scholarly journals Genomic surveillance and improved molecular typing of Bordetella pertussis using wgMLST

2020 ◽  
Author(s):  
Michael R. Weigand ◽  
Yanhui Peng ◽  
Hannes Pouseele ◽  
Dane Kania ◽  
Katherine E. Bowden ◽  
...  

ABSTRACTMulti-Locus Sequence Typing (MLST) provides allele-based characterization of bacterial pathogens in a standardized framework. However, current MLST schemes for Bordetella pertussis, the causative agent of whooping cough, seldom reveal diversity among the small number of gene targets and thereby fail to delineate population structure. To improve discriminatory power of allele-based molecular typing of B. pertussis, we have developed a whole-genome MLST (wgMLST) scheme from 214 reference-quality genome assemblies. Iterative refinement and allele curation resulted in a scheme of 3,506 coding sequences and covering 81.4% of the B. pertussis genome. This wgMLST scheme was further evaluated with data from a convenience sample of 2,389 B. pertussis isolates sequenced on Illumina instruments, including isolates from known outbreaks and epidemics previously characterized by existing molecular assays, as well as replicates collected from individual patients. wgMLST demonstrated concordance with whole-genome single nucleotide polymorphisms (SNP) profiles, accurately resolved outbreak and sporadic cases in a retrospective comparison, and clustered replicate isolates collected from individual patients during diagnostic confirmation. Additionally, a re-analysis of isolates from two statewide epidemics using wgMLST reconstructed the population structures of circulating strains with increased resolution, revealing new clusters of related cases. Comparison with an existing core-genome (cgMLST) scheme highlights the genomic stability of this bacterium and forms the initial foundation for necessary standardization. These results demonstrate the utility of wgMLST for improving B. pertussis characterization and genomic surveillance during the current pertussis disease resurgence.

2021 ◽  
Vol 59 (5) ◽  
Author(s):  
Michael R. Weigand ◽  
Yanhui Peng ◽  
Hannes Pouseele ◽  
Dane Kania ◽  
Katherine E. Bowden ◽  
...  

ABSTRACT Multilocus sequence typing (MLST) provides allele-based characterization of bacterial pathogens in a standardized framework. However, classical MLST schemes for Bordetella pertussis, the causative agent of whooping cough, seldom reveal diversity among the small number of gene targets and thereby fail to delineate population structure. To improve the discriminatory power of allele-based molecular typing of B. pertussis, we have developed a whole-genome MLST (wgMLST) scheme from 225 reference-quality genome assemblies. Iterative refinement and allele curation resulted in a scheme of 3,506 coding sequences and covering 81.4% of the B. pertussis genome. This wgMLST scheme was further evaluated with data from a convenience sample of 2,389 B. pertussis isolates sequenced on Illumina instruments, including isolates from known outbreaks and epidemics previously characterized by existing molecular assays, as well as replicates collected from individual patients. wgMLST demonstrated concordance with whole-genome single nucleotide polymorphism (SNP) profiles, accurately resolved outbreak and sporadic cases in a retrospective comparison, and clustered replicate isolates collected from individual patients during diagnostic confirmation. Additionally, a reanalysis of isolates from two statewide epidemics using wgMLST reconstructed the population structures of circulating strains with increased resolution, revealing new clusters of related cases. Comparison with an existing core genome (cgMLST) scheme highlights the stable gene content of this bacterium and forms the initial foundation for necessary standardization. These results demonstrate the utility of wgMLST for improving B. pertussis characterization and genomic surveillance during the current pertussis disease resurgence.


2017 ◽  
Vol 5 (17) ◽  
Author(s):  
Yusuf Sofyan Efendi ◽  
Dwi Susanti ◽  
Erman Tritama ◽  
Michelle Lueders Pasier ◽  
Gilang Nadia Niwan Putri ◽  
...  

ABSTRACT PT Bio Farma, the sole World Health Organization-approved Indonesian vaccine producer, manufactures a whole-cell whooping cough vaccine (wP) that, as part of a pentavalent diphtheria-tetanus-pertussis/hepatitis B/Haemophilus influenzae b (DTP/HB/Hib) vaccine, is used in Indonesia and many other countries. We report here the whole-genome sequence for Bordetella pertussis Pelita III, PT Bio Farma’s wP production strain.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Xianhang Wang ◽  
Mingxing Tu ◽  
Ya Wang ◽  
Wuchen Yin ◽  
Yu Zhang ◽  
...  

