Imperial College London


Faculty of MedicineDepartment of Infectious Disease

Casual - Other work



+44 (0)20 7594 3717elizabeth.powell




Medical SchoolSt Mary's Campus





Publication Type

7 results found

Powell E, Sumner E, Shaw A, Calvez R, Fink C, Kroll JSet al., 2022, The temporal pattern and lifestyle associations of respiratory virus infection in a cohort study spanning the first two years of life, BMC Pediatrics, Vol: 22, ISSN: 1471-2431

Background:Respiratory virus infection is common in early childhood, and children may be symptomatic or symptom-free. Little is known regarding the association between symptomatic/asymptomatic infection and particular clinical factors such as breastfeeding as well as the consequences of such infection.Method:We followed an unselected cohort of term neonates to two years of age (220 infants at recruitment, 159 who remained in the study to 24 months), taking oral swabs at birth and oropharyngeal swabs at intervals subsequently (at 1.5, 6, 9, 12, 18 and 24 months and in a subset at 3 and 4.5 months) while recording extensive metadata including the presence of respiratory symptoms and breastfeeding status. After 2 years medical notes from the general practitioner were inspected to ascertain whether doctor-diagnosed wheeze had occurred by this timepoint. Multiplex PCR was used to detect a range of respiratory viruses: influenza (A&B), parainfluenza (1–4), bocavirus, human metapneumovirus, rhinovirus, coronavirus (OC43, 229E, NL63, HKU1), adenovirus, respiratory syncytial virus (RSV), and polyomavirus (KI, WU). Logistic regression and generalised estimating equations were used to identify associations between clinical factors and virus detection.Results:Overall respiratory viral incidence increased with age. Rhinovirus was the virus most frequently detected. The detection of a respiratory virus was positively associated with respiratory symptoms, male sex, season, childcare and living with another child. We did not observe breastfeeding (whether assessed as the number of completed months of breastfeeding or current feed status) to be associated with the detection of a respiratory virus. There was no association between early viral infection and doctor-diagnosed wheeze by age 2 years.Conclusion:Asymptomatic and symptomatic viral infection is common in the first 2 years of life with rhinovirus infection being the most common. Whilst there was no association betwee

Journal article

Powell E, Fontanella S, Boakes E, Belgrave D, Shaw A, Cornwell E, Fernandez-Crespo R, Fink C, Custovic A, Kroll JSet al., 2019, Temporal association of the development of oropharyngeal microbiota with early life wheeze in a population-based birth cohort, EBioMedicine, Vol: 46, Pages: 486-498, ISSN: 2352-3964

Background A critical window in infancy has been proposed, during which the microbiota may affect subsequent health. The longitudinal development of the oropharyngeal microbiota is under-studied and may be associated with early-life wheeze. We aimed to investigate the temporal association of the development of the oropharyngeal microbiota with early-life wheeze.Methods A population-based birth cohort based in London, UK was followed for 24 months. We collected oropharyngeal swabs at six time-points. Microbiota was determined using sequencing of the V3-V5 region of the 16S rRNA-encoding gene. Medical records were reviewed for the outcome of doctor diagnosed wheeze. We used a time-varying model to investigate the temporal association between the development of microbiota and doctor-diagnosed wheeze. Findings 159 participants completed the study to 24 months and for 98 there was complete sequencing data at all timepoints and outcome data. Of these, 26 had doctor-diagnosed wheeze. We observed significant increase in the abundance of Neisseria between 9 and 24 months in children who developed wheeze (p=0∙003), while in those without wheezing there was a significant increment in the abundance of Granulicatella (p=0 ∙012) between 9 and 12 months, and of Prevotella (p=0 ∙018) after 18 months. Interpretation A temporal association between the respiratory commensal Granulicatella and also Prevotella with wheeze (negative), and between Neisseria and wheeze (positive) was identified in infants prior to one year of age. This adds to evidence for the proposed role of the microbiota in the development of wheeze.

Journal article

Shaw AG, Sim K, Powell E, Cornwell E, Cramer T, McClure Z, Li M, Kroll Jet al., 2016, Latitude in Sample Handling and Storage for Infant Faecal Microbiota Studies: The Elephant in the Room?, Microbiome, Vol: 4, ISSN: 2049-2618

BackgroundIn this manuscript we investigate the “stones best left unturned” of sample storage and preparation and their implications for the next-generation sequencing of infant faecal microbial communities by the 16S rRNA gene.We present a number of experiments that investigate the potential effects of often overlooked methodology factors, establishing a “normal” degree of variation expected between replica sequenced samples. Sources of excess variation are then identified, as measured by observation of alpha diversity, taxonomic group counts and beta diversity magnitudes between microbial communities. ResultsExtraction of DNA from samples on different dates, by different people and even using varied sample weights results in little significant difference in downstream sequencing data. A key assumption in many studies is the stability of samples stored long term at -80°C prior to extraction. After two years, we see relatively few changes; increased abundances of lactobacilli and bacilli and a reduction in the overall OTU count. Where samples cannot be frozen, we find that storing samples at room temperature does lead to significant changes in the microbial community after two days. Mailing of samples during this time period (a common form of sample collection from out-patients for example) does not lead to any additional variation.ConclusionsImportant methodological standards can be drawn from these results; painstakingly created archives of infant faecal samples stored at -80 °C are still largely representative of the original community and varying factors in DNA extraction methodology have comparatively little effect on overall results. Samples taken should ideally be either frozen at -80 °C or extracted within two days if stored at room temperature, with mail samples being mailed on the day of collection.

Journal article

Sim K, Powell E, Shaw AG, McClure Z, Bangham M, Kroll JSet al., 2013, The neonatal gastrointestinal microbiota: the foundation of future health?, ARCHIVES OF DISEASE IN CHILDHOOD-FETAL AND NEONATAL EDITION, Vol: 98, Pages: F362-F364, ISSN: 1359-2998

Journal article

Robertson NJ, Faulkner S, Fleiss B, Bainbridge A, Andorka C, Price D, Powell E, Lecky-Thompson L, Thei L, Chandrasekaran M, Hristova M, Cady EB, Gressens P, Golay X, Raivich Get al., 2013, Melatonin augments hypothermic neuroprotection in a perinatal asphyxia model, BRAIN, Vol: 136, Pages: 90-105, ISSN: 0006-8950

Journal article

Powell E, Faulkner S, Bainbridge A, Kereyni A, Kelen D, Chandrasekaran M, Lecky-Thompson L, Price D, Cady E, Raivich G, Golay X, Robertson NJet al., 2011, IMPROVED NEUROPROTECTION WITH MELATONIN-AUGMENTED HYPOTHERMIA VS HYPOTHERMIA ALONE IN A PERINATAL ASPHYXIA MODEL: A RANDOMIZED STUDY, PEDIATRIC RESEARCH, Vol: 70, Pages: 67-67, ISSN: 0031-3998

Journal article

Winckworth LC, Powell E, 2010, Question 1 Does caffeine treatment for apnoea of prematurity improve neurodevelopmental outcome in later life?, Archives of Disease in Childhood, Vol: 95, Pages: 757-759, ISSN: 0003-9888

Journal article

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