Avaliação da ação dos mananoligossacarídeos fosforilados em infecções experimentais causadas pelas Escherichia coli enteropatogênicas de cães (DEPEC)

Abstract

“Infant diarrhea” is the name of the disease caused by enteropathogenic Escherichia coli (EPEC), which cause diarrhea with fever, nausea and vomits. The EPEC strains in this study have virulence factors similar to those of EPECs isolated from humans and are potentially infective for children and nursing mothers. In the present study, a phosphorylated mannanoligosacharide (Bio-Mos®) was employed; it is a non-digestible prebiotic, neither hydrolyzed nor absorbed at the upper part of the gastrointestinal tract and occupies the binding site for the pathogen in the intestine, preventing thus that bacteria bind to mannose at the intestinal epithelium. Of seven EPEC strains from dogs, SPA14 and 4083 were chosen for having caused diarrhea in preliminary tests. Experimental units consisted of 25 dogs distributed into five groups, one control and four inoculated, two groups treated with the prebiotic. When the animals were 60 days old, the hematological variables (lymphocytes, neutrophils and monocytes) and stool texture were observed after days 0, 5, 10, 15 and 20 after inoculation of both strains. The immunological variables IgG and IgA were analyzed at days 0, 10 and 20 and the bacteriological parameters (presence of the gene eae from EPEC reisolated from fecal culture) were assessed after 24h, 48h and 72h of the experimental infection; the experiment ended when the animals were 80 days old. Both strains caused diarrhea after 24 to 48 hours of inoculation and, in some cases, up to 72 hours. Polymerase Chain Reaction (PCR) indicated that there was a recuperation of the virulence factor by amplification of eae gene after inoculation of 4083 and SPA14 strains. There was no significant difference between groups as to number of blood cells and production of IgA and IgG. MOS was effective in the recovery of stool texture since the animals that received the prebiotic recovered more rapidly from the infection, compared to those that did not receive the treatment, showing thus its importance once diarrhea cause dehydration with nutrient and electrolytes losses. Studies characterizing EPECs improve the knowledge of the pathogenicity of these bacteria and become relevant in the field of Public Health.