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1.
J Eval Clin Pract ; 29(3): 485-494, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-36412040

RESUMEN

RATIONALE: Offering a primary care service that can provide good quality primary care at emergency departments may reduce pressure on usual emergency department (ED) services. AIMS AND OBJECTIVES: To evaluate the acceptability, satisfaction, and potential impacts of a co-located primary care service at an emergency department. METHODS: This is a prospective feasibility study and service evaluation comprising a narrative summary of activity, satisfaction, well-being, and safety, and comparisons of wait times for ED services by patient category ('minor', 'majors', 'paediatric' or 'resus') before and during the service operation. Patients and staff were asked using semistructured interview topic guides about service perception, well-being, representation within 48 h, safety concerns, and/or satisfaction. Wait times for patient categories in usual ED care service were in secondary care electronic records. Pathway changes were captured under primary care electronic records. RESULTS: Approximately 96% of general practitioner streaming and treatment (GPST) patients were seen within 1 h. There was a statistically significant reduction in ED patients with minor injuries or illnesses waiting >4 h for admission or discharge 'breaches' during the 3 months that GPST was operating compared with the previous 3 months (p ≤ 0.005). Wait times for other ED services did not significantly improve. A total of 769 walk-in patients received GPST consultation and 661 (86%) needed no further ED intervention. Fast discharge was a major determinant of patient satisfaction. No staff expressed dissatisfaction, but some suggested possible improvements in eligibility criteria and built environment design features. CONCLUSION: Provision of GPST correlated with shorter waits for discharge from ED. Patient and staff experiences of GPST were positive.


Asunto(s)
Médicos Generales , Humanos , Niño , Estudios Prospectivos , Estudios de Factibilidad , Servicio de Urgencia en Hospital , Calidad de la Atención de Salud , Satisfacción del Paciente
2.
Health Technol Assess ; 25(1): 1-202, 2021 01.
Artículo en Inglés | MEDLINE | ID: mdl-33410736

RESUMEN

BACKGROUND: Sleep disturbance affects around 60% of people living with dementia and can negatively affect their quality of life and that of their carers. Hypnotic Z-drugs (zolpidem, zopiclone and zaleplon) are commonly used to treat insomnia, but their safety and efficacy have not been evaluated for people living with dementia. OBJECTIVES: To estimate the benefits and harms of Z-drugs in people living with dementia with sleep disturbance. DESIGN: A series of observational cohort studies using existing data from (1) primary care linked to hospital admission data and (2) clinical cohort studies of people living with dementia. DATA SOURCES: Primary care study - Clinical Practice Research Datalink linked to Hospital Episode Statistics and Office for National Statistics mortality data. Clinical cohort studies - the Resource Use and Disease Course in Dementia - Nursing Homes (REDIC) study, National Alzheimer's Coordinating Centre (NACC) clinical data set and the Improving Well-being and Health for People with Dementia (WHELD) in nursing homes randomised controlled trial. SETTING: Primary care study - 371 primary care practices in England. Clinical cohort studies - 47 nursing homes in Norway, 34 Alzheimer's disease centres in the USA and 69 care homes in England. PARTICIPANTS: Primary care study - NHS England primary care patients diagnosed with dementia and aged > 55 years, with sleep disturbance or prescribed Z-drugs or low-dose tricyclic antidepressants, followed over 2 years. Clinical cohort studies - people living with dementia consenting to participate, followed over 3 years, 12 years and 9 months, for REDIC, NACC and WHELD, respectively. INTERVENTIONS: The primary exposure was prescription or use of Z-drugs. Secondary exposures included prescription or use of benzodiazepines, low-dose tricyclic antidepressants and antipsychotics. MAIN OUTCOME MEASURES: Falls, fractures, infection, stroke, venous thromboembolism, mortality, cognitive function and quality of life. There were insufficient data to investigate sleep disturbance. RESULTS: The primary care study and combined clinical cohort studies included 6809 and 18,659 people living with dementia, with 3089 and 914 taking Z-drugs, respectively. New Z-drug use was associated with a greater risk of fractures (hazard ratio 1.40, 95% confidence interval 1.01 to 1.94), with risk increasing with greater cumulative dose (p = 0.002). The hazard ratio for Z-drug use and hip fracture was 1.59 (95% confidence interval 1.00 to 2.53) and for mortality was 1.34 (95% confidence interval 1.10 to 1.64). No excess risks of falls, infections, stroke or venous thromboembolism were detected. Z-drug use also did not have an impact on cognition, neuropsychiatric symptoms, disability or quality of life. LIMITATIONS: Primary care study - possible residual confounding because of difficulties in identifying patients with sleep disturbance and by dementia severity. Clinical cohort studies - the small numbers of people living with dementia taking Z-drugs and outcomes not necessarily being measured before Z-drug initiation restricted analyses. CONCLUSIONS: We observed a dose-dependent increase in fracture risk, but no other harms, with Z-drug use in dementia. However, multiple outcomes were examined, increasing the risk of false-positive findings. The mortality association was unlikely to be causal. Further research is needed to confirm the increased fracture risk. Decisions to prescribe Z-drugs may need to consider the risk of fractures, balanced against the impact of improved sleep for people living with dementia and that of their carers. Our findings suggest that when Z-drugs are prescribed, falls prevention strategies may be needed, and that the prescription should be regularly reviewed. FUTURE WORK: More research is needed on safe and effective management strategies for sleep disturbance in people living with dementia. STUDY REGISTRATION: This study is registered as European Union electronic Register of Post-Authorisation Studies (EU PAS) 18006. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 1. See the NIHR Journals Library website for further project information.


