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Snooks H, Watkins A, Lyons J, Akbari A, Bailey R, Bethell L, Carson-Stevens A, Dale J, Edwards A, Emery H, Evans BA, Jolles S, John A, Kingston M, Porter A, Sewell B, Williams V, Lyons RA. Corrigendum to "Did the UK's public health shielding policy protect the clinically extremely vulnerable during the COVID-19 pandemic in wales? Results of EVITE immunity, a linked data retrospective study" [Public Health 218 (2023) 12-20]. Public Health 2023; 222:229. [PMID: 37463828 PMCID: PMC11021201 DOI: 10.1016/j.puhe.2023.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Affiliation(s)
- H Snooks
- Swansea University, Medical School, ILS 2, Singleton Park, SA2 8PP, Swansea, UK.
| | - A Watkins
- Swansea University, Medical School, ILS 2, Singleton Park, SA2 8PP, Swansea, UK
| | - J Lyons
- Population Data Science, Swansea University, Medical School, Data Science Building, Singleton Park, SA2 8PP, Swansea, UK
| | - A Akbari
- Population Data Science, Swansea University, Medical School, Data Science Building, Singleton Park, SA2 8PP, Swansea, UK
| | - R Bailey
- Population Data Science, Swansea University, Medical School, Data Science Building, Singleton Park, SA2 8PP, Swansea, UK
| | - L Bethell
- Swansea University, Medical School, ILS 2, Singleton Park, SA2 8PP, Swansea, UK
| | - A Carson-Stevens
- Cardiff University, Division of Population Medicine, University Hospital of Wales, Neuadd Meirionnydd, Heath Park, Cardiff, CF14 4YS, UK
| | - J Dale
- The University of Warwick, Medical School, Coventry CV4 7AL, UK
| | - A Edwards
- Cardiff University, Division of Population Medicine, University Hospital of Wales, Neuadd Meirionnydd, Heath Park, Cardiff, CF14 4YS, UK
| | - H Emery
- Swansea University, Medical School, ILS 2, Singleton Park, SA2 8PP, Swansea, UK
| | - B A Evans
- Swansea University, Medical School, ILS 2, Singleton Park, SA2 8PP, Swansea, UK
| | - S Jolles
- Immunodeficiency Centre for Wales, University Hospital of Wales, Heath Park, Cardiff, CF14 4XW, UK
| | - A John
- Population Data Science, Swansea University, Medical School, Data Science Building, Singleton Park, SA2 8PP, Swansea, UK
| | - M Kingston
- Swansea University, Medical School, ILS 2, Singleton Park, SA2 8PP, Swansea, UK
| | - A Porter
- Swansea University, Medical School, ILS 2, Singleton Park, SA2 8PP, Swansea, UK
| | - B Sewell
- Swansea University, School of Health and Social Care, Vivian Tower, Singleton Park, SA2 8PP, Swansea, UK
| | - V Williams
- Swansea University, Medical School, ILS 2, Singleton Park, SA2 8PP, Swansea, UK
| | - R A Lyons
- Population Data Science, Swansea University, Medical School, Data Science Building, Singleton Park, SA2 8PP, Swansea, UK
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Abstract
Iron is essential for growth in most bacteria due to its redox activity and its role in essential metabolic reactions; it is a cofactor for many bacterial enzymes. The bacterium Acinetobacter baumannii is a multidrug-resistant nosocomial pathogen. A. baumannii responds to low iron availability imposed by the host through the exploitation of multiple iron-acquisition strategies, which are likely to deliver iron to the cell under a variety of environmental conditions, including human and animal infection. To date, six different gene clusters for active iron uptake have been described in A. baumannii , encoding protein systems involved in (i) ferrous iron uptake (feo ); (ii) haem uptake (hemT and hemO ); and (iii) synthesis and transport of the baumannoferrin(s) (bfn ), acinetobactin (bas /bau ) and fimsbactin(s) (fbs ) siderophores. Here we describe the structure, distribution and phylogeny of iron-uptake gene clusters among >1000 genotypically diverse A. baumannii isolates, showing that feo , hemT , bfn and bas /bau clusters are very prevalent across the dataset, whereas the additional haem-uptake system hemO is only present in a portion of the dataset and the fbs gene cluster is very rare. Since the expression of multiple iron-uptake clusters can be linked to virulence, the presence of the additional haem-uptake system hemO may have contributed to the success of some A. baumannii clones.
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Affiliation(s)
- Irene Artuso
- Department of Science, Roma Tre University, Viale G. Marconi 446, 00146 Rome, Italy
| | - Harsh Poddar
- Department of Science, Roma Tre University, Viale G. Marconi 446, 00146 Rome, Italy
| | - Benjamin A. Evans
- Norwich Medical School, University of East Anglia, Rosalind Franklin Road, Norwich Research Park, Norwich, NR4 7UQ, UK
| | - Paolo Visca
- Department of Science, Roma Tre University, Viale G. Marconi 446, 00146 Rome, Italy
- Fondazione Santa Lucia IRCCS, Via Ardeatina, 306/354, 00179 Rome, Italy
- National Biodiversity Future Centre, Palermo 90133, Italy
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Mateo-Estrada V, Tyrrell C, Evans BA, Aguilar-Vera A, Drissner D, Castillo-Ramirez S, Walsh F. Acinetobacter baumannii from grass: novel but non-resistant clones. Microb Genom 2023; 9:mgen001054. [PMID: 37439781 PMCID: PMC10438806 DOI: 10.1099/mgen.0.001054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Accepted: 05/26/2023] [Indexed: 07/14/2023] Open
Abstract
Acinetobacter baumannii is one the most worrisome nosocomial pathogens, which has long been considered almost mainly as a hospital-associated bacterium. There have been some studies about animal and environmental isolates over the last decade. However, little effort has been made to determine if this pathogen dwells in the grass. Here, we aim to determine the evolutionary relationships and antibiotic resistance of clones of A. baumannii sampled from grass to the major human international clones and animal clones. Two hundred and forty genomes were considered in total from four different sources for this study. Our core and accessory genomic epidemiology analyses showed that grass isolates cluster in seven groups well differentiated from one another and from the major human and animal isolates. Furthermore, we found new sequence types under both multilocus sequence typing schemes: two under the Pasteur scheme and seven for the Oxford scheme. The grass isolates contained fewer antibiotic-resistance genes and were not resistant to the antibiotics tested. Our results demonstrate that these novel clones appear to have limited antibiotic resistance potential. Given our findings, we propose that genomic epidemiology and surveillance of A. baumannii should go beyond the hospital settings and consider the environment in an explicit One Health approach.
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Affiliation(s)
- Valeria Mateo-Estrada
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Ciara Tyrrell
- Department of Biology, The Kathleen Lonsdale Human Health Institute, Maynooth University, Maynooth, Co. Kildare, Ireland
| | | | - Alejandro Aguilar-Vera
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - David Drissner
- Department of Life Sciences, Albstadt-Sigmaringen University, 72488 Sigmaringen, Germany
| | - Santiago Castillo-Ramirez
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Fiona Walsh
- Department of Biology, The Kathleen Lonsdale Human Health Institute, Maynooth University, Maynooth, Co. Kildare, Ireland
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Maarouf L, Amin M, Evans BA, Abouelfetouh A. Knowledge, attitudes and behaviour of Egyptians towards antibiotic use in the community: can we do better? Antimicrob Resist Infect Control 2023; 12:50. [PMID: 37226221 DOI: 10.1186/s13756-023-01249-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 05/05/2023] [Indexed: 05/26/2023] Open
Abstract
BACKGROUND Infectious diseases are among the leading causes of death worldwide. This is concerning because of the increasing capacity of the pathogens to develop antibiotic resistance. Antibiotic overuse and misuse remain the main drivers of resistance development. In the USA and Europe, annual campaigns raise awareness of antibiotic misuse hazards and promote their judicial use. Similar efforts are lacking in Egypt. This study assessed the knowledge of the public in Alexandria, Egypt of antibiotic misuse risks and their habits towards antibiotic use, in addition to conducting a campaign to increase awareness of the safe use of antibiotics. METHODS A questionnaire assessing knowledge, attitudes and behaviour towards antibiotics was used to collect responses from study participants at various sports clubs in Alexandria in 2019. An awareness campaign to correct misconceptions and a post awareness survey followed. RESULTS Most of the participants were well-educated (85%), in their middle age (51%) and took antibiotics last year (80%). 22% would take an antibiotic for common cold. This dropped to 7% following the awareness. There was a 1.6 time increase in participants who would start an antibiotic on a healthcare professional's advice following the campaign. A 1.3 time increase in participants who would finish an antibiotic regimen was also observed. The campaign made all participants recognize that unwise antibiotic use is harmful to them or others; and 1.5 more participants would spread the word about antibiotic resistance. Despite learning of the risks of antibiotic use, there was no change in how often participants thought they should take antibiotics. CONCLUSIONS Although awareness of antibiotic resistance is rising, some wrong perceptions hold fast. This highlights the need for patient and healthcare-tailored awareness sessions as part of a structured and national public health program directed to the Egyptian population.
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Affiliation(s)
- Lina Maarouf
- Department of Microbiology and Immunology, Faculty of Pharmacy, Alexandria University, 1 Khartoum Sq, Azarita, Alexandria, 21521, Egypt
- Norwich Medical School, University of East Anglia, Norwich, UK
| | - Mohamed Amin
- Department of Pharmacy Practice and Clinical Pharmacy, Faculty of Pharmacy, Alamein International University, New Alamein City, 51718, Egypt
| | | | - Alaa Abouelfetouh
- Department of Microbiology and Immunology, Faculty of Pharmacy, Alexandria University, 1 Khartoum Sq, Azarita, Alexandria, 21521, Egypt.
- Department of Microbiology and Immunology, Faculty of Pharmacy, Alamein International University, New Alamein City, 51718, Egypt.
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Snooks H, Watkins A, Lyons J, Akbari A, Bailey R, Bethell L, Carson-Stevens A, Edwards A, Emery H, Evans BA, Jolles S, John A, Kingston M, Porter A, Sewell B, Williams V, Lyons RA. Did the UK's public health shielding policy protect the clinically extremely vulnerable during the COVID-19 pandemic in Wales? Results of EVITE Immunity, a linked data retrospective study. Public Health 2023; 218:12-20. [PMID: 36933354 PMCID: PMC9928733 DOI: 10.1016/j.puhe.2023.02.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 02/03/2023] [Accepted: 02/07/2023] [Indexed: 02/17/2023]
Abstract
INTRODUCTION The UK shielding policy intended to protect people at the highest risk of harm from COVID-19 infection. We aimed to describe intervention effects in Wales at 1 year. METHODS Retrospective comparison of linked demographic and clinical data for cohorts comprising people identified for shielding from 23 March to 21 May 2020; and the rest of the population. Health records were extracted with event dates between 23 March 2020 and 22 March 2021 for the comparator cohort and from the date of inclusion until 1 year later for the shielded cohort. RESULTS The shielded cohort included 117,415 people, with 3,086,385 in the comparator cohort. The largest clinical categories in the shielded cohort were severe respiratory condition (35.5%), immunosuppressive therapy (25.9%) and cancer (18.6%). People in the shielded cohort were more likely to be female, aged ≥50 years, living in relatively deprived areas, care home residents and frail. The proportion of people tested for COVID-19 was higher in the shielded cohort (odds ratio [OR] 1.616; 95% confidence interval [CI] 1.597-1.637), with lower positivity rate incident rate ratios 0.716 (95% CI 0.697-0.736). The known infection rate was higher in the shielded cohort (5.9% vs 5.7%). People in the shielded cohort were more likely to die (OR 3.683; 95% CI: 3.583-3.786), have a critical care admission (OR 3.339; 95% CI: 3.111-3.583), hospital emergency admission (OR 2.883; 95% CI: 2.837-2.930), emergency department attendance (OR 1.893; 95% CI: 1.867-1.919) and common mental disorder (OR 1.762; 95% CI: 1.735-1.789). CONCLUSION Deaths and healthcare utilisation were higher amongst shielded people than the general population, as would be expected in the sicker population. Differences in testing rates, deprivation and pre-existing health are potential confounders; however, lack of clear impact on infection rates raises questions about the success of shielding and indicates that further research is required to fully evaluate this national policy intervention.
