Benefits Of Whole Genome Sequencing Research Articles

Mycobacterium Abscessus – Diagnostic and Therapeutic Frontiers in Infection Management

Abstract Mycobacterium (M.) abscessus, a highly pathogenic non-tuberculous mycobacterium, is responsible for several clinical manifestations. A very frequent occurrence is proven in patient with various lung diseases. Furthermore, it can result in complications such as skin and soft tissue diseases, central nervous system infections, bacteremia, eye infections, and others. M. abscessus is a clinical contraindication in cystic fibrosis patients awaiting a lung transplant, as it can exacerbate disease progression. Its pathogenicity and the emergence of resistance are influenced by factors including the composition of the cell envelope, rough and smooth M. abscessus morphotypes, efflux pumps, antibiotic-modifying/inactivating enzymes, and genetic polymorphisms in target genes. Management of the infection requires multicomponent therapy due to the high level of resistance. The following antibiotics are recommended according to the guidelines from the year 2017: amikacin, tigecycline, and imipenem with a macrolide. In order to properly manage patients with M. abscessus infection, correct identification of the subspecies as well as determination of resistance is essential. To achieve this goal, molecular-genetic techniques, such as whole-genome sequencing, are becoming increasingly favored in modern clinical practice. In this review, we provide up-to-date information on the issue of infections caused by non-tuberculous M. abscessus. We focus on its characteristics, possible infectious diseases, cystic fibrosis, and resistance, as well as the benefits of whole-genome sequencing.

Unexpected Diversity of Pseudomonads Associated with Bacterial Leaf Spot of Cucurbits in the Southeastern United States.

Bacterial leaf spot of cucurbits (BLS) is an emerging disease in the southeastern United States that is capable of causing widespread outbreaks under conducive conditions. Historically attributed solely to the bacterium Pseudomonas syringae pv. lachrymans, recent studies have identified additional P. syringae pathovars as causal agents of the disease. To further investigate the identity and diversity of P. syringae strains associated with BLS in the southeastern United States, 47 bacterial isolates were recovered from symptomatic cucurbits from Florida, Alabama, and Georgia. Strains were characterized using the LOPAT testing scheme, fluorescence, and pathogenicity to watermelon and squash seedlings. Thirty-eight fluorescent isolates underwent whole-genome sequencing and were further characterized with 16S rRNA, four gene multilocus sequence analysis (MLSA) phylogeny, and average nucleotide identity analysis. Thirty-four isolates were identified as members of the P. syringae species complex, including P. syringae sensu stricto (12), P. alliivorans (12), P. capsici (nine), and P. viridiflava (one). An additional four isolates were found to belong to the Pseudomonas genus outside of the syringae species complex, though they did not share 95% or greater average nucleotide identity to any validly published species and are believed to belong to three novel Pseudomonas species. These results reveal an unpredicted level of diversity of Pseudomonas strains associated with BLS in the region and show the benefits of whole-genome sequencing for strain identification. Identification of P. capsici, which is capable of causing disease at higher temperatures than P. syringae, as a causal agent of BLS may also affect management strategies in the future.

The benefit of diagnostic whole genome sequencing in schizophrenia and other psychotic disorders.

Schizophrenia has a multifactorial etiology, involving a polygenic architecture. The potential benefit of whole genome sequencing (WGS) in schizophrenia and other psychotic disorders is not well studied. We investigated the yield of clinical WGS analysis in 251 families with a proband diagnosed with schizophrenia (N = 190), schizoaffective disorder (N = 49), or other conditions involving psychosis (N = 48). Participants were recruited in Israel and USA, mainly of Jewish, Arab, and other European ancestries. Trio (parents and proband) WGS was performed for 228 families (90.8%); in the other families, WGS included parents and at least two affected siblings. In the secondary analyses, we evaluated the contribution of rare variant enrichment in particular gene sets, and calculated polygenic risk score (PRS) for schizophrenia. For the primary outcome, diagnostic rate was 6.4%; we found clinically significant, single nucleotide variants (SNVs) or small insertions or deletions (indels) in 14 probands (5.6%), and copy number variants (CNVs) in 2 (0.8%). Significant enrichment of rare loss-of-function variants was observed in a gene set of top schizophrenia candidate genes in affected individuals, compared with population controls (N = 6,840). The PRS for schizophrenia was significantly increased in the affected individuals group, compared to their unaffected relatives. Last, we were also able to provide pharmacogenomics information based on CYP2D6 genotype data for most participants, and determine their antipsychotic metabolizer status. In conclusion, our findings suggest that WGS may have a role in the setting of both research and genetic counseling for individuals with schizophrenia and other psychotic disorders and their families.

Continuing the sequence? Towards an economic evaluation of whole genome sequencing for the diagnosis of rare diseases in Scotland

Novel developments in genomic medicine may reduce the length of the diagnostic odyssey for patients with rare diseases. Health providers must thus decide whether to offer genome sequencing for the diagnosis of rare conditions in a routine clinical setting. We estimated the costs of singleton standard genetic testing and trio-based whole genome sequencing (WGS), in the context of the Scottish Genomes Partnership (SGP) study. We also explored what users value about genomic sequencing. Insights from the costing and value assessments will inform a subsequent economic evaluation of genomic medicine in Scotland. An average cost of £1,841 per singleton was estimated for the standard genetic testing pathway, with significant variability between phenotypes. WGS cost £6625 per family trio, but this estimate reflects the use of WGS during the SGP project and large cost savings may be realised if sequencing was scaled up. Patients and families valued (i) the chance of receiving a diagnosis (and the peace of mind and closure that brings); (ii) the information provided by WGS (including implications for family planning and secondary findings); and (iii) contributions to future research. Our costings will be updated to address limitations of the current study for incorporation in budget impact modelling and cost-effectiveness analysis (cost per diagnostic yield). Our insights into the benefits of WGS will guide the development of a discrete choice experiment valuation study. This will inform a user-perspective cost–benefit analysis of genome-wide sequencing, accounting for the broader non-health outcomes. Taken together, our research will inform the long-term strategic development of NHS Scotland clinical genetics testing services, and will be of benefit to others seeking to undertake similar evaluations in different contexts.