AbstractThe CRISPR (clustered regularly interspaced short palindromic repeats)-associated protein 9 (Cas9) system is a powerful tool for targeted genome editing, with applications that include plant biotechnology and functional genomics research. However, the specificity of Cas9 targeting is poorly investigated in many plant species, including fruit trees. To assess the off-target mutation rate in grapevine (Vitis vinifera), we performed whole-genome sequencing (WGS) of seven Cas9-edited grapevine plants in which one of two genes was targeted by CRISPR/Cas9 and three wild-type (WT) plants. In total, we identified between 202,008 and 272,397 single nucleotide polymorphisms (SNPs) and between 26,391 and 55,414 insertions/deletions (indels) in the seven Cas9-edited grapevine plants compared with the three WT plants. Subsequently, 3272 potential off-target sites were selected for further analysis. Only one off-target indel mutation was identified from the WGS data and validated by Sanger sequencing. In addition, we found 243 newly generated off-target sites caused by genetic variants between the Thompson Seedless cultivar and the grape reference genome (PN40024) but no true off-target mutations. In conclusion, we observed high specificity of CRISPR/Cas9 for genome editing of grapevine.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ho-Yon Hwang ◽  
Jiou Wang

AbstractGenetic mapping is used in forward genetics to narrow the list of candidate mutations and genes corresponding to the mutant phenotype of interest. Even with modern advances in biology such as efficient identification of candidate mutations by whole-genome sequencing, mapping remains critical in pinpointing the responsible mutation. Here we describe a simple, fast, and affordable mapping toolkit that is particularly suitable for mapping in Caenorhabditis elegans. This mapping method uses insertion-deletion polymorphisms or indels that could be easily detected instead of single nucleotide polymorphisms in commonly used Hawaiian CB4856 mapping strain. The materials and methods were optimized so that mapping could be performed using tiny amount of genetic material without growing many large populations of mutants for DNA purification. We performed mapping of previously known and unknown mutations to show strengths and weaknesses of this method and to present examples of completed mapping. For situations where Hawaiian CB4856 is unsuitable, we provide an annotated list of indels as a basis for fast and easy mapping using other wild isolates. Finally, we provide rationale for using this mapping method over other alternatives as a part of a comprehensive strategy also involving whole-genome sequencing and other methods.


Author(s):  
Emmanuel Lecorche ◽  
Côme Daniau ◽  
Kevin La ◽  
Faiza Mougari ◽  
Hanaa Benmansour ◽  
...  

Abstract Background Post-surgical infections due to Mycobacterium chimaera appeared as a novel nosocomial threat in 2015, with a worldwide outbreak due to contaminated heater-cooler units used in open chest surgery. We report the results of investigations conducted in France including whole genome sequencing comparison of patient and HCU isolates. Methods We sought M. chimaera infection cases from 2010 onwards through national epidemiological investigations in healthcare facilities performing cardiopulmonary bypass together with a survey on good practices and systematic heater-cooler unit microbial analyses. Clinical and HCU isolates were subjected to whole genome sequencing analyzed with regards to the reference outbreak strain Zuerich-1. Results Only two clinical cases were shown to be related to the outbreak, although 23% (41/175) heater-cooler units were declared positive for M. avium complex. Specific measures to prevent infection were applied in 89% (50/56) healthcare facilities although only 14% (8/56) of them followed the manufacturer maintenance recommendations. Whole genome sequencing comparison showed that the clinical isolates and 72% (26/36) of heater-cooler unit isolates belonged to the epidemic cluster. Within clinical isolates, 5 to 9 non-synonymous single nucleotide polymorphisms were observed, among which an in vivo mutation in a putative efflux pump gene observed in a clinical isolate obtained for one patient under antimicrobial treatment. Conclusions Cases of post-surgical M. chimaera infections were declared to be rare in France, although heater-cooler units were contaminated as in other countries. Genomic analyses confirmed the connection to the outbreak and identified specific single nucleotide polymorphisms, including one suggesting fitness evolution in vivo.


Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 258
Author(s):  
Karim Karimi ◽  
Duy Ngoc Do ◽  
Mehdi Sargolzaei ◽  
Younes Miar

Characterizing the genetic structure and population history can facilitate the development of genomic breeding strategies for the American mink. In this study, we used the whole genome sequences of 100 mink from the Canadian Centre for Fur Animal Research (CCFAR) at the Dalhousie Faculty of Agriculture (Truro, NS, Canada) and Millbank Fur Farm (Rockwood, ON, Canada) to investigate their population structure, genetic diversity and linkage disequilibrium (LD) patterns. Analysis of molecular variance (AMOVA) indicated that the variation among color-types was significant (p < 0.001) and accounted for 18% of the total variation. The admixture analysis revealed that assuming three ancestral populations (K = 3) provided the lowest cross-validation error (0.49). The effective population size (Ne) at five generations ago was estimated to be 99 and 50 for CCFAR and Millbank Fur Farm, respectively. The LD patterns revealed that the average r2 reduced to <0.2 at genomic distances of >20 kb and >100 kb in CCFAR and Millbank Fur Farm suggesting that the density of 120,000 and 24,000 single nucleotide polymorphisms (SNP) would provide the adequate accuracy of genomic evaluation in these populations, respectively. These results indicated that accounting for admixture is critical for designing the SNP panels for genotype-phenotype association studies of American mink.


