1
|
Shelbaya O, Baartman R, Braun P, Jung PM, Kester O, Planche T, Podlech H, Rädel SD. Tuning methods for multigap drift tube linacs. Rev Sci Instrum 2024; 95:033302. [PMID: 38456758 DOI: 10.1063/5.0191603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 02/12/2024] [Indexed: 03/09/2024]
Abstract
Multigap cavities are used extensively in linear accelerators to achieve velocities up to a few percent of the speed of light, driving nuclear physics research around the world. Unlike for single-gap structures, there is no closed-form expression to calculate the output beam parameters from the cavity voltage and phase. To overcome this, we propose to use a method based on the integration of the first and second moments of the beam distribution through the axially symmetric time-dependent fields of the cavity. A beam-based calibration between the model's electric field scaling and the machine's rf amplitudes is presented, yielding a fast online energy change method, returning cavity amplitude and phase necessary for a desired output beam energy and energy spread. The method is validated with 23Na6+ beam energy measurements.
Collapse
Affiliation(s)
- O Shelbaya
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics and Astronomy, University of Victoria, P.O. Box 1700 STN CSC, Victoria, British Columbia V8W 2Y2, Canada
| | - R Baartman
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics and Astronomy, University of Victoria, P.O. Box 1700 STN CSC, Victoria, British Columbia V8W 2Y2, Canada
| | - P Braun
- Institute for Applied Physics, Goethe Universität, Max-von-Laue-Straße 1, D-60438 Frankfurt a. M., Germany
| | - P M Jung
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics and Astronomy, University of Victoria, P.O. Box 1700 STN CSC, Victoria, British Columbia V8W 2Y2, Canada
| | - O Kester
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics and Astronomy, University of Victoria, P.O. Box 1700 STN CSC, Victoria, British Columbia V8W 2Y2, Canada
| | - T Planche
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics and Astronomy, University of Victoria, P.O. Box 1700 STN CSC, Victoria, British Columbia V8W 2Y2, Canada
| | - H Podlech
- Institute for Applied Physics, Goethe Universität, Max-von-Laue-Straße 1, D-60438 Frankfurt a. M., Germany
- Helmholtz Research Academy Hesse for FAIR (HFHF), 60438 Frankfurt a. M, Germany
| | - S D Rädel
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| |
Collapse
|
2
|
Esplen N, Egoriti L, Planche T, Rädel S, Koay HW, Humphries B, Ren X, Ford N, Hoehr C, Gottberg A, Bazalova-Carter M. Dosimetric characterization of a novel UHDR megavoltage X-ray source for FLASH radiobiological experiments. Sci Rep 2024; 14:822. [PMID: 38191885 PMCID: PMC10774358 DOI: 10.1038/s41598-023-50412-w] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Accepted: 12/19/2023] [Indexed: 01/10/2024] Open
Abstract
A first irradiation platform capable of delivering 10 MV X-ray beams at ultra-high dose rates (UHDR) has been developed and characterized for FLASH radiobiological research at TRIUMF. Delivery of both UHDR (FLASH mode) and low dose-rate conventional (CONV mode) irradiations was demonstrated using a common source and experimental setup. Dose rates were calculated using film dosimetry and a non-intercepting beam monitoring device; mean values for a 100 μA pulse (peak) current were nominally 82.6 and 4.40 × 10-2 Gy/s for UHDR and CONV modes, respectively. The field size for which > 40 Gy/s could be achieved exceeded 1 cm down to a depth of 4.1 cm, suitable for total lung irradiations in mouse models. The calculated delivery metrics were used to inform subsequent pre-clinical treatments. Four groups of 6 healthy male C57Bl/6J mice were treated using thoracic irradiations to target doses of either 15 or 30 Gy using both FLASH and CONV modes. Administration of UHDR X-ray irradiation to healthy mouse models was demonstrated for the first time at the clinically-relevant beam energy of 10 MV.
Collapse
Affiliation(s)
- Nolan Esplen
- Physics and Astronomy, University of Victoria, Victoria, V8P 5C2, Canada
| | - Luca Egoriti
- TRIUMF, Vancouver, V6T 2A3, Canada
- Chemistry, University of British Columbia, Vancouver, V6T 1Z1, Canada
| | | | | | | | | | - Xi Ren
- Physics and Astronomy, University of British Columbia, Vancouver, V6T 1Z1, Canada
| | - Nancy Ford
- Physics and Astronomy, University of British Columbia, Vancouver, V6T 1Z1, Canada
- Oral Biological and Medical Sciences, University of British Columbia, Vancouver, V6T 1Z1, Canada
| | - Cornelia Hoehr
- Physics and Astronomy, University of Victoria, Victoria, V8P 5C2, Canada
- TRIUMF, Vancouver, V6T 2A3, Canada
| | - Alexander Gottberg
- Physics and Astronomy, University of Victoria, Victoria, V8P 5C2, Canada
- TRIUMF, Vancouver, V6T 2A3, Canada
| | | |
Collapse
|
3
|
Dillmann I, Kester O, Baartman R, Chen A, Junginger T, Herwig F, Kaltchev D, Lennarz A, Planche T, Ruiz C, Vassh N. Measuring neutron capture cross sections of radioactive nuclei: From activations at the FZK Van de Graaff to direct neutron captures in inverse kinematics with a storage ring at TRIUMF. Eur Phys J A Hadron Nucl 2023; 59:105. [PMID: 37187510 PMCID: PMC10182137 DOI: 10.1140/epja/s10050-023-01012-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 04/13/2023] [Indexed: 05/17/2023]
Abstract
Measuring neutron capture cross sections of radioactive nuclei is a crucial step towards a better understanding of the origin of the elements heavier than iron. For decades, the precise measurement of direct neutron capture cross sections in the "stellar" energy range (eV up to a few MeV) was limited to stable and longer-lived nuclei that could be provided as physical samples and then irradiated with neutrons. New experimental methods are now being developed to extend these direct measurements towards shorter-lived radioactive nuclei (t 1 / 2 < 1 y). One project in this direction is a low-energy heavy-ion storage ring coupled to the ISAC facility at TRIUMF, Canada's accelerator laboratory in Vancouver BC, which has a compact neutron source in the ring matrix. Such a pioneering facility could be built within the next 10 years and store a wide range of radioactive ions provided directly from the existing ISOL facility, allowing for the first time to carry out direct neutron capture measurements on short-lived isotopes in inverse kinematics.
