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For the last 500 years, the Americas have been a melting pot both for genetically diverse humans and for the pathogenic and commensal organisms associated with them. One such organism is the stomach-dwelling bacterium Helicobacter pylori, which is highly prevalent in Latin America where it is a major current public health challenge because of its strong association with gastric cancer. By analyzing the genome sequence of H. pylori isolated in North, Central and South America, we found evidence for admixture between H. pylori of European and African origin throughout the Americas, without substantial input from pre-Columbian (hspAmerind) bacteria. In the US, strains of African and European origin have remained genetically distinct, while in Colombia and Nicaragua, bottlenecks and rampant genetic exchange amongst isolates have led to the formation of national gene pools. We found three outer membrane proteins with atypical levels of Asian ancestry in American strains, as well as alleles that were nearly fixed specifically in South American isolates, suggesting a role for the ethnic makeup of hosts in the colonization of incoming strains. Our results show that new H. pylori subpopulations can rapidly arise, spread and adapt during times of demographic flux, and suggest that differences in transmission ecology between high and low prevalence areas may substantially affect the composition of bacterial populations.
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Infecções por Helicobacter/genética , Helicobacter pylori/genética , Filogenia , Neoplasias Gástricas/genética , Alelos , DNA Mitocondrial/genética , Evolução Molecular , Genoma Bacteriano , Infecções por Helicobacter/epidemiologia , Helicobacter pylori/patogenicidade , Humanos , Indígenas Norte-Americanos , América Latina , Neoplasias Gástricas/epidemiologia , Neoplasias Gástricas/microbiologia , População BrancaRESUMO
[This corrects the article DOI: 10.1371/journal.pgen.1006546.].
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BACKGROUND: Helicobacter pylori are stomach-dwelling bacteria that are present in about 50% of the global population. Infection is asymptomatic in most cases, but it has been associated with gastritis, gastric ulcers and gastric cancer. Epidemiological evidence shows that progression to cancer depends upon the host and pathogen factors, but questions remain about why cancer phenotypes develop in a minority of infected people. Here, we use comparative genomics approaches to understand how genetic variation amongst bacterial strains influences disease progression. RESULTS: We performed a genome-wide association study (GWAS) on 173 H. pylori isolates from the European population (hpEurope) with known disease aetiology, including 49 from individuals with gastric cancer. We identified SNPs and genes that differed in frequency between isolates from patients with gastric cancer and those with gastritis. The gastric cancer phenotype was associated with the presence of babA and genes in the cag pathogenicity island, one of the major virulence determinants of H. pylori, as well as non-synonymous variations in several less well-studied genes. We devised a simple risk score based on the risk level of associated elements present, which has the potential to identify strains that are likely to cause cancer but will require refinement and validation. CONCLUSION: There are a number of challenges to applying GWAS to bacterial infections, including the difficulty of obtaining matched controls, multiple strain colonization and the possibility that causative strains may not be present when disease is detected. Our results demonstrate that bacterial factors have a sufficiently strong influence on disease progression that even a small-scale GWAS can identify them. Therefore, H. pylori GWAS can elucidate mechanistic pathways to disease and guide clinical treatment options, including for asymptomatic carriers.