WHAT WAS THE PROBLEM?: Poor sleep is common in people living with dementia. It can worsen their own and their carer's quality of life. Sleeping tablets called Z-drugs (zolpidem, zopiclone and zaleplon) are often given to people with dementia. Some studies suggest that Z-drugs may be harmful, but no studies have looked into the effects of Z-drugs for people with dementia. Good sleep is important, but we need to understand if Z-drugs cause harm. WHAT DID WE DO?: Using existing medical records, we compared the quality of life, memory and number of falls, infections, strokes, broken bones and deaths for a group of people living with dementia taking a Z-drug, with those for a group not taking any sleep drug. WHAT DID WE FIND?: Z-drug users were no more likely to suffer falls, infection or stroke, but they were more likely to break a bone. We also found that Z-drug users died earlier, but we could not be sure that this was as a result of taking the Z-drug. Using Z-drugs did not appear to affect quality of life or memory. We talked to carers and health-care practitioners, who told us that decisions about Z-drugs need to balance a range of complicated health and social factors. WHAT DOES THIS MEAN?: We found that people living with dementia who take Z-drugs are more likely to break a bone or to die sooner than similar people with dementia who are not taking Z-drugs. However, we cannot be certain that these problems are caused by Z-drugs, as many other factors can also lead to broken bones and death. Further work is needed to clarify the risk of broken bones, but if sleep problems can be managed in other ways then this may be preferable. Patients and family carers should be involved in decisions about Z-drugs, so that they can balance the possible harms against the benefits.


Asunto(s)
Demencia , Calidad de Vida , Benzodiazepinas , Estudios de Cohortes , Demencia/tratamiento farmacológico , Humanos , Hipnóticos y Sedantes/efectos adversos , Sueño
3.
BMC Health Serv Res ; 20(1): 1010, 2020 Nov 04.
Artículo en Inglés | MEDLINE | ID: mdl-33148232

RESUMEN

BACKGROUND: 'Older People's Shoes' is a training intervention designed for healthcare assistants (HCAs) to improve the relational care of older people in hospital. The intervention formed part of a broader evaluation, in this paper we describe its development from a learning design and methodological perspective. METHODS: Learning theory and an instructional design model were key components of the In-PREP (Input, Process, Review and Evaluation, Product) development methodology used in the design of the 'Older People's Shoes' training intervention to improve the delivery of relational care by front-line hospital staff. An expert panel, current evidence, and pedagogical theory were used to co-design a training programme tailored to a challenging work environment and taking account of trainees' diverse educational experience. Peer review and process evaluation were built into the development model. RESULTS: In-PREP provided a methodological scaffold for producing evidence-based, peer-reviewed, co-designed training. The product, 'Older People's Shoes', involved a one-day Train the Trainers event, followed by delivery of a two-day, face-to-face training programme by the trainers, with accompanying handbooks underpinned by a range of digital resources. Evaluation found the approach met learner needs, was applicable in practice and won approval from trainers. DISCUSSION: In-PREP enables high quality learning content, alignment with learner needs and a product that is relevant, practical and straightforward to implement.