Collapse
Affiliation(s)
- Iris Dillmann
- TRIUMF, Vancouver, BC V6T 2A3 Canada
- Department of Physics and Astronomy, University of Victoria, Victoria, BC V8P 5C2 Canada
| | - Oliver Kester
- TRIUMF, Vancouver, BC V6T 2A3 Canada
- Department of Physics and Astronomy, University of Victoria, Victoria, BC V8P 5C2 Canada
| | - Richard Baartman
- TRIUMF, Vancouver, BC V6T 2A3 Canada
- Department of Physics and Astronomy, University of Victoria, Victoria, BC V8P 5C2 Canada
| | - Alan Chen
- Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1 Canada
| | - Tobias Junginger
- TRIUMF, Vancouver, BC V6T 2A3 Canada
- Department of Physics and Astronomy, University of Victoria, Victoria, BC V8P 5C2 Canada
| | - Falk Herwig
- Department of Physics and Astronomy, University of Victoria, Victoria, BC V8P 5C2 Canada
| | | | - Annika Lennarz
- TRIUMF, Vancouver, BC V6T 2A3 Canada
- Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1 Canada
| | - Thomas Planche
- TRIUMF, Vancouver, BC V6T 2A3 Canada
- Department of Physics and Astronomy, University of Victoria, Victoria, BC V8P 5C2 Canada
| | - Chris Ruiz
- TRIUMF, Vancouver, BC V6T 2A3 Canada
- Department of Physics and Astronomy, University of Victoria, Victoria, BC V8P 5C2 Canada
| | | |
Collapse
|
4
|
Logan C, Hemsley C, Fife A, Edgeworth J, Mazzella A, Wade P, Goodman A, Hopkins P, Wyncoll D, Ball J, Planche T, Schelenz S, Bicanic T. A multisite evaluation of antifungal use in critical care: implications for antifungal stewardship. JAC Antimicrob Resist 2022; 4:dlac055. [PMID: 35756574 PMCID: PMC9217759 DOI: 10.1093/jacamr/dlac055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 04/28/2022] [Indexed: 12/02/2022] Open
Abstract
Background ICUs are settings of high antifungal consumption. There are few data on prescribing practices in ICUs to guide antifungal stewardship implementation in this setting. Methods An antifungal therapy (AFT) service evaluation (15 May-19 November 2019) across ICUs at three London hospitals, evaluating consumption, prescribing rationale, post-prescription review, de-escalation and final invasive fungal infection (IFI) diagnostic classification. Results Overall, 6.4% of ICU admissions (305/4781) received AFT, accounting for 11.41 days of therapy/100 occupied bed days (DOT/100 OBD). The dominant prescribing mode was empirical (41% of consumption), followed by targeted (22%), prophylaxis (18%), pre-emptive (12%) and non-invasive (7%). Echinocandins were the most commonly prescribed drug class (4.59 DOT/100 OBD). In total, 217 patients received AFT for suspected or confirmed IFI; 12%, 10% and 23% were classified as possible, probable or proven IFI, respectively. Hence, in 55%, IFI was unlikely. Proven IFI (n = 50) was mostly invasive candidiasis (92%), of which 48% had been initiated on AFT empirically before yeast identification. Where on-site (1 → 3)-β-d-glucan (BDG) testing was available (1 day turnaround), in those with suspected but unproven invasive candidiasis, median (IQR) AFT duration was 10 (7-15) days with a positive BDG (≥80 pg/mL) versus 8 (5-9) days with a negative BDG (<80 pg/mL). Post-prescription review occurred in 79% of prescribing episodes (median time to review 1 [0-3] day). Where suspected IFI was not confirmed, 38% episodes were stopped and 4% de-escalated within 5 days. Conclusions Achieving a better balance between promptly treating IFI patients and avoiding inappropriate antifungal prescribing in the ICU requires timely post-prescription review by specialist multidisciplinary teams and improved, evidence-based-risk prescribing strategies incorporating rapid diagnostics to guide AFT start and stop decisions.
Collapse
Affiliation(s)
- C Logan
- Corresponding author. E-mail:
| | - C Hemsley
- Department of Infectious Diseases, Guy’s & St Thomas’ NHS Foundation Trust, London, UK
| | - A Fife
- Infection Sciences, King’s College Hospital NHS Foundation Trust, London, UK
| | - J Edgeworth
- Department of Infectious Diseases, Guy’s & St Thomas’ NHS Foundation Trust, London, UK,Centre for Clinical Infection and Diagnostics Research, Department of Infectious Diseases, King’s College London Guy’s & St Thomas’ NHS Foundation Trust, London, UK
| | - A Mazzella
- Clinical Infection Group, St George’s University Hospitals NHS Foundation Trust, London, UK,Institute of Infection & Immunity, St George’s University of London, London, UK
| | - P Wade
- Department of Infectious Diseases, Guy’s & St Thomas’ NHS Foundation Trust, London, UK,Directorate of Pharmacy & Medicines Optimisation, Guy’s & St Thomas’s NHS Foundation Trust, London, UK
| | - A Goodman
- Department of Infectious Diseases, Guy’s & St Thomas’ NHS Foundation Trust, London, UK,Centre for Clinical Infection and Diagnostics Research, Department of Infectious Diseases, King’s College London Guy’s & St Thomas’ NHS Foundation Trust, London, UK,MRC Clinical Trials Unit at University College London, London, UK
| | - P Hopkins
- Department of Critical Care, King’s College Hospital NHS Foundation Trust, London, UK
| | - D Wyncoll
- Department of Critical Care, Guy’s & St Thomas’ NHS Foundation Trust, London, UK
| | - J Ball
- Department of Critical Care, St George’s University Hospitals NHS Foundation Trust, London, UK
| | - T Planche
- Clinical Infection Group, St George’s University Hospitals NHS Foundation Trust, London, UK,Institute of Infection & Immunity, St George’s University of London, London, UK
| | - S Schelenz
- Infection Sciences, King’s College Hospital NHS Foundation Trust, London, UK
| | - T Bicanic
- Clinical Infection Group, St George’s University Hospitals NHS Foundation Trust, London, UK,Institute of Infection & Immunity, St George’s University of London, London, UK
| |
Collapse
|
5
|
Esplen N, Egoriti L, Paley B, Planche T, Hoehr C, Gottberg A, Bazalova-Carter M. Design optimization of an electron-to-photon conversion target for ultra-high dose rate x-ray (FLASH) experiments at TRIUMF. Phys Med Biol 2022; 67. [DOI: 10.1088/1361-6560/ac5ed6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 03/17/2022] [Indexed: 12/29/2022]
Abstract
Abstract
Objective. To develop a bremsstrahlung target and megavoltage (MV) x-ray irradiation platform for ultrahigh dose-rate (UHDR) irradiation of small-animals on the Advanced Rare Isotope Laboratory (ARIEL) electron linac (e-linac) at TRIUMF. Approach. An electron-to-photon converter design for UHDR radiotherapy (RT) was centered around optimization of a tantalum–aluminum (Ta–Al) explosion-bonded target. Energy deposition within a homogeneous water-phantom and the target itself were evaluated using EGSnrc and FLUKA MC codes, respectively, for various target thicknesses (0.5–1.5 mm), beam energies (E
e− = 8, 10 MeV) and electron (Gaussian) beam sizes (
2
σ
= 2–10 mm). Depth dose-rates in a 3D-printed mouse phantom were also calculated to infer the compatibility of the 10 MV dose distributions for FLASH-RT in small-animal models. Coupled thermo-mechanical FEA simulations in ANSYS were subsequently used to inform the stress–strain conditions and fatigue life of the target assembly. Main results. Dose-rates of up to 128 Gy s−1 at the phantom surface, or 85 Gy s−1 at 1 cm depth, were obtained for a 1 × 1 cm2 field size, 1 mm thick Ta target and 7.5 cm source-to-surface distance using the FLASH-mode beam (E
e− = 10 MeV, 2
σ
= 5 mm, P = 1 kW); furthermore, removal of the collimation assembly and using a shorter (3.5 cm) SSD afforded dose-rates >600 Gy s−1, albeit at the expense of field conformality. Target temperatures were maintained below the tantalum, aluminum and cooling-water thresholds of 2000 °C, 300 °C and 100 °C, respectively, while the aluminum strain behavior remained everywhere elastic and helped ensure the converter survives its prescribed 5 yr operational lifetime. Significance. Effective design iteration, target cooling and failure mitigation have culminated in a robust target compatible with intensive transient (FLASH) and steady-state (diagnostic) applications. The ARIEL UHDR photon source will facilitate FLASH-RT experiments concerned with sub-second, pulsed or continuous beam irradiations at dose rates in excess of 40 Gy s−1.
