Determination of big six E. coli serotypes in samples collected from food and food contact surfaces in hotel kitchens and cafetaries

Foodborne illness is defined by the World Health Organization (WHO) as a disease of an infectious or toxic nature caused by the consumption of food or water. There are more than 250 microorganisms known to cause foodborne illness and most of them are caused by bacteria. One of the most important foodborne disease agents is Escherichia coli (E. coli). Shiga toxin-producing E. coli (STEC) has emerged as a significant threat to public health worldwide. STEC was the third most frequently reported foodborne zoonotic disease in the European Union (EU) and European Economic Area (EEA) in 2022. E. coli O157 is one of the most important shiga toxin-producing E. coli serogroups and causes many foodborne diseases that affect all age groups, especially young children, resulting in death. In recent years, the identification of different serogroups in studies on foodborne diseases caused by E. coli has led to remarkable results on a global scale. Accordingly, the US Food and Drug Administration (FDA) has announced six Non-O157 E. coli serogroups (O26, 045, O103, O111, O121, O145) known as the "Big Six". These serogroups have caused serious foodborne illnesses in recent years. Both the European Food Safety Authority (EFSA) and the US Centers for Disease Control and Prevention (CDC) have published reports on this issue. In our study, 98 food samples and 102 food contact surfaces samples were collected from the kitchens, restaurants and cafeterias of different categories of hotels in Beyoğlu, the cultural, historical and touristic district of Istanbul. As a result of the analysis, stx1, stx2 and eae virulence genes were detected in 8 (8.70%) food samples and 9 (8.82%) food contact surface samples, but no Big Six E. coli was detected in the analyzed samples. With this study, the prevalence of E. coli in hotels located in touristic areas in Beyoğlu district of Istanbul was revealed and an evaluation was made regarding the current hygienic conditions and the risks that may occur. It is aimed to contribute to the protection of public health, tourism sector and current scientific developments.