Asunto(s)
Técnicos Medios en Salud , Aprendizaje , Anciano , Anciano de 80 o más Años , Humanos
4.
BMC Med ; 18(1): 351, 2020 11 24.
Artículo en Inglés | MEDLINE | ID: mdl-33228664

RESUMEN

BACKGROUND: Sleep disturbance is common in dementia and often treated with Z-drugs (zopiclone, zaleplon, and zolpidem). While some observational studies suggest that Z-drugs are associated with adverse events such as falls and fracture risks in older people, this has not been studied in dementia. METHODS: We used data from 27,090 patients diagnosed with dementia between January 2000 and March 2016 from the Clinical Practice Research Datalink linked to Hospital Episodes Statistics data in England. We compared adverse events for 3532 patients newly prescribed Z-drugs by time-varying dosage to (1) 1833 non-sedative-users with sleep disturbance; (2) 10,214 non-sedative-users with proximal GP consultation matched on age, sex, and antipsychotic use; and (3) 5172 patients newly prescribed benzodiazepines. We defined higher dose Z-drugs and benzodiazepines as prescriptions equivalent to ≥ 7.5 mg zopiclone or > 5 mg diazepam daily. Cox regression was used to estimate hazard ratios (HRs) for incident fracture, hip fracture, fall, mortality, acute bacterial infection, ischaemic stroke/transient ischaemic attack, and venous thromboembolism over a 2-year follow-up, adjusted for demographic- and health-related covariates. RESULTS: The mean (SD) age of patients was 83 (7.7) years, and 16,802 (62%) were women. Of 3532 patients prescribed Z-drugs, 584 (17%) were initiated at higher doses. For patients prescribed higher dose Z-drugs relative to non-users with sleep disturbance, the HRs (95% confidence interval) for fractures, hip fractures, falls, and ischaemic stroke were 1.67 (1.13-2.46), 1.96 (1.16-3.31), 1.33 (1.06-1.66), and 1.88 (1.14-3.10), respectively. We observed similar associations when compared to non-sedative-users with proximal GP consultation. Minimal or inconsistent excess risks were observed at ≤ 3.75 mg zopiclone or equivalent daily, and for mortality, infection, and venous thromboembolism. We observed no differences in adverse events for Z-drugs compared to benzodiazepines, except lower mortality rates with Z-drugs (HR [95% confidence interval] of 0.73 [0.64-0.83]). CONCLUSIONS: Higher dose Z-drug use in dementia is associated with increased fracture and stroke risks, similar or greater to that for higher dose benzodiazepines. Higher dose Z-drugs should be avoided, if possible, in people living with dementia, and non-pharmacological alternatives preferentially considered. Prescriptions for higher dose Z-drugs in dementia should be regularly reviewed. TRIAL REGISTRATION: ENCePP e-register of studies, EUPAS18006.


Asunto(s)
Acetamidas/efectos adversos , Compuestos de Azabiciclo/efectos adversos , Demencia/tratamiento farmacológico , Piperazinas/efectos adversos , Pirimidinas/efectos adversos , Trastornos del Sueño-Vigilia/tratamiento farmacológico , Zolpidem/efectos adversos , Anciano de 80 o más Años , Estudios de Cohortes , Femenino , Humanos , Masculino
5.
Int J Nurs Stud ; 79: 145-153, 2018 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29272810

RESUMEN

BACKGROUND: Ever-growing demands on care systems have increased reliance on healthcare support workers. In the UK, their training has been variable, but organisation-wide failures in care have prompted questions about how this crucial section of the workforce should be developed. Their training, support and assessment has become a policy priority. OBJECTIVES: This paper examines: healthcare support workers' access to training, support and assessment; perceived gaps in training provision; and barriers and facilitators to implementation of relevant policies in acute care. DESIGN AND SETTINGS: We undertook a qualitative study of staff caring for older inpatients at ward, divisional or organisational-level in three acute National Health Service hospitals in England in 2014. PARTICIPANTS: 58 staff working with older people (30 healthcare support workers and 24 staff managing or working alongside them) and 4 healthcare support worker training leads. METHODS: One-to-one semi-structured interviews included: views and experiences of training and support; translation of training into practice; training, support and assessment policies and difficulties of implementing them. Transcripts were analysed to identify themes. RESULTS: Induction training was valued, but did not fully prepare healthcare support workers for the realities of the ward. Implementation of hospital policies concerning supervision and formal assessment of competencies varied between and within hospitals, and was subject to availability of appropriate staff and competing demands on staff time. Gaps identified in training provision included: caring for people with cognitive impairment; managing the emotions of patients, families and themselves; and having difficult conversations. Access to ongoing training was affected by: lack of time; infrequent provision; attitudes of ward managers to additional support workforce training, and their need to balance this against patients' and other staff members' needs; and the use of e-learning as a default mode of training delivery. CONCLUSIONS: With the current and unprecedented policy focus on training, support and assessment of healthcare support workers, our study suggests improved training would be welcomed by them and their managers. Provision of training, support and assessment could be improved by organisational policy that promotes and protects healthcare support worker training; formalising the provision and availability of on-ward support; and training and IT support provided on a drop-in basis. Challenges in implementation are likely to be faced in all international settings where there is increased reliance on a support workforce. While recent policies in the UK offers scope to overcome some of these challenges there is a risk that some will be exacerbated.