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Variação Genética , Genoma Bacteriano , Estudo de Associação Genômica Ampla , Helicobacter pylori/genética , Neoplasias Gástricas/microbiologia , Gastrite/etiologia , Humanos , Metaplasia/etiologia , Polimorfismo de Nucleotídeo Único , Risco , Neoplasias Gástricas/epidemiologia , Fatores de Virulência/genéticaRESUMO
Environmental pollution often accompanies the expansion and urbanization of human populations where sewage and wastewaters commonly have an impact on the marine environments. Here, we explored the potential for faecal bacterial pathogens, of anthropic origin, to spread to marine wildlife in coastal areas. The common zoonotic bacterium Campylobacter was isolated from grey seals (Halichoerus grypus), an important sentinel species for environmental pollution, and compared to isolates from wild birds, agricultural sources and clinical samples to characterize possible transmission routes. Campylobacter jejuni was present in half of all grey seal pups sampled (24/50 dead and 46/90 live pups) in the breeding colony on the Isle of May (Scotland), where it was frequently associated with histological evidence of disease. Returning yearling animals (19/19) were negative for C. jejuni suggesting clearance of infection while away from the localized colony infection source. The genomes of 90 isolates from seals were sequenced and characterized using a whole-genome multilocus sequence typing (MLST) approach and compared to 192 published genomes from multiple sources using population genetic approaches and a probabilistic genetic attribution model to infer the source of infection from MLST data. The strong genotype-host association has enabled the application of source attribution models in epidemiological studies of human campylobacteriosis, and here assignment analyses consistently grouped seal isolates with those from human clinical samples. These findings are consistent with either a common infection source or direct transmission of human campylobacter to grey seals, raising concerns about the spread of human pathogens to wildlife marine sentinel species in coastal areas.
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Infecções por Campylobacter/veterinária , Campylobacter/isolamento & purificação , Focas Verdadeiras/microbiologia , Animais , Técnicas de Tipagem Bacteriana/classificação , Campylobacter/genética , Infecções por Campylobacter/epidemiologia , DNA Bacteriano/genética , Monitoramento Ambiental , Modelos Genéticos , Tipagem de Sequências Multilocus , Filogenia , Escócia , Análise de Sequência de DNA , Zoonoses/microbiologiaRESUMO
Fifty-six α-hemolytic streptococcal isolates were identified using MALDI Biotyper MS (Bruker Daltonics), API 20 Strep (bioMérieux), and BD Phoenix (Becton, Dickinson). The gold standard for identification was 16S rRNA gene sequence analysis with 16S-23S rRNA intergenic spacer sequencing. The following percentages of isolates were correctly identified to the species level: MALDI Biotyper, 46%; BD Phoenix, 35%; and API 20 Strep, 26%.
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Técnicas de Tipagem Bacteriana/métodos , Análise de Sequência de DNA/métodos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Infecções Estreptocócicas/diagnóstico , Infecções Estreptocócicas/microbiologia , Streptococcus/classificação , Streptococcus/isolamento & purificação , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Intergênico/química , DNA Intergênico/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Humanos , RNA Ribossômico 16S/genética , Streptococcus/química , Streptococcus/genéticaRESUMO
INTRODUCTION: Preventable adverse effects of medicines often pass unnoticed, but lead to real harm. INTERVENTION: Nurse-led monitoring using the structured Adverse Drug Reaction (ADRe) Profile identifies and addresses adverse effects of mental health medicines. OBJECTIVES: This study investigated the implementation and clinical impact of ADRe, and barriers to and facilitators of sustained utilisation in routine practice. METHODS: Administration of ADRe was observed for 30 residents prescribed mental health medicines in ten care homes. The study pharmacist reviewed completed ADRes against medication records. Policy context was explored in 30 interviews with service users, nurse managers and strategic leads in Wales. RESULTS: Residents were aged 60-95, and prescribed 1-17 (median 9 [interquartile range (IQR) 7-13]) medicines. ADRe identified a median of 18 [IQR 11.5-23] problems per resident and nurses made 2 [1-2] changes to care per resident. For example: falls were reported for 9 residents, and care was modified for 5; pain was identified in 8 residents, and alleviated for 7; all 6 residents recognised as dyspnoeic were referred to prescribers. Nurses referred 17 of 30 residents to prescribers. Pharmacists recommended review for all 30. Doubts about administering ADRe, sometimes expressed by people who had not yet used it, diminished as it became familiar. ADRe was needed to bridge communication between resident, nurses and prescribers. When barriers of time, complacency, and doctors' non-availability were overcome, reporting with ADRe made prescribers more likely to heed nurses' concerns regarding residents' welfare. Clinical gains were facilitated by one-to-one time, staff-resident relationships, and unification of documentation. IMPLICATIONS: To our knowledge, ADRe is the only instrument that brings a full account of patients' problems to medication reviews. This juxtaposition of signs and symptoms against prescriptions facilitates dose adjustments and de-prescribing and leads to: reduced pain and sedation; early identification of problems linked to ADRs, such as falls; and timely medication reviews e.g. for dyspnoea.
