scholarly journals Genetic diversity and epidemiology of accessory gene regulator loci in Clostridioides difficile

2020 ◽  
Vol 2 (7) ◽  
Author(s):  
Yuta Okada ◽  
Shu Okugawa ◽  
Mahoko Ikeda ◽  
Tatsuya Kobayashi ◽  
Ryoichi Saito ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
In Silico ◽  
Type Species ◽  
Clinical Samples ◽  
Pcr Analysis ◽  
Accessory Gene ◽  
Content Type ◽  
Link Type ◽  
Accessory Gene Regulator ◽  
Clostridioides Difficile

Quorum sensing is known to regulate bacterial virulence, and the accessory gene regulator (agr) loci is one of the genetic loci responsible for its regulation. Recent reports examining Clostridioides difficile show that two agr loci, agr1 and agr2, regulate toxin production, but the diversity of agr loci and their epidemiology is unknown. In our study, in silico analysis was performed to research genetic diversity of agr, and C. difficile isolates from clinical samples underwent multilocus sequence typing (MLST) and PCR analysis of agr loci. To reveal the distribution of agr among different strains, phylogenetic analysis was also performed. In our in silico analysis, two different subtypes, named agr2R and agr2M, were found in agr2, which were previously reported. PCR analysis of 133 C . difficile isolates showed that 131 strains had agr1, 61 strains had agr2R, and 26 strains had agr2M; agr2R was mainly found in clade 1 or clade 2 organisms, whereas agr2M was only found in clade 4. With rare exception, agr1-negative sequence types (STs) belonged to clade C-Ⅰ and C-Ⅲ, and one clade 4 strain had agr2R. Our study revealed subtypes of agr2 not previously recognized, and the distribution of several agr loci in C. difficile . These findings provide a foundation for further functional and clinical research of the agr loci.

scholarly journals An in silico survey of Clostridioides difficile extrachromosomal elements

2019 ◽  
Vol 5 (9) ◽  
Author(s):  
Bastian V. H. Hornung ◽  
Ed J. Kuijper ◽  
Wiep Klaas Smits
Keyword(s):  
In Silico ◽  
Type Species ◽  
Sequence Data ◽  
Bacterial Isolates ◽  
Content Type ◽  
Link Type ◽  
Clostridioides Difficile ◽  
Extrachromosomal Elements ◽  
Healthcare Associated ◽  
Systematic Identification

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.

scholarly journals Significant variability exists in the cytotoxicity of global methicillin-resistant Staphylococcus aureus lineages

Microbiology ◽  
2021 ◽  
Vol 167 (12) ◽  
Author(s):  
Maisem Laabei ◽  
Sharon J. Peacock ◽  
Beth Blane ◽  
Sarah L. Baines ◽  
Benjamin P. Howden ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Type Species ◽  
Healthcare Setting ◽  
Health Concern ◽  
Accessory Gene ◽  
Methicillin Resistant ◽  
Content Type ◽  
Link Type ◽  
Accessory Gene Regulator ◽  
Toxin Regulation

Staphylococcus aureus is a major human pathogen where the emergence of antibiotic resistant lineages, such as methicillin-resistant S. aureus (MRSA), is a major health concern. While some MRSA lineages are restricted to the healthcare setting, the epidemiology of MRSA is changing globally, with the rise of specific lineages causing disease in healthy people in the community. In the past two decades, community-associated MRSA (CA-MRSA) has emerged as a clinically important and virulent pathogen associated with serious skin and soft-tissue infections (SSTI). These infections are primarily cytotoxin driven, leading to the suggestion that hypervirulent lineages/multi-locus sequence types (STs) exist. To examine this, we compared the cytotoxicity of 475 MRSA isolates representing five major MRSA STs (ST22, ST93, ST8, ST239 and ST36) by employing a monocyte-macrophage THP-1 cell line as a surrogate for measuring gross cytotoxicity. We demonstrate that while certain MRSA STs contain highly toxic isolates, there is such variability within lineages to suggest that this aspect of virulence should not be inferred from the genotype of any given isolate. Furthermore, by interrogating the accessory gene regulator (Agr) sequences in this collection we identified several Agr mutations that were associated with reduced cytotoxicity. Interestingly, the majority of isolates that were attenuated in cytotoxin production contained no mutations in the agr locus, indicating a role of other undefined genes in S. aureus toxin regulation.