Collapse
|
6
|
Anton-Vazquez V, Suarez C, Krishna S, Planche T. Factors influencing antimicrobial prescription attitudes in bloodstream infections: susceptibility results and beyond. An exploratory survey. J Hosp Infect 2021; 111:140-147. [PMID: 33581245 DOI: 10.1016/j.jhin.2021.01.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 01/23/2021] [Accepted: 01/28/2021] [Indexed: 01/26/2023]
Abstract
BACKGROUND Novel rapid antimicrobial susceptibility testing (RAST) methods promise quicker de-escalation of broad-spectrum antibiotics. However, other behavioural and situational factors influencing antimicrobial prescription are not well known. AIM To explore factors associated with optimal antimicrobial prescription in patients with Gram-negative bloodstream infection and to propose specific scenarios in which a rapid antimicrobial susceptibility result may help to optimize prescribing. METHODS Exploratory survey (April-August 2018) in the UK and Spain using clinical case-related questions. Seniority, specialty and country of practice were recorded. Cases described patients with Gram-negative bloodstream infections, their empirical treatment and clinical course and the hypothetical RAST result. Respondents chose one of several options regarding antibiotic treatment management. Microbiologically optimal antibiotic choice (MOAC) was agreed by expert consensus beforehand. Responses were categorized as MOAC, request for support or sub-optimal choice. The relationship between the RAST result and the clinical course was defined as concordant (susceptible organism-clinical improvement; resistant organism-clinical deterioration) or as discordant otherwise. FINDINGS A total of 426 respondents (UK: 332; Spain: 94) and 1494 answers were analysed. Multivariate analysis identified that requests for support were 87% less likely in Spain; that antimicrobial resistance and clinical deterioration were associated with both increased request for support (odds ratio (OR) 7.66 and OR 4.26, respectively) and MOAC (OR 2.08 and OR 2.06, respectively). A discordant clinical course was associated with 82% lower odds for MOAC. Out-of-hours results, seniority and specialty did not have an effect. CONCLUSION Antimicrobial choice is influenced by each country's type of practice, clinical course and susceptibility results. Antimicrobial resistance was associated with increased optimal treatment, suggesting RAST may be less useful for step-down decisions in settings with low baseline resistance rates.
Collapse
Affiliation(s)
- V Anton-Vazquez
- Institute of Infection and Immunity, St. George's University of London, London, UK.
| | - C Suarez
- Institute of Infection and Immunity, St. George's University of London, London, UK
| | - S Krishna
- Institute of Infection and Immunity, St. George's University of London, London, UK
| | - T Planche
- Institute of Infection and Immunity, St. George's University of London, London, UK; Department of Medical Microbiology, Southwest London Pathology, St. George's Hospital, London, UK; Infection Care Group, St George's University Hospitals NHS Foundation Trust, London, UK
| |
Collapse
|
7
|
Youngs J, Planche T, Carrington D. Reply to: Concerns regarding the validity of the conclusion in a recently published paper on Roche Liat implementation. J Hosp Infect 2019; 102:356-357. [PMID: 30880266 DOI: 10.1016/j.jhin.2019.03.003] [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] [Received: 03/05/2019] [Accepted: 03/06/2019] [Indexed: 10/27/2022]
Affiliation(s)
- J Youngs
- Infection Care Group, St George's University Hospitals NHS Foundation Trust, London, UK.
| | - T Planche
- Infection Care Group, St George's University Hospitals NHS Foundation Trust, London, UK; Institute of Infection, St George's University of London, London, UK
| | - D Carrington
- Infection Care Group, St George's University Hospitals NHS Foundation Trust, London, UK
| |
Collapse
|
8
|
Youngs J, Iqbal Y, Glass S, Riley P, Pope C, Planche T, Carrington D. Implementation of the cobas Liat influenza point-of-care test into an emergency department during a high-incidence season: a retrospective evaluation following real-world implementation. J Hosp Infect 2018; 101:285-288. [PMID: 30562558 PMCID: PMC7124296 DOI: 10.1016/j.jhin.2018.12.008] [Citation(s) in RCA: 12] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 12/11/2018] [Indexed: 01/05/2023]
Abstract
The cobas Liat influenza A/B and respiratory syncytial virus (RSV) assay (Liat) was used in the adult emergency department of a large London hospital from 21st January 2018 to 14th April 2018. Influenza was detected in 308 of 1027 (30%) samples tested; influenza A in 157 (15.3%), influenza B in 149 (14.5%) and RSV in 28 (2.7%). When compared against Fast Track Diagnostics Respiratory Pathogens 21 multiplex polymerase chain reaction and Cepheid Xpert Xpress Flu/RSV assay, Liat performance for the detection of influenza A or B was: sensitivity 85% [95% confidence interval (CI) 76–92)], specificity 98% (95% CI 97–99), negative predictive value 94% (95% CI 92–96) and positive predictive value 95% (95% CI 91–97).
Collapse
Affiliation(s)
- J Youngs
- Infection Care Group, St George's University Hospitals NHS Foundation Trust, London, UK.
| | - Y Iqbal
- Department of Emergency Medicine, St George's University Hospitals NHS Foundation Trust, London, UK
| | - S Glass
- Department of Microbiology, East Kent Hospitals University NHS Foundation Trust, Ashford, UK
| | - P Riley
- Infection Care Group, St George's University Hospitals NHS Foundation Trust, London, UK
| | - C Pope
- Infection Care Group, St George's University Hospitals NHS Foundation Trust, London, UK; Institute of Infection, St George's University of London, London, UK
| | - T Planche
- Infection Care Group, St George's University Hospitals NHS Foundation Trust, London, UK; Institute of Infection, St George's University of London, London, UK
| | - D Carrington
- Infection Care Group, St George's University Hospitals NHS Foundation Trust, London, UK
| |
Collapse
|
9
|
Youngs J, Marshall B, Farragher M, Whitney L, Glass S, Pope C, Planche T, Riley P, Carrington D. Implementation of influenza point-of-care testing and patient cohorting during a high-incidence season: a retrospective analysis of impact on infection prevention and control and clinical outcomes. J Hosp Infect 2018; 101:276-284. [PMID: 30471317 DOI: 10.1016/j.jhin.2018.11.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 11/12/2018] [Indexed: 12/31/2022]
Abstract
BACKGROUND During high-incidence influenza seasons, a robust infection prevention and control policy is imperative to reduce nosocomial transmission of influenza. AIM To assess the impact of influenza point-of-care testing (POCT) in an emergency department (ED) and patient cohorting on an influenza ward on infection prevention and control and clinical outcomes. METHODS Influenza POCT was operational in the study ED from 21st January 2018 and patient cohorting was operational on an influenza ward from 25th January 2018. A retrospective 'before-after' analysis was performed with pre-intervention defined as 1st November 2017 to 20th January 2018 and post-intervention defined as 21st January 2018 to 30th April 2018. The primary outcome was the rate of hospital-acquired influenza. Secondary outcomes included antiviral prescription and length of stay. The length of time that inpatients remained influenza-positive was estimated by polymerase chain reaction (PCR). FINDINGS There were 654 inpatients with confirmed influenza during the 2017/18 influenza season: 223 pre- and 431 post-intervention. Post-intervention, there were fewer cases of hospital-acquired influenza per day (0.66 vs 0.95, P < 0.0001), median length of stay was shorter (5.5 vs 7.5 days, P = 0.005) and antiviral prescription was more frequent (80% vs 64.1%, P < 0.0001). Cohorting released 779 single rooms for use elsewhere in the trust. The fixed probability of being PCR-negative by the next day (P) was 0.14 [95% confidence interval (CI) 0.12-0.16] for immunocompetent patients. This implies that half of immunocompetent patients are PCR-negative by five days post-diagnosis (95% CI 5-6). CONCLUSION Influenza POCT in an ED and patient cohorting on an influenza ward were associated with reduced nosocomial transmission of influenza and improved patient flow. A policy of retesting immunocompetent patients five days post-diagnosis could allow half of these patients to come out of respiratory isolation earlier.
