Antibiotic Resistance in Enterobacteriaceae Isolated From Portuguese Deli Meats

This study aimed to identify the presence of β‐lactam‐resistant bacteria in different types of Portuguese deli meats. The numbers of ampicillin resistant bacteria varied from negative in 25 g to 1.0 × 108colony‐forming units/g. Within 78 randomly selected β‐lactam‐resistant bacteria, 24 different resistant phenotypes were found and 35.9% were multidrug resistant (MDR). The majority (87.2%) of the isolates identified belonged to the Enterobacteriaceae family. The presence of the blaTEM gene was detected in 23 out of 67 isolates (34.3%) and 16 of them presented MDR phenotypes. Four Klebsiella oxytoca isolates (6%) harbored a gene for the CTX‐M/OXY‐type enzyme. The direct sequencing of their purified amplicons confirmed the presence of three types of blaOXYgenes (blaOXY‐1, blaOXY‐2 and blaOXY‐5). These results suggest that without good hygienic practices, deli meats may act as a vehicle of transfer of β‐lactam‐resistant bacteria to the gastrointestinal tract of consumers. PRACTICAL APPLICATIONS In the current regulation on microbiological criteria for foodstuffs the test for Enterobacteriaceae is used as indicator of hygiene and contamination after processing. Nevertheless, the major concern for public health related to the presence of these bacteria in food is because of the emerging antibiotic resistance in this family, namely to β‐lactams. Consequently, the ever‐increasing consumption of ready‐to‐eat (RTE) food, can contribute to the spread of these resistant strains. In the present study different types of deli meats, sold at retail outlets in Portugal, presented levels of β‐lactam‐resistant Enterobacteriaceae that suggested the lack of strict hygiene control measures in the food chain. Without good hygienic practices, the dissemination in the community of antibiotic resistance genes may assume serious proportions.