Distribuição de bactérias clinicamente relevantes em alface e rúcula de cultivo convencional e orgânico e susceptibilidade aos antimicrobianos de amostras representativas da família Enterobacteriaceae isoladas

Abstract

Lettuce and arugula represent two of the most consumed vegetables in Brazil, because their nutritional values, availability, easy cultivation and / or low purchase price. Its cultivation is carried out in varied ways - conventional, organic and hydroponic cultivation - with emphasis on conventional and organic crops as the main ones practiced. The use of water for irrigation with antimicrobial residues or contaminated by microorganisms, plus manure and fertilizers are factors that favor the potential occurrence of resistence microorganisms against some antimicrobials. Outbreaks of diseases caused by food-borne microorganisms have been reported and the main etiologic agent identified is bacteria. The vegetables consumption by Brazilians happens basically in its fresh form, like salads, where the sanitization processes are not always enough for these agents elimination that may be pathogenic or not, but with the potential to spread antimicrobials resistance. It is therefore important to know the bacterial population present in vegetables and evaluate the susceptibility profiles against antimicrobials. In this study, 40 samples were obtained, 20 curly lettuce and 20 arugula, divided into 10 curly lettuce samples and 10 arugula ones from conventional cultivation and plus 10 curly lettuce samples and 10 arugula ones from organic cultivation. The tests were carried out at the Microbiology Study Center (CEMIC). Initially, the samples went through a manual, aseptic process, of removing damaged leaves, proceeding with dilutions and plating in selective media. Subsequently, the colonies were characterized and quantified according to the morphotype and staining using the Gram method for isolating the bacterial groups of interest. The results obtained, in the analyzed samples, showed a total of 359 isolates, divided into Gram positive cocci (114), Gram positive cocci suggestive of Enterococcus (55) and Gram negative bacillus (190). From this total, according to the morphotype characterization, qualitatively, 23 isolates were common to both cultivation types, while five morphotypes were found exclusively in conventional vegetables cultivation and 19 morphotypes in organic cultivation. Because the relevance in the antimicrobial resistance genes dissemination, the group of Gram negative bacillus was selected for further analysis. From a total of 190 Gram negative bacillus, 140 isolates belong to the Enterobacteriaceae family, and were used in this study. These 140 bacterial isolates were subjected to antimicrobial susceptibility testing and CLSI (Clinical and Laboratory Standards Institute) guidelines for phenotypic characterization.