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Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/epidemiologia , Implementação de Plano de Saúde , Saúde Mental/estatística & dados numéricos , Monitorização Fisiológica/estatística & dados numéricos , Enfermeiras e Enfermeiros , Casas de Saúde/estatística & dados numéricos , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Saúde Mental/normas , Monitorização Fisiológica/métodos , Monitorização Fisiológica/normas , Casas de Saúde/normas , FarmacêuticosRESUMO
INTRODUCTION: Improved medicines' management could lead to real and sustainable improvements to the care of older adults. The overuse of mental health medicines has featured in many reports, and insufficient patient monitoring has been identified as an important cause of medicine-related harms. Nurse-led monitoring using the structured adverse drug reaction (ADRe) profile identifies and addresses the adverse effects of mental health medicines. Our study investigates clinical impact and what is needed to sustain utilisation in routine practice in care homes. METHODS AND ANALYSIS: This process evaluation will use interviews and observations with the participants of all five homes involved in earlier research, and five newly recruited homes caring for people prescribed mental health medicines. The ADRe profile is implemented by nurses, within existing resources, to check for signs and symptoms of ADRs, initiate amelioration and share findings with pharmacists and prescribers for medication review. Outcome measures are the numbers and nature of problems addressed and understanding of changes needed to optimise clinical gain and sustain implementation. Data will be collected by 30 observations and 30 semistructured interviews. Clinical gains will be described and narrated. Interview analysis will be based on the constant comparative method. ETHICS AND DISSEMINATION: Ethical approval was conferred by the National Health Service Wales Research Ethics Committee. If the ADRe profile can be sustained in routine practice, it has potential to (1) improve the lives of patients, for example, by reducing pain and sedation, and (2) assist in early identification of problems caused by ADRs. Therefore, in addition to peer-reviewed publications and conferences, we shall communicate our findings to healthcare professionals, policy-makers and sector regulators. TRIAL REGISTRATION NUMBER: NCT03110471.
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Monitoramento de Medicamentos , Casas de Saúde , Recursos Humanos de Enfermagem , Psicotrópicos/efeitos adversos , Humanos , Estudos Observacionais como AssuntoRESUMO
The opportunistic pathogens Staphylococcus aureus and Staphylococcus epidermidis represent major causes of severe nosocomial infection, and are associated with high levels of mortality and morbidity worldwide. These species are both common commensals on the human skin and in the nasal pharynx, but are genetically distinct, differing at 24% average nucleotide divergence in 1,478 core genes. To better understand the genome dynamics of these ecologically similar staphylococcal species, we carried out a comparative analysis of 324 S. aureus and S. epidermidis genomes, including 83 novel S. epidermidis sequences. A reference pan-genome approach and whole genome multilocus-sequence typing revealed that around half of the genome was shared between the species. Based on a BratNextGen analysis, homologous recombination was found to have impacted on 40% of the core genes in S. epidermidis, but on only 24% of the core genes in S. aureus. Homologous recombination between the species is rare, with a maximum of nine gene alleles shared between any two S. epidermidis and S. aureus isolates. In contrast, there was considerable interspecies admixture of mobile elements, in particular genes associated with the SaPIn1 pathogenicity island, metal detoxification, and the methicillin-resistance island SCCmec. Our data and analysis provide a context for considering the nature of recombinational boundaries between S. aureus and S. epidermidis and, the selective forces that influence realized recombination between these species.