scholarly journals Amedibacterium intestinale gen. nov., sp. nov., isolated from human faeces, and reclassification of Eubacterium dolichum Moore et al. 1976 (Approved Lists 1980) as Amedibacillus dolichus gen. nov., comb. nov

2020 ◽  
Vol 70 (6) ◽  
pp. 3656-3664 ◽  
Author(s):  
Nao Ikeyama ◽  
Atsushi Toyoda ◽  
Sho Morohoshi ◽  
Tadao Kunihiro ◽  
Takumi Murakami ◽  
...  
Keyword(s):  
In Silico ◽  
Type Species ◽  
Novel Species ◽  
Sequence Similarity ◽  
Rrna Gene ◽  
Content Type ◽  
Monophyletic Cluster ◽  
Link Type ◽  
Gene Sequence Analysis ◽  
Faecal Samples

Four strains (9CBEGH2T, 9BBH35, 6BBH38 and 6EGH11) of Gram-stain-positive, obligately anaerobic, rod-shaped bacteria were isolated from faecal samples from healthy Japanese humans. The results of 16S rRNA gene sequence analysis indicated that the four strains represented members of the family Erysipelotrichaceae and formed a monophyletic cluster with ‘ Absiella argi ’ strain N6H1-5 (99.4% sequence similarity) and Eubacterium sp. Marseille-P5640 (99.3 %). Eubacterium dolichum JCM 10413T (94.2 %) and Eubacterium tortuosum ATCC 25548T (93.7 %) were located near this monophyletic cluster. The isolates, 9CBEGH2T, ‘ A. argi ’ JCM 30884 and Eubacterium sp. Marseille-P5640 shared 98.7–99.1% average nucleotide identity (ANI) with each other. Moreover, the in silico DNA–DNA hybridization (DDH) values among three strains were 88.4–90.6%, indicating that these strains represent the same species. Strain 9CBEGH2T showed 21.5–24.1 % in silico DDH values with other related taxa. In addition, the ANI values between strain 9CBEGH2T and other related taxa ranged from 71.2 % to 73.5 %, indicating that this strain should be considered as representing a novel species on the basis of whole-genome relatedness. Therefore, we formally propose a novel name for ‘ A. argi ’ strains identified because the name ‘ A. argi ’ has been effectively, but not validly, published since 2017. On the basis of the collected data, strain 9CBEGH2T represents a novel species of a novel genus, for which the name Amedibacterium intestinale gen. nov., sp. nov. is proposed. The type strain of A. intestinale is 9CBEGH2T (=JCM 33778T=DSM 110575T).

scholarly journals Neisseria oralis sp. nov., isolated from healthy gingival plaque and clinical samples

2013 ◽  
Vol 63 (Pt_4) ◽  
pp. 1323-1328 ◽  
Author(s):  
William J. Wolfgang ◽  
Teresa V. Passaretti ◽  
Reashma Jose ◽  
Jocelyn Cole ◽  
An Coorevits ◽  
...  
Keyword(s):  
Type Strain ◽  
Type Species ◽  
Novel Species ◽  
Sequence Similarity ◽  
23S Rrna ◽  
Clinical Samples ◽  
Rrna Gene ◽  
The Novel ◽  
Content Type ◽  
Link Type

A polyphasic analysis was undertaken of seven independent isolates of Gram-negative cocci collected from pathological clinical samples from New York, Louisiana, Florida and Illinois and healthy subgingival plaque from a patient in Virginia, USA. The 16S rRNA gene sequence similarity among these isolates was 99.7–100 %, and the closest species with a validly published name was Neisseria lactamica (96.9 % similarity to the type strain). DNA–DNA hybridization confirmed that these isolates are of the same species and are distinct from their nearest phylogenetic neighbour, N. lactamica . Phylogenetic analysis of 16S and 23S rRNA gene sequences indicated that the novel species belongs in the genus Neisseria . The predominant cellular fatty acids were C16 : 0, summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH) and C18 : 1ω7c. The cellular fatty acid profile, together with other phenotypic characters, further supports the inclusion of the novel species in the genus Neisseria . The name Neisseria oralis sp. nov. (type strain 6332T  = DSM 25276T  = LMG 26725T) is proposed.

