ORCID Profile
0000-0001-7586-6050
Current Organisations
Liverpool School of Tropical Medicine
,
University of Oxford
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Oxford University Press (OUP)
Date: 28-01-2019
Publisher: Springer Science and Business Media LLC
Date: 05-07-2019
DOI: 10.1038/S41467-019-10814-9
Abstract: Streptococcus pneumoniae is the main bacterial pathogen involved in pneumonia. Pneumococcal acquisition and colonization density is probably affected by viral co-infections, the local microbiome composition and mucosal immunity. Here, we report the interactions between live-attenuated influenza vaccine (LAIV), successive pneumococcal challenge, and the healthy adult nasal microbiota and mucosal immunity using an experimental human challenge model. Nasal microbiota profiles at baseline are associated with consecutive pneumococcal carriage outcome (non-carrier, low-dense and high-dense pneumococcal carriage), independent of LAIV co-administration. Corynebacterium / Dolosigranulum -dominated profiles are associated with low-density colonization. Lowest rates of natural viral co-infection at baseline and post-LAIV influenza replication are detected in the low-density carriers. Also, we detected the fewest microbiota perturbations and mucosal cytokine responses in the low-density carriers compared to non-carriers or high-density carriers. These results indicate that the complete respiratory ecosystem affects pneumococcal behaviour following challenge, with low-density carriage representing the most stable ecological state.
Publisher: Elsevier BV
Date: 02-2020
Publisher: American Thoracic Society
Date: 05-2019
Publisher: American Society for Clinical Investigation
Date: 04-2022
DOI: 10.1172/JCI157124
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 11-2019
Publisher: European Respiratory Society (ERS)
Date: 31-03-2022
DOI: 10.1183/23120541.00586-2021
Abstract: Streptococcus pneumoniae (pneumococcus) is the most commonly identified bacterial cause of pneumonia and the leading infectious cause of death in children under 5 years of age worldwide. Pneumococcal disease follows a seasonal pattern with increased incidence during winter. Pneumonia burden is also associated with poor air quality. Nasopharyngeal carriage of the bacterium is a pre-requisite of invasive disease. We aimed to determine if susceptibility to nasopharyngeal pneumococcal carriage varied by season and which environmental factors might explain such variation. We also evaluated the influence of sex on susceptibility of carriage. We collated data from five studies in which human volunteers underwent intranasal pneumococcal challenge. Generalised linear mixed-effects models were used to identify factors associated with altered risk of carriage acquisition, specifically climate and air-quality data. During 2011–2017, 374 healthy adults were challenged with type 6B pneumococcus. Odds of carriage were significantly lower in males (OR, 0.61 95% CI, 0.40–0.92 p=0.02), and higher with cooler temperatures (OR, 0.79 95% CI, 0.63–0.99 p=0.04). Likelihood of carriage was also associated with lower concentrations of local fine particulate matter concentrations (PM 2.5 ) and increased local rainfall. In contrast to epidemiological series, experimental challenge allowed us to test propensity to acquisition during controlled exposures immunological explanations for sex and climatic differences should be sought.
Publisher: American Thoracic Society
Date: 15-12-2016
Publisher: American Society for Clinical Investigation
Date: 26-01-2021
Publisher: American Thoracic Society
Date: 03-2021
Publisher: American Society for Clinical Investigation
Date: 16-09-2019
DOI: 10.1172/JCI128865
Publisher: European Respiratory Society (ERS)
Date: 10-2018
Publisher: American Thoracic Society
Date: 12-2022
Publisher: Wiley
Date: 14-09-2017
DOI: 10.1111/COA.12956
Abstract: Saline irrigation of the nasal cavity and paranasal sinuses has a recognised role in the management of chronic rhinosinusitis. However, bacterial recontamination of irrigation bottles through backflow from the sinonasal cavity is a concern in recurrent sinus cavity infections. While patients are encouraged to clean the irrigation bottles regularly, there remains significant concern that the use of contaminated bottles may perpetuate chronic rhinosinusitis. This study assesses the optimal microwave duration to achieve decontamination for each irrigation bottle component part (reservoir, tube and nozzle) using a standard, commercially available microwave. In addition, the irrigation fluid was also tested for contamination after each microwave cycle. Laboratory-based experimental study. No patients were involved in this study. The percentage in vitro decontamination of the bottles' components was determined following 30, 60, 90, 120, 150 seconds of microwave cycles. Complete decontamination of the bottles was not achieved at any of the tested microwave cycles. Levels of decontamination differed for the different bottle components, and the greatest degree of decontamination for all bottle components occurred at 90 seconds. Although higher levels of decontamination were observed at microwave durations exceeding 90 seconds, this was at the expense of thermal degradation and deformation of the reservoir plastic component of the irrigation bottle. Similarly, lowest contamination of irrigation fluid was observed at 120 seconds. This study highlights the importance of establishing precise decontamination procedures and recommends a microwave cycle of 90 seconds for optimal decontamination.
Publisher: Cold Spring Harbor Laboratory
Date: 29-04-2020
DOI: 10.1101/2020.04.23.20077073
Abstract: Pneumococcal colonisation is key to the pathogenesis of invasive disease, but is also immunogenic in young adults, protecting against re-colonisation. Colonisation is rarely detected in older adults, despite high rates of pneumococcal disease. To establish experimental human pneumococcal colonisation in healthy adults aged 50—84 years, to measure the immune response to pneumococcal challenge, and to assess the protective effect of prior colonisation against autologous strain rechallenge. Sixty-four participants were inoculated with Streptococcus pneumoniae (serotype 6B, 80,000CFU in each nostril). Colonisation was determined by bacterial culture of nasal wash, serum anti-6B capsular IgG responses by ELISA, and anti-protein immune responses by multiplex electrochemiluminescence. Experimental colonisation was established in 39% of participants (25/64) with no adverse events. Colonisation occurred in 47% (9/19) of participants aged 50—59 compared with 21% (3/14) in those aged ≥70 years. Previous pneumococcal polysaccharide vaccination did not protect against colonisation. Colonisation did not confer serotype-specific immune boosting: GMT (95% CI) 2.7μg/mL (1.9—3.8) pre-challenge versus 3.0 (1.9—4.7) four weeks post-colonisation (p = 0.53). Furthermore, pneumococcal challenge without colonisation led to a drop in specific antibody levels from 2.8μg/mL (2.0—3.9) to 2.2μg/mL (1.6—3.0) post-challenge (p = 0.006). Anti-protein antibody levels increased following successful colonisation. Rechallenge with the same strain after a median of 8.5 months (IQR 6.7—10.1) led to recolonisation in 5/16 (31%). In older adults, experimental pneumococcal colonisation is feasible and safe, but demonstrates different immunological outcomes compared with younger adults in previous studies.
Publisher: American Thoracic Society
Date: 02-2020
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Dr Elena Mitsi.