The Benefits of Whole Genome Sequencing for Foodborne Outbreak Investigation from the Perspective of a National Reference Laboratory in a Smaller Country.

Gradually, conventional methods for foodborne pathogen typing are replaced by whole genome sequencing (WGS). Despite studies describing the overall benefits, National Reference Laboratories of smaller countries often show slower uptake of WGS, mainly because of significant investments required to generate and analyze data of a limited amount of samples. To facilitate this process and incite policy makers to support its implementation, a Shiga toxin-producing Escherichia coli (STEC) O157:H7 (stx1+, stx2+, eae+) outbreak (2012) and a STEC O157:H7 (stx2+, eae+) outbreak (2013) were retrospectively analyzed using WGS and compared with their conventional investigations. The corresponding results were obtained, with WGS delivering even more information, e.g., on virulence and antimicrobial resistance genotypes. Besides a universal, all-in-one workflow with less hands-on-time (five versus seven actual working days for WGS versus conventional), WGS-based cgMLST-typing demonstrated increased resolution. This enabled an accurate cluster definition, which remained unsolved for the 2013 outbreak, partly due to scarce epidemiological linking with the suspect source. Moreover, it allowed detecting two and one earlier circulating STEC O157:H7 (stx1+, stx2+, eae+) and STEC O157:H7 (stx2+, eae+) strains as closely related to the 2012 and 2013 outbreaks, respectively, which might have further directed epidemiological investigation initially. Although some bottlenecks concerning centralized data-sharing, sampling strategies, and perceived costs should be considered, we delivered a proof-of-concept that even in smaller countries, WGS offers benefits for outbreak investigation, if a sufficient budget is available to ensure its implementation in surveillance. Indeed, applying a database with background isolates is critical in interpreting isolate relationships to outbreaks, and leveraging the true benefit of WGS in outbreak investigation and/or prevention.

Newborn Screening and Whole Genome Sequencing

Canadian newborn screening (NBS) programs aresuccessful in improving the prognosis of many affectedneonates with early-onset disorders by enabling rapiddiagnosis and treatment. However, many problems still existwith NBS programs including inconsistent coverage acrossprovinces or territories, gaps in disease screening, andvariable testing methodologies. Whole-genome sequencing(WGS) represents an increasingly cost-effective means ofscreening all genetic conditions with a single primary assay.Many benefits of WGS have been cited, including the ability to determine the exact causative mutation of a condition which could enable targeted therapy. Despite this, WGS in NBS carries serious ethical ramifications pertaining to disclosure of results, storage of data, and future development in NBS programs. Due to these factors, we are as-of-yet unprepared to incorporate WGS into Canadian NBS programs.

Whole Genome Sequence Analysis of CTX-M-15 Producing Klebsiella Isolates Allowed Dissecting a Polyclonal Outbreak Scenario.

Extended-spectrum β-lactamase (ESBL) producing Klebsiella pneumoniae pose an important threat of infection with increased morbidity and mortality, especially for immunocompromised patients. Here, we use the rise of multidrug-resistant K. pneumoniae in a German neurorehabilitation center from April 2015 to April 2016 to dissect the benefit of whole genome sequencing (WGS) for outbreak analyses. In total, 53 isolates were obtained from 52 patients and examined using WGS. Two independent analysis strategies (reference-based and -free) revealed the same distinct clusters of two CTX-M-15 producing K. pneumoniae clones (ST15, n = 31; ST405, n = 7) and one CTX-M-15 producing Klebsiella quasipneumoniae strain (ST414, n = 8). Additionally, we determined sequence variations associated with antimicrobial resistance phenotypes in single isolates expressing carbapenem and colistin resistance, respectively. For rapid detection of the major K. pneumoniae outbreak clone (ST15), a selective triplex PCR was deduced from WGS data of the major outbreak strain and K. pneumoniae genome data deposited in central databases. Moreover, we introduce two novel open-source applications supporting reference genome selection (refRank; https://gitlab.com/s.fuchs/refRank) and alignment-based SNP-filtering (SNPfilter; https://gitlab.com/s.fuchs/snpfilter) in NGS analyses.

Whole Genome Sequencing as a Diagnostic Test: Challenges and Opportunities

Extraordinary technological advances and decreases in the cost of DNA sequencing have made the possibility of whole genome sequencing (WGS) as a highly accessible clinical test for numerous indications feasible. There have been many recent, successful applications of WGS in establishing the etiology of complex diseases and guiding therapeutic decision-making in neoplastic and nonneoplastic diseases and in various aspects of reproductive health. However, there are major, but not insurmountable, obstacles to the increased clinical implementation of WGS, such as hidden costs, issues surrounding sequencing and analysis, quality assurance and standardization protocols, ethical dilemmas, and difficulties with interpretation of the results. The widespread use of WGS in routine clinical practice remains a distant proposition. Prospective trials will be needed to establish if, and for whom, the benefits of WGS will outweigh the likely substantial costs associated with follow-up tests, the risks of overdiagnosis and overtreatment, and the associated emotional distress. WGS should be carefully implemented in the clinic to allow the realization of its potential to improve patient health in specific indications. To minimize harm the use of WGS for all other reasons must be carefully evaluated before clinical implementation.