Outbreak of Salmonella enteritidis PT14b gastroenteritis at a restaurant in England: the use of molecular typing to achieve a successful prosecution

Relationship between ATP Bioluminescence Measurements and Microbial Assessments in Studies Conducted in Food Establishments: A Systematic Literature Review and Meta-Analysis

ABSTRACT

Adherence to proper environmental cleaning practices is critical in food establishments. To validate cleanliness, cleaning practices should be routinely monitored, preferably by a rapid, reliable, and cost-effective method. The aim of this study was to determine whether a correlation exists between ATP bioluminescence measurements and selected microbial assessments in studies conducted in food establishments. A systematic literature review and meta-analysis was conducted using the principles of preferred reporting items for systematic reviews and meta-analyses. Twelve online databases and search engines were selected for the review. Peer-reviewed articles published in English between January 2000 and July 2020 were included in the search. From a total of 19 eligible studies, 3 that included Pearson correlation coefficients (r) between ATP bioluminescence measurements and microbial assessments were used for the meta-analysis calculations. Only the fixed-effect model produced a strong correlation because one value dominated the estimates: r = 0.9339 (0.9278, 0.9399). In contrast, both the random effects model, 0.2978 (0.24, 0.3471), and the mixed effects model, r = 0.3162 (-0.0387, 0.6711), indicated a weak relationship between ATP bioluminescence and microbial assessments, with no evidence of a strong correlation. The meta-analysis results indicated no sufficient evidence of a strong correlation between ATP bioluminescence measurements and microbial assessments when applied within food establishments. This lack of evidence for a strong correlation between the results of these two monitoring tools suggests that food establishments cannot depend on only one method. Yet, with immediate feedback and quantification of organic soiling, ATP bioluminescence could be an effective monitoring tool to use in food establishments.

HIGHLIGHTS

Prevalence and Antibiotic Resistance of Salmonella Enteritidis and Salmonella Typhimurium in Ground Beef and Meatball Samples in Samsun, Turkey

The aims of this study were to evaluate the prevalence of Salmonella spp., including S. Enteritidis and S. Typhimurium, their antibiotic resistance profiles, and the presence/absence of class 1 integron (intI1) in 50 raw ground beef and 50 raw, meatball samples collected in the Samsun Province, Turkey. For the detection of Salmonella, conventional culture technique and PCR assay were used. The antibiotic resistance profiles of the isolates against nine antibiotics were tested. Salmonella spp. was detected in 20 (n = 86 isolates) samples, namely 12 ground beef and 8 meatball samples. Salmonella Enteritidis (n = 12; 24 isolates) or S. Typhimurium (n = 3; 6 isolates) was detected in 15 (75.00%, n = 30 isolates) samples. At least one species-specific gene (oriC or invA) was detected in the isolates. All isolates were sensitive to two of the third-generation cephalosporins and also nalidixic acid. There was a different level of multidrug resistance (MDR) between S. Enteritidis and Typhimurium isolates. Class 1 integron was detected in four samples (n = 7 isolates); seven isolates were S. Enteritidis and four out of the seven S. Enteritidis isolates were also MDR. In conclusion, the presence of Salmonella, particularly S. Enteritidis and S. Typhimurium, in ground beef and meatballs may cause foodborne infections. The presence of antibiotic-resistant Salmonella and S. Enteritidis with the Cls1integron is important for horizontal antibiotic gene transfer.

Condições higiênico-sanitárias e perfil da comunidade microbiana de utensílios e mesas higienizadas de um serviço de alimentação localizado no Rio de Janeiro

Resumo O objetivo deste estudo foi avaliar as condições higiênico-sanitárias e o perfil da comunidade microbiana dos utensílios e das mesas de um serviço de alimentação localizado no município do Rio de Janeiro. A caracterização do processo de higienização dos utensílios (pratos, bandejas e talheres) e das mesas foi realizada por observação sistemática. Verificou-se que os utensílios eram lavados em máquina de lavar e as mesas, manualmente. Após a higienização, os utensílios apresentavam umidade e resíduos de alimentos. Pelo método dependente de cultivo, foram analisadas 126 amostras higienizadas (utensílios: n=90 e mesas: n=36). Pesquisaram-se bactérias mesófilas, coliformes, Escherichia coli, Staphylococcus aureus e fungos. Das amostras analisadas, 100% dos utensílios e 80% das mesas apresentaram contagens microbianas superiores ao recomendado na literatura, estando em condições higiênico-sanitárias inadequadas. E. coli foi isolada nos utensílios e S. aureus, nas mesas. Pelos métodos independentes de cultivo (PCR-DGGE e sequenciamento da subunidade 16S do rRNA), foram analisadas 36 amostras (utensílios: n=27 e mesas: n=9). Klebsiella sp. e Acinetobacter sp. Foram detectadas em todas as amostras, Citrobacter sp. sobre as mesas e Aeromonas hydrophila, nos talheres. Houve falha no processo de higienização, que foi confirmada pelas análises realizadas, que evidenciaram a presença de microrganismos indicadores e patogênicos, que podem causar a perda da qualidade das refeições, assim como danos à saúde dos comensais. Desta forma, é necessário adequar o processo de higienização, a fim de minimizar o risco de contaminação e o surto de doenças transmitidas por alimentos (DTA).

Comparative analysis of core genome MLST and SNP typing within a European Salmonella serovar Enteritidis outbreak

Multi-country outbreaks of foodborne bacterial disease present challenges in their detection, tracking, and notification. As food is increasingly distributed across borders, such outbreaks are becoming more common. This increases the need for high-resolution, accessible, and replicable isolate typing schemes. Here we evaluate a core genome multilocus typing (cgMLST) scheme for the high-resolution reproducible typing of Salmonella enterica (S. enterica) isolates, by its application to a large European outbreak of S. enterica serovar Enteritidis. This outbreak had been extensively characterised using single nucleotide polymorphism (SNP)-based approaches. The cgMLST analysis was congruent with the original SNP-based analysis, the epidemiological data, and whole genome MLST (wgMLST) analysis. Combination of the cgMLST and epidemiological data confirmed that the genetic diversity among the isolates predated the outbreak, and was likely present at the infection source. There was consequently no link between country of isolation and genetic diversity, but the cgMLST clusters were congruent with date of isolation. Furthermore, comparison with publicly available Enteritidis isolate data demonstrated that the cgMLST scheme presented is highly scalable, enabling outbreaks to be contextualised within the Salmonella genus. The cgMLST scheme is therefore shown to be a standardised and scalable typing method, which allows Salmonella outbreaks to be analysed and compared across laboratories and jurisdictions.

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cgMLST is proposed as a universal typing scheme for Salmonella.

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cgMLST is congruent with SNP analyses and easier to implement across laboratories.

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Genomic data are consistent with the epidemiology of the outbreak.