Prospecção de peptídeos antimicrobianos em solo do Cerrado e avaliação de antimicrobianos combinados no controle de Escherichia coli, Klebsiella pneumoniae e Staphylococcus aureus in vitro

Abstract

Bacterial resistance is one of the greatest world health threats, reducing the effective infections treatment and increasing mortality associated to common bacterial diseases. In this context, the strategies search for pathogens and antimicrobial resistance control is necessary. Two of the strategies developed to combat these microorganisms have been the combined antimicrobials therapy and antimicrobial peptides prospection. In the present work, we have investigated the in vitro peptides effectiveness prospected from the Cerrado soil and the in vitro effectiveness of antimicrobials diminazene aceturate, chloramphenicol and streptomycin alone and in combination against clinical isolates of E. coli, K. pneumoniae and S. aureus. For bioprospection, the material was collected from native Cerrado soil, the total proteins were extracted and the peptides were further identified by LC-MS / MS. Peptides were analyzed by sense the moment and CAMP algorithms, in order to predict antimicrobial peptides. Of all peptides with possible antimicrobial activities, 7 were selected, synthesized and in vitro tested against bacterial isolates. Synthetized peptides did not show antimicrobial activity when challenged by Gram-positive and Gram-negative bacteria. Thus, for this work, in silico prospecting, the metaproteomics associated with the prediction algorithms, has not been shown to be an effective method for the identification of antimicrobial peptides. In addition, for the second control strategy, aceturate has been shown to be synergistic with streptomycin and chloramphenicol against E. coli and K. pneumoniae isolated from humans and animals. Against S. aureus, otherwise, a synergistic effect was observed in combination with aceturate and chloramphenicol. These combinations of antimicrobials showed important results, demonstrating that this strategy can be used as an alternative at pathogens control.