Project description:Isolates of methicillin-resistant Staphylococcus aureus (MRSA) belonging to a single lineage are often indistinguishable by means of current typing techniques. Whole-genome sequencing may provide improved resolution to define transmission pathways and characterize outbreaks.We investigated a putative MRSA outbreak in a neonatal intensive care unit. By using rapid high-throughput sequencing technology with a clinically relevant turnaround time, we retrospectively sequenced the DNA from seven isolates associated with the outbreak and another seven MRSA isolates associated with carriage of MRSA or bacteremia in the same hospital.We constructed a phylogenetic tree by comparing single-nucleotide polymorphisms (SNPs) in the core genome to a reference genome (an epidemic MRSA clone, EMRSA-15 [sequence type 22]). This revealed a distinct cluster of outbreak isolates and clear separation between these and the nonoutbreak isolates. A previously missed transmission event was detected between two patients with bacteremia who were not part of the outbreak. We created an artificial "resistome" of antibiotic-resistance genes and demonstrated concordance between it and the results of phenotypic susceptibility testing; we also created a "toxome" consisting of toxin genes. One outbreak isolate had a hypermutator phenotype with a higher number of SNPs than the other outbreak isolates, highlighting the difficulty of imposing a simple threshold for the number of SNPs between isolates to decide whether they are part of a recent transmission chain.Whole-genome sequencing can provide clinically relevant data within a time frame that can influence patient care. The need for automated data interpretation and the provision of clinically meaningful reports represent hurdles to clinical implementation. (Funded by the U.K. Clinical Research Collaboration Translational Infection Research Initiative and others.).
Project description:Two Southeast Asian students attending the same school in the United Kingdom presented with pulmonary tuberculosis. An epidemiological investigation failed to link the two cases, and drug resistance profiles of the Mycobacterium tuberculosis isolates were discrepant. Whole-genome sequencing of the isolates found them to be genetically identical, suggesting a missed transmission event.
Project description:Whole genome sequencing (WGS) has become the new gold standard for bacterial outbreak investigation, due to the high resolution available for typing. While sequencing is currently predominantly performed on Illumina devices, the preceding library preparation can be performed using various protocols. Enzymatic fragmentation library preparation protocols are fast, have minimal hands-on time, and work with small quantities of DNA. The aim of our study was to compare three library preparation protocols for molecular typing: Nextera XT (Illumina); Nextera Flex (Illumina); and QIAseq FX (Qiagen). We selected 12 ATCC strains from human Gram-positive and Gram-negative pathogens with %G+C-content ranging from 27% (Fusobacterium nucleatum) to 73% (Micrococcus luteus), each having a high quality complete genome assembly available, to allow in-depth analysis of the resulting Illumina sequence data quality. Additionally, we selected isolates from previously analyzed cases of vancomycin-resistant Enterococcus faecium (VRE) (n = 7) and a local outbreak of Klebsiella aerogenes (n = 5). The number of protocol steps and time required were compared, in order to test the suitability for routine laboratory work. Data analyses were performed with standard tools commonly used in outbreak situations: Ridom SeqSphere+ for cgMLST; CLC genomics workbench for SNP analysis; and open source programs. Nextera Flex and QIAseq FX were found to be less sensitive than Nextera XT to variable %G+C-content, resulting in an almost uniform distribution of read-depth. Therefore, low coverage regions are reduced to a minimum resulting in a more complete representation of the genome. Thus, with these two protocols, more alleles were detected in the cgMLST analysis, producing a higher resolution of closely related isolates. Furthermore, they result in a more complete representation of accessory genes. In particular, the high data quality and relative simplicity of the workflow of Nextera Flex stood out in this comparison. This thorough comparison within an ISO/IEC 17025 accredited environment will be of interest to those aiming to optimize their clinical microbiological genome sequencing.
Project description:BackgroundThe COVID-19 pandemic has hit all corners of the world, challenging governments to act promptly in controlling the spread of the pandemic. Due to limited resources and inferior technological capacities, developing countries including Vietnam have faced many challenges in combating the pandemic. Since the first cases were detected on 23 January 2020, Vietnam has undergone a 3-month fierce battle to control the outbreak with stringent measures from the government to mitigate the adverse impacts. In this study, we aim to give insights into the Vietnamese government's progress during the first three months of the outbreak. Additionally, we relatively compare Vietnam's response with that of other Southeast Asia countries to deliver a clear and comprehensive view on disease control strategies.MethodsThe data on the number of COVID-19 confirmed and recovered cases in Vietnam was obtained from the Dashboard for COVID-19 statistics of the Ministry of Health (https://ncov.vncdc.gov.vn/). The review on Vietnam's country-level responses was conducted by searching for relevant government documents issued on the online database 'Vietnam Laws Repository' (https://thuvienphapluat.vn/en/index.aspx), with the grey literature on Google and relevant official websites. A stringency index of government policies and the countries' respective numbers of confirmed cases of nine Southeast Asian countries were adapted from the Oxford COVID-19 Government Response Tracker (https://www.bsg.ox.ac.uk/research/research-projects/coronavirus-government-response-tracker). All data was updated as of 24 April 2020.ResultsPreliminary positive results have been achieved given that the nation confirmed no new community-transmitted cases since 16 April and zero COVID-19 - related deaths throughout the 3-month pandemic period. To date, the pandemic has been successfully controlled thanks to the Vietnamese government's prompt, proactive and decisive responses including mobilization of the health care systems, security forces, economic policies, along with a creative and effective communication campaign corresponding with crucial milestones of the epidemic's progression.ConclusionsVietnam could be one of the role models in pandemic control for low-resource settings. As the pandemic is still ongoing in an unpredictable trajectory, disease control measures should continue to be put in place in the foreseeable short term.