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Affiliation(s)
- H Snooks
- Swansea University, Medical School, ILS 2, Singleton Park, Swansea, SA2 8PP, UK.
| | - A Watkins
- Swansea University, Medical School, ILS 2, Singleton Park, Swansea, SA2 8PP, UK.
| | - J Lyons
- Population Data Science, Swansea University, Medical School, Data Science Building, Singleton Park, Swansea, SA2 8PP, UK.
| | - A Akbari
- Population Data Science, Swansea University, Medical School, Data Science Building, Singleton Park, Swansea, SA2 8PP, UK.
| | - R Bailey
- Population Data Science, Swansea University, Medical School, Data Science Building, Singleton Park, Swansea, SA2 8PP, UK.
| | - L Bethell
- Swansea University, Medical School, ILS 2, Singleton Park, Swansea, SA2 8PP, UK.
| | - A Carson-Stevens
- Cardiff University, Division of Population Medicine, Neuadd Meirionnydd, University Hospital of Wales, Heath Park, Cardiff, CF14 4YS, UK.
| | - A Edwards
- Cardiff University, Division of Population Medicine, Neuadd Meirionnydd, University Hospital of Wales, Heath Park, Cardiff, CF14 4YS, UK.
| | - H Emery
- Swansea University, Medical School, ILS 2, Singleton Park, Swansea, SA2 8PP, UK.
| | - B A Evans
- Swansea University, Medical School, ILS 2, Singleton Park, Swansea, SA2 8PP, UK.
| | - S Jolles
- Immunodeficiency Centre for Wales, University Hospital of Wales, Heath Park, Cardiff, CF14 4XW, UK.
| | - A John
- Population Data Science, Swansea University, Medical School, Data Science Building, Singleton Park, Swansea, SA2 8PP, UK.
| | - M Kingston
- Swansea University, Medical School, ILS 2, Singleton Park, Swansea, SA2 8PP, UK.
| | - A Porter
- Swansea University, Medical School, ILS 2, Singleton Park, Swansea, SA2 8PP, UK.
| | - B Sewell
- Swansea University, School of Health and Social Care, Vivian Tower, Singleton Park, Swansea, SA2 8PP, UK.
| | - V Williams
- Swansea University, Medical School, ILS 2, Singleton Park, Swansea, SA2 8PP, UK.
| | - R A Lyons
- Population Data Science, Swansea University, Medical School, Data Science Building, Singleton Park, Swansea, SA2 8PP, UK.
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Karah N, Mateo-Estrada V, Castillo-Ramírez S, Higgins PG, Havenga B, Khan W, Domingues S, Da Silva GJ, Poirel L, Nordmann P, Ambrosi C, Ma C, McClean S, Quiroga MP, Alvarez VE, Centron D, Zarrilli R, Kenyon JJ, Russo TA, Evans BA, Opazo-Capurro A, Rafei R, Hamze M, Daoud Z, Ahmad I, Rather PN, Hall RM, Wilharm G, Uhlin BE. The Acinetobacter baumannii website (Ab-web): a multidisciplinary knowledge hub, communication platform, and workspace. FEMS Microbes 2023; 4:xtad009. [PMID: 37333444 PMCID: PMC10132847 DOI: 10.1093/femsmc/xtad009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 04/13/2023] [Indexed: 06/20/2023] Open
Abstract
Acinetobacter baumannii is a Gram-negative bacterium increasingly implicated in hospital-acquired infections and outbreaks. Effective prevention and control of such infections are commonly challenged by the frequent emergence of multidrug-resistant strains. Here we introduce Ab-web (https://www.acinetobacterbaumannii.no), the first online platform for sharing expertise on A. baumannii. Ab-web is a species-centric knowledge hub, initially with 10 articles organized into two main sections, 'Overview' and 'Topics', and three themes, 'epidemiology', 'antibiotic resistance', and 'virulence'. The 'workspace' section provides a spot for colleagues to collaborate, build, and manage joint projects. Ab-web is a community-driven initiative amenable to constructive feedback and new ideas.
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Affiliation(s)
- Nabil Karah
- Corresponding author. Department of Molecular Biology and Umeå Centre for Microbial Research (UCMR), Umeå University, 901 87 Umeå, Sweden. E-mail:
| | - Valeria Mateo-Estrada
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, 62210 Cuernavaca, México
| | - Santiago Castillo-Ramírez
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, 62210 Cuernavaca, México
| | - Paul G Higgins
- Institute for Medical Microbiology, Immunology and Hygiene, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50935 Cologne, Germany
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, D-50935 Cologne, Germany
| | - Benjamin Havenga
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, 7602 Stellenbosch, South Africa
| | - Wesaal Khan
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, 7602 Stellenbosch, South Africa
| | - Sara Domingues
- Faculty of Pharmacy, University of Coimbra, 3000-458 Coimbra, Portugal
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal
| | - Gabriela Jorge Da Silva
- Faculty of Pharmacy, University of Coimbra, 3000-458 Coimbra, Portugal
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal
| | - Laurent Poirel
- Medical and Molecular Microbiology, Department of Medicine, Faculty of Science and Medicine, University of Fribourg, Chemin du Musée 18, 1700 Fribourg, Switzerland
- Swiss National Reference Center for Emerging Antibiotic Resistance (NARA), University of Fribourg, 1700 Fribourg, Switzerland
| | - Patrice Nordmann
- Medical and Molecular Microbiology, Department of Medicine, Faculty of Science and Medicine, University of Fribourg, Chemin du Musée 18, 1700 Fribourg, Switzerland
- Swiss National Reference Center for Emerging Antibiotic Resistance (NARA), University of Fribourg, 1700 Fribourg, Switzerland
| | - Cecilia Ambrosi
- Department of Human Sciences and Promotion of the Quality of Life, San Raffaele Open University, IRCCS, 00166 Rome, Italy
| | - Chaoying Ma
- School of Biomolecular and Biomedical Sciences, University College Dublin, Belfield D04 V1W8, Dublin 4, Ireland
| | - Siobhán McClean
- School of Biomolecular and Biomedical Sciences, University College Dublin, Belfield D04 V1W8, Dublin 4, Ireland
| | - María Paula Quiroga
- Laboratorio de Investigaciones en Mecanismos de Resistencia a Antibióticos, Instituto de Investigaciones en Microbiología y Parasitología Médica, Facultad de Medicina, Universidad de Buenos Aires - Consejo Nacional de Investigaciones Científicas y Tecnológicas (IMPaM, UBA-CONICET), 1245 Ayacucho (C1111AAI), Buenos Aires, Argentina
| | - Verónica E Alvarez
- Laboratorio de Investigaciones en Mecanismos de Resistencia a Antibióticos, Instituto de Investigaciones en Microbiología y Parasitología Médica, Facultad de Medicina, Universidad de Buenos Aires - Consejo Nacional de Investigaciones Científicas y Tecnológicas (IMPaM, UBA-CONICET), 1245 Ayacucho (C1111AAI), Buenos Aires, Argentina
| | - Daniela Centron
- Laboratorio de Investigaciones en Mecanismos de Resistencia a Antibióticos, Instituto de Investigaciones en Microbiología y Parasitología Médica, Facultad de Medicina, Universidad de Buenos Aires - Consejo Nacional de Investigaciones Científicas y Tecnológicas (IMPaM, UBA-CONICET), 1245 Ayacucho (C1111AAI), Buenos Aires, Argentina
| | - Raffaele Zarrilli
- Department of Public Health, University of Naples Federico II, 80138 Naples, Italy
| | - Johanna J Kenyon
- Centre for Immunology and Infection Control, School of Biomedical Sciences, Faculty of Health,, Queensland University of Technology, Brisbane City QLD 4000, Australia
| | - Thomas A Russo
- Veterans Administration Western NY, Healthcare System, epartment of Medicine, Jacobs School of Medicine and Biomedical Sciences, University Buffalo, Buffalo, NY 14260, United States
| | - Benjamin A Evans
- Norwich Medical School, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Andres Opazo-Capurro
- Laboratorio de Investigación en Agentes Antibacterianos, Departamento de Microbiología, Facultad de Ciencias Biológicas, Universidad de Concepción, 4070386 Concepción, Chile
| | - Rayane Rafei
- Laboratoire Microbiologie Santé et Environnement, Doctoral School of Sciences and Technology, Faculty of Public Health, Lebanese University, Tripoli 1300, Lebanon
| | - Monzer Hamze
- Laboratoire Microbiologie Santé et Environnement, Doctoral School of Sciences and Technology, Faculty of Public Health, Lebanese University, Tripoli 1300, Lebanon
| | - Ziad Daoud
- College of Medicine, Central Michigan University, Mount Pleasant, MI 48859, United States
- Department of Clinical Microbiology, Michigan Health Clinics, Saginaw, MI 48604, United States
| | - Irfan Ahmad
- Department of Molecular Biology and Umeå Centre for Microbial Research (UCMR), Umeå University, 901 87 Umeå, Sweden
- Institute of Biomedical and Allied Health Sciences, University of Health Sciences, Lahore, Punjab 54600, Pakistan
| | - Philip N Rather
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30307, United States
- Research Service, Department of Veterans Affairs, Atlanta Veterans Affairs (VA) Medical Center, Decatur, GA 30033, United States
| | - Ruth M Hall
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Gottfried Wilharm
- Robert Koch Institute, Project Group P2 (Acinetobacter baumannii—Biology of a Nosocomial Pathogen), Burgstr 37, 38855 Wernigerode, Germany
| | - Bernt Eric Uhlin
- Department of Molecular Biology and Umeå Centre for Microbial Research (UCMR), Umeå University, 901 87 Umeå, Sweden
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Takebayashi Y, Henderson SR, Chirgadze DY, Warburton PJ, Evans BA. OXA-66 structure and oligomerisation of OXA Ab enzymes. Access Microbiol 2022; 4:acmi000412. [PMID: 36415731 PMCID: PMC9675178 DOI: 10.1099/acmi.0.000412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 08/04/2022] [Indexed: 06/16/2023] Open
Abstract
The OXA β-lactamases are responsible for hydrolysing β-lactam antibiotics and contribute to the multidrug-resistant phenotype of several major human pathogens. The OXAAb enzymes are intrinsic to Acinetobacter baumannii and can confer resistance to carbapenem antibiotics. Here we determined the structure of the most prevalent OXAAb enzyme, OXA-66. The structure of OXA-66 was solved at a resolution of 2.1 Å and found to be very similar to the structure of OXA-51, the only other OXAAb enzyme that has had its structure solved. Our data contained one molecule per asymmetric unit, and analysis of positions responsible for dimer formation in other OXA enzymes suggest that OXA-66 likely exists as a monomer.
