From an individual approach to a Cluster strategy

Contaminated food and water are usual vehicles for bacterial pathogens transmission. According to EFSA they promote foodborne illness. Salmonella sp., Campylobacter sp., Listeria monocytogenes, Escherichia coli and Staphylococcus aureus are the most foodborne pathogens reported. Bacterial contamination levels remain at high level, particularly in Europe, despite regulatory efforts to address the situation. The need of new diagnostic tools is crucial. Ideally, tests easy to perform, enough accurate and low cost. The present work talk about optimization of a multiplex PCR (mPCR) test used to detect 5 foodborne contaminants: Salmonella sp., Campylobacter sp., L. monocytogenes, E. coli and S. aureus. For specificity evaluation, 5 PCR amplification reference DNA were used respectively: 103bp, 174bp, 151bp, 121bp and 136bp. No amplification was observed when primers and DNA from mismatching species were subject to PCR amplification. Furthermore, the sensitivity of this assay was evaluated by using serial dilutions of DNA extracted from clean 1CFU culture of each pathogen. This assay will be optimized by using Real-Time PCR and DNA plasmids containing a single copy of each gene, towards a new and rapid test for food and food manipulated surfaces control. Results are promising and allow us to postulate the design of an accurate and useful assay for bacterial control. Introduction Scientific literature indicates more than 1415 species known to be pathogenic for humans, and 61% of them are zoonotic (Taylor, et al., 2001). Despite the efforts done by industries, foodborne pathogens continue to be a challenge to public health institutions and a threat for consumers (Garrido, et al., 2013). According EFSA data, human cases of infections by Campylobacter sp. has shown a slightly decreased in 2012 for the first time in five years, but remain responsible for 214000 infections (EFSA 2014). Salmonella sp. is recognized as a major human foodborne pathogen (CDC 2008) and represents a human health concern (Carraco, et al., 2012). Human infection by Salmonella sp. has been decreasing, even if 91034 cases have been reported in 2012 (EFSA 2014). Human infections by Listeria sp., mainly by L. monocytogenes accounted for 10,5% more reported cases in 2012 than in 2011 and has been gradually increasing over the past five years (EFSA 2014). E. coli is a common commensal bacterium of mammalians. However, several strains integrate virulence factors promoting diarrhea, urologic, or systemic illnesses (CDC 2012, Jandhyala, et al., 2013). S. aureus is commonly associated with staphylococcal food poisoning (Alarcón et al., 2006). All these bacteria cause serious problem for human and animal health. So, it is of utmost importance to detect them by tracing food chain with rapid, sensitive, specific and low cost diagnostic tests (Fisher, et al., 2007). The aim of this work is to perform a new mPCR assay to detect these five foodborne pathogens.