RESUMO
Metagenomic-based analyses have the potential to revolutionize our understanding of the microbiology of food production and processing environments. By adopting such approaches, it will be possible to more accurately determine sources of microbial contamination, identify critical control points for such contaminants, and select practices that optimize quality and safety. This mini-review will discuss the merits of adopting metagenostic-based approaches, highlight novel insights that they have provided to date and consider how they could be further implemented.
Assuntos
Bactérias/genética , Contaminação de Alimentos/análise , Microbiologia de Alimentos/métodos , Inocuidade dos Alimentos/métodos , Doenças Transmitidas por Alimentos/prevenção & controle , Metagenômica/métodos , Bactérias/classificação , Meio Ambiente , Manipulação de Alimentos , Doenças Transmitidas por Alimentos/microbiologia , Humanos , Metagenoma/genéticaRESUMO
In pasture-based systems, changes in dairy herd habitat due to seasonality results in the exposure of animals to different environmental niches. These niches contain distinct microbial communities that may be transferred to raw milk, with potentially important food quality and safety implications for milk producers. It is postulated that the extent to which these microorganisms are transferred could be limited by the inclusion of a teat preparation step prior to milking. High-throughput sequencing on a variety of microbial niches on farms was used to study the patterns of microbial movement through the dairy production chain and, in the process, to investigate the impact of seasonal housing and the inclusion/exclusion of a teat preparation regime on the raw milk microbiota from the same herd over two sampling periods, i.e., indoor and outdoor. Beta diversity and network analyses showed that environmental and milk microbiotas separated depending on whether they were sourced from an indoor or outdoor environment. Within these respective habitats, similarities between the milk microbiota and that of teat swab samples and, to a lesser extent, fecal samples were apparent. Indeed, SourceTracker identified the teat surface as the most significant source of contamination, with herd feces being the next most prevalent source of contamination. In milk from cows grazing outdoors, teat prep significantly increased the numbers of total bacteria present. In summary, sequence-based microbiota analysis identified possible sources of raw milk contamination and highlighted the influence of environment and farm management practices on the raw milk microbiota. IMPORTANCE: The composition of the raw milk microbiota is an important consideration from both a spoilage perspective and a food safety perspective and has implications for milk targeted for direct consumption and for downstream processing. Factors that influence contamination have been examined previously, primarily through the use of culture-based techniques. We describe here the extensive application of high-throughput DNA sequencing technologies to study the relationship between the milk production environment and the raw milk microbiota. The results show that the environment in which the herd was kept was the primary driver of the composition of the milk microbiota composition.
Assuntos
Bovinos , Indústria de Laticínios/métodos , Abrigo para Animais , Glândulas Mamárias Animais/microbiologia , Microbiota/fisiologia , Leite/microbiologia , Estações do Ano , Animais , Fezes/microbiologia , Feminino , Microbiologia de Alimentos , Sequenciamento de Nucleotídeos em Larga EscalaRESUMO
We report a case of a 16-year-old adolescent male born with univentricular congenital cyanotic heart disease (CCHD) who was diagnosed with an incidental paraganglioma while awaiting a cardiac transplant. The coexistence of paraganglioma and univentricular CCHD is very rare, with no previous cases described in the literature of a patient concurrently requiring a cardiac transplant. The complex physiology associated with a common atrium, common ventricle, aortopulmonary lung perfusion and a hypoplastic left lung rendered our patient extremely vulnerable to catecholamine-mediated effects of preload, contractility and afterload. The interactions and interdependence between these systems provided unique difficulties for perioperative management with serious implications for prospective cardiac transplant.