Asunto(s)
Personal de Salud/educación , Hospitales Públicos/organización & administración , Capacitación en Servicio/organización & administración , Enfermedad Aguda , Inglaterra , Humanos , Investigación Cualitativa , Medicina Estatal/organización & administración
6.
Health Technol Assess ; 20(50): 1-250, 2016 07.
Artículo en Inglés | MEDLINE | ID: mdl-27385430

RESUMEN

BACKGROUND: Medication organisation devices (MODs) provide compartments for a patient's medication to be organised into the days of the week and the recommended times the medication should be taken. AIM: To define the optimal trial design for testing the clinical effectiveness and cost-effectiveness of MODs. DESIGN: The feasibility study comprised a systematic review and focus groups to inform a randomised controlled trial (RCT) design. The resulting features were tested on a small scale, using a 2 × 2 factorial design to compare MODs with usual packaging and to compare weekly with monthly supply. The study design was then evaluated. SETTING: Potential participants were identified by medical practices. PARTICIPANTS: Aged over 75 years, prescribed at least three solid oral dosage form medications, unintentionally non-adherent and self-medicating. Participants were excluded if deemed by their health-care team to be unsuitable. INTERVENTIONS: One of three MODs widely used in routine clinical practice supplied either weekly or monthly. OBJECTIVES: To identify the most effective method of participant recruitment, to estimate the prevalence of intentional and unintentional non-adherence in an older population, to provide a point estimate of the effect size of MODs relative to usual care and to determine the feasibility and acceptability of trial participation. METHODS: The systematic review included MOD studies of any design reporting medication adherence, health and social outcomes, resource utilisation or dispensing or administration errors. Focus groups with patients, carers and health-care professionals supplemented the systematic review to inform the RCT design. The resulting design was implemented and then evaluated through questionnaires and group discussions with participants and health-care professionals involved in trial delivery. RESULTS: Studies on MODs are largely of poor quality. The relationship between adherence and health outcomes is unclear. Of the limited studies reporting health outcomes, some reported a positive relationship while some reported increased hospitalisations associated with MODs. The pre-trial focus groups endorsed the planned study design, but suggested a minimum recruitment age of 50-60 years. A total of 35.4% of patients completing the baseline questionnaire were excluded because they already used a MOD. Active recruitment yielded a higher consent rate, but passive recruitment was more cost-effective. The prevalence of intentional non-adherence was 24.7% [n = 71, 95% confidence interval (CI) 19.7% to 29.6%] of participants. Of the remaining 76 participants, 46.1% (95% CI 34.8% to 57.3%) were unintentionally non-adherent. There was no indication of a difference in adherence between the study arms. Participants reported a high level of satisfaction with the design. Five adverse/serious adverse events were identified in the MOD study arms and none was identified in the control arms. There was no discernible difference in health economic outcomes between the four study arms; the mean intervention cost was £20 per month greater for MOD monthly relative to usual supply monthly. CONCLUSIONS: MOD provision to unintentionally non-adherent older people may cause medication-related adverse events. The primary outcome for a definitive MOD trial should be health outcomes. Such a trial should recruit patients by postal invitation and recruit younger patients. FUTURE WORK: A study examining the association between MOD initiation and adverse effects is necessary and a strategy to safely introduce MODs should be explored. A definitive study testing the clinical effectiveness and cost-effectiveness of MODs is also required. STUDY REGISTRATION: Current Controlled Trials ISRCTN 30626972 and UKCRN 12739. FUNDING: This project was funded by National Institute for Health Research (NIHR) Health Technology Assessment Programme and will be published in full in Health Technology Assessment; Vol. 20, No. 50. See the NIHR Journals Library website for further project information.