1962 ◽  
Vol 60 (3) ◽  
pp. 289-293 ◽  
Author(s):  
Neda Köhler-Kubelka

Investigations carried out to ascertain the ability of various strains of Bordetella pertussis and B. parapertussis to produce agglutinins have shown that the agglutinin response is considerably greater with B. parapertussis.Children inoculated with a combined vaccine in which the parapertussis element contained B. parapertussis in only one-twelfth of the concentration of B. pertussis in the pertussis element showed agglutinins in their sera in titres well above 1:300 for both organisms. There were no cross-reactions and the serological responses were specific throughout. The vaccine used was the standard diphtheria-tetanus-pertussis (DTP) prophylactic to which had been added a vaccine prepared from recently isolated strains of B. parapertussis.Agglutinin titres of both whooping cough components with the combined vaccine were somewhat lower in mice than was the case when monovalent vaccines were used, but they were considered to be satisfactory.It is suggested that the agglutination production test in mice could be used for the assessment of protective power of B. parapertussis vaccines against infection.I wish to thank Dr Ikić, director of the Institute of Immunology, Zagreb, who enabled me to perform all these examinations, further to Dr B. Mravunac and Dr Z. Radanov for having carried out vaccination in children and for the clinical examination of post vaccination reactions.


2020 ◽  
Vol 41 (S1) ◽  
pp. s434-s434
Author(s):  
Grant Vestal ◽  
Steven Bruzek ◽  
Amanda Lasher ◽  
Amorce Lima ◽  
Suzane Silbert

Background: Hospital-acquired infections pose a significant threat to patient health. Laboratories are starting to consider whole-genome sequencing (WGS) as a molecular method for outbreak detection and epidemiological surveillance. The objective of this study was to assess the use of the iSeq100 platform (Illumina, San Diego, CA) for accurate sequencing and WGS-based outbreak detection using the bioMérieux EPISEQ CS, a novel cloud-based software for sequence assembly and data analysis. Methods: In total, 25 isolates, including 19 MRSA isolates and 6 ATCC strains were evaluated in this study: A. baumannii ATCC 19606, B. cepacia ATCC 25416, E. faecalis ATCC 29212, E. coli ATCC 25922, P. aeruginosa ATCC 27853 and S. aureus ATCC 25923. DNA extraction of all isolates was performed on the QIAcube (Qiagen, Hilden, Germany) using the DNEasy Ultra Clean Microbial kit extraction protocol. DNA libraries were prepared for WGS using the Nextera DNA Flex Library Prep Kit (Illumina) and sequenced at 2×150-bp on the iSeq100 according to the manufacturer’s instructions. The 19 MRSA isolates were previously characterized by the DiversiLab system (bioMérieux, France). Upon validation of the iSeq100 platform, a new outbreak analysis was performed using WGS analysis using EPISEQ CS. ATCC sequences were compared to assembled reference genomes from the NCBI GenBank to assess the accuracy of the iSeq100 platform. The FASTQ files were aligned via BowTie2 version 2.2.6 software, using default parameters, and FreeBayes version 1.1.0.46-0 was used to call homozygous single-nucleotide polymorphisms (SNPs) with a minimum coverage of 5 and an allele frequency of 0.87 using default parameters. ATCC sequences were analyzed using ResFinder version 3.2 and were compared in silico to the reference genome. Results: EPISEQ CS classified 8 MRSA isolates as unrelated and grouped 11 isolates into 2 separate clusters: cluster A (5 isolates) and cluster B (6 isolates) with similarity scores of ≥99.63% and ≥99.50%, respectively. This finding contrasted with the previous characterization by DiversiLab, which identified 3 clusters of 2, 8, and 11 isolates, respectively. The EPISEQ CS resistome data detected the mecA gene in 18 of 19 MRSA isolates. Comparative analysis of the ATCCsequences to the reference genomes showed 99.9986% concordance of SNPs and 100.00% concordance between the resistance genes present. Conclusions: The iSeq100 platform accurately sequenced the bacterial isolates and could be an affordable alternative in conjunction with EPISEQ CS for epidemiological surveillance analysis and infection prevention.Funding: NoneDisclosures: None


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