958. Unlike these species, strain S3360T is able to metabolize carbohydrates (glucose). The average nucleotide identities of strain S3360T with E. longinqua (NML 02-A-017T) and E. corrodens (NCTC 10596T), the type species of the genus, were 90.5 and 84.7 %, respectively, and the corresponding genome-to-genome distance values were 41.3 and 29.0 %, respectively. The DNA G+C content of strain S3360T was 58.4 mol%. Based on the phenotypical, biochemical and genetic findings, strain S3360T is considered to represent a novel species within the genus Eikenella , for which the name Eikenella glucosivorans sp. nov. is proposed. The type strain is S3360T (DSM 110714T=CCOS 1935T=CCUG 74293T). In addition, an emendation of the genus Eikenella is proposed to include species which are saccharolytic.


Author(s):  
Caixin Yang ◽  
Yibo Bai ◽  
Kui Dong ◽  
Jing Yang ◽  
Xin-He Lai ◽  
...  

Four Gram-stain-positive, catalase-negative, non-spore-forming, rod-shaped bacterial strains (zg-325T, zg329, dk561T and dk752) were isolated from the respiratory tract of marmot (Marmota himalayana) and the faeces of Tibetan gazelle (Procapra picticaudata) from the Qinghai-Tibet Plateau of PR China. The results of 16S rRNA gene sequence-based phylogenetic analyses indicated that strains zg-325T and dk561T represent members of the genus Actinomyces , most similar to Actinomyces denticolens DSM 20671T and Actinomyces ruminicola B71T, respectively. The DNA G+C contents of strains zg-325T and dk561T were 71.6 and 69.3 mol%, respectively. The digital DNA–DNA hybridization values of strains zg-325T and dk561T with their most closely related species were below the 70 % threshold for species demarcation. The four strains grew best at 35 °C in air containing 5 % CO2 on brain heart infusion (BHI) agar with 5 % sheep blood. All four strains had C18:1ω9c and C16:0 as the major cellular fatty acids. MK-8 and MK-9 were the major menaquinones in zg-325T while MK-10 was predominant in dk561T. The major polar lipids included diphosphatidylglycerol and phosphatidylinositol. On the basis of several lines of evidence from phenotypic and phylogenetic analyses, zg-325T and dk561T represent novel species of the genus Actinomyces , for which the name Actinomyces marmotae sp. nov. and Actinomyces procaprae sp. nov. are proposed. The type strains are zg-325T (=GDMCC 1.1724T=JCM 34091T) and dk561T (=CGMCC 4.7566T=JCM 33484T). We also propose, on the basis of the phylogenetic results herein, the reclassification of Actinomyces liubingyangii and Actinomyces tangfeifanii as Boudabousia liubingyangii comb. nov. and Boudabousia tangfeifanii comb. nov., respectively.


Author(s):  
So-Ra Ko ◽  
Ve Van Le ◽  
Long Jin ◽  
Sang-Ah Lee ◽  
Chi-Yong Ahn ◽  
...  

A novel Gram-stain-negative, rod-shaped, aerobic, non-motile bacterial strain, designated M5A1MT, was isolated from seawater collected from the South Sea of the Republic of Korea. Based on 16S rRNA gene sequence similarity, strain M5A1MT was closely related to Mariniflexile gromovii KMM 6038T (95.3 %), Mariniflexile fucanivorans SW5T (95.2 %), Mariniflexile soesokkakense RSSK-9T (95.1 %), Yeosuana aromativorans GW1-1T (94.6 %) and Confluentibacter lentus HJM-3T (94.6 %). Genome-based phylogenetic analyses revealed that strain M5A1MT formed a distinct cluster with the type strains of the genus Mariniflexile . The major cellular fatty acid constituents (>5 % of the total fatty acids) were iso-C15:0, anteiso-C15 : 0, iso-C15 : 0 3-OH, iso-C15 : 1 G, iso-C16:03-OH and iso-C17 : 0 3-OH. The respiratory quinone was identified as MK-6. The major polar lipids were phosphatidylethanolamine and one unidentified polar lipid. The genomic DNA G+C content of strain M5A1MT was determined to be 37.7 mol%. On the basis of its phenotypic, phylogenetic and chemotaxonomic characteristics, strain M5A1MT is considered to represent a novel species within the genus Mariniflexile , for which the name Mariniflexile maritimum sp. nov. is proposed. The type strain is M5A1MT (=KCTC 72895T=JCM 33982T).


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