Asunto(s)
Cumplimiento de la Medicación , Sistemas Recordatorios , Proyectos de Investigación , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Análisis Costo-Beneficio , Estudios de Factibilidad , Grupos Focales , Cumplimiento de la Medicación/estadística & datos numéricos , Satisfacción del Paciente , Selección de Paciente , Sistemas Recordatorios/instrumentación
7.
BMC Health Serv Res ; 16: 202, 2016 07 06.
Artículo en Inglés | MEDLINE | ID: mdl-27381448

RESUMEN

BACKGROUND: Suboptimal medication adherence is a significant threat to public health and resources. Devices that organise weekly doses by time and day are commonly used to reduce unintentional non-adherence. However, there is limited evidence to support their use. This systematic review was conducted to evaluate current evidence for their efficacy, safety and costs. METHODS: A pre-defined search of electronic databases from inception to January 2013 augmented with hand-searching was conducted. No limits were placed on publication date. Studies that compared organisation devices used by patients administering their own medication with standard medication packaging regardless of study design were eligible for inclusion. Studies that solely explored dispensing aspects of organisation devices were included whether or not they compared this to standard care. Screening of articles for inclusion and data extraction were completed independently by two reviewers with disagreements resolved by discussion. Outcomes were categorised into impact on health, medication adherence, healthcare utilisation, dispensing errors, supply procedures and costs. Risk of bias was also assessed. RESULTS: Seventeen studies met the inclusion criteria. Health outcomes were investigated in seven studies of which three reported a positive effect associated with organisation devices. Medication adherence was reported in eight studies of which three reported a positive effect. Three studies reported health care utilisation data but overall results are inconclusive. No optimal dispensing or supply procedures were identified. Economic assessment of the impact of organisation devices is lacking. All studies were subject to a high risk of bias. CONCLUSIONS: Evidence regarding the effects of medication organisation devices was limited, and the available evidence was susceptible to a high risk of bias. Organisation devices may help unintentional medication non-adherence and could improve health outcomes. There is a strong need for more studies that explore the impact of such devices on patients, and an equally pressing need for studies that explore the impacts on healthcare services. TRIAL REGISTRATION: This systematic review is registered with PROSPERO (Registration number CRD42011001718 ).


Asunto(s)
Embalaje de Medicamentos , Cumplimiento de la Medicación , Errores de Medicación , Humanos , Errores de Medicación/prevención & control , Farmacias , Calidad de Vida , Sistemas Recordatorios , Resultado del Tratamiento
8.
Trials ; 16: 559, 2015 Dec 09.
Artículo en Inglés | MEDLINE | ID: mdl-26646251

RESUMEN

BACKGROUND: People aged 75 years and over account for 1 in 4 of all hospital admissions. There has been increasing recognition of problems in the care of older people, particularly in hospitals. Evidence suggests that older people judge the care they receive in terms of kindness, empathy, compassion, respectful communication and being seen as a person not just a patient. These are aspects of care to which we refer when we use the term 'relational care'. Healthcare assistants deliver an increasing proportion of direct care to older people, yet their training needs are often overlooked. METHODS/DESIGN: This study will determine the acceptability and feasibility of a cluster randomised controlled trial of 'Older People's Shoes' a 2-day training intervention for healthcare assistants caring for older people in hospital. Within this pilot, 2-arm, parallel, cluster randomised controlled trial, healthcare assistants within acute hospital wards are randomised to either the 2-day training intervention or training as usual. Registered nurses deliver 'Older People's Shoes' over 2 days, approximately 1 week apart. It contains three components: experiential learning about ageing, exploration of older people's stories, and customer care. Outcomes will be measured at the level of patient (experience of emotional care and quality of life during their hospital stay), healthcare assistant (empathy and attitudes towards older people), and ward (quality of staff/patient interaction). Semi-structured interviews of a purposive sample of healthcare assistants receiving the intervention, and all trainers delivering the intervention, will be undertaken to gain insights into the experiences of both the intervention and the trial, and its perceived impact on practice. DISCUSSION: Few training interventions for care staff have been rigorously tested using randomised designs. This study will establish the viability of a definitive cluster randomised controlled trial of a new training intervention to improve the relational care proided by healthcare assistants working with older people in hospital. TRIAL REGISTRATION: The study was registered as an International Standard Randomised Controlled Trial ( ISRCTN10385799 ) on 29 December 2014.


