scholarly journals Clostridium difficile clade 3 (RT023) have a modified cell surface and contain a large transposable island with novel cargo

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Helen Alexandra Shaw ◽  
Ladan Khodadoost ◽  
Mark D. Preston ◽  
Jeroen Corver ◽  
Peter Mullany ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Clostridium Difficile ◽  
Abc Transporters ◽  
Reference Strain ◽  
Whole Genome ◽  
Bacterial Strains ◽  
Live Attenuated Vaccines ◽  
Clostridioides Difficile ◽  
Niche Adaptation ◽  
Genes Encoding

Abstract The major global pathogen Clostridium difficile (recently renamed Clostridioides difficile) has large genetic diversity including multiple mobile genetic elements. In this study, whole genome sequencing of 86 strains from the poorly characterised clade 3, predominantly PCR ribotype (RT)023, of C. difficile revealed distinctive surface architecture characteristics and a large mobile genetic island. These strains have a unique sortase substrate phenotype compared with well-characterised strains of C. difficile, and loss of the phage protection protein CwpV. A large genetic insertion (023_CTnT) comprised of three smaller elements (023_CTn1-3) is present in 80/86 strains analysed in this study, with genes common among other bacterial strains in the gut microbiome. Novel cargo regions of 023_CTnT include genes encoding a sortase, putative sortase substrates, lantibiotic ABC transporters and a putative siderophore biosynthetic cluster. We demonstrate the excision of 023_CTnT and sub-elements 023_CTn2 and 023_CTn3 from the genome of RT023 reference strain CD305 and the transfer of 023_CTn3 to a non-toxigenic C. difficile strain, which may have implications for the use of non-toxigenic C. difficile strains as live attenuated vaccines. Finally, we show that the genes within the island are expressed in a regulated manner in C. difficile RT023 strains conferring a distinct “niche adaptation”.

scholarly journals Diversity of cwp loci in clinical isolates of Clostridium difficile

2013 ◽  
Vol 62 (9) ◽  
pp. 1444-1452 ◽  
Author(s):  
Manuele Biazzo ◽  
Rossella Cioncada ◽  
Luigi Fiaschi ◽  
Vittorio Tedde ◽  
Patrizia Spigaglia ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Clostridium Difficile ◽  
Total Cell ◽  
The Other ◽  
Clinical Isolates ◽  
Cell Wall Proteins ◽  
High Genetic Diversity ◽  
Cell Extracts ◽  
Number Of Genes ◽  
Genes Encoding

An increased incidence of Clostridium difficile infection (CDI) is associated with the emergence of epidemic strains characterized by high genetic diversity. Among the factors that may have a role in CDI is a family of 29 paralogues, the cell-wall proteins (CWPs), which compose the outer layer of the bacterial cell and are likely to be involved in colonization. Previous studies have shown that 12 of the 29 cwp genes are clustered in the same region, named after slpA (cwp1), the slpA locus, whereas the remaining 17 paralogues are distributed throughout the genome. The variability of 14 of these 17 cwp paralogues was determined in 40 C. difficile clinical isolates belonging to six of the currently prevailing PCR ribotypes. Based on sequence conservation, these cwp genes were divided into two groups, one comprising nine cwp loci having highly conserved sequences in all isolates, and the other five loci showing low genetic conservation among isolates of the same PCR ribotype, as well as between different PCR ribotypes. Three conserved CWPs, Cwp16, Cwp18 and Cwp25, and two variable ones, Cwp26 and Cwp27, were characterized further by Western blot analysis of total cell extracts or surface-layer preparations of the C. difficile clinical isolates. Expression of genetically invariable CWPs was well conserved in all isolates, whilst genetically variable CWPs were not always expressed at comparable levels, even in strains containing identical sequences but belonging to different PCR ribotypes. This is the first report on the distribution and variability of a number of genes encoding CWPs in C. difficile.

scholarly journals Morphological and Genetic Diversity of Temperate Phages in Clostridium difficile

2007 ◽  
Vol 73 (22) ◽  
pp. 7358-7366 ◽  
Author(s):  
Louis-Charles Fortier ◽  
Sylvain Moineau
Keyword(s):  
Electron Microscopy ◽  
Genetic Diversity ◽  
Clostridium Difficile ◽  
Dna Hybridization ◽  
Southern Hybridization ◽  
The Other ◽  
Restriction Profile ◽  
Transmission Electron ◽  
The Family ◽  
Genes Encoding

ABSTRACT Eight temperate phages were characterized after mitomycin C induction of six Clostridium difficile isolates corresponding to six distinct PCR ribotypes. The hypervirulent C. difficile strain responsible for a multi-institutional outbreak (NAP1/027 or QCD-32g58) was among these prophage-containing strains. Observation of the crude lysates by transmission electron microscopy (TEM) revealed the presence of three phages with isometric capsids and long contractile tails (Myoviridae family), as well as five phages with long noncontractile tails (Siphoviridae family). TEM analyses also revealed the presence of a significant number of phage tail-like particles in all the lysates. Southern hybridization experiments with restricted prophage DNA showed that C. difficile phages belonging to the family Myoviridae are highly similar and most likely related to previously described prophages φC2, φC5, and φCD119. On the other hand, members of the Siphoviridae phage family are more genetically divergent, suggesting that they originated from distantly related ancestors. Our data thus suggest that there are at least three genetically distinct groups of temperate phages in C. difficile; one group is composed of highly related myophages, and the other two groups are composed of more genetically heterogeneous siphophages. Finally, no gene homologous to genes encoding C. difficile toxins or toxin regulators could be identified in the genomes of these phages using DNA hybridization. Interestingly, each unique phage restriction profile correlated with a specific C. difficile PCR ribotype.

