Occurrence of virulent Serratia marcescens with co-existing antibiotic resistance determinants in ready-to-eat food samples

Background: Foodborne illness is a global concern and identification of pathogens that cause foodborne disease is a public health priority. Serratia marcescens is an opportunistic pathogen responsible for food poisoning due to its ability to colonize the gastrointestinal surfaces. S. marcescens is also responsible for causing a wide range of extraintestinal infections like pneumonia, urinary tract infection, keratitis, etc. Aim: The current study investigated the presence of antibiotic resistant virulent S. marcescens from street food samples. Methods: Two pigmented S. marcescens were recovered from Panipuri samples which were then identified using VITEK® GN cards. The virulence genes and the antibiotic resistance genes harboured by the S. marcescens isolates were investigated and further transformation assay was conducted to check the horizontal transferability of the plasmid carrying the antimicrobial resistance genes. Incompatibility typing of the transformants were also assessed and ERIC PCR was performed to check the heterogeneity of the S. marcescens isolates. Results: Two S. marcescens isolates harbouring virulence genes as well as antibiotic resistance genes were detected in this study and it was observed that Inc FIB type plasmid was carrying the resistance genes. Conclusion: The co-existence of both the virulence and antibiotic resistance genes in the two S. marcescens isolates warrants proper surveillance in order to prevent the spread of such pathogenic strains in environment as well as community through food samples.