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Transferência Genética Horizontal , Staphylococcus aureus/genética , Staphylococcus epidermidis/genética , Fenômenos Ecológicos e Ambientais , Evolução Molecular , Genes Fúngicos , Variação Genética , Genoma Fúngico , Recombinação HomólogaRESUMO
Oxidative stress contributes to many disease etiologies including ageing, neurodegeneration, and cancer, partly through DNA damage induction (genotoxicity). Understanding the i nteractions of free radicals with DNA is fundamental to discern mutation risks. In genetic toxicology, regulatory authorities consider that most genotoxins exhibit a linear relationship between dose and mutagenic response. Yet, homeostatic mechanisms, including DNA repair, that allow cells to tolerate low levels of genotoxic exposure exist. Acceptance of thresholds for genotoxicity has widespread consequences in terms of understanding cancer risk and regulating human exposure to chemicals/drugs. Three pro-oxidant chemicals, hydrogen peroxide (H(2)O(2)), potassium bromate (KBrO(3)), and menadione, were examined for low dose-response curves in human lymphoblastoid cells. DNA repair and antioxidant capacity were assessed as possible threshold mechanisms. H(2)O(2) and KBrO(3), but not menadione, exhibited thresholded responses, containing a range of nongenotoxic low doses. Levels of the DNA glycosylase 8-oxoguanine glycosylase were unchanged in response to pro- oxidant stress. DNA repair-focused gene expression arrays reported changes in ATM and BRCA1, involved in double-strand break repair, in response to low-dose pro-oxidant exposure; however, these alterations were not substantiated at the protein level. Determination of oxidatively induced DNA damage in H(2)O(2)-treated AHH-1 cells reported accumulation of thymine glycol above the genotoxic threshold. Further, the H(2)O(2) dose-response curve was shifted by modulating the antioxidant glutathione. Hence, observed pro- oxidant thresholds were due to protective capacities of base excision repair enzymes and antioxidants against DNA damage, highlighting the importance of homeostatic mechanisms in "genotoxic tolerance."
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Dano ao DNA , Homeostase , Linfócitos/efeitos dos fármacos , Mutagênicos/toxicidade , Espécies Reativas de Oxigênio/toxicidade , Western Blotting , Bromatos/toxicidade , Linhagem Celular , Aberrações Cromossômicas , Reparo do DNA , Relação Dose-Resposta a Droga , Cromatografia Gasosa-Espectrometria de Massas , Glutationa/farmacologia , Humanos , Peróxido de Hidrogênio/toxicidade , Masculino , Reação em Cadeia da Polimerase , Vitamina K 3/toxicidadeRESUMO
This study evaluated a multiplex real-time PCR method specific for the mecA, femA-SA and femA-SE genes for rapid identification of Staphylococcus aureus, Staphylococcus epidermidis and non-S. epidermidis coagulase-negative staphylococci (CoNS), and meticillin susceptibility testing directly in positive blood cultures that grew Gram-positive cocci in clusters. A total of 100 positive blood cultures produced: 39 S. aureus [12 meticillin-resistant S. aureus (MRSA), 31% of all the S. aureus]; 30 S. epidermidis (56.6% of the CoNS), 8 Staphylococcus capitis (15.1%), 3 Staphylococcus saprophyticus (5.7%), 4 Staphylococcus hominis (7.5%), 3 Staphylococcus haemolyticus (5.7%), 2 Staphylococcus warneri (3.8%), 1 Staphylococcus cohnii (1.9%) and 2 unidentified Staphylococcus spp. (3.8%); and 1 Micrococcus luteus in pure culture. Two blood cultures had no growth on subculture and five blood cultures grew mixed CoNS. For the 95 blood cultures with pure growth or no growth on subculture, there was very good agreement between real-time PCR and the BD Phoenix identification system for staphylococcal species categorization in S. aureus, S. epidermidis and non-S. epidermidis CoNS and meticillin-resistance determination (Cohen's unweighted kappa coefficient κ=0.882). All MRSA and meticillin-susceptible S. aureus were correctly identified by mecA amplification. PCR amplification of mecA was more sensitive for direct detection of meticillin-resistant CoNS in positive blood cultures than testing with the BD Phoenix system. There were no major errors when identifying staphylococcal isolates and their meticillin susceptibility within 2.5 h. Further studies are needed to evaluate the clinical benefit of using such a rapid test on the consumption of glycopeptide antibiotics and the alteration of empiric therapy in the situation of positive blood cultures growing staphylococci, and the respective clinical outcomes.