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Affiliation(s)
- Yuiko Takebayashi
- Department of Biomedical and Forensic Science, Anglia Ruskin University, Cambridge, UK
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK
| | - Sara R. Henderson
- Norwich Medical School, University of East Anglia, Norwich, UK
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | | | - Philip J. Warburton
- Department of Biomedical and Forensic Science, Anglia Ruskin University, Cambridge, UK
- School of Biomedical Sciences, Faculty of Health, University of Plymouth, Plymouth, UK
| | - Benjamin A. Evans
- Department of Biomedical and Forensic Science, Anglia Ruskin University, Cambridge, UK
- Norwich Medical School, University of East Anglia, Norwich, UK
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Mateo-Estrada V, Vali L, Hamouda A, Evans BA, Castillo-Ramírez S. Acinetobacter baumannii Sampled from Cattle and Pigs Represent Novel Clones. Microbiol Spectr 2022; 10:e0128922. [PMID: 35766493 PMCID: PMC9431080 DOI: 10.1128/spectrum.01289-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 06/08/2022] [Indexed: 11/20/2022] Open
Abstract
Acinetobacter baumannii is a very important human pathogen. Nonetheless, we know very little about nonhuman isolates of A. baumannii. Here, we determine the genomic identity of 15 Scottish cattle and pig isolates, as well as their antibiotic and virulence genetic determinants, and compare them with 148 genomes from the main human clinical international clones. Our results demonstrate that cattle and pig isolates represent novel clones well separated from the major international clones. Furthermore, these new clones showed fewer antibiotic resistance genes and may have fewer virulence genes than human clinical isolates. IMPORTANCE Over the last decades, huge amounts of information have been obtained for clinical isolates of A. baumannii and the clones they belong to. In contrast, very little is known about the genomic identity and the genomic basis for virulence and resistance of animal isolates. To fulfil this gap, we conducted a genomic epidemiology study of 15 Scottish cattle and pig isolates in the context of almost 150 genomes belonging to the main international clones of A. baumannii. Our findings show that these animal isolates represent novel clones clearly different from the major international clones. Furthermore, these new clones are distinct in nature considering both antibiotic resistance and virulence when compared with their human clinical counterparts.
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Affiliation(s)
- Valeria Mateo-Estrada
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Leila Vali
- Medical Laboratory Sciences, Faculty of Allied Health, Kuwait University, Sulaibekhat, Kuwait
| | | | - Benjamin A. Evans
- Norwich Medical School, University of East Anglia, Norwich, United Kingdom
| | - Santiago Castillo-Ramírez
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México
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9
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Ambrose SJ, Evans BA, Hall RM. Origin of the oxa235 carbapenem resistance gene found in transposon Tn6252. J Antimicrob Chemother 2022; 77:1197-1199. [PMID: 35094082 PMCID: PMC9165733 DOI: 10.1093/jac/dkac013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Stephanie J. Ambrose
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | | | - Ruth M. Hall
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
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10
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Abouelfetouh A, Mattock J, Turner D, Li E, Evans BA. Diversity of carbapenem-resistant Acinetobacter baumannii and bacteriophage-mediated spread of the Oxa23 carbapenemase. Microb Genom 2022; 8. [PMID: 35104206 PMCID: PMC8942029 DOI: 10.1099/mgen.0.000752] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Carbapenem-resistant Acinetobacter baumannii are prevalent in low- and middle-income countries such as Egypt, but little is known about the molecular epidemiology and mechanisms of resistance in these settings. Here, we characterize carbapenem-resistant A. baumannii from Alexandria, Egypt, and place it in a regional context. Fifty-four carbapenem-resistant isolates from Alexandria Main University Hospital (AMUH), Alexandria, Egypt, collected between 2010 and 2015 were genome sequenced using Illumina technology. Genomes were de novo assembled and annotated. Genomes for 36 isolates from the Middle East region were downloaded from GenBank. The core-gene compliment was determined using Roary, and analyses of recombination were performed in Gubbins. Multilocus sequence typing (MLST) sequence type (ST) and antibiotic-resistance genes were identified. The majority of Egyptian isolates belonged to one of three major clades, corresponding to Pasteur MLST clonal complex (CCPAS) 1, CCPAS2 and STPAS158. Strains belonging to STPAS158 have been reported almost exclusively from North Africa, the Middle East and Pakistan, and may represent a region-specific lineage. All isolates carried an oxa23 gene, six carried bla NDM-1 and one carried bla NDM-2. The oxa23 gene was located on a variety of different mobile elements, with Tn2006 predominant in CCPAS2 strains, and Tn2008 predominant in other lineages. Of particular concern, in 8 of the 13 CCPAS1 strains, the oxa23 gene was located in a temperate bacteriophage phiOXA, previously identified only once before in a CCPAS1 clone from the USA military. The carbapenem-resistant A. baumannii population in AMUH is very diverse, and indicates an endemic circulating population, including a region-specific lineage. A major mechanism for oxa23 dissemination in CCPAS1 isolates appears to be a bacteriophage, presenting new concerns about the ability of these carbapenemases to spread throughout the bacterial population.
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Affiliation(s)
- Alaa Abouelfetouh
- Department of Microbiology and Immunology, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | | | - Dann Turner
- Department of Applied Sciences, University of the West of England, Bristol, UK
| | - Erica Li
- Norwich Medical School, University of East Anglia, Norwich, UK
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11
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Mair LO, Adam G, Chowdhury S, Davis A, Arifin DR, Vassoler FM, Engelhard HH, Li J, Tang X, Weinberg IN, Evans BA, Bulte JWM, Cappelleri DJ. Soft Capsule Magnetic Millirobots for Region-Specific Drug Delivery in the Central Nervous System. Front Robot AI 2021; 8:702566. [PMID: 34368238 PMCID: PMC8340882 DOI: 10.3389/frobt.2021.702566] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 07/06/2021] [Indexed: 01/03/2023] Open
Abstract
Small soft robotic systems are being explored for myriad applications in medicine. Specifically, magnetically actuated microrobots capable of remote manipulation hold significant potential for the targeted delivery of therapeutics and biologicals. Much of previous efforts on microrobotics have been dedicated to locomotion in aqueous environments and hard surfaces. However, our human bodies are made of dense biological tissues, requiring researchers to develop new microrobotics that can locomote atop tissue surfaces. Tumbling microrobots are a sub-category of these devices capable of walking on surfaces guided by rotating magnetic fields. Using microrobots to deliver payloads to specific regions of sensitive tissues is a primary goal of medical microrobots. Central nervous system (CNS) tissues are a prime candidate given their delicate structure and highly region-specific function. Here we demonstrate surface walking of soft alginate capsules capable of moving on top of a rat cortex and mouse spinal cord ex vivo, demonstrating multi-location small molecule delivery to up to six different locations on each type of tissue with high spatial specificity. The softness of alginate gel prevents injuries that may arise from friction with CNS tissues during millirobot locomotion. Development of this technology may be useful in clinical and preclinical applications such as drug delivery, neural stimulation, and diagnostic imaging.
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Affiliation(s)
- Lamar O Mair
- Weinberg Medical Physics, Inc., North Bethesda, MD, United States
| | - Georges Adam
- Multi-Scale Robotics and Automation Lab, School of Mechanical Engineering, Purdue University, West Lafayette, IN, United States
| | - Sagar Chowdhury
- Weinberg Medical Physics, Inc., North Bethesda, MD, United States.,Multi-Scale Robotics and Automation Lab, School of Mechanical Engineering, Purdue University, West Lafayette, IN, United States
| | - Aaron Davis
- Multi-Scale Robotics and Automation Lab, School of Mechanical Engineering, Purdue University, West Lafayette, IN, United States
| | - Dian R Arifin
- Russel H. Morgan Department of Radiology and Radiological Science, Division of Magnetic Resonance Research, The Johns Hopkins University School of Medicine, Baltimore, MD, United States.,Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Fair M Vassoler
- Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA, United States
| | - Herbert H Engelhard
- Affiliated Neurosurgery Corporation, Chicago, IL, United States.,Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States
| | - Jinxing Li
- Department of Biomedical Engineering, Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, United States
| | - Xinyao Tang
- Weinberg Medical Physics, Inc., North Bethesda, MD, United States
| | | | | | - Jeff W M Bulte
- Russel H. Morgan Department of Radiology and Radiological Science, Division of Magnetic Resonance Research, The Johns Hopkins University School of Medicine, Baltimore, MD, United States.,Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, United States.,Departments of Oncology, Biomedical Engineering and Chemical and Biomolecular Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - David J Cappelleri
- Multi-Scale Robotics and Automation Lab, School of Mechanical Engineering, Purdue University, West Lafayette, IN, United States.,Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
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12
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Takebayashi Y, Findlay J, Heesom KJ, Warburton PJ, Avison MB, Evans BA. Variability in carbapenemase activity of intrinsic OxaAb (OXA-51-like) β-lactamase enzymes in Acinetobacter baumannii. J Antimicrob Chemother 2021; 76:587-595. [PMID: 33338207 DOI: 10.1093/jac/dkaa502] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 11/03/2020] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES To measure the variability in carbapenem susceptibility conferred by different OxaAb variants, characterize the molecular evolution of oxaAb and elucidate the contribution of OxaAb and other possible carbapenem resistance factors in the clinical isolates using WGS and LC-MS/MS. METHODS Antimicrobial susceptibility tests were performed on 10 clinical Acinetobacter baumannii isolates. Carbapenem MICs were evaluated for all oxaAb variants cloned into A. baumannii CIP70.10 and BM4547, with and without their natural promoters. Molecular evolution analysis of the oxaAb variants was performed using FastTree and SplitsTree4. Resistance determinants were studied in the clinical isolates using WGS and LC-MS/MS. RESULTS Only the OxaAb variants with I129L and L167V substitutions, OxaAb(82), OxaAb(83), OxaAb(107) and OxaAb(110) increased carbapenem MICs when expressed in susceptible A. baumannii backgrounds without an upstream IS element. Carbapenem resistance was conferred with the addition of their natural upstream ISAba1 promoter. LC-MS/MS analysis on the original clinical isolates confirmed overexpression of the four I129L and L167V variants. No other differences in expression levels of proteins commonly associated with carbapenem resistance were detected. CONCLUSIONS Elevated carbapenem MICs were observed by expression of OxaAb variants carrying clinically prevalent substitutions I129L and L167V. To drive carbapenem resistance, these variants required overexpression by their upstream ISAba1 promoter. This study clearly demonstrates that a combination of IS-driven overexpression of oxaAb and the presence of particular amino acid substitutions in the active site to improve carbapenem capture is key in conferring carbapenem resistance in A. baumannii and other mechanisms are not required.