Kerstersia similis sp. nov., isolated from human clinical samples

2012 ◽  
Vol 62 (Pt_9) ◽  
pp. 2156-2159 ◽  
Author(s):  
Peter Vandamme ◽  
Evie De Brandt ◽  
Kurt Houf ◽  
Thierry De Baere
Keyword(s):  
Type Strain ◽  
Type Species ◽  
Gene Sequence ◽  
Clinical Samples ◽  
Content Type ◽  
Biochemical Characteristics ◽  
Link Type ◽  
Gene Sequence Analysis ◽  
The Usa ◽  
Kerstersia Gyiorum

Analysis of gyrB gene sequences, (GTG)5-primed PCR fingerprinting and biochemical characteristics determined in the Biolog GEN III microtest system were used to differentiate an unnamed Kerstersia species from Kerstersia gyiorum , the type and only named species in this genus. The inability to oxidize d-galacturonic and d-glucuronic acids and the ability to oxidize d-serine, along with gyrB gene sequence analysis and (GTG)5-PCR fingerprints, readily differentiated the unnamed taxon from the type species. Therefore, we propose to formally classify this unnamed taxon as Kerstersia similis sp. nov. with strain LMG 5890T ( = CCUG 46999T), isolated from a leg wound in the USA in 1983, as the type strain.

scholarly journals Accuracy of an amplicon-sequencing nanopore approach to identify variants in tuberculosis drug-resistance-associated genes

2021 ◽  
Vol 7 (12) ◽  
Author(s):  
Carla Mariner-Llicer ◽  
Galo A. Goig ◽  
Laura Zaragoza-Infante ◽  
Manuela Torres-Puente ◽  
Luis Villamayor ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Type Species ◽  
Variant Calling ◽  
Targeted Sequencing ◽  
Clinical Samples ◽  
Drug Resistant ◽  
Content Type ◽  
Link Type ◽  
Resistant Strains ◽  
Drug Resistant Strains

A rapid and accurate diagnostic assay represents an important means to detect Mycobacterium tuberculosis , identify drug-resistant strains and ensure treatment success. Currently employed techniques to diagnose drug-resistant tuberculosis include slow phenotypic tests or more rapid molecular assays that evaluate a limited range of drugs. Whole-genome-sequencing-based approaches can detect known drug-resistance-conferring mutations and novel variations; however, the dependence on growing samples in culture, and the associated delays in achieving results, represents a significant limitation. As an alternative, targeted sequencing strategies can be directly performed on clinical samples at high throughput. This study proposes a targeted sequencing assay to rapidly detect drug-resistant strains of M. tuberculosis using the Nanopore MinION sequencing platform. We designed a single-tube assay that targets nine genes associated with drug resistance to seven drugs and two phylogenetic-determining regions to determine strain lineage and tested it in nine clinical isolates and six sputa. The study’s main aim is to calibrate MinNION variant calling to detect drug-resistance-associated mutations with different frequencies to match the accuracy of Illumina (the current gold-standard sequencing technology) from both culture and sputum samples. After calibrating Nanopore MinION variant calling, we demonstrated 100% agreement between Illumina WGS and our MinION set up to detect known drug resistance and phylogenetic variants in our dataset. Importantly, other variants in the amplicons are also detected, decreasing the recall. We identify minority variants and insertions/deletions as crucial bioinformatics challenges to fully reproduce Illumina WGS results.

scholarly journals A global to local genomics analysis of Clostridioides difficile ST1/RT027 identifies cryptic transmission events in a northern Arizona healthcare network

2019 ◽  
Vol 5 (7) ◽  
Author(s):  
Charles H. D. Williamson ◽  
Nathan E. Stone ◽  
Amalee E. Nunnally ◽  
Heidie M. Hornstra ◽  
David M. Wagner ◽  
...  
Keyword(s):  
Type Species ◽  
Sequence Type ◽  
Infection Prevention And Control ◽  
Polymorphism Analysis ◽  
Whole Genome ◽  
Content Type ◽  
Northern Arizona ◽  
Healthcare Network ◽  
Link Type ◽  
Clostridioides Difficile

