57 research outputs found

    Molecular investigation of the Aum Shinrikyo anthrax release in Kameido, Japan

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    In 1993, the Aum Shinrikyo cult aerosolized Bacillus anthracis spores over Kameido, Japan. Spore samples were obtained from the release site, cultured, and characterized by molecular genetic typing. The isolates were consistent with strain Sterne 34F2, which is used in Japan for animal prophylaxis against anthrax

    PCR-based method for targeting 16S-23S rRNA intergenic spacer regions among Vibrio species

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    <p>Abstract</p> <p>Background</p> <p>The genus <it>Vibrio </it>is a diverse group of Gram-negative bacteria comprised of 74 species. Furthermore, the genus has and is expected to continue expanding with the addition of several new species annually. Consequently, it is of paramount importance to have a method which is able to reliably and efficiently differentiate the numerous <it>Vibrio </it>species.</p> <p>Results</p> <p>In this study, a novel and rapid polymerase chain reaction (PCR)-based intergenic spacer (IGS)-typing system for vibrios was developed that is based on the well-known IGS regions located between the 16S and 23S rRNA genes on the bacterial chromosome. The system was optimized to resolve heteroduplex formation as well as to take advantage of capillary gel electrophoresis technology such that reproducible analyses could be achieved in a rapid manner. System validation was achieved through testing of 69 archetypal <it>Vibrio </it>strains, representing 48 <it>Vibrio </it>species, from which an 'IGS-type' profile database was generated. These data, presented here in several cluster analyses, demonstrated successful differentiation of the 69 type strains showing that this PCR-based fingerprinting method easily discriminates bacterial strains at the species level among <it>Vibrio</it>. Furthermore, testing 36 strains each of <it>V. parahaemolyticus </it>and <it>V. vulnificus</it>, important food borne pathogens, isolated from a variety of geographical locations with the IGS-typing method demonstrated distinct IGS-typing patterns indicative of subspecies divergence in both populations making this technique equally useful for intraspecies differentiation, as well.</p> <p>Conclusion</p> <p>This rapid, reliable and efficient IGS-typing system, especially in combination with 16S rRNA gene sequencing, has the capacity to not only discern and identify vibrios at the species level but, in some cases, at the sub-species level, as well. This procedure is particularly well-suited for preliminary species identification and, lends itself nicely to epidemiological investigations providing information more quickly than other time-honoured methods traditionally used in these types of analyses.</p

    Bacillus anthracis Bioterrorism Incident, Kameido, Tokyo, 1993

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    In July 1993, a liquid suspension of Bacillus anthracis was aerosolized from the roof of an eight-story building in Kameido, Tokyo, Japan, by the religious group Aum Shinrikyo. During 1999 to 2001, microbiologic tests were conducted on a liquid environmental sample originally collected during the 1993 incident. Nonencapsulated isolates of B. anthracis were cultured from the liquid. Multiple-locus, variable-number tandem repeat analysis found all isolates to be identical to a strain used in Japan to vaccinate animals against anthrax, which was consistent with the Aum Shinrikyo members’ testimony about the strain source. In 1999, a retrospective case-detection survey was conducted to identify potential human anthrax cases associated with the incident, but none were found. The use of an attenuated B. anthracis strain, low spore concentrations, ineffective dispersal, a clogged spray device, and inactivation of the spores by sunlight are all likely contributing factors to the lack of human cases

    High resolution clustering of Salmonella enterica serovar Montevideo strains using a next-generation sequencing approach

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    <p>Abstract</p> <p>Background</p> <p>Next-Generation Sequencing (NGS) is increasingly being used as a molecular epidemiologic tool for discerning ancestry and traceback of the most complicated, difficult to resolve bacterial pathogens. Making a linkage between possible food sources and clinical isolates requires distinguishing the suspected pathogen from an environmental background and placing the variation observed into the wider context of variation occurring within a serovar and among other closely related foodborne pathogens. Equally important is the need to validate these high resolution molecular tools for use in molecular epidemiologic traceback. Such efforts include the examination of strain cluster stability as well as the cumulative genetic effects of sub-culturing on these clusters. Numerous isolates of <it>S</it>. Montevideo were shot-gun sequenced including diverse lineage representatives as well as numerous replicate clones to determine how much variability is due to bias, sequencing error, and or the culturing of isolates. All new draft genomes were compared to 34 <it>S</it>. Montevideo isolates previously published during an NGS-based molecular epidemiological case study.</p> <p>Results</p> <p>Intraserovar lineages of <it>S</it>. Montevideo differ by thousands of SNPs, that are only slightly less than the number of SNPs observed between <it>S</it>. Montevideo and other distinct serovars. Much less variability was discovered within an individual <it>S</it>. Montevideo clade implicated in a recent foodborne outbreak as well as among individual NGS replicates. These findings were similar to previous reports documenting homopolymeric and deletion error rates with the Roche 454 GS Titanium technology. In no case, however, did variability associated with sequencing methods or sample preparations create inconsistencies with our current phylogenetic results or the subsequent molecular epidemiological evidence gleaned from these data.</p> <p>Conclusions</p> <p>Implementation of a validated pipeline for NGS data acquisition and analysis provides highly reproducible results that are stable and predictable for molecular epidemiological applications. When draft genomes are collected at 15×-20× coverage and passed through a quality filter as part of a data analysis pipeline, including sub-passaged replicates defined by a few SNPs, they can be accurately placed in a phylogenetic context. This reproducibility applies to all levels within and between serovars of <it>Salmonella </it>suggesting that investigators using these methods can have confidence in their conclusions.</p