Collapse
Affiliation(s)
- J Youngs
- Infection Care Group, St George's University Hospitals NHS Foundation Trust, London, UK.
| | - B Marshall
- Analytical Services, Ministry of Justice, London, UK
| | - M Farragher
- Infection Prevention and Control Team, St George's University Hospitals NHS Foundation Trust, London, UK
| | - L Whitney
- Pharmacy Department, St George's University Hospitals NHS Foundation Trust, London, UK
| | - S Glass
- Department of Microbiology, East Kent Hospitals University NHS Foundation Trust, Ashford, UK
| | - C Pope
- Infection Care Group, St George's University Hospitals NHS Foundation Trust, London, UK; Institute of Infection and Immunity, St George's University of London, London, UK
| | - T Planche
- Infection Care Group, St George's University Hospitals NHS Foundation Trust, London, UK; Institute of Infection and Immunity, St George's University of London, London, UK
| | - P Riley
- Infection Care Group, St George's University Hospitals NHS Foundation Trust, London, UK; Institute of Infection and Immunity, St George's University of London, London, UK
| | - D Carrington
- Infection Care Group, St George's University Hospitals NHS Foundation Trust, London, UK; Institute of Infection and Immunity, St George's University of London, London, UK
| |
Collapse
|
10
|
Oakeshott P, Kerry-Barnard S, Fleming C, Phillips R, Drennan VM, Adams EJ, Majewska W, Harding-Esch EM, Cousins EC, Planche T, Green A, Bartholomew RI, Sadiq ST, Reid F. 'Test n Treat' (TnT): a cluster randomized feasibility trial of on-site rapid Chlamydia trachomatis tests and treatment in ethnically diverse, sexually active teenagers attending technical colleges. Clin Microbiol Infect 2018; 25:865-871. [PMID: 30391581 DOI: 10.1016/j.cmi.2018.10.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 10/24/2018] [Accepted: 10/25/2018] [Indexed: 10/28/2022]
Abstract
OBJECTIVES We conducted a cluster-randomized feasibility trial of 90-minute Chlamydia trachomatis tests and same day on-site treatment ('Test n Treat/TnT') in six technical colleges in London, England, to assess TnT uptake rates; follow-up rates; prevalence of C. trachomatis at baseline and 7 months; time to treatment; acceptability of TnT. METHODS Participants completed questionnaires and provided genitourinary samples at baseline and 7 months. Participants were informed that baseline samples would not be tested for 7 months and were advised to get screened independently. Colleges were randomly allocated 1:1 to intervention (TnT) or control (no TnT). One month and 4 months post recruitment, participants at intervention colleges were texted invitations for on-site free C. trachomatis tests. A purposive sample of students who did/did not attend for screening were interviewed (n = 26). RESULTS Five hundred and nine sexually active students were recruited: median age 17.9 years, 47% male, 50% black ethnicity, 55% reporting two or more sexual partners in the previous year. TnT uptake was 13% (33/259; 95% CI 8.9-17.4%) at 1 month and 10% (26/259; 6.7-14.4%) at 4 months with overall C. trachomatis positivity 5.1% (3/59; 1.1-14.2%). Follow-up at 7 months was 62% (317/509) for questionnaires and 52% (264/509) for samples. C. trachomatis prevalence was 6.2% (31/503) at baseline and 6.1% (16/264) at 7 months. Median time from test to treatment was 15 h. Interviews suggested low test uptake was associated with not feeling at risk, perceptions of stigma, and little knowledge of sexually transmitted infections (STIs). CONCLUSIONS Despite high C. trachomatis rates at baseline and follow-up, uptake of testing was low. Like many countries, England urgently needs better sex education, including making STI testing routine/normal. Trial registration ISRCTN58038795.
Collapse
Affiliation(s)
- P Oakeshott
- Population Health Research Institute, St George's, University of London, London UK.
| | - S Kerry-Barnard
- Population Health Research Institute, St George's, University of London, London UK
| | - C Fleming
- Population Health Research Institute, St George's, University of London, London UK
| | - R Phillips
- School of Population Health and Environmental Sciences, King's College London, London, UK
| | - V M Drennan
- Centre for Health & Social Care Research, Kingston University & St George's, University of London, London, UK
| | - E J Adams
- Aquarius Population Health Limited, London, UK
| | | | - E M Harding-Esch
- Institute for Infection and Immunity, St George's, University of London, London, UK; Public Health England, London, UK
| | - E C Cousins
- Institute for Infection and Immunity, St George's, University of London, London, UK
| | - T Planche
- Institute for Infection and Immunity, St George's, University of London, London, UK
| | - A Green
- Population Health Research Institute, St George's, University of London, London UK
| | - R I Bartholomew
- Population Health Research Institute, St George's, University of London, London UK; Institute for Infection and Immunity, St George's, University of London, London, UK
| | - S T Sadiq
- Institute for Infection and Immunity, St George's, University of London, London, UK
| | - F Reid
- School of Population Health and Environmental Sciences, King's College London, London, UK
| |
Collapse
|
11
|
Harding-Esch EM, Fuller SS, Chow SLC, Nori AV, Harrison MA, Parker M, Piepenburg O, Forrest MS, Brooks DG, Patel R, Hay PE, Fearnley N, Pond MJ, Dunbar JK, Butcher PD, Planche T, Lowndes CM, Sadiq ST. Diagnostic accuracy of a prototype rapid chlamydia and gonorrhoea recombinase polymerase amplification assay: a multicentre cross-sectional preclinical evaluation. Clin Microbiol Infect 2018; 25:380.e1-380.e7. [PMID: 29906594 PMCID: PMC6420679 DOI: 10.1016/j.cmi.2018.06.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [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: 03/14/2018] [Revised: 05/31/2018] [Accepted: 06/01/2018] [Indexed: 11/27/2022]
Abstract
Objectives Rapid and accurate sexually transmitted infection diagnosis can reduce onward transmission and improve treatment efficacy. We evaluated the accuracy of a 15-minute run-time recombinase polymerase amplification–based prototype point-of-care test (TwistDx) for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG). Methods Prospective, multicentre study of symptomatic and asymptomatic patients attending three English sexual health clinics. Research samples provided were additional self-collected vulvovaginal swab (SCVS) (female participants) and first-catch urine (FCU) aliquot (female and male participants). Samples were processed blind to the comparator (routine clinic CT/NG nucleic acid amplification test (NAAT)) results. Discrepancies were resolved using Cepheid CT/NG GeneXpert. Results Both recombinase polymerase amplification and routine clinic NAAT results were available for 392 male and 395 female participants. CT positivity was 8.9% (35/392) (male FCU), 7.3% (29/395) (female FCU) and 7.1% (28/395) (SCVS). Corresponding NG positivity was 3.1% (12/392), 0.8% (3/395) and 0.8% (3/395). Specificity and positive predictive values were 100% for all sample types and both organisms, except male CT FCU (99.7% specificity (95% confidence interval (CI) 98.4–100.0; 356/357), 97.1% positive predictive value (95% CI 84.7–99.9; 33/34)). For CT, sensitivity was ≥94.3% for FCU and SCVS. CT sensitivity for female FCU was higher (100%; 95% CI, 88.1–100; 29/29) than for SCVS (96.4%; 95% CI, 81.7–99.9; 27/28). NG sensitivity and negative predictive values were 100% in FCU (male and female). Conclusions This prototype test has excellent performance characteristics, comparable to currently used NAATs, and fulfils several World Health Organization ASSURED criteria. Its rapidity without loss of performance suggests that once further developed and commercialized, this test could positively affect clinical practice and public health.
