Ability of Escherichia Coli to Form Biofilm in Tomato Fruits (Solanum Lycopersicum L.)

Abstract

Foodborne diseases are a serious public health problem worldwide, frequently caused by bacterial pathogens, many of these microorganisms are capable of protecting themselves from unfavorable environmental conditions by forming a biofilm, which allows them to colonize successfully inert surfaces and living substrates, such as edible fruits. The objective of this study was to evaluate the formation of biofilms by Escherichia coli of different origins, using the microtiter technique, which allows measuring the Optical Densities (OD) produced by the adhesion of bacterial communities to the surfaces, we evaluated a total of 12 E. coli strains, using two different culture media (minimum essential medium with glucose and Bertanni broth) and 24, 48 and 72 hours of incubation. The results showed that the strains differed in their biofilm production levels, with no difference between the two-culture media, reaching its maximum production level at 72 hours. Once the biofilm production results were obtained, the E. coli-producing strains, serotype O157:H7 and 93300 157:H7, were subjected in the laboratory to a bacterial adhesion test on the epidermis of tomato fruits (Solanum lycopersicumL. ) in order to obtain OD, an acetic-curing silicone-based well was designed, which allowed the microtiter technique to be used accurately; when favorable results were obtained, the study was set up under greenhouse conditions, simulating the natural form of these bacteria to reach the fruits still cultivated, the results showed that both strains form biofilms in the tomato fruits, both in green and ripe fruits, greenhouse conditions provide microenvironmental advantages to the bacteria capable of protecting them from external conditions, including the cleaning and disinfection, which could increase its incidence and morbidity.