"Clostridium difficile"pervalencia e importancia ecológica en animales domésticos y fauna salvaje

Abstract

Clostridium difficile is a grampositive anaerobic bacillus. It is known as causal agent, for different pathologies, affecting human beings. The most important ones are the antibiotic associated diarrhea and the pseudomembranous colitis. Moreover, it can cause pathologies as colitis or typhlocolitis in other animal species (mice, horses, dogs, cats, pigs, ostrichs,...). Furthermore, it is present in the intestinal tract of many different animals, although not related yet with any pathology. The main pathogenicity factors of C. difficile are A (tcdA) and B (tcdB) toxins, released by most of the strains and coded in the same pathogenicity locus. Their toxic activity acts in various intestinal mucous cells, mainly enterocytes, provoking injuries in the intestinal mucous and inflammation that end with diarrhea, colitis or pseudomembranous colitis. Some strains present the binary toxin (CDT) as well, which acts sinergically with both others two toxins. The example is the C. difficile hipervirulent strain 027. However, important details are absents in the study of this microorganism to elucidate its infective cycle, like its natural reservoir and the interactions in the intestinal ecosystem. According to that, in this thesis the reservoir of C. difficile has been studied, as well as the role of different animals in the keeping of the illness. Additionally, non described bacterial species that may form part of the animal intestinal normal flora, controlling growing C. difficile, have been isolated and studied, too.