Asunto(s)
Actitud del Personal de Salud , Conocimientos, Actitudes y Práctica en Salud , Personal de Salud/educación , Servicios de Salud para Ancianos , Capacitación en Servicio , Relaciones Profesional-Paciente , Anciano , Análisis por Conglomerados , Comunicación , Empatía , Inglaterra , Estudios de Factibilidad , Femenino , Personal de Salud/psicología , Personal de Salud/normas , Investigación sobre Servicios de Salud , Servicios de Salud para Ancianos/normas , Humanos , Pacientes Internos , Capacitación en Servicio/normas , Entrevistas como Asunto , Masculino , Satisfacción del Paciente , Proyectos Piloto , Mejoramiento de la Calidad , Indicadores de Calidad de la Atención de Salud , Calidad de Vida , Proyectos de Investigación , Factores de Tiempo , Recursos Humanos
9.
Int J Food Microbiol ; 166(1): 72-6, 2013 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-23838282

RESUMEN

A survey of dried mushrooms (Lentinula edodes (Shiitake) and Auricularia auricula (Wood Ear)) sourced from China was carried out to determine the natural contamination of these mushrooms with spores of proteolytic Clostridium botulinum and non-proteolytic C. botulinum. The mushrooms were collected from supermarkets and retailers in 21 cities in China during October 2008. Spore loads of C. botulinum in mushrooms have a degree of uncertainty and variability and this study contributes valuable data for determining prevalence of spores of C. botulinum in mushrooms. An optimized detection protocol that combined selective enrichment culture with multiplex PCR was used to test for spores of proteolytic and non-proteolytic C. botulinum. Detection limits were calculated, using a maximum likelihood protocol, from mushroom samples inoculated with defined numbers of spores of proteolytic C. botulinum or non-proteolytic C. botulinum. Based on the maximum likelihood detection limit, it is estimated that dried mushroom A. auricula contained <550spores/kg of proteolytic C. botulinum, and <350spores/kg of non-proteolytic C. botulinum. Dried L. edodes contained <1500spores/kg of proteolytic C. botulinum and it was not possible to determine reliable detection limits for spores of non-proteolytic C. botulinum using the current detection protocol.


Asunto(s)
Agaricales , Clostridium botulinum/fisiología , Microbiología de Alimentos , Verduras/microbiología , China , Clostridium botulinum/genética , Clostridium botulinum/aislamiento & purificación , Genes Fúngicos/genética , Límite de Detección , Reacción en Cadena de la Polimerasa , Esporas/genética , Esporas/aislamiento & purificación , Esporas/fisiología
10.
Appl Environ Microbiol ; 76(19): 6607-14, 2010 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-20709854

RESUMEN

The highly potent botulinum neurotoxins are responsible for botulism, a severe neuroparalytic disease. Strains of nonproteolytic Clostridium botulinum form neurotoxins of types B, E, and F and are the main hazard associated with minimally heated refrigerated foods. Recent developments in quantitative microbiological risk assessment (QMRA) and food safety objectives (FSO) have made food safety more quantitative and include, as inputs, probability distributions for the contamination of food materials and foods. A new method that combines a selective enrichment culture with multiplex PCR has been developed and validated to enumerate specifically the spores of nonproteolytic C. botulinum. Key features of this new method include the following: (i) it is specific for nonproteolytic C. botulinum (and does not detect proteolytic C. botulinum), (ii) the detection limit has been determined for each food tested (using carefully structured control samples), and (iii) a low detection limit has been achieved by the use of selective enrichment and large test samples. The method has been used to enumerate spores of nonproteolytic C. botulinum in 637 samples of 19 food materials included in pasta-based minimally heated refrigerated foods and in 7 complete foods. A total of 32 samples (5 egg pastas and 27 scallops) contained spores of nonproteolytic C. botulinum type B or F. The majority of samples contained <100 spores/kg, but one sample of scallops contained 444 spores/kg. Nonproteolytic C. botulinum type E was not detected. Importantly, for QMRA and FSO, the construction of probability distributions will enable the frequency of packs containing particular levels of contamination to be determined.