Assuntos
Cardiopatias Congênitas , Transplante de Coração , Paraganglioma , Coração Univentricular , Adolescente , Cianose/etiologia , Cardiopatias Congênitas/cirurgia , Humanos , Masculino , Paraganglioma/complicações , Paraganglioma/cirurgia , Estudos ProspectivosRESUMO
BACKGROUND: Following oesophagectomy, the most concerning complication is that of anastomotic leak (AL). Prompt diagnosis and intervention are crucial to facilitate an optimal outcome. Other complications, particularly respiratory, are not infrequent. Early identification of AL versus other sources of the inflammatory response can be problematic. AIMS: To evaluate the role of serial CRP as a prognosticator for oesophagogastric AL. METHODS: All oesophagectomies carried out at our institution from 2010 to 2017 were included. Serial C-reactive protein (CRP) and white cell count (WCC) were recorded pre-operatively and on each consecutive day up to day 10 post-op. All complications were recorded and the timing of diagnosis compared with serial CRP and WCC measurements to determine any correlation. RESULTS: One hundred and two patients underwent oesophagectomy (84 male, 18 female) with a mean age of 62.5 years (± 9.8). Forty-seven patients developed post-operative complications, with pulmonary (n = 28) the most common. There were 5 cases of AL. Patients in the AL group (n = 5) had a significantly higher mean CRP compared to those who did not develop AL (n = 97) pre-operatively (50 vs. 14, p = 0.046), on post-op day 3 (300 vs. 218, p = 0.02) and on post-op day 4 (279 vs. 184, p = 0.009). There was no significant difference in mean daily CRP between patients with pulmonary complications (PC, n = 29) and those who did not develop complications (NC, n = 54). CONCLUSIONS: Elevated CRP may be a useful marker in facilitating the prompt diagnosis of AL following oesophagectomy. Serial CRP may not contribute to identifying lower respiratory tract infections, partly as a result of the pro-inflammatory response following surgery.
Assuntos
Fístula Anastomótica/diagnóstico , Proteína C-Reativa/metabolismo , Esofagectomia/métodos , Fístula Anastomótica/sangue , Proteína C-Reativa/análise , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Anaerobic sporeformers, specifically spoilage and pathogenic members of the genus Clostridium, are a concern for producers of dairy products, and of powdered dairy products in particular. As an alternative to testing for individual species, the traditional, and still current, approach to detecting these sporeformers, including non-spoilage/non-pathogenic species, in dairy products has involved testing for a sulphite reducing phenotype [Sulphite reducing Clostridia (SRCs)] under anaerobic conditions. This phenotype is conserved throughout the Order Clostridia. Unfortunately, however, this phenotype is exhibited by other sulphite reducing bacteria (SRBs) also, potentially leading to potential for false positives. Here, this risk was borne out through the identification of several SRBs from industry samples that were identified as Proteus mirabilis and various Bacillus/Paenibacillus sp. Genome wide comparison of a number of representative SRCs and SRBs was employed to determine phylogenetic relationships, especially among SRCs, and to characterize the genes responsible for the sulphite reducing phenotype. This screen identified two associated operons, i.e., asrABC in SRCs, and cysJI in Bacillus/Paenibacillus spp. and P. mirabilis. This screen identified spp. belonging to sensu stricto, Lachnospiraceae and Cluster XIV of the Clostridia all producing the SRC phenotype. This study highlights the inaccuracy of the industry standard SRC test but highlights the potential to generate an equivalent molecular test designed to detect the genes responsible for this phenotype in clostridia.
RESUMO
Low temperature is used to control the growth of bacteria in milk, both pre- and post-pasteurization. As the duration of refrigerated storage extends, psychrotrophs dominate the milk microbiota, that can produce heat stable lipases which negatively impact the organoleptic qualities of milk. Here we examine the influence that refrigeration temperature (2°C, 4°C and 6°C) and storage duration (96h) have on the microbiota composition (16S profiling) of raw bulk tank milk (BTM). To reflect a proposed change to current farming practices, raw milk was blended after each milking (8 milkings) and stored for five consecutive days in each temperature-specific tank. Here 16S rRNA-based microbiota compositional analysis was performed after milk was collected on day 1 and again after the final addition of milk at day 5. In addition to assessing the impact of the duration and temperature of storage, the influence of lactation stage, i.e. mid- versus late-lactation, on the microbiota of the blended BTM was also examined. Overall, both temperature and length of storage had surprisingly little influence on the raw milk microbiota, other than an increase in proportions of Gammaproteobacteria in the blended milk samples collected after pooling on day 5, and in samples stored at 6°C. However, lactation stage had a considerable influence on microbiota composition, with milk from mid-lactation containing higher proportions of Bacteroides, Faecalibacterium, Campylobacter and Rhodanobacter, and late-lactation milk containing higher proportions of Actinobacteria. Overall, the study demonstrates that current temperature and storage duration practises impact the microbiota of raw milk, but these impacts are modest relative to the more considerable differences between mid and late-lactation milk.
