Differential Proteomic Analysis of Lactic Acid Bacteria-Escherichia coli O157:H7 Interaction and Its Contribution to Bioprotection Strategies in Meat.

Alejandra Orihuel,Lucrecia Terán,Jenny Renaut,André M De Almeida,Graciela M Vignolo,Silvina Fadda,María L Saavedra

doi:10.3389/fmicb.2018.01083

Abstract

Human infection by Enterohemorrhagic Escherichia (E.) coli (EHEC) occurs through the ingestion of contaminated foods such as milk, vegetable products, water-based drinks, and particularly minced meats. Indeed EHEC is a pathogen that threatens public health and meat industry. The potential of different Lactic Acid Bacteria (LAB) strains to control EHEC in a meat-based medium was evaluated by using a simple and rapid method and by analyzing the growth kinetics of co-cultures (LAB-EHEC) in a meat-based medium. The activity of LAB toward EHEC in co-cultures showed variable inhibitory effect. Although, LAB were able to control EHEC, neither the produced acid nor bacteriocins were responsible of the inhibition. The bacteriocinogenic Enteroccus (Ent.) mundtii CRL35 presented one of the highest inhibition activities. A proteomic approach was used to evaluate bacterial interaction and antagonistic mechanisms between Ent. mundtii and EHEC. Physiological observations, such as growth kinetics, acidification ability and EHEC inhibitory potential were supported by the proteomic results, demonstrating significant differences in protein expression in LAB: (i) due to the presence of the pathogen and (ii) according to the growth phase analyzed. Most of the identified proteins belonged to carbohydrate/amino acid metabolism, energy production, transcription/translation, and cell division. These results contribute to the knowledge of competition strategies used by Ent. mundtii during its co-culture with EHEC setting new perspectives for the use of LAB to control this pathogen in meat.

Highlights

Contamination with Shiga toxin-producing Escherichia (E.) coli (STEC) and related enteric pathogens is among the main causes of concern and fresh meat product recalls
Yang et al (2017) studied mixed cultures of bifidobacteria with Listeria monocytogenes to detect the changes in their growth pattern after mutual interaction by applying a proteomic approach
The present study is the first where the Lactic Acid Bacteria (LAB) inhibitory potential against E. coli O157:H7 is evaluated in co-cultures using physiological and proteomic approaches

Summary

Introduction

Contamination with Shiga toxin-producing Escherichia (E.) coli (STEC) and related enteric pathogens is among the main causes of concern and fresh meat product recalls. In the United States, the Centers for Disease Control and Prevention (CDC) have estimated that STEC infections cause 73,000 illnesses, 2,200 hospitalizations, and 60 deaths yearly. High economic losses in meat industry and the high cost of the illness evidence the necessity of additional efforts to control this pathogen. STEC/EHEC constitutes a serious threat to public health and a major concern for the sustainability of the meat industry as well as for its entire production chain. Consumers assumed a crucial role requiring safer and healthier foods. This context highlights the need to provide the meat industry with sustainable and ecofriendly solutions to limit and prevent future risks surrounding this problematic

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