Collapse
Affiliation(s)
- E M Harding-Esch
- Applied Diagnostic Research & Evaluation Unit (ADREU), Institute for Infection & Immunity, St George's University of London, London, UK; HIV/STI Department, National Infection Service, Public Health England, London, UK
| | - S S Fuller
- Applied Diagnostic Research & Evaluation Unit (ADREU), Institute for Infection & Immunity, St George's University of London, London, UK; HIV/STI Department, National Infection Service, Public Health England, London, UK
| | - S-L C Chow
- Applied Diagnostic Research & Evaluation Unit (ADREU), Institute for Infection & Immunity, St George's University of London, London, UK
| | - A V Nori
- Applied Diagnostic Research & Evaluation Unit (ADREU), Institute for Infection & Immunity, St George's University of London, London, UK; HIV/STI Department, National Infection Service, Public Health England, London, UK; St George's University Hospitals NHS Foundation Trust, London, UK
| | - M A Harrison
- Applied Diagnostic Research & Evaluation Unit (ADREU), Institute for Infection & Immunity, St George's University of London, London, UK
| | | | | | | | | | - R Patel
- Department of Sexual Health, University of Southampton, Southampton, UK
| | - P E Hay
- St George's University Hospitals NHS Foundation Trust, London, UK
| | - N Fearnley
- Bradford Teaching Hospitals NHS Foundation Trust, Bradford, UK
| | - M J Pond
- Applied Diagnostic Research & Evaluation Unit (ADREU), Institute for Infection & Immunity, St George's University of London, London, UK
| | - J K Dunbar
- HIV/STI Department, National Infection Service, Public Health England, London, UK
| | - P D Butcher
- Applied Diagnostic Research & Evaluation Unit (ADREU), Institute for Infection & Immunity, St George's University of London, London, UK
| | - T Planche
- Applied Diagnostic Research & Evaluation Unit (ADREU), Institute for Infection & Immunity, St George's University of London, London, UK; St George's University Hospitals NHS Foundation Trust, London, UK
| | - C M Lowndes
- Applied Diagnostic Research & Evaluation Unit (ADREU), Institute for Infection & Immunity, St George's University of London, London, UK; HIV/STI Department, National Infection Service, Public Health England, London, UK
| | - S T Sadiq
- Applied Diagnostic Research & Evaluation Unit (ADREU), Institute for Infection & Immunity, St George's University of London, London, UK; HIV/STI Department, National Infection Service, Public Health England, London, UK; St George's University Hospitals NHS Foundation Trust, London, UK.
| |
Collapse
|
12
|
Jain A, Pope C, Wilks M, Planche T. Identification of Clostridium difficile: evaluation of genotypic, phenotypic and proteomic methods. Br J Biomed Sci 2018; 70:128-9. [DOI: 10.1080/09674845.2013.11978277] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- A. Jain
- Department of Medical Microbiology, Barts Health NHS Trust, London, UK
| | - C. Pope
- Department of Medical Microbiology, Barts Health NHS Trust, London, UK
| | - M. Wilks
- MedLab Pathology, Unit 3, Sandyford Business Centre, Sandyford Business Park, Dublin18
| | - T. Planche
- Department of Medical Microbiology, Barts Health NHS Trust, London, UK
| |
Collapse
|
13
|
Crobach MJT, Planche T, Eckert C, Barbut F, Terveer EM, Dekkers OM, Wilcox MH, Kuijper EJ. European Society of Clinical Microbiology and Infectious Diseases: update of the diagnostic guidance document for Clostridium difficile infection. Clin Microbiol Infect 2016; 22 Suppl 4:S63-81. [PMID: 27460910 DOI: 10.1016/j.cmi.2016.03.010] [Citation(s) in RCA: 350] [Impact Index Per Article: 43.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 03/02/2016] [Accepted: 03/10/2016] [Indexed: 12/14/2022]
Abstract
In 2009 the first European Society of Clinical Microbiology and Infectious Diseases (ESCMID) guideline for diagnosing Clostridium difficile infection (CDI) was launched. Since then newer tests for diagnosing CDI have become available, especially nucleic acid amplification tests. The main objectives of this update of the guidance document are to summarize the currently available evidence concerning laboratory diagnosis of CDI and to formulate and revise recommendations to optimize CDI testing. This update is essential to improve the diagnosis of CDI and to improve uniformity in CDI diagnosis for surveillance purposes among Europe. An electronic search for literature concerning the laboratory diagnosis of CDI was performed. Studies evaluating a commercial laboratory test compared to a reference test were also included in a meta-analysis. The commercial tests that were evaluated included enzyme immunoassays (EIAs) detecting glutamate dehydrogenase, EIAs detecting toxins A and B and nucleic acid amplification tests. Recommendations were formulated by an executive committee, and the strength of recommendations and quality of evidence were graded using the Grades of Recommendation Assessment, Development and Evaluation (GRADE) system. No single commercial test can be used as a stand-alone test for diagnosing CDI as a result of inadequate positive predictive values at low CDI prevalence. Therefore, the use of a two-step algorithm is recommended. Samples without free toxin detected by toxins A and B EIA but with positive glutamate dehydrogenase EIA, nucleic acid amplification test or toxigenic culture results need clinical evaluation to discern CDI from asymptomatic carriage.
