First report of Escherichia coli O157:H7 in ready-to-eat sushi.
AIMS
The aim of this study was to evaluate the microbiological quality of commercially prepared ready-to-eat (RTE) sushi by enumerating aerobic mesophilic bacteria (AMB) and thermotolerant coliforms (TC) and detecting Escherichia coli and Salmonella ssp. An isolate was identified as E. coli O157:H7 which was evaluated for its virulence and antimicrobial resistance profiling as well as its ability to form biofilms on stainless steel.


METHODS AND RESULTS
There were four sampling events in seven establishments, totalling 28 pools of sushi samples. Mean AMB counts ranged between 5·2 and 7·7 log CFU per gram. The enumeration of TC varied between 2·1 and 2·7 log MPN per gram. Salmonella ssp. were not detected, and one sample was positive for E. coli and was identified as E. coli O157:H7. To the best of our knowledge, this is the first report of E. coli O157:H7 in sushi samples in the world literature. This isolate presented virulence genes stx1, stx2, eae and hlyA. It was also susceptible to 14 antimicrobials tested and had the ability to form biofilms on stainless steel.


CONCLUSIONS
There is a need to improve the good hygiene practices adopted in establishments selling sushi in the city of Pelotas, Brazil. In addition, the isolated E. coli O157:H7 carries a range of important virulence genes being a potential risk to consumer health, as sushi is a RTE food. This isolate also presents biofilm formation ability, therefore, may trigger a constant source of contamination in the production line of this food.


SIGNIFICANCE AND IMPACT OF THE STUDY
The increase in the consumption of sushi worldwide attracts attention regarding the microbiological point of view, since it is a ready-to-eat food. To our knowledge, this was the first time that E. coli O157:H7 was identified in sushi samples.
['Ramires|T|T|https://orcid.org/0000-0002-2842-4409', 'Iglesias|M A|MA|', 'Vitola|H S|HS|', 'Núncio|A S P|ASP|', 'Kroning|I S|IS|https://orcid.org/0000-0002-1527-9724', 'Kleinubing|N R|NR|', 'Fiorentini|Â M|ÂM|https://orcid.org/0000-0003-3945-0079', 'da Silva|W P|WP|']
D000818:Animals D000900:Anti-Bacterial Agents D018441:Biofilms D001938:Brazil D015169:Colony Count, Microbial D019453:Escherichia coli O157 D005516:Food Microbiology D008826:Microbial Sensitivity Tests D017747:Seafood D013193:Stainless Steel D000071436:Thermotolerance D014774:Virulence
ready-to-eat sushi E. coli O157:H7 biofilm STEC