Assuntos
Biodiversidade , Armazenamento de Alimentos/normas , Lactação , Microbiota/fisiologia , Leite/microbiologia , Temperatura , Animais , Bactérias/classificação , Bactérias/genética , Bovinos , Indústria de Laticínios , Feminino , Microbiota/genética , RNA Ribossômico 16S/genética , Fatores de TempoRESUMO
Sporeforming bacteria are a significant concern for the international dairy industry. Spores present in milk survive heat treatments and can persist during downstream processing. If they are present in sufficient numbers in dairy products they can cause spoilage or lead to illness as a result of toxin production. While many reviews have highlighted the threat posed by spores of aerobic bacteria to the dairy industry, few have focused on problems caused by the array of different species of anaerobic sporeformers (Clostridium and related genera) that can be found in milk. This is despite of the fact that members of these bacteria are found throughout the dairy farm environment, and can be toxigenic, neurotoxigenic or spoilage bacteria. This makes the possible presence of Clostridium and related spores in bulk tank milk (BTM) important from both a financial and a public health perspective. In this review dairy associated anaerobic sporeformers are assessed from a number of perspectives. This includes the taxonomy of this group of bacteria, the important subgroup of this genus the "sulphite reducing clostridia" (SRC), how these bacteria are detected in milk products, the epidemiological data regarding pathogenic species and strains within the SRC group as well as the influence of farming practices on the presence of SRC in BTM.
Assuntos
Clostridium/fisiologia , Laticínios/microbiologia , Microbiologia de Alimentos , Leite/microbiologia , Animais , Clostridium/classificação , Infecções por Clostridium/epidemiologia , Infecções por Clostridium/microbiologia , Infecções por Clostridium/transmissão , Indústria de Laticínios/normas , Doenças Transmitidas por Alimentos/epidemiologia , Doenças Transmitidas por Alimentos/microbiologia , Humanos , Saúde Pública/normasRESUMO
BACKGROUND: Microinsurance or Community-Based Health Insurance is a promising healthcare financing mechanism, which is increasingly applied to aid rural poor persons in low-income countries. Robust empirical evidence on the causal relations between Community-Based Health Insurance and healthcare utilisation, financial protection and other areas is scarce and necessary. This paper contains a discussion of the research design of three Cluster Randomised Controlled Trials in India to measure the impact of Community-Based Health Insurance on several outcomes. METHODS/DESIGN: Each trial sets up a Community-Based Health Insurance scheme among a group of micro-finance affiliate families. Villages are grouped into clusters which are congruous with pre-existing social groupings. These clusters are randomly assigned to one of three waves of implementation, ensuring the entire population is offered Community-Based Health Insurance by the end of the experiment. Each wave of treatment is preceded by a round of mixed methods evaluation, with quantitative, qualitative and spatial evidence on impact collected. Improving upon practices in published Cluster Randomised Controlled Trial literature, we detail how research design decisions have ensured that both the households offered insurance and the implementers of the Community-Based Health Insurance scheme operate in an environment replicating a non-experimental implementation. DISCUSSION: When a Cluster Randomised Controlled Trial involves randomizing within a community, generating adequate and valid conclusions requires that the research design must be made congruous with social structures within the target population, to ensure that such trials are conducted in an implementing environment which is a suitable analogue to that of a non-experimental implementing environment.