Collapse
Affiliation(s)
- M J T Crobach
- Department of Medical Microbiology, Centre for Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - T Planche
- Department of Medical Microbiology, St. George's Hospital, London, UK
| | - C Eckert
- National Reference Laboratory for Clostridium difficile, Paris, France
| | - F Barbut
- National Reference Laboratory for Clostridium difficile, Paris, France
| | - E M Terveer
- Department of Medical Microbiology, Centre for Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - O M Dekkers
- Departments of Clinical Epidemiology and Internal Medicine, Leiden University Medical Center, Leiden, The Netherlands; Department of Clinical Epidemiology, Aarhus University, Aarhus, Denmark
| | - M H Wilcox
- Department of Microbiology, Leeds Teaching Hospitals & University of Leeds, Leeds, UK
| | - E J Kuijper
- Department of Medical Microbiology, Centre for Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands.
| |
Collapse
|
14
|
Goldenberg SD, Brown S, Edwards L, Gnanarajah D, Howard P, Jenkins D, Nayar D, Pasztor M, Oliver S, Planche T, Sandoe JAT, Wade P, Whitney L. The impact of the introduction of fidaxomicin on the management of Clostridium difficile infection in seven NHS secondary care hospitals in England: a series of local service evaluations. Eur J Clin Microbiol Infect Dis 2015; 35:251-9. [PMID: 26661400 PMCID: PMC4724367 DOI: 10.1007/s10096-015-2538-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 11/09/2015] [Indexed: 11/24/2022]
Abstract
Clostridium difficile infection (CDI) is associated with high mortality. Reducing incidence is a priority for patients, clinicians, the National Health Service (NHS) and Public Health England alike. In June 2012, fidaxomicin (FDX) was launched for the treatment of adults with CDI. The objective of this evaluation was to collect robust real-world data to understand the effectiveness of FDX in routine practice. In seven hospitals introducing FDX between July 2012 and July 2013, data were collected retrospectively from medical records on CDI episodes occurring 12 months before/after the introduction of FDX. All hospitalised patients aged ≥18 years with primary CDI (diarrhoea with presence of toxin A/B without a previous CDI in the previous 3 months) were included. Recurrence was defined as in-patient diarrhoea re-emergence requiring treatment any time within 3 months after the first episode. Each hospital had a different protocol for the use of FDX. In hospitals A and B, where FDX was used first line for all primary and recurrent episodes, the recurrence rate reduced from 10.6 % to 3.1 % and from 16.3 % to 3.1 %, with a significant difference in 28-day mortality from 18.2 % to 3.1 % (p < 0.05) and 17.3 % to 6.3 % (p < 0.05) for hospitals A and B, respectively. In hospitals using FDX in selected patients only, the changes in recurrence rates and mortality were less marked. The pattern of adoption of FDX appears to affect its impact on CDI outcome, with maximum reduction in recurrence and all-cause mortality where it is used as first-line treatment.
Collapse
Affiliation(s)
- S D Goldenberg
- Centre for Clinical Infection and Diagnostics Research, King's College, London and Guy's and St Thomas' NHS Foundation Trust, 5th Floor, North Wing, St Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, UK.
| | - S Brown
- Department of Microbiology, County Durham and Darlington NHS Foundation Trust, Durham, UK
| | - L Edwards
- University Hospitals of Leicester NHS Trust, Leicester, UK
| | | | - P Howard
- Department of Microbiology, University of Leeds and Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | - D Jenkins
- University Hospitals of Leicester NHS Trust, Leicester, UK
| | - D Nayar
- Department of Microbiology, County Durham and Darlington NHS Foundation Trust, Durham, UK
| | - M Pasztor
- University Hospitals of Morecambe Bay NHS Foundation Trust, Lancaster, UK
| | | | - T Planche
- St George's Healthcare NHS Trust, London, UK
| | - J A T Sandoe
- Department of Microbiology, University of Leeds and Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | - P Wade
- Centre for Clinical Infection and Diagnostics Research, King's College, London and Guy's and St Thomas' NHS Foundation Trust, 5th Floor, North Wing, St Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, UK
| | - L Whitney
- St George's Healthcare NHS Trust, London, UK
| |
Collapse
|
15
|
Pond MJ, Hall C, Cole M, Laing KG, Miari V, Jagatia H, Harding-Esch E, Monahan I, Planche T, Hinds J, Ison C, Chisholm S, Butcher PD, Sadiq ST. 005.2 Diagnostic and clinical implications of genotypic fluoroquinolone susceptibility detection for neisseria gonorrhoeae. Br J Vener Dis 2015. [DOI: 10.1136/sextrans-2015-052270.104] [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]
|
16
|
Miari VF, Pond MJ, Laing K, Jagatia H, Monahan I, Planche T, Butcher PD, Sadiq ST. P5.098 Clinical Prediction of Fluoroquinolone Susceptibility, Directly from Residual Routine NAAT Gonococcal-Positive Samples Using a gyrASNP Detection Assay. Br J Vener Dis 2013. [DOI: 10.1136/sextrans-2013-051184.1142] [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]
|
17
|
Jain A, Planche T, Ison C. P2.080 Diversity of Neisseria GonorrhoeaeAntimicrobial Susceptibility Testing Methodologies in the United Kingdom. Br J Vener Dis 2013. [DOI: 10.1136/sextrans-2013-051184.0344] [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]
|
18
|
Knight GM, Budd EL, Whitney L, Thornley A, Al-Ghusein H, Planche T, Lindsay JA. Shift in dominant hospital-associated methicillin-resistant Staphylococcus aureus (HA-MRSA) clones over time. J Antimicrob Chemother 2012; 67:2514-22. [DOI: 10.1093/jac/dks245] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
|
19
|
Kremsner PG, Taylor T, Issifou S, Kombila M, Chimalizeni Y, Kawaza K, Bouyou Akotet MK, Duscha M, Mordmuller B, Kosters K, Humberg A, Scott Miller R, Weina P, Duparc S, Mohrle J, Kun JFJ, Planche T, Teja-Isavadharm P, Simpson JA, Kohler C, Krishna S. A Simplified Intravenous Artesunate Regimen for Severe Malaria-Reply. J Infect Dis 2012. [DOI: 10.1093/infdis/jis391] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
20
|
Chan SY, King R, Borgulya G, Pakianathan M, Sadiq ST, Hay P, Planche T. P183 How likely is environmental contamination of Chlamydia trachomatisDNA to lead to false positive results in patients attending our clinic? Br J Vener Dis 2012. [DOI: 10.1136/sextrans-2012-050601c.183] [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]
|
21
|
Francis ST, Rawal S, Roberts H, Riley P, Planche T, Kennea NL. Detection of meticillin-resistant staphylococcus aureus (MRSA) colonization in newborn infants using real-time polymerase chain reaction (PCR). Acta Paediatr 2010; 99:1691-4. [PMID: 20528798 DOI: 10.1111/j.1651-2227.2010.01899.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Meticillin-resistant staphylococcus aureus (MRSA) colonization on neonatal units is a common and important clinical problem. Effectiveness of polymerase chain reaction (PCR) for detecting MRSA nasal colonization of infants was evaluated and compared to culture-based methods. The effect of skin decolonization in affected infants was studied. METHODS Paired nasal swabs were collected from infants in our neonatal unit over a 12-month period (September 2007-2008). Colonization with MRSA was determined with a commercially available PCR method and compared to culture. RESULTS A total of 696 paired nasal swabs were taken. Three infants were colonized at the beginning and were included. There were positive PCRs in 12 infants. Five infants cultured MRSA from a nasal swab at the same time. No infants were culture-positive when PCR was negative (sensitivity 100%, specificity 99% compared to culture). PCR results were available within 24 h. Five infants were PCR+ and isolated meticillin-sensitive Staphylococcus aureus. This organism gave a false-positive PCR result. Two infants transferred in on broad-spectrum antibiotics were PCR+ and negative by culture. Decolonization led to negative nasal PCR and culture in 4/5 infants to discharge. CONCLUSIONS PCR methods are sensitive and specific for detection of MRSA colonization in newborn infants of all gestations with results 1-2 days before culture.