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Affiliation(s)
- Yuiko Takebayashi
- Department of Biomedical and Forensic Science, Anglia Ruskin University, Cambridge, UK.,School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK
| | - Jacqueline Findlay
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK.,Division of Infection & Immunity, Faculty of Medical Sciences, University College London, UK
| | - Kate J Heesom
- Bristol Proteomics Facility, University of Bristol, Bristol, UK
| | - Philip J Warburton
- Department of Biomedical and Forensic Science, Anglia Ruskin University, Cambridge, UK.,School of Biomedical Sciences, Faculty of Health, University of Plymouth, Plymouth, UK
| | - Matthew B Avison
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK
| | - Benjamin A Evans
- Department of Biomedical and Forensic Science, Anglia Ruskin University, Cambridge, UK.,Norwich Medical School, University of East Anglia, UK
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Ha M, Cañón Bermúdez GS, Liu JAC, Oliveros Mata ES, Evans BA, Tracy JB, Makarov D. Reconfigurable Magnetic Origami Actuators with On-Board Sensing for Guided Assembly. Adv Mater 2021; 33:e2008751. [PMID: 33969551 DOI: 10.1002/adma.202008751] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 03/19/2021] [Indexed: 06/12/2023]
Abstract
Origami utilizes orchestrated transformation of soft 2D structures into complex 3D architectures, mimicking shapes and functions found in nature. In contrast to origami in nature, synthetic origami lacks the ability to monitor the environment and correspondingly adjust its behavior. Here, magnetic origami actuators with capabilities to sense their orientation and displacement as well as detect their own magnetization state and readiness for supervised folding are designed, fabricated, and demonstrated. These origami actuators integrate photothermal heating and magnetic actuation by using composite thin films (≈60 µm thick) of shape-memory polymers with embedded magnetic NdFeB microparticles. Mechanically compliant magnetic field sensors, known as magnetosensitive electronic skins, are laminated on the surface of the soft actuators. These ultrathin actuators accomplish sequential folding and recovery, with hinge locations programmed on the fly. Endowing mechanically active smart materials with cognition is an important step toward realizing intelligent, stimuli-responsive structures.
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Affiliation(s)
- Minjeong Ha
- Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, Bautzner Landstrasse 400, Dresden, 01328, Germany
| | - Gilbert Santiago Cañón Bermúdez
- Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, Bautzner Landstrasse 400, Dresden, 01328, Germany
| | - Jessica A-C Liu
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Eduardo Sergio Oliveros Mata
- Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, Bautzner Landstrasse 400, Dresden, 01328, Germany
| | | | - Joseph B Tracy
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Denys Makarov
- Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, Bautzner Landstrasse 400, Dresden, 01328, Germany
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14
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Evans BA, Kumar A, Castillo-Ramírez S. Editorial: Genomic Basis of Antibiotic Resistance and Virulence in Acinetobacter. Front Microbiol 2021; 12:670975. [PMID: 33859632 PMCID: PMC8042409 DOI: 10.3389/fmicb.2021.670975] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 03/08/2021] [Indexed: 11/18/2022] Open
Affiliation(s)
- Benjamin A Evans
- Norwich Medical School, University of East Anglia, Norwich, United Kingdom
| | - Ayush Kumar
- Department of Microbiology, University of Manitoba, Winnipeg, MB, Canada
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15
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Abstract
Acinetobacter baumannii is nowadays a relevant nosocomial pathogen characterized by multidrug resistance (MDR) and concomitant difficulties to treat infections. OmpA is the most abundant A. baumannii outer membrane (OM) protein, and is involved in virulence, host-cell recognition, biofilm formation, regulation of OM stability, permeability and antibiotic resistance. OmpA members are two-domain proteins with an N-terminal eight-stranded β-barrel domain with four external loops (ELs) interacting with the environment, and a C-terminal periplasmic domain binding non-covalently to the peptidoglycan. Here, we combined data from genome sequencing, phylogenetic and multilocus sequence analyses from 975 strains/isolates of the Acinetobacter calcoaceticus/Acinetobacter baumannii complex (ACB), 946 from A. baumannii, to explore ompA microevolutionary divergence. Five major ompA variant groups were identified (V1 to V5) in A. baumannii, encompassing 52 different alleles coding for 23 different proteins. Polymorphisms were concentrated in five regions corresponding to the four ELs and the C-terminal end, and provided evidence for intra-genic recombination. ompA variants were not randomly distributed across the A. baumannii phylogeny, with the most frequent V1(lct)a1 allele found in most clonal complex 2 (CC2) strains and the second most frequent V2(lct)a1 allele in the majority of CC1 strains. Evidence was found for assortative exchanges of ompA alleles not only between separate A. baumannii lineages, but also different ACB species. The overall results have implications for A. baumannii evolution, epidemiology, virulence and vaccine design.
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Affiliation(s)
- Alejandro M Viale
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET) and Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), 2000 Rosario, Argentina
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16
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Porter A, Edwards A, Edwards BM, Evans BA, Gripper PC, Hughes H, John A, Khanom A, Petterson R, Philips CJ, Scott J, Tee A, Watkins A, Snooks H. PP31 Strategies to manage emergency ambulance telephone callers with sustained high needs – an evaluation using linked data (STRETCHED). Arch Emerg Med 2019. [DOI: 10.1136/emermed-2019-999abs.31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BackgroundAmbulance services across the UK have recognised a clinical and operational problem with persistent high users of the 999 service, but there is a lack of evidence about what works in this setting and how. We aim to evaluate the effectiveness, safety and efficiency of multi-agency case management approaches to the care of people who frequently call the emergency ambulance service, and gain understanding of barriers and facilitators to implementation.MethodsWe will carry out a mixed methods evaluation using anonymised linked routine data outcomes in a ‘natural experiment’ cohort design in four UK ambulance services, with one case management intervention site and one control site within each service. We will describe the epidemiology of ‘frequent calling’; assess the effects of case management on process, outcomes, safety and costs up to six months for 300 high users per service (n-1200); and examine the views of stakeholders, including patients, through qualitative methods. We will synthesise quantitative and qualitative findings, informed by a logic model describing predicted mechanisms of change.ResultsWe received confirmation of NIHR grant funding for this study in 2018 so do not yet have results to report.ConclusionsTelephone callers with sustained high needs represent a significant, high profile policy challenge to emergency ambulance services. Such callers may be indicative of gaps elsewhere in the health care system, which could be more effectively addressed by pro-active care. The STRETCHED study provides the opportunity to contribute to the currently sparse evidence base on interventions for this patient group.
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17
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Liu JAC, Gillen JH, Mishra SR, Evans BA, Tracy JB. Photothermally and magnetically controlled reconfiguration of polymer composites for soft robotics. Sci Adv 2019; 5:eaaw2897. [PMID: 31414046 PMCID: PMC6677553 DOI: 10.1126/sciadv.aaw2897] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 06/22/2019] [Indexed: 05/22/2023]
Abstract
New materials are advancing the field of soft robotics. Composite films of magnetic iron microparticles dispersed in a shape memory polymer matrix are demonstrated for reconfigurable, remotely actuated soft robots. The composite films simultaneously respond to magnetic fields and light. Temporary shapes obtained through combined magnetic actuation and photothermal heating can be locked by switching off the light and magnetic field. Subsequent illumination in the absence of the magnetic field drives recovery of the permanent shape. In cantilevers and flowers, multiple cycles of locking and unlocking are demonstrated. Scrolls show that the permanent shape of the film can be programmed, and they can be frozen in intermediate configurations. Bistable snappers can be magnetically and optically actuated, as well as biased, by controlling the permanent shape. Grabbers can pick up and release objects repeatedly. Simulations of combined photothermal heating and magnetic actuation are useful for guiding the design of new devices.
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Affiliation(s)
- Jessica A.-C. Liu
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695, USA
| | - Jonathan H. Gillen
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695, USA
| | - Sumeet R. Mishra
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695, USA
| | | | - Joseph B. Tracy
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695, USA
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18
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Mair LO, Chowdhury S, Paredes-Juarez GA, Guix M, Bi C, Johnson B, English BW, Jafari S, Baker-McKee J, Watson-Daniels J, Hale O, Stepanov P, Sun D, Baker Z, Ropp C, Raval SB, Arifin DR, Bulte JWM, Weinberg IN, Evans BA, Cappelleri DJ. Magnetically Aligned Nanorods in Alginate Capsules (MANiACs): Soft Matter Tumbling Robots for Manipulation and Drug Delivery. Micromachines (Basel) 2019; 10:E230. [PMID: 30935105 PMCID: PMC6523834 DOI: 10.3390/mi10040230] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 03/23/2019] [Accepted: 03/27/2019] [Indexed: 12/20/2022]
Abstract
Soft, untethered microrobots composed of biocompatible materials for completing micromanipulation and drug delivery tasks in lab-on-a-chip and medical scenarios are currently being developed. Alginate holds significant potential in medical microrobotics due to its biocompatibility, biodegradability, and drug encapsulation capabilities. Here, we describe the synthesis of MANiACs-Magnetically Aligned Nanorods in Alginate Capsules-for use as untethered microrobotic surface tumblers, demonstrating magnetically guided lateral tumbling via rotating magnetic fields. MANiAC translation is demonstrated on tissue surfaces as well as inclined slopes. These alginate microrobots are capable of manipulating objects over millimeter-scale distances. Finally, we demonstrate payload release capabilities of MANiACs during translational tumbling motion.
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Affiliation(s)
- Lamar O Mair
- Weinberg Medical Physics, Inc., North Bethesda, MD 20852, USA.
| | - Sagar Chowdhury
- Weinberg Medical Physics, Inc., North Bethesda, MD 20852, USA.
- Multi-Scale Robotics and Automation Lab, School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907, USA.
| | - Genaro A Paredes-Juarez
- Russel H. Morgan Department of Radiology, Division of Magnetic Resonance Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Maria Guix
- Multi-Scale Robotics and Automation Lab, School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907, USA.
| | - Chenghao Bi
- Multi-Scale Robotics and Automation Lab, School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907, USA.
| | - Benjamin Johnson
- Multi-Scale Robotics and Automation Lab, School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907, USA.
| | | | - Sahar Jafari
- Weinberg Medical Physics, Inc., North Bethesda, MD 20852, USA.
| | | | | | - Olivia Hale
- Weinberg Medical Physics, Inc., North Bethesda, MD 20852, USA.
| | - Pavel Stepanov
- Weinberg Medical Physics, Inc., North Bethesda, MD 20852, USA.
| | - Danica Sun
- Weinberg Medical Physics, Inc., North Bethesda, MD 20852, USA.
| | - Zachary Baker
- Weinberg Medical Physics, Inc., North Bethesda, MD 20852, USA.
| | - Chad Ropp
- Weinberg Medical Physics, Inc., North Bethesda, MD 20852, USA.
| | | | - Dian R Arifin
- Russel H. Morgan Department of Radiology, Division of Magnetic Resonance Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Jeff W M Bulte
- Russel H. Morgan Department of Radiology, Division of Magnetic Resonance Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
- Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
- Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
- Department of Chemical & Biomolecular Engineering, The Johns Hopkins School of Engineering, Baltimore, MD 21218, USA.
| | | | | | - David J Cappelleri
- Multi-Scale Robotics and Automation Lab, School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907, USA.
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AbuHassan KJ, Bakhori NM, Kusnin N, Azmi UZM, Tania MH, Evans BA, Yusof NA, Hossain MA. Automatic diagnosis of tuberculosis disease based on Plasmonic ELISA and color-based image classification. Annu Int Conf IEEE Eng Med Biol Soc 2018; 2017:4512-4515. [PMID: 29060900 DOI: 10.1109/embc.2017.8037859] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Tuberculosis (TB) remains one of the most devastating infectious diseases and its treatment efficiency is majorly influenced by the stage at which infection with the TB bacterium is diagnosed. The available methods for TB diagnosis are either time consuming, costly or not efficient. This study employs a signal generation mechanism for biosensing, known as Plasmonic ELISA, and computational intelligence to facilitate automatic diagnosis of TB. Plasmonic ELISA enables the detection of a few molecules of analyte by the incorporation of smart nanomaterials for better sensitivity of the developed detection system. The computational system uses k-means clustering and thresholding for image segmentation. This paper presents the results of the classification performance of the Plasmonic ELISA imaging data by using various types of classifiers. The five-fold cross-validation results show high accuracy rate (>97%) in classifying TB images using the entire data set. Future work will focus on developing an intelligent mobile-enabled expert system to diagnose TB in real-time. The intelligent system will be clinically validated and tested in collaboration with healthcare providers in Malaysia.