Genetic diversity of enteroaggregative Escherichia coli

2020 ◽  
Vol 65 (11) ◽  
pp. 707-711
Author(s):  
M. A. Makarova ◽  
L. A. Kaftyreva
Keyword(s):  
Escherichia Coli ◽  
Genetic Diversity ◽  
High Risk ◽  
Urine Samples ◽  
Whole Genome ◽  
Epidemic Spread ◽  
E Coli ◽  
Genes Encoding ◽  
Stool Samples ◽  
O Antigens

Studied 74 E. coli strains isolated from stool samples (60) and urine samples (14) of patients examined for clinical indications. Molecular methods included: PCR with electrophoretic detection of genes associated with diarrheal E. coli pathogroup EAgEC (aggR, aaf, aap, aatA, pet, ast, aai) and ExPEC pathogroup UPEC (pap, sfa, afa, kpsMT II, iutA, hlyA, cnf), MLST typing, whole genome sequencing. Strains isolated from stool samples were significantly more likely (88.3%, p > 0.05) to be typical EAgECaggR+ compared to atypical EAgECaggR-. Strains isolated from urine samples, significant differences between typical and atypical EAgEC were not detected (p > 0.05). Genes associated with ExPEC were present in all strains isolated from urine samples and in 45 strains (75%) isolated from stool samples. Coproisolates belonged to 10 serogroups and 13 serovars: O3:H2, O11:H10, O16:H48, O51:H30, O55:H21, O73:H18, O73:H33, O86:H2, O86:H10, O92:H33, O140:H2, O159:H10. Two strains had unique nucleotide sequences of genes encoding O-antigens that were missing from the SerotypeFinder database. 80% of EAgEC isolated from feces and urine was characterized by an enteroaggregative/uropathogenic genotype (EAgEC/UPEC). Most of the strains isolated from urine belonged to the virulent clone of high-risk epidemic spread ST 38 associated with hybrid strains of UPEC / EAgEC.

scholarly journals Clostridioides difficile Whole-Genome Sequencing Reveals Limited Within-Host Genetic Diversity in a Pediatric Cohort

2019 ◽  
Vol 57 (9) ◽  
Author(s):  
Aakash Balaji ◽  
Egon A. Ozer ◽  
Larry K. Kociolek
Keyword(s):  
Genetic Diversity ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Core Genome ◽  
Genetic Relatedness ◽  
The Other ◽  
Whole Genome ◽  
Content Type ◽  
Clostridioides Difficile ◽  
Host Genetic

ABSTRACT Whole-genome sequencing (WGS) is a highly sensitive method for identifying genetic relatedness and transmission of Clostridioides difficile strains. Previous studies suggest that as few as 3 core genome single-nucleotide variants (SNVs) discriminate between genetically distinct isolates. Because a single C. difficile colony is selected from culture for WGS, significant within-host genetic diversity could preclude identification of transmission events. To evaluate the likelihood of missed transmission events using WGS of single colonies from culture, we examined within-host genetic diversity among C. difficile isolates collected from children. We performed WGS using an Illumina MiSeq instrument on 8 C. difficile colonies randomly selected from each culture performed on stool collected from 10 children (8 children diagnosed with C. difficile infection and 2 children with asymptomatic carriage); 77/80 (96%) isolate sequences were successfully assembled. Among 8/10 (80%) children, all isolates were the same sequence type (ST). The other 2 children each had mixed infection with two STs, although one ST predominated. Among 9/10 (90%) children, isotypic isolates differed by ≤2 SNVs; an isotypic isolate in the remaining child differed by 3 to SNVs relative to the other isolates from that child. Overall, among the 77 isolates collected from 10 stool cultures, 74/77 (96%) were clonal (i.e., same ST and ≤2 core genome SNVs) to other isolates in stool culture. In summary, we identified rare C. difficile within-host genetic diversity in children, suggesting that WGS of a single colony from stool is likely to appropriately characterize isolate clonality and putative transmission events in the majority of cases.