Clostridioides difficile is a ubiquitous, diarrhoeagenic pathogen often associated with healthcare-acquired infections that can cause a range of symptoms from mild, self-limiting disease to toxic megacolon and death. Since the early 2000s, a large proportion of C. difficile cases have been attributed to the ribotype 027 (RT027) lineage, which is associated with sequence type 1 (ST1) in the C. difficile multilocus sequence typing scheme. The spread of ST1 has been attributed, in part, to resistance to fluoroquinolones used to treat unrelated infections, which creates conditions ideal for C. difficile colonization and proliferation. In this study, we analysed 27 isolates from a healthcare network in northern Arizona, USA, and 1352 publicly available ST1 genomes to place locally sampled isolates into a global context. Whole genome, single nucleotide polymorphism analysis demonstrated that at least six separate introductions of ST1 were observed in healthcare facilities in northern Arizona over an 18-month sampling period. A reconstruction of transmission networks identified potential nosocomial transmission of isolates, which were only identified via whole genome sequence analysis. Antibiotic resistance heterogeneity was observed among ST1 genomes, including variability in resistance profiles among locally sampled ST1 isolates. To investigate why ST1 genomes are so common globally and in northern Arizona, we compared all high-quality C. difficile genomes and identified that ST1 genomes have gained and lost a number of genomic regions compared to all other C. difficile genomes; analyses of other toxigenic C. difficile sequence types demonstrate that this loss may be anomalous and could be related to niche specialization. These results suggest that a combination of antimicrobial resistance and gain and loss of specific genes may explain the prominent association of this sequence type with C. difficile infection cases worldwide. The degree of genetic variability in ST1 suggests that classifying all ST1 genomes into a quinolone-resistant hypervirulent clone category may not be appropriate. Whole genome sequencing of clinical C. difficile isolates provides a high-resolution surveillance strategy for monitoring persistence and transmission of C. difficile and for assessing the performance of infection prevention and control strategies.

scholarly journals Veillonella seminalis sp. nov., a novel anaerobic Gram-stain-negative coccus from human clinical samples, and emended description of the genus Veillonella

2014 ◽  
Vol 64 (Pt_10) ◽  
pp. 3526-3531 ◽  
Author(s):  
Fabien Aujoulat ◽  
Philippe Bouvet ◽  
Estelle Jumas-Bilak ◽  
Hélène Jean-Pierre ◽  
Hélène Marchandin
Keyword(s):  
Sequence Analysis ◽  
16S Rrna ◽  
Type Strain ◽  
Type Species ◽  
Clinical Samples ◽  
Rrna Gene ◽  
Gram Stain ◽  
Content Type ◽  
Link Type ◽  
Emended Description

Ten isolates of unknown, Gram-stain-negative, anaerobic cocci were recovered from human clinical samples, mainly from semen. On the basis of their phenotypic features, including morphology, main metabolic end products, gas production, nitrate reduction and decarboxylation of succinate, the strains were identified as members of the genus Veillonella. Multi-locus sequence analysis and corresponding phylogenies were based on 16S rRNA, dnaK and rpoB genes, and on the newly proposed gltA gene. The strains shared high levels of genetic sequence similarity and were related most closely to Veillonella ratti . The strains could not be differentiated from V. ratti on the basis of 16S rRNA gene sequence analysis while gltA, rpoB and dnaK gene sequences showed 85.1, 93.5 and 90.2 % similarity with those of the type strain of V. ratti , respectively. Phylogenetic analyses revealed that the isolates formed a robust clade in the V. ratti – Veillonella criceti – Veillonella magna subgroup of the genus Veillonella . As observed for V. criceti , the isolates were able to ferment fructose. In contrast to other members of the genus Veillonella , the 10 strains were not able to metabolize lactate. Cellular fatty acid composition was consistent with that of other species of the genus Veillonella . From these data, the 10 isolates are considered to belong to a novel species in the genus Veillonella , for which the name Veillonella seminalis sp. nov. is proposed. The type strain is ADV 4313.2T ( = CIP 107810T = LMG 28162T). Veillonella strain ACS-216-V-Col6b subjected to whole genome sequencing as part as the Human Microbiome Project is another representative of V. seminalis sp. nov. An emended description of the genus Veillonella is also proposed.

scholarly journals The magnitude of extended-spectrum beta-lactamase- producing Enterobacteriaceae from clinical samples in Ethiopia: a systematic review and meta-analysis