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20
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Miller EL, Evans BA, Cornejo OE, Roberts IS, Rozen DE. Pherotype Polymorphism in Streptococcus pneumoniae Has No Obvious Effects on Population Structure and Recombination. Genome Biol Evol 2017; 9:2546-2559. [PMID: 28992304 PMCID: PMC5629823 DOI: 10.1093/gbe/evx188] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/14/2017] [Indexed: 12/30/2022] Open
Abstract
Natural transformation in the Gram-positive pathogen Streptococcus pneumoniae occurs when cells become "competent," a state that is induced in response to high extracellular concentrations of a secreted peptide signal called competence stimulating peptide (CSP) encoded by the comC locus. Two main CSP signal types (pherotypes) are known to dominate the pherotype diversity across strains. Using 4,089 fully sequenced pneumococcal genomes, we confirm that pneumococcal populations are highly genetically structured and that there is significant variation among diverged populations in pherotype frequencies; most carry only a single pherotype. Moreover, we find that the relative frequencies of the two dominant pherotypes significantly vary within a small range across geographical sites. It has been variously proposed that pherotypes either promote genetic exchange among cells expressing the same pherotype, or conversely that they promote recombination between strains bearing different pherotypes. We attempt to distinguish these hypotheses using a bioinformatics approach by estimating recombination frequencies within and between pherotypes across 4,089 full genomes. Despite underlying population structure, we observe extensive recombination between populations; additionally, we found significantly higher (although marginal) rates of genetic exchange between strains expressing different pherotypes than among isolates carrying the same pherotype. Our results indicate that pherotypes do not restrict, and may even slightly facilitate, recombination between strains; however, these marginal effects suggest the more likely possibility that the cause of CSP polymorphism lies outside of its effects on transformation. Our results suggest that the CSP balanced polymorphism does not causally underlie population differentiation. Therefore, when strains carrying different pherotypes encounter one another during cocolonization, genetic exchange can occur without restriction.
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Affiliation(s)
- Eric L. Miller
- School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, United Kingdom
- Institute of Biology, Leiden University, The Netherlands
| | - Benjamin A. Evans
- School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, United Kingdom
- Norwich Medical School, University of East Anglia, Norwich, United Kingdom
| | | | - Ian S. Roberts
- School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, United Kingdom
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21
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Schmauch MM, Mishra SR, Evans BA, Velev OD, Tracy JB. Chained Iron Microparticles for Directionally Controlled Actuation of Soft Robots. ACS Appl Mater Interfaces 2017; 9:11895-11901. [PMID: 28349697 DOI: 10.1021/acsami.7b01209] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Magnetic field-directed self-assembly of magnetic particles in chains is useful for developing directionally responsive materials for applications in soft robotics. Using materials with greater complexity allows advanced functions, while still using simple device architectures. Elastomer films containing chained magnetic microparticles were prepared through solvent casting and formed into magnetically actuated lifters, accordions, valves, and pumps. Chaining both enhances actuation and imparts a directional response. Cantilevers used as lifters were able to lift up to 50 times the mass of the polymer film. We introduce the "specific torque", the torque per field per mass of magnetic particles, as a figure of merit for assessing and comparing the performance of lifters and related devices. Devices in this work generated specific torques of 68 Nm/kgT, which is significantly higher than in previously reported actuators. Applying magnetic fields to folded accordion structures caused extension and compression, depending on the accordion's orientation. In peristaltic pumps comprised of composite tubes containing embedded chains, magnetic fields caused a section of the tube to pinch closed where the field was applied. These results will facilitate both the further development of soft robots based on chained magnetic particles and efforts to engineer materials with higher specific torque.
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Affiliation(s)
- Marissa M Schmauch
- Department of Chemistry and Biochemistry, University of Tulsa , Tulsa, Oklahoma 74104, United States
| | | | - Benjamin A Evans
- Department of Physics, Elon University , Elon, North Carolina 27244, United States
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Mair LO, Evans BA, Nacev A, Stepanov PY, Hilaman R, Chowdhury S, Jafari S, Wang W, Shapiro B, Weinberg IN. Magnetic microkayaks: propulsion of microrods precessing near a surface by kilohertz frequency, rotating magnetic fields. Nanoscale 2017; 9:3375-3381. [PMID: 28229134 DOI: 10.1039/c6nr09459g] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Surface-swimming nano- and micromotors hold significant potential for on-chip mixing, flow generation, sample manipulation, and microrobotics. Here we describe rotating microrods magnetized nearly orthogonally to their long axes. When actuated near a solid surface, these microrods demonstrate precessing motion, with rods describing a double cone similar to the motion of a kayaker's paddle. The precessing motion induces translation. At 1 kHz, these "microkayaks" move at translational velocities of ≈14 μm s-1 and generate advective flows up to 10 μm s-1.
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Affiliation(s)
- L O Mair
- Weinberg Medical Physics, Inc., North Bethesda, Maryland 20817, USA.
| | - B A Evans
- Department of Physics, Elon University, CB# 2625, Elon, North Carolina 27244, USA
| | - A Nacev
- Weinberg Medical Physics, Inc., North Bethesda, Maryland 20817, USA.
| | - P Y Stepanov
- Weinberg Medical Physics, Inc., North Bethesda, Maryland 20817, USA.
| | - R Hilaman
- Weinberg Medical Physics, Inc., North Bethesda, Maryland 20817, USA.
| | - S Chowdhury
- Weinberg Medical Physics, Inc., North Bethesda, Maryland 20817, USA.
| | - S Jafari
- Weinberg Medical Physics, Inc., North Bethesda, Maryland 20817, USA.
| | - W Wang
- School of Material Sciences and Engineering, Harbin Institute of Technology, Shenzhen Graduate School, Shenzhen, China 518055 and Center for Soft and Living Matter, Institute of Basic Sciences, Ulsan, Korea
| | - B Shapiro
- Fischell Department of Bioengineering, University of Maryland, College Park, USA
| | - I N Weinberg
- Weinberg Medical Physics, Inc., North Bethesda, Maryland 20817, USA.
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Ohiri KA, Evans BA, Shields CW, Gutiérrez RA, Carroll NJ, Yellen BB, López GP. Magnetically Responsive Negative Acoustic Contrast Microparticles for Bioanalytical Applications. ACS Appl Mater Interfaces 2016; 8:25030-25035. [PMID: 27622731 DOI: 10.1021/acsami.6b09591] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Smart colloidal particles are routinely used as carriers for biological molecules, fluorescent reporters, cells, and other analytes for the purposes of sample preparation and detection. However, such particles are typically engineered to respond to a single type of stimulus (e.g., commercial magnetic beads to magnetic fields). Here, we demonstrate a unique class of particles that display both positive magnetic contrast and negative acoustic contrast in water. This dual functionality allows for fine spatiotemporal control, enabling multiple separation modalities and increasing the utility of the particles in various chemical and biological assays.
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Affiliation(s)
| | - Benjamin A Evans
- Department of Physics, Elon University , Elon, North Carolina 27244, United States
| | | | | | | | | | - Gabriel P López
- Department of Chemical & Biological Engineering, University of New Mexico , Albuquerque, New Mexico 87131, United States
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Lyons RA, Rodgers SE, Thomas S, Bailey R, Brunt H, Thayer D, Bidmead J, Evans BA, Harold P, Hooper M, Snooks H. Effects of an air pollution personal alert system on health service usage in a high-risk general population: a quasi-experimental study using linked data. J Epidemiol Community Health 2016. [PMID: 27217535 DOI: 10.1136/jech-2016–207222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND There is no evidence to date on whether an intervention alerting people to high levels of pollution is effective in reducing health service utilisation. We evaluated alert accuracy and the effect of a targeted personal air pollution alert system, airAware, on emergency hospital admissions, emergency department attendances, general practitioner contacts and prescribed medications. METHODS Quasi-experimental study describing accuracy of alerts compared with pollution triggers; and comparing relative changes in healthcare utilisation in the intervention group to those who did not sign-up. Participants were people diagnosed with asthma, chronic obstructive pulmonary disease (COPD) or coronary heart disease, resident in an industrial area of south Wales and registered patients at 1 of 4 general practices. Longitudinal anonymised record linked data were modelled for participants and non-participants, adjusting for differences between groups. RESULTS During the 2-year intervention period alerts were correctly issued on 208 of 248 occasions; sensitivity was 83.9% (95% CI 78.8% to 87.9%) and specificity 99.5% (95% CI 99.3% to 99.6%). The intervention was associated with a 4-fold increase in admissions for respiratory conditions (incidence rate ratio (IRR) 3.97; 95% CI 1.59 to 9.93) and a near doubling of emergency department attendance (IRR=1.89; 95% CI 1.34 to 2.68). CONCLUSIONS The intervention was associated with increased emergency admissions for respiratory conditions. While findings may be context specific, evidence from this evaluation questions the benefits of implementing near real-time personal pollution alert systems for high-risk individuals.
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Affiliation(s)
- R A Lyons
- Swansea University Medical School, Swansea, UK
| | - S E Rodgers
- Swansea University Medical School, Swansea, UK
| | - S Thomas
- Cwm Taf Public Health Team, Public Health Wales, Keir Hardie University Health Park, Merthyr Tydfil, UK
| | - R Bailey
- Swansea University Medical School, Swansea, UK
| | - H Brunt
- Health Protection Team, Public Health Wales, Cardiff, UK
| | - D Thayer
- Swansea University Medical School, Swansea, UK
| | | | - B A Evans
- Swansea University Medical School, Swansea, UK
| | - P Harold
- Public Health England, Centre for Radiation Chemical and Environmental Hazards (Wales), Metropolitan University, Cardiff, UK
| | - M Hooper
- Neath Port Talbot County Borough Council, Neath, UK
| | - H Snooks
- Swansea University Medical School, Swansea, UK
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25
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Lyons RA, Rodgers SE, Thomas S, Bailey R, Brunt H, Thayer D, Bidmead J, Evans BA, Harold P, Hooper M, Snooks H. Effects of an air pollution personal alert system on health service usage in a high-risk general population: a quasi-experimental study using linked data. J Epidemiol Community Health 2016; 70:1184-1190. [PMID: 27217535 PMCID: PMC5136690 DOI: 10.1136/jech-2016-207222] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 04/28/2016] [Accepted: 05/06/2016] [Indexed: 11/04/2022]
Abstract
BACKGROUND There is no evidence to date on whether an intervention alerting people to high levels of pollution is effective in reducing health service utilisation. We evaluated alert accuracy and the effect of a targeted personal air pollution alert system, airAware, on emergency hospital admissions, emergency department attendances, general practitioner contacts and prescribed medications. METHODS Quasi-experimental study describing accuracy of alerts compared with pollution triggers; and comparing relative changes in healthcare utilisation in the intervention group to those who did not sign-up. Participants were people diagnosed with asthma, chronic obstructive pulmonary disease (COPD) or coronary heart disease, resident in an industrial area of south Wales and registered patients at 1 of 4 general practices. Longitudinal anonymised record linked data were modelled for participants and non-participants, adjusting for differences between groups. RESULTS During the 2-year intervention period alerts were correctly issued on 208 of 248 occasions; sensitivity was 83.9% (95% CI 78.8% to 87.9%) and specificity 99.5% (95% CI 99.3% to 99.6%). The intervention was associated with a 4-fold increase in admissions for respiratory conditions (incidence rate ratio (IRR) 3.97; 95% CI 1.59 to 9.93) and a near doubling of emergency department attendance (IRR=1.89; 95% CI 1.34 to 2.68). CONCLUSIONS The intervention was associated with increased emergency admissions for respiratory conditions. While findings may be context specific, evidence from this evaluation questions the benefits of implementing near real-time personal pollution alert systems for high-risk individuals.