Comparative analysis of an expanded Clostridium difficile reference strain collection reveals genetic diversity and evolution through six lineages

2012 ◽  
Vol 12 (7) ◽  
pp. 1577-1585 ◽  
Author(s):  
Cornelis W. Knetsch ◽  
Elisabeth M. Terveer ◽  
Chris Lauber ◽  
Alexander E. Gorbalenya ◽  
Céline Harmanus ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Comparative Analysis ◽  
Clostridium Difficile ◽  
Reference Strain ◽  
Strain Collection

scholarly journals Comparative Phylogenomics of Clostridium difficile Reveals Clade Specificity and Microevolution of Hypervirulent Strains

2006 ◽  
Vol 188 (20) ◽  
pp. 7297-7305 ◽  
Author(s):  
R. A. Stabler ◽  
D. N. Gerding ◽  
J. G. Songer ◽  
D. Drudy ◽  
J. S. Brazier ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Dna Microarrays ◽  
Control Strategies ◽  
Whole Genome ◽  
Nosocomial Diarrhea ◽  
Niche Adaptation ◽  
Animal Isolates ◽  
Genome Comparisons ◽  
Animal Strains ◽  
Insight Into

ABSTRACT Clostridium difficile is the most frequent cause of nosocomial diarrhea worldwide, and recent reports suggested the emergence of a hypervirulent strain in North America and Europe. In this study, we applied comparative phylogenomics (whole-genome comparisons using DNA microarrays combined with Bayesian phylogenies) to model the phylogeny of C. difficile, including 75 diverse isolates comprising hypervirulent, toxin-variable, and animal strains. The analysis identified four distinct statistically supported clusters comprising a hypervirulent clade, a toxin A− B+ clade, and two clades with human and animal isolates. Genetic differences among clades revealed several genetic islands relating to virulence and niche adaptation, including antibiotic resistance, motility, adhesion, and enteric metabolism. Only 19.7% of genes were shared by all strains, confirming that this enteric species readily undergoes genetic exchange. This study has provided insight into the possible origins of C. difficile and its evolution that may have implications in disease control strategies.

scholarly journals Molecular characterization of clinical carbapenem-resistant Enterobacterales from Qatar

2021 ◽  
Author(s):  
Fatma Ben Abid ◽  
Clement K. M. Tsui ◽  
Yohei Doi ◽  
Anand Deshmukh ◽  
Christi L. McElheny ◽  
...  
Keyword(s):  
Common Species ◽  
Clinical Samples ◽  
Whole Genome ◽  
E Coli ◽  
Carbapenem Resistant ◽  
Genes Encoding ◽  
Encoding Genes ◽  
Sequence Types ◽  
Common Sequence

AbstractOne hundred forty-nine carbapenem-resistant Enterobacterales from clinical samples obtained between April 2014 and November 2017 were subjected to whole genome sequencing and multi-locus sequence typing. Klebsiella pneumoniae (81, 54.4%) and Escherichia coli (38, 25.5%) were the most common species. Genes encoding metallo-β-lactamases were detected in 68 (45.8%) isolates, and OXA-48-like enzymes in 60 (40.3%). blaNDM-1 (45; 30.2%) and blaOXA-48 (29; 19.5%) were the most frequent. KPC-encoding genes were identified in 5 (3.6%) isolates. Most common sequence types were E. coli ST410 (8; 21.1%) and ST38 (7; 18.4%), and K. pneumoniae ST147 (13; 16%) and ST231 (7; 8.6%).

scholarly journals Whole genome-based characterisation of antimicrobial resistance and genetic diversity in Campylobacter jejuni and Campylobacter coli from ruminants

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Medelin Ocejo ◽  
Beatriz Oporto ◽  
José Luis Lavín ◽  
Ana Hurtado
Keyword(s):  
Genetic Diversity ◽  
Antimicrobial Resistance ◽  
Campylobacter Jejuni ◽  
Resistance Genes ◽  
Campylobacter Coli ◽  
Whole Genome ◽  
Northern Spain ◽  
Sequence Alignments ◽  
Phenotypic Data ◽  
Wide Range

AbstractCampylobacter, a leading cause of gastroenteritis in humans, asymptomatically colonises the intestinal tract of a wide range of animals.Although antimicrobial treatment is restricted to severe cases, the increase of antimicrobial resistance (AMR) is a concern. Considering the significant contribution of ruminants as reservoirs of resistant Campylobacter, Illumina whole-genome sequencing was used to characterise the mechanisms of AMR in Campylobacter jejuni and Campylobacter coli recovered from beef cattle, dairy cattle, and sheep in northern Spain. Genome analysis showed extensive genetic diversity that clearly separated both species. Resistance genotypes were identified by screening assembled sequences with BLASTn and ABRicate, and additional sequence alignments were performed to search for frameshift mutations and gene modifications. A high correlation was observed between phenotypic resistance to a given antimicrobial and the presence of the corresponding known resistance genes. Detailed sequence analysis allowed us to detect the recently described mosaic tet(O/M/O) gene in one C. coli, describe possible new alleles of blaOXA-61-like genes, and decipher the genetic context of aminoglycoside resistance genes, as well as the plasmid/chromosomal location of the different AMR genes and their implication for resistance spread. Updated resistance gene databases and detailed analysis of the matched open reading frames are needed to avoid errors when using WGS-based analysis pipelines for AMR detection in the absence of phenotypic data.

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