Prevalence of staphylococcal toxin in food contaminated by Staphylococcus spp.: protocol for a systematic review with meta-analysis
Creators: name: Freitas, Juliana
name: de Assis, Cristiane
name: de Oliveira, Thailla
name: Maia, Cláudio Márcio de Medeiros
name: de Sousa, Bruno
name: de Medeiros, Gidyenne
name: Seabra, Larissa
name: da Silva Chaves Damasceno, Karla
Publisher: name: Open Science Framework
Year: 2022
Subjects: subject: Microbiology
subject: FOS: Biological sciences
subject: Nutrition
subject: Nutritional Epidemiology
subject: Life Sciences
subject: Food Microbiology
subject: Pathogenic Microbiology
subject: Food Science

description: Summary: Food contamination by enterotoxigenic strains of Staphylococcus spp. is quite common as a result of the natural habitation of human and animals, especially in dairy animals, making it easy to contaminate. During its multiplication, several species of the genus can produce enterotoxins, causing staphylococcal food poisoning, which despite the underreporting caused by the short duration of clinical symptoms and lack of medical care, is one of the most common Foodborne Diseases in the world. So far, worldwide prevalence records of staphylococcal enterotoxin in food contaminated by Staphylococcus spp. are not available. Several studies on the topic, including reports of possible outbreaks involving this bacterium, do not have conclusive results, since research on the bacterium or on the gene responsible for the production of the SE is observed, which do not necessarily confirm the presence of the toxin in food. Therefore, awareness and discussion of the occurrence of SE in food is important to put this topic in evidence and highlight the need to identify the toxin effectively and quickly, aiming at food safety. Review question: What is the worldwide prevalence of staphylococcal enterotoxins in food contaminated by Staphylococcus spp.? Search strategy: The following databases will be used: Medline (OVID), GALE, Science Direct, CAB Direct (CABI), and Google Scholar. In addition, manual search will be done in records’ reference lists, directory of theses and dissertations, and countries’ health agencies. Gray literature will be included. Studies from the last 20 years (2002-2022) will be included. There will be no language restriction. The terms used were defined based on information from PECOS, which would convey the criteria in formulating a search strategy. Terms related to population (staphylococcal enterotoxins) and exposure (contaminated food, food contamination, staphylococcal food poisoning, disease outbreak, foodborne disease, food poisoning, Staphylococcus spp.) will be used. The operators ‘AND’, ‘OR’ and ‘AND NOT’ will also be used in the construction of the search strategy which will be adapted to meet the specifications of the search syntax of each database. Population (inclusion and exclusion criteria): Inclusion criteria: Primary studies reporting staphylococcal enterotoxin (SE) analysis in food. Exclusion criteria: Studies on SE in humans, domestic or food-producing animals, fomites or surfaces; Studies only aimed at the microorganism or gene responsible for the production of the SE. Comparative control: - Not applicable. Exposure (inclusion and exclusion criteria): Inclusion criteria: Foods exposed to Staphylococcus spp. Exclusion criteria: Studies which are not connected to the exposition of food to Staphylococcus spp. Studies which report direct contamination of food with SE, in laboratory settings Outcomes Inclusion criteria Quantification of SE in foods contaminated with Staphylococcus spp; Types of SE found in food; Types of food contaminated with Staphylococcus spp. Exclusion criteria: Limited to the presence of Staphylococcus spp; Limited to the presence of the gene responsible for the production of the SE. Main outcome Quantification of SE in foods contaminated with Staphylococcus spp. Measures of effect: Concentration, in ng or equivalent unit, of staphylococcal toxin in food. Percentage of foods with the staphylococcal toxin. Additional outcome(s): Types of toxins found in food Contaminated food types Screening and data extraction: After executing the search strategy, all found publications will be sent to Rayyan software. Initially, automatic duplicate detection will be performed, and then a researcher will decide to manually delete the possibly duplicate studies. Then, two researchers will independently read the titles and abstracts identified from the initial research to select studies that meet the inclusion criteria. And in case of disagreement, a third researcher will decide on the eligibility of the study. After this step, the included articles will undergo a full reading, by two researchers independently, so that eligibility is confirmed. Cases of divergences will be resolved by consensus and when there is persistence, a third researcher will resolve