2021 ◽  
Author(s):  
Kuma Diriba ◽  
Ephrem Awulachew ◽  
Aschelew Gemede ◽  
Asrat Anja
Keyword(s):  
Systematic Review ◽  
Type Species ◽  
Meta Analysis ◽  
High Rate ◽  
Cochrane Library ◽  
Clinical Samples ◽  
Content Type ◽  
Link Type ◽  
Extended Spectrum ◽  
Pooled Prevalence

Background. The rapid spread of resistance among extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae is a serious problem around the world. It results in serious clinical complications in humans and has become a global threat. Therefore, this systematic review and meta-analysis was aimed to estimate the pooled prevalence of ESBL-producing Enterobacteriaceae in different clinical samples in Ethiopia. Methods. A systematic search was conducted on PubMed, Web of Science, Embase, Google Scholar and the Cochrane Library. All identified observational studies reporting the prevalence of ESBL-producing Enterobacteriaceae from clinical samples in Ethiopia were included. Four authors independently extracted data and analysed using R software version 3.6.1 and STATA statistical software version 13. A random-effects model was computed to estimate the pooled prevalence of ESBL-producing Enterobacteriaceae in Ethiopia. Results. Of 142 articles reviewed, 14 studies that fulfilled the inclusion criteria were included in the meta-analysis. The pooled prevalence of ESBL-producing Enterobacteriaceae in the different clinical specimens in Ethiopia was 49 % (95 % CI: 39, 60). Klebsiella pneumoniae was the leading ESBL-producing Enterobacteriaceae followed by Escherichia coli and Acinetobacter baumannii with a prevalence of 74, 67 and 60 %, respectively. ESBL-producing isolates showed a high rate of resistance to cefotaxime, ceftriaxone, ceftazidime, Amoxicillin clavulanic acid (AMC), ampicillin and aztreonam. The better options for the treatment of ESBL-producing Enterobacteriaceae are amikacin and Imipenem. Conclusion. The magnitude of ESBL-producing Enterobacteriaceae in different clinical samples in Ethiopia is alarmingly high and represents a threat to human health. Hence, a coordinated effort needs to be implemented for the prevention and control of these Enterobacteriaceae .

scholarly journals ECTyper: in silico Escherichia coli serotype and species prediction from raw and assembled whole-genome sequence data

2021 ◽  
Vol 7 (12) ◽  
Author(s):  
Kyrylo Bessonov ◽  
Chad Laing ◽  
James Robertson ◽  
Irene Yong ◽  
Kim Ziebell ◽  
...  
Keyword(s):  
Public Health ◽  
Escherichia Coli ◽  
In Silico ◽  
Type Species ◽  
Outbreak Detection ◽  
Health Concern ◽  
Whole Genome ◽  
Content Type ◽  
Link Type ◽  
O Antigens

Escherichia coli is a priority foodborne pathogen of public health concern and phenotypic serotyping provides critical information for surveillance and outbreak detection activities. Public health and food safety laboratories are increasingly adopting whole-genome sequencing (WGS) for characterizing pathogens, but it is imperative to maintain serotype designations in order to minimize disruptions to existing public health workflows. Multiple in silico tools have been developed for predicting serotypes from WGS data, including SRST2, SerotypeFinder and EToKi EBEis, but these tools were not designed with the specific requirements of diagnostic laboratories, which include: speciation, input data flexibility (fasta/fastq), quality control information and easily interpretable results. To address these specific requirements, we developed ECTyper (https://github.com/phac-nml/ecoli_serotyping) for performing both speciation within Escherichia and Shigella , and in silico serotype prediction. We compared the serotype prediction performance of each tool on a newly sequenced panel of 185 isolates with confirmed phenotypic serotype information. We found that all tools were highly concordant, with 92–97 % for O-antigens and 98–100 % for H-antigens, and ECTyper having the highest rate of concordance. We extended the benchmarking to a large panel of 6954 publicly available E. coli genomes to assess the performance of the tools on a more diverse dataset. On the public data, there was a considerable drop in concordance, with 75–91 % for O-antigens and 62–90 % for H-antigens, and ECTyper and SerotypeFinder being the most concordant. This study highlights that in silico predictions show high concordance with phenotypic serotyping results, but there are notable differences in tool performance. ECTyper provides highly accurate and sensitive in silico serotype predictions, in addition to speciation, and is designed to be easily incorporated into bioinformatic workflows.

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