Asunto(s)
Clostridium botulinum/aislamiento & purificación , Microbiología de Alimentos , Inocuidad de los Alimentos/métodos , Reacción en Cadena de la Polimerasa/métodos , Esporas/aislamiento & purificación , Carga Bacteriana/métodos , Clostridium botulinum/genética , Clostridium botulinum/crecimiento & desarrollo , Sensibilidad y Especificidad , Esporas/genética , Esporas/crecimiento & desarrollo
11.
Appl Environ Microbiol ; 75(20): 6457-61, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19684163

RESUMEN

Botulinum neurotoxin (BoNT), the most toxic substance known, is produced by the spore-forming bacterium Clostridium botulinum and, in rare cases, also by some strains of Clostridium butyricum and Clostridium baratii. The standard procedure for definitive detection of BoNT-producing clostridia is a culture method combined with neurotoxin detection using a standard mouse bioassay (SMB). The SMB is highly sensitive and specific, but it is expensive and time-consuming and there are ethical concerns due to use of laboratory animals. PCR provides a rapid alternative for initial screening for BoNT-producing clostridia. In this study, a previously described multiplex PCR assay was modified to detect all type A, B, E, and F neurotoxin genes in isolated strains and in clinical, food, environmental samples. This assay includes an internal amplification control. The effectiveness of the multiplex PCR method for detecting clostridia possessing type A, B, E, and F neurotoxin genes was evaluated by direct comparison with the SMB. This method showed 100% inclusivity and 100% exclusivity when 182 BoNT-producing clostridia and 21 other bacterial strains were used. The relative accuracy of the multiplex PCR and SMB was evaluated using 532 clinical, food, and environmental samples and was estimated to be 99.2%. The multiplex PCR was also used to investigate 110 freshly collected food and environmental samples, and 4 of the 110 samples (3.6%) were positive for BoNT-encoding genes.


Asunto(s)
Toxinas Botulínicas/biosíntesis , Toxinas Botulínicas/genética , Clostridium/genética , Clostridium/aislamiento & purificación , Microbiología Ambiental , Microbiología de Alimentos , Neurotoxinas/biosíntesis , Neurotoxinas/genética , Reacción en Cadena de la Polimerasa/métodos , Animales , Secuencia de Bases , Bioensayo/estadística & datos numéricos , Clostridium/metabolismo , Clostridium botulinum/genética , Clostridium botulinum/aislamiento & purificación , Clostridium botulinum/metabolismo , Cartilla de ADN/genética , ADN Bacteriano/genética , Genes Bacterianos , Humanos , Ratones , Reacción en Cadena de la Polimerasa/estadística & datos numéricos , Sensibilidad y Especificidad
12.
J AOAC Int ; 87(1): 68-77, 2004.
Artículo en Inglés | MEDLINE | ID: mdl-15084089

RESUMEN

An interlaboratory study was conducted for the validation of 3 methods for the detection of all verotoxin-producing Escherichia coli (VTEC) in foods. The methods were a multi-analyte 1-step lateral flow immunoassay (LFIA) for detection of E. coli O157 and verotoxin (VT); an enzyme-linked immunosorbent assay targeted against VT1, VT2, and VT2c (VT-ELISA); and a polymerase chain reaction (PCR) method for detection of VT genes (VT-PCR). Aliquots (25 g or 25 mL) of 4 food types (raw minced [ground] beef, unpasteurized milk, unpasteurized apple juice [cider], and salami) were individually inoculated with low numbers (<9 to 375 cells/25 g) of 6 test strains of E. coli (serogroups O26, O103, O111, O145, and O157) with differing VT-producing capabilities. Five replicates for each test strain and 5 uninoculated samples were prepared for each food type. Fourteen participating laboratories analyzed samples using the LFIA, 9 analyzed the samples by ELISA, and 9 by PCR. The LFIA for O157 and VT had a specificity (correct identification of negative samples) of 92 and 94%, respectively, and a sensitivity (correct identification of positive samples) of 94 and 55%, respectively. The VT-ELISA and VT-PCR had a specificity of 98 and 99%, respectively, and a sensitivity of 89 and 72%, respectively.


Asunto(s)
Escherichia coli/química , Escherichia coli/metabolismo , Microbiología de Alimentos , Toxinas Shiga/análisis , Toxinas Shiga/biosíntesis , Animales , Bebidas/análisis , Recuento de Colonia Microbiana , Ensayo de Inmunoadsorción Enzimática , Escherichia coli O157/química , Inmunoensayo , Malus/química , Carne/análisis , Carne/microbiología , Leche/química , Leche/microbiología , Reproducibilidad de los Resultados , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa
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