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Affiliation(s)
- R A Lyons
- Swansea University Medical School, Swansea, UK
| | - S E Rodgers
- Swansea University Medical School, Swansea, UK
| | - S Thomas
- Cwm Taf Public Health Team, Public Health Wales, Keir Hardie University Health Park, Merthyr Tydfil, UK
| | - R Bailey
- Swansea University Medical School, Swansea, UK
| | - H Brunt
- Health Protection Team, Public Health Wales, Cardiff, UK
| | - D Thayer
- Swansea University Medical School, Swansea, UK
| | | | - B A Evans
- Swansea University Medical School, Swansea, UK
| | - P Harold
- Public Health England, Centre for Radiation Chemical and Environmental Hazards (Wales), Metropolitan University, Cardiff, UK
| | - M Hooper
- Neath Port Talbot County Borough Council, Neath, UK
| | - H Snooks
- Swansea University Medical School, Swansea, UK
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Affiliation(s)
- Benjamin A Evans
- Department of Biomedical and Forensic Sciences, Anglia Ruskin University, East Road, Cambridge CB1 1PT, UK
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Vali L, Dashti K, Opazo-Capurro AF, Dashti AA, Al Obaid K, Evans BA. Diversity of multi-drug resistant Acinetobacter baumannii population in a major hospital in Kuwait. Front Microbiol 2015; 6:743. [PMID: 26257720 PMCID: PMC4513246 DOI: 10.3389/fmicb.2015.00743] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 07/06/2015] [Indexed: 11/13/2022] Open
Abstract
Acinetobacter baumannii is one of the most important opportunistic pathogens that causes serious health care associated complications in critically ill patients. In the current study we report on the diversity of the clinical multi-drug resistant (MDR) A. baumannii in Kuwait by molecular characterization. One hundred A. baumannii were isolated from one of the largest governmental hospitals in Kuwait. Following the identification of the isolates by molecular methods, the amplified blaOXA-51-like gene product of one isolate (KO-12) recovered from blood showed the insertion of the ISAba19 at position 379 in blaOXA-78. Of the 33 MDR isolates, 28 (85%) contained blaOXA-23, 2 (6%) blaOXA-24 and 6 (18%) blaPER-1 gene. We did not detect blaOXA-58, blaVIM, blaIMP, blaGES,blaVEB, and blaNDM genes in any of the tested isolates. In three blaPER-1 positive isolates the genetic environment of blaPER-1 consisted of two copies of ISPa12 (tnpiA1) surrounding the blaPER-1 gene on a highly stable plasmid of ca. 140-kb. Multilocus-sequence typing (MLST) analysis of the 33 A. baumannii isolates identified 20 different STs, of which six (ST-607, ST-608, ST-609, ST-610, ST-611, and ST-612) were novel. Emerging STs such as ST15 (identified for the first time in the Middle East), ST78 and ST25 were also detected. The predominant clonal complex was CC2. Pulsed-field gel electrophoresis and MLST defined the MDR isolates as multi-clonal with diverse lineages. Our results lead us to believe that A. baumannii is diverse in clonal origins and/or is undergoing clonal expansion continuously while multiple lineages of MDR A. baumannii circulate in hospital ward simultaneously.
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Affiliation(s)
- Leila Vali
- Department of Medical Laboratory Sciences, Faculty of Allied Health Sciences, Kuwait University Sulaibekhat, Kuwait
| | - Khadija Dashti
- Department of Medical Laboratory Sciences, Faculty of Allied Health Sciences, Kuwait University Sulaibekhat, Kuwait
| | - Andrés F Opazo-Capurro
- Laboratorio de Investigación en Agentes Antibacterianos, Departamento de Microbiología, Facultad de Ciencias Biológicas, Universidad de Concepción Concepción, Chile
| | - Ali A Dashti
- Department of Medical Laboratory Sciences, Faculty of Allied Health Sciences, Kuwait University Sulaibekhat, Kuwait
| | | | - Benjamin A Evans
- Department of Biomedical and Forensic Sciences, Faculty of Science and Technology, Anglia Ruskin University Cambridge, UK
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Al-Sultan AA, Evans BA, Aboulmagd E, Al-Qahtani AA, Bohol MFF, Al-Ahdal MN, Opazo AF, Amyes SGB. Dissemination of multiple carbapenem-resistant clones of Acinetobacter baumannii in the Eastern District of Saudi Arabia. Front Microbiol 2015; 6:634. [PMID: 26191044 PMCID: PMC4488750 DOI: 10.3389/fmicb.2015.00634] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 06/11/2015] [Indexed: 11/13/2022] Open
Abstract
It has previously been shown that carbapenem-resistant Acinetobacter baumannii are frequently detected in Saudi Arabia. The present study aimed to identify the epidemiology and distribution of antibiotic resistance determinants in these bacteria. A total of 83 A. baumannii isolates were typed by pulsed-field gel electrophoresis (PFGE), and screened by PCR for carbapenemase genes and insertion sequences. Antibiotic sensitivity to imipenem, meropenem, tigecycline, and colistin were determined. Eight different PFGE groups were identified, and were spread across multiple hospitals. Many of the PFGE groups contained isolates belonging to World-wide clone 2. Carbapenem resistance or intermediate resistance was detected in 69% of isolates. The blaVIM gene was detected in 94% of isolates, while blaOXA–23–like genes were detected in 58%. The data demonstrate the co-existence and wide distribution of a number of clones of carbapenem-resistant A. baumannii carrying multiple carbapenem-resistance determinants within hospitals in the Eastern Region of Saudi Arabia.
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Affiliation(s)
| | - Benjamin A Evans
- Department of Biomedical and Forensic Sciences, Faculty of Science and Technology, Anglia Ruskin University , Cambridge, UK
| | | | - Ahmed A Al-Qahtani
- Department of Infection and Immunity, Research Center, King Faisal Specialist Hospital and Research Center , Riyadh, Saudi Arabia ; Department of Microbiology and Immunology, Alfaisal University College of Medicine , Riyadh, Saudi Arabia ; Liver Disease Research Center, King Saud University , Riyadh, Saudi Arabia
| | - Marie Fe F Bohol
- Department of Infection and Immunity, Research Center, King Faisal Specialist Hospital and Research Center , Riyadh, Saudi Arabia
| | - Mohammed N Al-Ahdal
- Department of Infection and Immunity, Research Center, King Faisal Specialist Hospital and Research Center , Riyadh, Saudi Arabia ; Department of Microbiology and Immunology, Alfaisal University College of Medicine , Riyadh, Saudi Arabia ; Department of Pathology and Laboratory Medicine, King Faisal Specialist Hospital and Research Center , Riyadh, Saudi Arabia
| | - Andres F Opazo
- Laboratorio de Investigación en Agentes Antibacterianos, Facultad de Ciencias Biológicas, Universidad de Concepción , Concepción, Chile
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Evans BA, Morrison-Rees S, Harris-Mayes R, Hurlin C. HOW DO PEOPLE WITH CHRONIC CONDITIONS EXPERIENCE CARE IN THE HYWEL DDA HEALTH BOARD AREA? FINDINGS FROM INTERVIEWS WITH PATIENTS. Arch Emerg Med 2015. [DOI: 10.1136/emermed-2015-204880.20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Koniotou M, Halter M, Evans BA, Porter A, Gaze S. DEVELOPING A MODEL TO INVOLVE SERVICE USERS IN A MULTI-CENTRED TRIAL OF A COMPLEX INTERVENTION IN PRE-HOSPITAL EMERGENCY CARE. Arch Emerg Med 2015. [DOI: 10.1136/emermed-2015-204880.23] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Alsultan AA, Aboulmagd E, Evans BA, Amyes SGB. Clonal diversity of Acinetobacter baumannii from diabetic patients in Saudi Arabian hospitals. J Med Microbiol 2014; 63:1460-1466. [DOI: 10.1099/jmm.0.079640-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Carbapenem-resistant Acinetobacter baumannii (CR-AB) represents a major health-care problem, causing high rates of morbidity and mortality. This study investigated the clonality of CR-AB isolated from diabetic patients from different regions in Saudi Arabia, as well as the relatedness of the β-lactamase genes. A total of 64 non-repetitive CR-AB clinical isolates were collected from 16 different regions in Saudi Arabia from intensive care patients. Isolates were identified phenotypically by the Vitek 2 compact system and genotypically by amplification of the bla
OXA-51-like gene. The target sequences were amplified by PCR and the clonal diversity of the isolates was explored by PFGE. Resistance studies revealed that the prevalence of imipenem and meropenem resistance was 92 % and 96 %, respectively, while the vast majority of the isolates were susceptible to tigecycline and colistin. In addition, bla
VIM and bla
OXA-23 were the most prevalent genes in the isolates under investigation, while ISAba1 was the most dominant insertion sequence. PFGE results showed 13 clusters; clone H was dominant, comprising 20 isolates from four hospitals, followed by clones C and F, comprising 11 isolates each from three and six hospitals, respectively. Moreover, the current study signified the clonal diversity of CR-AB in Saudi Arabia and showed the ability of some clones to infect patients in many different cities.