    Enhanced Subtyping Scheme for Salmonella Enteritidis

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    To improve pulsed-field gel electrophoresis–based strain discrimination of 76 Salmonella Enteritidis strains, we evaluated 6 macro-restriction endonucleases, separately and in various combinations. One 3-enzyme subset, SfiI/PacI/NotI, was highly discriminatory. Five different indices, including the Simpson diversity index, supported this 3-enzyme combination for improved differentiation of S. Enteritidis

    Children\u27s Sleep during COVID-19: How Sleep Influences Surviving and Thriving in Families

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    Objective The COVID-19 pandemic has the potential to disrupt the lives of families and may have implications for children with existing sleep problems. As such, we aimed to: (1) characterize sleep changes during the COVID-19 pandemic in children who had previously been identified as having sleep problems, (2) identify factors contributing to sleep changes due to COVID-19 safety measures, and (3) understand parents and children s needs to support sleep during the pandemic. Methods Eighty-five Canadian parents with children aged 4 14 years participated in this explanatory sequential, mixed-methods study using an online survey of children s and parents sleep, with a subset of 16 parents, selected based on changes in their children s sleep, participating in semi-structured interviews. Families had previously participated in the Better Nights, Better Days (BNBD) randomized controlled trial. Results While some parents perceived their child s sleep quality improved during the COVID-19 pandemic (14.1%, n 12), many parents perceived their child s sleep had worsened (40.0%, n 34). Parents attributed children s worsened sleep to increased screen time, anxiety, and decreased exercise. Findings from semi-structured interviews highlighted the effect of disrupted routines on sleep and stress, and that stress reciprocally influenced children s and parents sleep. Conclusions The sleep of many Canadian children was affected by the first wave of the COVID-19 pandemic, with the disruption of routines influencing children s sleep. eHealth interventions, such as BNBD with modifications that address the COVID-19 context, could help families address these challenges

    Incidence and Tracking of Escherichia coli O157:H7 in a Major Produce Production Region in California

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    Fresh vegetables have become associated with outbreaks caused by Escherichia coli O157:H7 (EcO157). Between 1995–2006, 22 produce outbreaks were documented in the United States, with nearly half traced to lettuce or spinach grown in California. Outbreaks between 2002 and 2006 induced investigations of possible sources of pre-harvest contamination on implicated farms in the Salinas and San Juan valleys of California, and a survey of the Salinas watershed. EcO157 was isolated at least once from 15 of 22 different watershed sites over a 19 month period. The incidence of EcO157 increased significantly when heavy rain caused an increased flow rate in the rivers. Approximately 1000 EcO157 isolates obtained from cultures of>100 individual samples were typed using Multi-Locus Variable-number-tandem-repeat Analysis (MLVA) to assist in identifying potential fate and transport of EcO157 in this region. A subset of these environmental isolates were typed by Pulse Field Gel Electrophoresis (PFGE) in order to make comparisons with human clinical isolates associated with outbreak and sporadic illness. Recurrence of identical and closely related EcO157 strains from specific locations in the Salinas and San Juan valleys suggests that transport of the pathogen is usually restricted. In a preliminary study, EcO157 was detected in water at multiple locations in a low-flow creek only within 135 meters of a point source. However, possible transport up to 32 km was detected during periods of higher water flow associated with flooding. During the 2006 baby spinach outbreak investigation, transport was also detected where water was unlikely to be involved. These results indicate that contamination of the environment is a dynamic process involving multiple sources and methods of transport. Intensive studies of the sources, incidence, fate and transport of EcO157 near produce production are required to determine the mechanisms of pre-harvest contamination and potential risks for human illness

    Meat, eggs, dairy products, and risk of breast cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort

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    Background: A Western diet is associated with breast cancer risk. Objective: We investigated the relation of meat, egg, and dairy product consumption with breast cancer risk by using data from the European Prospective Investigation into Cancer and Nutrition (EPIC). Design: Between 1992 and 2003, information on diet was collected from 319,826 women. Disease hazard ratios were estimated with multivariate Cox proportional hazard models. Results: Breast cancer cases (n = 7119) were observed during 8.8 y (median) of follow-up. No consistent association was found between breast cancer risk and the consumption of any of the food groups under study, when analyzed by both categorical and continuous exposure variable models. High processed meat consumption was associated with a modest increase in breast cancer risk in the categorical model (hazard ratio: 1.10; 95% CI: 1.00, 1.20; highest compared with lowest quintile: P for trend = 0.07). Subgroup analyses suggested an association with butter consumption, limited to premenopausal women (hazard ratio: 1.28; 95% CI: 1.06, 1.53; highest compared with lowest quintile: P for trend = 0.21). Between-country heterogeneity was found for red meat (Q statistic = 18.03; P = 0.05) and was significantly explained (P = 0.023) by the proportion of meat cooked at high temperature. Conclusions: We have not consistently identified intakes of meat, eggs, or dairy products as risk factors for breast cancer. Future studies should investigate the possible role of high-temperature cooking in the relation of red meat intake with breast cancer risk. Am J Clin Nutr 2009;90:602-12

    Finishing the euchromatic sequence of the human genome

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    The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead
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