Collapse
Affiliation(s)
- S T Francis
- Regional Neonatal Unit, St George's Hospital, London, UK
| | | | | | | | | | | |
Collapse
|
22
|
Jarvis JN, Planche T, Bicanic T, Dzeing-Ella A, Kombila M, Issifou S, Borrmann S, Kremsner PG, Krishna S. Lactic Acidosis in Gabonese Children with Severe Malaria Is Unrelated to Dehydration. Clin Infect Dis 2006; 42:1719-25. [PMID: 16705578 DOI: 10.1086/504329] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2005] [Accepted: 02/18/2006] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND Hyperlactatemia is an important and common complication of severe malaria. We investigated changes in fluid compartment volumes in patients with severe malaria and control patients with the use of bioimpedence analysis. METHODS We estimated extracellular water and total body water volumes in a total of 180 children: 56 with severe malaria, 94 with moderate malaria, 24 with respiratory tract infection, and 6 with severe diarrhea. RESULTS There was a mean (+/-SD) decrease in total body water volume of 17+/-24 mL/kg (or 3% of total body water volume) in patients with severe malaria. This compares with a mean (+/-SD) decrease in total body water volume of 33+/-28 mL/kg (or 6% of total body water volume) in patients with severe diarrhea. There was no increase in extracellular water volume in patients with severe malaria, suggesting no significant intravascular volume depletion in patients with severe malaria. There was no relationship between lactatemia and any changes in fluid compartment volumes. CONCLUSIONS The changes in fluid volumes that were observed are unlikely to be of physiological significance in the pathophysiology of severe malaria.
Collapse
Affiliation(s)
- J N Jarvis
- Department of Cellular and Molecular Medicine, Infectious Diseases, St. George's Hospital Medical School, London, United Kingdom
| | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Planche T. Molecular approaches to malaria. Clin Mol Pathol 2006. [DOI: 10.1136/jcp.2005.035782] [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]
|
24
|
Abstract
Metabolic complications of severe malaria are some of the most important and potentially treatable manifestations of this deadly disease. The commonest metabolic complications (lactic acidosis and hypoglycaemia) arise from increased host anaerobic metabolism probably due to a mismatch between tissue oxygen supply and requirement. Optimising treatments for these complications should be guided by detailed understanding of their underlying pathophysiology, and may help to reduce the intolerably high case fatality rate of severe malaria.
Collapse
Affiliation(s)
- T Planche
- Division of Cellular and Molecular Medicine, Centre for Infection, St. George's University of London, London SW17 0RE, UK.
| | | |
Collapse
|
25
|
Abstract
Metabolic complications of malaria are increasingly recognized as contributing to severe and fatal malaria. Disorders of carbohydrate metabolism, including hypoglycaemia and lactic acidosis, are amongst the most important markers of disease severity both in adults and children infected with Plasmodium falciparum. Amino acid and lipid metabolism are also altered by malaria. In adults, hypoglycaemia is associated with increased glucose turnover and quinine-induced hyperinsulinaemia, which causes increased peripheral uptake of glucose. Hypoglycaemia in children results from a combination of decreased production and/or increased peripheral uptake of glucose, due to increased anaerobic glycolysis. Patients with severe malaria should be monitored frequently for hypoglycaemia and treated rapidly with intravenous glucose if hypoglycaemia is detected. The most common aetiology of hyperlactataemia in severe malaria is probably increased anaerobic glucose metabolism, caused by generalized microvascular sequestration of parasitized erythrocytes that reduces blood flow to tissues. Several potential treatments for hyperlactataemia have been investigated, but their effect on mortality from severe malaria has not been determined.
Collapse
Affiliation(s)
- T Planche
- Division of Cellular and Molecular Medicine, Centre for Infection, St. George's University of London, Cranmer Terrace, London SW17 ORE, UK.
| | | | | | | | | |
Collapse
|
26
|
Planche T, Dzeing A, Emmerson AC, Onanga M, Kremsner PG, Engel K, Kombila M, Ngou-Milama E, Krishna S. Plasma glutamine and glutamate concentrations in Gabonese children with Plasmodium falciparum infection. QJM 2002; 95:89-97. [PMID: 11861956 DOI: 10.1093/qjmed/95.2.89] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Low plasma glutamine levels in critical illness, neonates and burns patients are associated with poor outcome and increased risk of intercurrent infection. AIM To investigate the relationship between plasma glutamine/glutamate levels and severity/outcome of malaria. DESIGN Two-hospital prospective study, with both febrile and healthy controls. METHODS We measured plasma glutamine and glutamate concentrations in 239 Gabonese patients: 145 children with malaria (86 with severe, 36 with moderate and 23 with uncomplicated disease), 42 healthy children, 44 febrile controls and eight healthy adults, and related findings to conventional markers of disease severity such as plasma lactate. RESULTS Median (IQR) plasma glutamine was lower in uncomplicated falciparum malaria and in moderate malaria than in healthy controls: 353 (287-474) and 379 (293-448) vs. 485 (428-531) micromol/l, respectively; p<0.01 for both malaria groups vs. controls. In contrast, plasma glutamine was within the normal range in those with severe malaria and in febrile control children: 431 (342-525) and 472 (338-547) micromol/l, respectively. Furthermore, plasma glutamine was significantly higher in the children who died with malaria than in survivors: 514 (374-813) (n=12) vs. 399 (316-475) micromol/l (n=133), respectively; p=0.001. There were no significant differences in plasma glutamate concentrations between any of the study groups. DISCUSSION In severe malaria, there was a positive correlation between plasma glutamine and lactate levels (p=0.009, r=0.281). This correlation may reflect impaired gluconeogenesis. Glutamine supplementation is probably not justified in severe P. falciparum infection.
Collapse
Affiliation(s)
- T Planche
- Department of Infectious Diseases, St George's Hospital Medical School, Cranmer Terrace, London, UK
| | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Planche T, Krishna S, Kombila M, Engel K, Faucher JF, Ngou-Milama E, Kremsner PG. Comparison of methods for the rapid laboratory assessment of children with malaria. Am J Trop Med Hyg 2001; 65:599-602. [PMID: 11716121 DOI: 10.4269/ajtmh.2001.65.599] [Citation(s) in RCA: 169] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Rapid diagnosis and accurate quantification of Plasmodium falciparum parasitemia are important for the management of malaria. The assessment of disease severity also depends on evaluation of metabolic indexes such as blood glucose and lactate concentrations. Here we describe an accurate and rapid alternative to conventional thick film examination (Lambaréné method). We also assess near-patient methods for measuring blood glucose (OneTouch) and lactate (Accusport). The accuracy of the Lambaréné method is similar to that of thin films. Results from the OneTouch glucose meter also are in good agreement with a YSI 2300 reference meter. Overall, the Accusport lactate meter agrees poorly with the YSI 2300 reference meter. However, the sensitivity and specificity to detect hyperlactatemia (blood lactate > or = 5 mmol/L) are 0.94 and 0.98, respectively.