the differences. Data extraction will be performed by filling out an electronic spreadsheet with a detailed description of the main information in the selected studies. This step will also be done by two researchers independently, in order to avoid measurement bias, which occurs due to misinterpretation or even the loss of important data to be collected. If necessary, records’ authors may be contacted to clarify possible doubts. Data mismatching will also be resolved by consensus and, when necessary, by a third researcher. In order for this information to be compared in a clear and objective way, simplifying the verification process, it was previously established which data should be collected, such as: study title, author, year of publication, journal in which the study was published, objective of the study, methodology used for the analysis of the toxin, and analyses results, including: food or food group analyzed, quantity of analyzed foods (number of samples), in which and how many of the analyzed foods the toxin was detected, prevalence (%), types of SE found and SE concentration (ng or equivalent unit). If the studies present the following pieces of information, they will also be collected: confidence interval (CI), significance level adopted, detection limit of the method used, minimum dose for intoxication. Risk of bias: After the selection of the primary studies that will be included in this systematic review, a critical evaluation of their quality will be carried out, using as reference a tool developed specifically for systematic reviews of incidence and prevalence by the Joana Briggs Institute. The tool was adapted to the study. The checklist includes questions related to the study sample (representativeness and size), the validity of the methodology used and standardization, the description of the study design, the analysis of the results, the statistical analysis of the data, and the response rate. For each item should be marked: "yes", "no", "no clear", or "does not apply". Seven questions will be considered. The methodological quality of the studies will be categorized as low risk of bias ( more than 5 "yes"), moderate risk of bias (4 - 5 "yes") and high risk of bias ( less than 4 "yes"). There will be a narrative summary of the general methodological quality of the included studies, which will be supported by a table with the results of the critical evaluation and classification adopted in this research, which will make clear the accuracy of the evaluation of the studies included and clarify the reasons for including deficient studies Data synthesis: The main outcome evaluated will be the prevalence of staphylococcal enterotoxin in foods contaminated by Staphylococcus sp. and analyzed. This will be calculated considering the number of foods contaminated by Staphylococcus sp. and analyzed and the number of foods analyzed that were identified staphylococcal toxin. Secondary outcomes such as types of toxins found in contaminated food and food types will also be analyzed. The heterogeneity of the results will be evaluated using the I² (I²) and χ² (χ²) statistics. The χ² test is one of the most used to assess the significance level of heterogeneity, if there is little variation between the studies, with a significance level of p &lt; 0.10 and values of the magnitude of heterogeneity, evaluated by I², less than 50%, we can conclude as viable the synthesis of results through meta-analysis. If the quantitative synthesis of the data through meta-analysis is not possible, the most relevant results will be summarized, described, and discussed, considering the risk of bias and seeking to provide conclusions about the evidence. The critical examination of systematic reviews for publication bias should be considered a routine procedure. If possible, this item will be evaluated through Funnel plots, a simple analysis of this chart will be a useful test for the probable presence of bias in meta-analyses. Egger and Begg's statistical tests will be carried out in a complementary manner and the publication bias will be considered when p&lt;0, 1 Analysis of subgroups: Because it is such a broad and variable population group (samples of various types of foods), it is expected that the results have a greater heterogeneity, to avoid this effect, if necessary, subgroups of foods with similar characteristics will be formed. The random variations between the point estimates of the subgroup of the primary study and the possible source of heterogeneity analysis can be made considering the types of enterotoxins found, food groups with characteristics similar to the toxin detection technique, and the countries. Quality of evidence appraisal GRADE (Grading of Recommendations Assessment, Development and Evaluation) will be used for assessing the quality of evidence Funding sources This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001