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Affiliation(s)
- Abdulrahman A. Alsultan
- Department of Medical Microbiology, College of Medicine, King Faisal University, Al-Ahsa 31982, PO Box 400, Kingdom of Saudi Arabia
| | - Elsayed Aboulmagd
- Department of Microbiology, Faculty of Pharmacy, Alexandria University, El-Khartoum Square, Azarita, Alexandria 21521, Egypt
- Department of Medical Microbiology, College of Medicine, King Faisal University, Al-Ahsa 31982, PO Box 400, Kingdom of Saudi Arabia
| | - Benjamin A. Evans
- Department of Life Sciences, Faculty of Science and Technology, Anglia Ruskin University, East Road, Cambridge CB1 1PT, UK
| | - Sebastian G. B. Amyes
- Department of Medical Microbiology, College of Medicine and Veterinary Medicine, University of Edinburgh, The Chancellor’s Building, 49 Little France Crescent, Edinburgh EH16 4SB, UK
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Alexander SPH, Benson HE, Faccenda E, Pawson AJ, Sharman JL, McGrath JC, Catterall WA, Spedding M, Peters JA, Harmar AJ, Abul-Hasn N, Anderson CM, Anderson CMH, Araiksinen MS, Arita M, Arthofer E, Barker EL, Barratt C, Barnes NM, Bathgate R, Beart PM, Belelli D, Bennett AJ, Birdsall NJM, Boison D, Bonner TI, Brailsford L, Bröer S, Brown P, Calo G, Carter WG, Catterall WA, Chan SLF, Chao MV, Chiang N, Christopoulos A, Chun JJ, Cidlowski J, Clapham DE, Cockcroft S, Connor MA, Cox HM, Cuthbert A, Dautzenberg FM, Davenport AP, Dawson PA, Dent G, Dijksterhuis JP, Dollery CT, Dolphin AC, Donowitz M, Dubocovich ML, Eiden L, Eidne K, Evans BA, Fabbro D, Fahlke C, Farndale R, Fitzgerald GA, Fong TM, Fowler CJ, Fry JR, Funk CD, Futerman AH, Ganapathy V, Gaisnier B, Gershengorn MA, Goldin A, Goldman ID, Gundlach AL, Hagenbuch B, Hales TG, Hammond JR, Hamon M, Hancox JC, Hauger RL, Hay DL, Hobbs AJ, Hollenberg MD, Holliday ND, Hoyer D, Hynes NA, Inui KI, Ishii S, Jacobson KA, Jarvis GE, Jarvis MF, Jensen R, Jones CE, Jones RL, Kaibuchi K, Kanai Y, Kennedy C, Kerr ID, Khan AA, Klienz MJ, Kukkonen JP, Lapoint JY, Leurs R, Lingueglia E, Lippiat J, Lolait SJ, Lummis SCR, Lynch JW, MacEwan D, Maguire JJ, Marshall IL, May JM, McArdle CA, McGrath JC, Michel MC, Millar NS, Miller LJ, Mitolo V, Monk PN, Moore PK, Moorhouse AJ, Mouillac B, Murphy PM, Neubig RR, Neumaier J, Niesler B, Obaidat A, Offermanns S, Ohlstein E, Panaro MA, Parsons S, Pwrtwee RG, Petersen J, Pin JP, Poyner DR, Prigent S, Prossnitz ER, Pyne NJ, Pyne S, Quigley JG, Ramachandran R, Richelson EL, Roberts RE, Roskoski R, Ross RA, Roth M, Rudnick G, Ryan RM, Said SI, Schild L, Sanger GJ, Scholich K, Schousboe A, Schulte G, Schulz S, Serhan CN, Sexton PM, Sibley DR, Siegel JM, Singh G, Sitsapesan R, Smart TG, Smith DM, Soga T, Stahl A, Stewart G, Stoddart LA, Summers RJ, Thorens B, Thwaites DT, Toll L, Traynor JR, Usdin TB, Vandenberg RJ, Villalon C, Vore M, Waldman SA, Ward DT, Willars GB, Wonnacott SJ, Wright E, Ye RD, Yonezawa A, Zimmermann M. The Concise Guide to PHARMACOLOGY 2013/14: overview. Br J Pharmacol 2014; 170:1449-58. [PMID: 24528237 DOI: 10.1111/bph.12444] [Citation(s) in RCA: 146] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The Concise Guide to PHARMACOLOGY 2013/14 provides concise overviews of the key properties of over 2000 human drug targets with their pharmacology, plus links to an open access knowledgebase of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties from the IUPHAR database. The full contents can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.12444/full. This compilation of the major pharmacological targets is divided into seven areas of focus: G protein-coupled receptors, ligand-gated ion channels, ion channels, catalytic receptors, nuclear hormone receptors, transporters and enzymes. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. A new landscape format has easy to use tables comparing related targets. It is a condensed version of material contemporary to late 2013, which is presented in greater detail and constantly updated on the website www.guidetopharmacology.org, superseding data presented in previous Guides to Receptors & Channels. It is produced in conjunction with NC-IUPHAR and provides the official IUPHAR classification and nomenclature for human drug targets, where appropriate. It consolidates information previously curated and displayed separately in IUPHAR-DB and GRAC and provides a permanent, citable, point-in-time record that will survive database updates.
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Affiliation(s)
- Stephen P H Alexander
- School of Life Sciences, University of Nottingham Medical School, Nottingham, NG7 2UH, UK
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Kingston MR, Porter AM, Evans BA, Hutchings HA, Snooks HA. PP51 Implementation of a predictive risk tool in primary care: examining understanding and engagement among practitioners. Br J Soc Med 2014. [DOI: 10.1136/jech-2014-204726.146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Abstract
Acinetobacter spp. are Gram-negative bacteria that have become one of the most difficult pathogens to treat. The species A. baumannii, largely unknown 30 years ago, has risen to prominence particularly because of its ability to cause infections in immunocompromised patients. It is now a predominant pathogen in many hospitals as it has acquired resistance genes to virtually all antibiotics capable of treating Gram-negative bacteria, including the fluoroquinolones and the cephalosporins. Some members of the species have accumulated these resistance genes in large resistance islands, located in a "hot-spot" within the bacterial chromosome. The only conventional remaining treatment options were the carbapenems. However, A. baumannii possesses an inherent class D β-lactamase gene (blaOXA-51-like) that can have the ability to confer carbapenem resistance. Additionally, mechanisms of carbapenem resistance have emerged that derive from the importation of the distantly related class D β-lactamase genes blaOXA-23 and blaOXA-58. Although not inducible, the expression of these genes is controlled by mobile promoters carried on ISAba elements. It has also been found that other resistance genes including the chromosomal class C β-lactamase genes conferring cephalosporin resistance are controlled in the same manner. Colistin is now considered to be the final drug capable of treating infections caused by carbapenem-resistant A. baumannii; however, strains are now being isolated that are resistant to this antibiotic as well. The increasing inability to treat infections caused by A. baumannii ensures that this pathogen more than ranks with MRSA or Clostridium difficile as a threat to modern medicine.
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Abstract
The naturally transformable bacterium Streptococcus pneumoniae is able to take up extracellular DNA and incorporate it into its genome. Maintaining natural transformation within a species requires that the benefits of transformation outweigh its costs. Although much is known about the distribution of natural transformation among bacterial species, little is known about the degree to which transformation frequencies vary within species. Here we find that there is significant variation in transformation frequency between strains of Streptococcus pneumoniae isolated from asymptomatic carriage, and that this variation is not concordant with isolate genetic relatedness. Polymorphism in the signalling system regulating competence is also not causally related to differences in transformation frequency, although this polymorphism does influence the degree of genetic admixture experienced by bacterial strains. These data suggest that bacteria can evolve new transformation frequencies over short evolutionary timescales. This facility may permit cells to balance the potential costs and benefits of transformation by regulating transformation frequency in response to environmental conditions.
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Affiliation(s)
- Benjamin A Evans
- University of Manchester, Faculty of Life Sciences, Oxford Road, Manchester, UK.
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Deatsch AE, Evans BA. Effect of Concentration on Heating Efficiency of Magnetic Nanoparticles for Application in Magnetic Hyperthermia. Biophys J 2013. [DOI: 10.1016/j.bpj.2012.11.3721] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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Evans BA, Fiser BL, Prins WJ, Rapp DJ, Shields AR, Glass DR, Superfine R. A Highly Tunable Silicone-Based Magnetic Elastomer with Nanoscale Homogeneity. J Magn Magn Mater 2012; 324:501-507. [PMID: 22184482 PMCID: PMC3241051 DOI: 10.1016/j.jmmm.2011.08.045] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Magnetic elastomers have been widely pursued for sensing and actuation applications. Silicone-based magnetic elastomers have a number of advantages over other materials such as hydrogels, but aggregation of magnetic nanoparticles within silicones is difficult to prevent. Aggregation inherently limits the minimum size of fabricated structures and leads to non-uniform response from structure to structure. We have developed a novel material which is a complex of a silicone polymer (polydimethylsiloxane-co-aminopropylmethylsiloxane) adsorbed onto the surface of magnetite (γ-Fe(2)0(3)) nanoparticles 7-10 nm in diameter. The material is homogenous at very small length scales (< 100 nm) and can be crosslinked to form a flexible, magnetic material which is ideally suited for the fabrication of micro- to nanoscale magnetic actuators. The loading fraction of magnetic nanoparticles in the composite can be varied smoothly from 0 - 50% wt. without loss of homogeneity, providing a simple mechanism for tuning actuator response. We evaluate the material properties of the composite across a range of nanoparticle loading, and demonstrate a magnetic-field-induced increase in compressive modulus as high as 300%. Furthermore, we implement a strategy for predicting the optimal nanoparticle loading for magnetic actuation applications, and show that our predictions correlate well with experimental findings.
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Affiliation(s)
- Benjamin A. Evans
- Department of Physics, Elon University, Elon, NC 27244 (USA)
- Corresponding author at: Elon University, CB# 2625, Elon, NC 27244, USA. Tel.: 13362786252. Fax: 3362786258.
| | - Briana L. Fiser
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 (USA)
| | - Willem J. Prins
- Department of Physics, Elon University, Elon, NC 27244 (USA)
| | - Daniel J. Rapp
- Department of Physics, Elon University, Elon, NC 27244 (USA)
| | - Adam R. Shields
- Center for Bio/Molecular Science and Engineering, US Naval Research Laboratory, SW Washington, DC, 20375 (USA)
| | - Daniel R. Glass
- Department of Physics, Elon University, Elon, NC 27244 (USA)
| | - R. Superfine
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 (USA)
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Ronecker JC, Evans BA. A Novel Silicone Magnetic Microsphere for Ligand-Targeted Drug Delivery. Biophys J 2012. [DOI: 10.1016/j.bpj.2011.11.3182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022] Open
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Deatsch AE, Evans BA. Silicone-Based Magnetic Microspheres for Magnetic Hyperthermia Therapeutics. Biophys J 2012. [DOI: 10.1016/j.bpj.2011.11.3183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Lopes BS, Evans BA, Amyes SGB. Disruption of the blaOXA-51-like gene by ISAba16 and activation of the blaOXA-58 gene leading to carbapenem resistance in Acinetobacter baumannii Ab244. J Antimicrob Chemother 2011; 67:59-63. [PMID: 21980071 DOI: 10.1093/jac/dkr415] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES This study examines the mechanism of carbapenem resistance in Acinetobacter baumannii isolate Ab244. METHODS A multiplex PCR for the detection of the bla(OXA-23-like), bla(OXA-40-like), bla(OXA-51-like) and bla(OXA-58-like) families was performed. MICs of imipenem and meropenem were determined by the agar dilution method. The sequence surrounding the bla(OXA-132) gene was determined by amplification with primer pairs encompassing a part of fxsA and an acetyltransferase gene (GNAT). The sequence upstream of the bla(OXA-58) gene was determined by sequencing. SDS-PAGE and carO PCR were performed to check the integrity of the outer membrane proteins. RT-PCRs for the expression of the bla(OXA-132) gene and the bla(OXA-58) gene were performed. RESULTS Isolate Ab244 harboured bla(OXA-132) belonging to the bla(OXA-51-like) gene cluster and a bla(OXA-58) gene. The 4239 bp region between fxsA and GNAT showed an insert of ISAba16 (where IS stands for insertion sequence) after the first 15 nucleotides of the bla(OXA-132) gene, with an 8 bp target site duplication at the 5' and 3' ends of ISAba16. The sequence oriented in the 5'→3' direction caused insertional inactivation of the bla(OXA-132) gene. The bla(OXA-58) gene was highly expressed by the promoters provided by an ISAba3-like structure found upstream of the gene. The isolate was resistant to meropenem and had intermediate resistance to imipenem, and was also positive for ISAba1. CONCLUSIONS This is the first report showing ISAba16-mediated inactivation of the bla(OXA-132) gene in strain Ab244. The resistance to carbapenems in strain Ab244 is related to the acquisition of the bla(OXA-58) gene, here governed by an ISAba3-like element.