Project description:Epidemiological investigations of Legionnaires' disease outbreaks rely on the rapid identification and typing of clinical and environmental Legionella isolates in order to identify and control the source of infection. Rapid bacterial whole-genome sequencing (WGS) is an emerging technology that has the potential to rapidly discriminate outbreak from non-outbreak isolates in a clinically relevant time frame.We performed a pilot study to determine the feasibility of using bacterial WGS to differentiate outbreak from non-outbreak isolates collected during an outbreak of Legionnaires' disease. Seven Legionella isolates (three clinical and four environmental) were obtained from the reference laboratory and sequenced using the Illumina MiSeq platform at Addenbrooke's Hospital, Cambridge. Bioinformatic analysis was performed blinded to the epidemiological data at the Wellcome Trust Sanger Institute.We were able to distinguish outbreak from non-outbreak isolates using bacterial WGS, and to confirm the probable environmental source. Our analysis also highlighted constraints, which were the small number of Legionella pneumophila isolates available for sequencing, and the limited number of published genomes for comparison.We have demonstrated the feasibility of using rapid WGS to investigate an outbreak of Legionnaires' disease. Future work includes building larger genomic databases of L pneumophila from both clinical and environmental sources, developing automated data interpretation software, and conducting a cost-benefit analysis of WGS versus current typing methods.
Project description:Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2-4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes-including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)-in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease.
Project description:Genomic surveillance is an important aspect of contemporary disease management but has yet to be used routinely to monitor endemic disease transmission and control in low- and middle-income countries. Rabies is an almost invariably fatal viral disease that causes a large public health and economic burden in Asia and Africa, despite being entirely vaccine preventable. With policy efforts now directed towards achieving a global goal of zero dog-mediated human rabies deaths by 2030, establishing effective surveillance tools is critical. Genomic data can provide important and unique insights into rabies spread and persistence that can direct control efforts. However, capacity for genomic research in low- and middle-income countries is held back by limited laboratory infrastructure, cost, supply chains and other logistical challenges. Here we present and validate an end-to-end workflow to facilitate affordable whole genome sequencing for rabies surveillance utilising nanopore technology. We used this workflow in Kenya, Tanzania and the Philippines to generate rabies virus genomes in two to three days, reducing costs to approximately £60 per genome. This is over half the cost of metagenomic sequencing previously conducted for Tanzanian samples, which involved exporting samples to the UK and a three- to six-month lag time. Ongoing optimization of workflows are likely to reduce these costs further. We also present tools to support routine whole genome sequencing and interpretation for genomic surveillance. Moreover, combined with training workshops to empower scientists in-country, we show that local sequencing capacity can be readily established and sustainable, negating the common misperception that cutting-edge genomic research can only be conducted in high resource laboratories. More generally, we argue that the capacity to harness genomic data is a game-changer for endemic disease surveillance and should precipitate a new wave of researchers from low- and middle-income countries.
Project description:Traditionally, genetic testing has been too slow or perceived to be impractical to initial management of the critically ill neonate. Technological advances have led to the ability to sequence and interpret the entire genome of a neonate in as little as 26 h. As the cost and speed of testing decreases, the utility of whole genome sequencing (WGS) of neonates for acute and latent genetic illness increases. Analyzing the entire genome allows for concomitant evaluation of the currently identified 5588 single gene diseases. When applied to a select population of ill infants in a level IV neonatal intensive care unit, WGS yielded a diagnosis of a causative genetic disease in 57% of patients. These diagnoses may lead to clinical management changes ranging from transition to palliative care for uniformly lethal conditions for alteration or initiation of medical or surgical therapy to improve outcomes in others. Thus, institution of 2-day WGS at time of acute presentation opens the possibility of early implementation of precision medicine. This implementation may create opportunities for early interventional, frequently novel or off-label therapies that may alter disease trajectory in infants with what would otherwise be fatal disease. Widespread deployment of rapid WGS and precision medicine will raise ethical issues pertaining to interpretation of variants of unknown significance, discovery of incidental findings related to adult onset conditions and carrier status, and implementation of medical therapies for which little is known in terms of risks and benefits. Despite these challenges, precision neonatology has significant potential both to decrease infant mortality related to genetic diseases with onset in newborns and to facilitate parental decision making regarding transition to palliative care.