RESUMO
The development of new antimicrobial peptides has become an attractive alternative to conventional antibiotics due to the increasing rates of microbial drug resistance. Ib-M corresponds to a family of cationic synthetic peptides, 20 amino acids in length, that have shown inhibitory effect against the non-pathogenic strain Escherichia coli K-12. This work evaluated the antimicrobial potential of Ib-M peptides against the pathogenic E. coli O157: H7 using a reference strain and a clinical isolate. The Ib-M peptides showed antibacterial activity against both strains of E. coli O157: H7; the minimum inhibitory concentration of Ib-M peptides ranged from 1.6 to 12.5 µM and the minimum bactericidal concentration ranged from 3.7 to 22.9 µM, being Ib-M1 and Ib-M2 the peptides that presented the highest inhibitory effect. Time-kill kinetics assay showed a reduction of the bacterial population by more than 95% after 4 hours of exposure to 1xMIC of Ib-M1. Low cytotoxicity was observed in VERO cells with 50% cytotoxic concentration in the range from 197.5 to more than 400 µM. All peptides showed a random structure in hydrophilic environments, except Ib-M1, and all of them transitioned to an α-helical structure when the hydrophobicity of the medium was increased. In conclusion, these findings support the in vitro antimicrobial effect of Ib-M peptides against the pathogenic bacteria E. coli O157: H7 and prove to be promising molecules for the development of new therapeutic alternatives.
Assuntos
Antibacterianos/farmacologia , Escherichia coli O157/efeitos dos fármacos , Animais , Chlorocebus aethiops , Resistência Microbiana a Medicamentos , Testes de Sensibilidade Microbiana , Células VeroRESUMO
Introducción: La transmisión de Trypanosoma cruzi por transfusiones sanguíneas representa la segundalínea de infección después de la vectorial, lo que hace necesario identificar algunas particularidadessocioepidemiológicas en los donantes que permitan predecir la infección por Trypanosoma cruzi. Objetivo: Determinar la prevalencia de anticuerpos anti-Trypanosoma cruzi y los factores de riesgo de seropositividad en donantes de sangre voluntarios del Hemocentro y Unidad de Aféresis de Valledupar, Colombia. Materiales y métodos: Se realizó un estudio descriptivo de corte transversal en 170 donantes de sangre voluntarios reclutados entre 2013 y 2014. La detección de anticuerpos IgG anti-Trypanosoma cruzi se realizó mediante pruebas serológicas. Las variables que predicen la seropositividadpara Trypanosoma cruzi se indagaron mediante un cuestionario socioepidemiológico y un posterioranálisis bivariado y de regresión logística...
Introduction: Transmission of Trypanosoma cruzi through blood transfusions represents the second most frequent mechanism after the vectorial transmission. Therefore, it is necessary to identify some socioepidemiological characteristics that allow predicting the Trypanosoma cruzi infection on the donors. Objective: To determine the prevalence of anti-Trypanosoma cruzi and risk factors for seropositivity in voluntary blood donors at the Hemocentro y Unidad de Aferesis de Valledupar, Colombia. Materialsand methods: A descriptive cross-sectional study was conducted in 170 volunteer blood donors recruited between 2013 and 2014. Detection of IgG antibodies anti-Trypanosoma cruzi was performed by serological tests. The inquiry about the predictors of seropositivity for Trypanosoma cruzi was made through a socioepidemiological questionnaire, followed by a bivariate analysis and logistic regression...