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Affiliation(s)
- Bruno S Lopes
- Centre for Infectious Diseases, The University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK
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Evans BA, Hamouda A, Abbasi SA, Khan FA, Amyes SGB. High prevalence of unrelated multidrug-resistant Acinetobacter baumannii isolates in Pakistani military hospitals. Int J Antimicrob Agents 2011; 37:580-1. [PMID: 21481570 DOI: 10.1016/j.ijantimicag.2011.01.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Revised: 01/21/2011] [Accepted: 01/24/2011] [Indexed: 11/18/2022]
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Evans BA, Hamouda A, Towner KJ, Amyes SGB. Novel genetic context of multiple bla OXA-58 genes in Acinetobacter genospecies 3. J Antimicrob Chemother 2010; 65:1586-8. [PMID: 20542900 DOI: 10.1093/jac/dkq180] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES The detection in Acinetobacter genospecies 3 isolates of OXA-type carbapenemases, resulting in reduced susceptibility to carbapenem antibiotics, is increasingly reported. We identified an Acinetobacter genospecies 3 isolate carrying the gene for OXA-58 and aimed to resolve the genetic environment surrounding the bla(OXA-58) gene. METHODS Species identification was confirmed by 16S-23S rRNA restriction analysis. MICs of imipenem, meropenem and ertapenem were determined, and the isolate was screened by PCR for bla(OXA-23-like), bla(OXA-40-like), bla(OXA-51-like) and bla(OXA-58-like) genes. The sequence surrounding bla(OXA-58) was determined through amplification by inverse PCR and genome walking followed by sequencing. Genetic localization was investigated by Southern blotting. RESULTS Isolate A164 was confirmed as belonging to Acinetobacter genospecies 3 and had reduced susceptibility to the carbapenems. The isolate was found to encode two bla(OXA-58) genes that may have been duplicated by the insertion sequence ISAba125, two copies of which were inserted into ISAba3 elements. The bla(OXA-58) genes appear to be plasmid borne. CONCLUSIONS This is the first report of beta-lactamase duplication in Acinetobacter genospecies 3 and of gene duplication mediated by ISAba125.
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Affiliation(s)
- B A Evans
- Faculty of Life Sciences, The University of Manchester, Manchester, UK
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Abstract
Quorum sensing (QS) in bacteria is thought to enable populations of cells to coordinately and cooperatively regulate gene expression for traits that confer group benefits. While this view has strong empirical and theoretical support, it is increasingly appreciated that QS under natural conditions may be incapable of monitoring bacterial numbers and, furthermore, that QS is evolutionarily unstable owing to conflicts of interest among competing cells. An alternative hypothesis, termed diffusion sensing (DS), proposes that autoinducer secretion monitors the diffusive properties of the local environment, with benefits that are directly realized by individual cells rather than populations. Here, we test central predictions of this hypothesis using the competence signalling system of Streptococcus pneumoniae as our model, which regulates the induction of natural transformation by the secretion and detection of a small diffusible peptide, CSP (competence-stimulating peptide). By experimentally manipulating the diffusive properties of the growth medium, we found that there is no fixed quorum for competence induction. Instead, induction cell density scales with diffusivity. In agreement with QS and DS expectations, we show that the benefit of signal exploitation by mutant cells that can use but not secrete CSP is strongly frequency-dependent. However, we also find that the magnitude of this benefit declines significantly as diffusion is reduced, a result more consistent with the predictions of DS. Together, these data provide strong support for the DS hypothesis for autoinducer response systems. More specifically, our results imply that autonomous rather than group benefits should be sought in order to more completely understand the role and evolution of CSP signalling in pneumococci.
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Affiliation(s)
- Jungwoo Yang
- University of Manchester, Manchester M13 9PT, UK
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Jiricny N, Diggle SP, West SA, Evans BA, Ballantyne G, Ross-Gillespie A, Griffin AS. Fitness correlates with the extent of cheating in a bacterium. J Evol Biol 2010; 23:738-47. [PMID: 20210835 DOI: 10.1111/j.1420-9101.2010.01939.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
There is growing awareness of the importance of cooperative behaviours in microbial communities. Empirical support for this insight comes from experiments using mutant strains, termed 'cheats', which exploit the cooperative behaviour of wild-type strains. However, little detailed work has gone into characterising the competitive dynamics of cooperative and cheating strains. We test three specific predictions about the fitness consequences of cheating to different extents by examining the production of the iron-scavenging siderophore molecule, pyoverdin, in the bacterium Pseudomonas aeruginosa. We create a collection of mutants that differ in the amount of pyoverdin that they produce (from 1% to 96% of the production of paired wild types) and demonstrate that these production levels correlate with both gene activity and the ability to bind iron. Across these mutants, we found that (1) when grown in a mixed culture with a cooperative wild-type strain, the relative fitness of a mutant is negatively correlated with the amount of pyoverdin that it produces; (2) the absolute and relative fitness of the wild-type strain in the mixed culture is positively correlated with the amount of pyoverdin that the mutant produces; and (3) when grown in a monoculture, the absolute fitness of the mutant is positively correlated with the amount of pyoverdin that it produces. Overall, we demonstrate that cooperative pyoverdin production is exploitable and illustrate how variation in a social behaviour determines fitness differently, depending on the social environment.
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Affiliation(s)
- N Jiricny
- Department of Zoology, Oxford University, Oxford, UK
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Alsultan AA, Hamouda A, Evans BA, Amyes SGB. Acinetobacter baumannii: emergence of four strains with novel bla(OXA-51-like) genes in patients with diabetes mellitus. J Chemother 2009; 21:290-5. [PMID: 19567349 DOI: 10.1179/joc.2009.21.3.290] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
UNLABELLED Diabetic patients are 10 times more likely to develop Acinetobacter baumannii infections than the rest of the population. Carbapenems are considered one of the very few antibiotics left to treat infections caused by this organism. the aim of this work was to characterise A. baumannii strains isolated from diabetic patients and to investigate whether there is a relationship between certain strains and low-level-carbapenem resistance. METHODS Clinical samples were collected from diabetic patients in hospitals throughout Saudi Arabia from December 2006 to April 2007. API 20 Ne, polymorphisms in the 16S-23S-rRNA intergenic region and the presence of a bla( OXA-51-like )gene were all used for identification. Susceptibility to antimicrobials was determined using agar dilution and disk diffusion methods. pulsed-field gel electrophoresis (pfGe) coupled with sequence analysis of the bla(OXA-51-like )genes were used for strain characterization. Polymerase chain reaction (pCR) and multiplex pCR were used to screen for the presence and location of ISAba1 elements and bla(OXA-23-like), bla(OXA-40-like), and bla(OXA-58-like )genes respectively. RESULTS Twenty isolates were identified as A. baumannii and were all highly resistant to 38% of the antibiotics tested and the majority of isolates were also resistant to 50% of the remaining antibiotics. four strains had low-level meropenem resistance (MIC 4-8 mg/l). All isolates were sensitive to imipenem and colistin. Nine strains possessed four novel bla( OXA-51-like )genes encoding beta-lactamases designated OXA-90, OXA-130, OXA-131 and OXA-132, and four strains contained bla(OXA-131 )with ISAba1 upstream of the gene structure. PFGE showed five separate clusters of OXA-51-like enzymes and the dissemination of strains carrying the four novel enzymes was clonal. this study showed that new strains of A. baumannii characterised by their new bla(OXA-51-like )gene have emerged. No genes encoding OXA-23-like, OXA-40-like, or OXA-58-like beta-lactamases were found. Surveillance of A. baumannii harbouring the bla( OXA-131-like )gene may be an essential step in monitoring their carbapenem resistance phenotype and may assist in preventing their spread in diabetics.
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Affiliation(s)
- A A Alsultan
- Molecular Chemotherapy, Centre for Infectious Diseases, The University of Edinburgh, Edinburgh, UK
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Darling EM, Pritchett PE, Evans BA, Superfine R, Zauscher S, Guilak F. Mechanical properties and gene expression of chondrocytes on micropatterned substrates following dedifferentiation in monolayer. Cell Mol Bioeng 2009; 2:395-404. [PMID: 20625462 DOI: 10.1007/s12195-009-0077-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Chondrocytes in articular cartilage normally exhibit high expression of collagen II and aggrecan but rapidly dedifferentiate to a fibroblastic phenotype if passaged in culture. Previous studies have suggested that the loss of chondrocyte phenotype is associated with changes in the structure of the F-actin cytoskeleton, which also controls cell mechanical properties. In this study, we examined how dedifferentiation in monolayer influences the mechanical properties of chondrocytes isolated from different zones of articular cartilage. Atomic force microscopy was used to measure the mechanical properties of superficial and middle/deep zone chondrocytes as they underwent serial passaging and subsequent growth on fibronectin-coated, micropatterned self-assembled monolayers (MSAMs) that restored a rounded cell shape in 2D culture. Chondrocytes exhibited significant increases in elastic and viscoelastic moduli with dedifferentiation in culture. These changes were only partially ameliorated by the restoration of a rounded shape on micropatterned surfaces. Furthermore, intrinsic zonal differences in cell mechanical properties were rapidly lost with passage. These findings indicate that cell mechanical properties may provide additional measures of phenotypic expression of chondrocytes as they undergo dedifferentiation and possibly redifferentiation in culture.
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Affiliation(s)
- Eric M Darling
- Department of Surgery, Duke University Medical Center, Durham, NC 27710 USA
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Evans BA, Hamouda A, Towner KJ, Amyes SGB. OXA-51-like beta-lactamases and their association with particular epidemic lineages of Acinetobacter baumannii. Clin Microbiol Infect 2008; 14:268-75. [PMID: 18190566 DOI: 10.1111/j.1469-0691.2007.01919.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Sixty diverse clinical Acinetobacter baumannii isolates of worldwide origin were assigned to sequence groups, based on a multiplex PCR for the ompA, csuE and bla(OXA-51-like) genes. The majority (77%) of isolates belonged to sequence groups 1 and 2 (SG1 and SG2), with sequence group 3 (SG3) and non-grouped isolates accounting for the remainder. The isolates were not closely related according to pulsed-field gel electrophoresis (PFGE), and the majority were sensitive to imipenem and meropenem. The construction of a linkage map of OXA-51-like beta-lactamase sequence relationships revealed two closely related clusters of enzymes, one focused around OXA-66 and the other around OXA-69. Isolates belonging to SG1 encoded an enzyme from the OXA-66 cluster, while those belonging to SG2 encoded an enzyme from the OXA-69 cluster. All SG3 isolates encoded OXA-71, which does not form part of a close enzyme grouping. Major multinational lineages accounted for a significant proportion of A. baumannii clinical isolates, and the evolution of the OXA-51-like enzymes appears to be an ongoing process.
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Affiliation(s)
- B A Evans
- Centre for Infectious Diseases, The University of Edinburgh, Edinburgh, UK
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Evans BA, Brown S, Hamouda A, Findlay J, Amyes SGB. Eleven novel OXA-51-like enzymes from clinical isolates of Acinetobacter baumannii. Clin Microbiol Infect 2007; 13:1137-8. [PMID: 17850339 DOI: 10.1111/j.1469-0691.2007.01828.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Abstract
We present a procedure for producing high-aspect-ratio cantilevered micro- and nanorod arrays of a PDMS-ferrofluid composite material. The rods have been produced with diameters ranging from 200 nm to 1 mum and aspect ratios as high as 125. We demonstrate actuation of these superparamagnetic rod arrays with an externally applied magnetic field from a permanent magnet and compare this actuation with a theoretical energy-minimization model. The structures produced by these methods may be useful in microfluidics, photonic, and sensing applications.
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Affiliation(s)
- B A Evans
- The Virtual Lung Project, Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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