Collapse
Affiliation(s)
- T Planche
- Department of Infectious Diseases, St. George's Hospital Medical School, London, United Kingdom
| | | | | | | | | | | | | |
Collapse
|
28
|
Krishna S, Nagaraja NV, Planche T, Agbenyega T, Bedo-Addo G, Ansong D, Owusu-Ofori A, Shroads AL, Henderson G, Hutson A, Derendorf H, Stacpoole PW. Population pharmacokinetics of intramuscular quinine in children with severe malaria. Antimicrob Agents Chemother 2001; 45:1803-9. [PMID: 11353629 PMCID: PMC90549 DOI: 10.1128/aac.45.6.1803-1809.2001] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2000] [Accepted: 03/13/2001] [Indexed: 11/20/2022] Open
Abstract
We present the first population pharmacokinetic analysis of quinine in patients with Plasmodium falciparum malaria. Ghanaian children (n = 120; aged 12 months to 10 years) with severe malaria received an intramuscular loading dose of quinine dihydrochloride (20 mg/kg of body weight). A two-compartment model with first-order absorption and elimination gave post hoc estimates for pharmacokinetic parameters that were consistent with those derived from non-population pharmacokinetic studies (clearance [CL] = 0.05 liter/h/kg of body weight; volume of distribution in the central compartment [V(1)] = 0.65 liter/kg; volume of distribution at steady state = 1.41 liter/kg; half-life at beta phase = 19.9 h). There were no covariates (including age, gender, acidemia, anemia, coma, parasitemia, or anticonvulsant use) that explained interpatient variability in weight-normalized CL and V(1). Intramuscular quinine was associated with minor, local toxicity in some patients (13 of 108; 12%), and 11 patients (10%) experienced one or more episodes of postadmission hypoglycemia. A loading dose of intramuscular quinine results in predictable population pharmacokinetic profiles in children with severe malaria and may be preferred to the intravenous route of administration in some circumstances.
Collapse
Affiliation(s)
- S Krishna
- Department of Infectious Diseases, St. George's Hospital Medical School, Cranmer Terrace, London SW17 ORE, United Kingdom.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Krishna S, Planche T, Agbenyega T, Woodrow C, Agranoff D, Bedu-Addo G, Owusu-Ofori AK, Appiah JA, Ramanathan S, Mansor SM, Navaratnam V. Bioavailability and preliminary clinical efficacy of intrarectal artesunate in Ghanaian children with moderate malaria. Antimicrob Agents Chemother 2001; 45:509-16. [PMID: 11158748 PMCID: PMC90320 DOI: 10.1128/aac.45.2.509-516.2001] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We report the first detailed pharmacokinetic assessment of intrarectal (i.r.) artesunate (ARS) in African children. Artesunate was given intravenously (i.v.; 2.4 mg/kg of body weight) and i.r. (10 or 20 mg/kg formulated as 50- or 200-mg suppositories [Rectocaps]) in a crossover study design to 34 Ghanaian children with moderate falciparum malaria. The median relative bioavailability of dihydroartemisinin (DHA), the active antimalarial metabolite of ARS, was higher in the low-dose i.r. group (10 mg/kg) than in the high-dose i.r. group (20 mg/kg) (58 versus 23%; P = 0.018). There was wide interpatient variation in the area under the concentration-time curve after i.r. ARS administration (up to 9-fold in the high-dose group and 20-fold in the low-dose group). i.r. administered ARS was more rapidly absorbed in the low-dose group than the high-dose group (median [range] absorption half-lives, 0.7 h [0.3 to 1.24 h] versus 1.1 h [0.6 to 2.7 h] [P = 0.023]. i.r. administered ARS was eliminated with a median (range) half-life of 0.8 h (0.4 to 2.7 h) (low-dose group and 0.9 h (0.1 to 2.5 h) (high-dose group) (P = 1). The fractional clearances of DHA were 3.9, 2.6, and 1.5 liters/kg/h for the 20-mg/kg, 10-mg/kg and i.v. groups, respectively (P = 0.001 and P = 0.06 for the high-and low-dose i.r. groups compared with the i.v. groups, respectively). The median volumes of distribution for DHA were 1.5 liters kg (20 mg/kg, i.r. group), 1.8 liters/kg (10 mg/kg, i.r. group), and 0.6 liters/kg (i.v. group) (P < 0.05 for both i.r. groups compared with the i.v. group). Parasite clearance kinetics were comparable in all treatment groups. i.r. administered ARS may be a useful alternative to parenterally administered ARS in the management of moderate childhood malaria and should be studied further.
Collapse
Affiliation(s)
- S Krishna
- Department of Infectious Diseases, St. George's Hospital Medical School, London SW17 ORE, United Kingdom
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Cowan G, Planche T, Agbenyega T, Bedu-Addo G, Owusu-Ofori A, Adebe-Appiah J, Agranoff D, Woodrow C, Castell L, Elford B, Krishna S. Plasma glutamine levels and falciparum malaria. Trans R Soc Trop Med Hyg 1999; 93:616-8. [PMID: 10717748 DOI: 10.1016/s0035-9203(99)90070-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Glutamine deficiency is associated with increased rates of sepsis and mortality, which can be prevented by glutamine supplementation. Changes in glutamine concentration were examined in Ghanaian children with acute falciparum malaria and control cases. The mean (SD) plasma glutamine concentration was lower in patients with acute malaria (401 (82) mumol/L, n = 50) than in control patients (623 (67) mumol/L, n = 7; P < 0.001). Plasma glutamine concentrations all rose in convalescence. The mean (SD) increase in plasma glutamine was 202 (123) mumol/L (n = 18; P < 0.001) compared with acute infection. We conclude that acute falciparum malaria is associated with large decreases in plasma glutamine and these falls may increase susceptibility to sepsis and dyserythropoeisis.
Collapse
Affiliation(s)
- G Cowan
- Department of Molecular Parasitology, John Radcliffe Hospital, Oxford, UK
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Dondorp AM, Planche T, de Bel EE, Angus BJ, Chotivanich KT, Silamut K, Romijn JA, Ruangveerayuth R, Hoek FJ, Kager PA, Vreeken J, White NJ. Nitric oxides in plasma, urine, and cerebrospinal fluid in patients with severe falciparum malaria. Am J Trop Med Hyg 1998; 59:497-502. [PMID: 9749651 DOI: 10.4269/ajtmh.1998.59.497] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
It has been suggested that nitric oxide (NO) plays an important role in the pathogenesis of severe falciparum malaria. Since NO has a very short half-life, nitrate and nitrite (NOx) levels, stable metabolites of NO, are used as measures of NO production. We measured plasma NOx levels in 24 adults with severe falciparum malaria on the Thai-Burmese border. After correction for renal function, there was no correlation between plasma NOx levels, or the total amount of NOx excreted in the urine, and disease severity. Plasma NOx levels decreased after the first 48 hr in all patients (P = 0.007), suggesting decreased NO production. The NOx levels in cerebrospinal fluid (CSF) correlated well with plasma NOx levels, but these did not show a correlation with coma depth, and were not significantly different from those in a healthy control group. These findings do not support the hypothesis that excessive NO production contributes to the pathogenesis of severe falciparum malaria. However, local changes in NO production, e.g., in the central nervous system, might not be reflected in the total NOx production or NOx levels in the CSF.
Collapse
Affiliation(s)
- A M Dondorp
- Department of Internal Medicine, Academic Medical Centre, Amsterdam, The Netherlands
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|