Sepsis is the result from a complex bacterial-host interaction, which is an often-fatal response when host protective molecular mechanisms designed to fight invading bacteria surpass the beneficial intensity to the point of causing injury to the host. Increasing evidences have implicated the bacterial translocation (BT) as the main source for the induction of sepsis, although the beneficial effect of BT process has been related to the development of the intestinal immune response by physiological interaction between bacteria and host. In this article, we examined evolving concepts concerning to BT and discussed about its potential role in the promotion of microcirculation injury, moreover, its possible participation in the sepsis induction. According to our data obtained from in-vivo BT animal-model, both bacterial overgrowth and bacterial pathogenic determinants seem to be major predisposing factors for the induction of BT. Besides, translocation of luminal bacteria through the lymphatic via elicits the activation of the GALT inflammatory response contributing to microcirculation injuries, and the haematological via of BT was responsible to the systemic bacterial spread. On other hand, the combination of BT process to the pre-existing host systemic infection played a crucial role in the worsening of the clinical outcome. In our understanding, studies concerning to intestinal immune response and the pathophysiology of bacterial-host interaction, under normal and disease conditions, seems to be the key elements to the development of therapeutic approaches towards sepsis.
Microcirculatory dysfunction plays a pivotal role in the pathogenesis of severe sepsis and septic shock; hence, microcirculation blood flow monitoring has gained increasing attention. However, microcirculatory imaging is still investigational in human sepsis and has not yet been incorporated into routine clinical practice for several reasons, including the difficult interpretation of microcirculation imaging data, difficulty to draw a parallel between sublingual microcirculation imaging and organ microcirculation dysfunction, as well as the absence of microvessel dysfunction parameters defining sequential microcirculatory changes from the early to late stages of the disease, which could aid in the context of therapeutic approaches and of prognostic parameters. The purpose of this review was to bridge the experimental abdominal organ microvascular derangement kinetics and clinical aspects of microcirculatory findings in the early phase of severe sepsis/septic shock.
Diarrhea is the second leading cause of death of children up to five years old in the developing countries. Among the etiological diarrheal agents are atypical enteropathogenic Escherichia coli (aEPEC), one of the diarrheagenic E. coli pathotypes that affects children and adults, even in developed countries. Currently, genotypic and biochemical approaches have helped to demonstrate that some strains classified as aEPEC are actually E. albertii, a recently recognized human enteropathogen. Studies on particular strains are necessary to explore their virulence potential in order to further understand the underlying mechanisms of E. albertii infections. Here we demonstrated for the first time that infection of fragments of rat intestinal mucosa is a useful tool to study the initial steps of E. albertii colonization. We also observed that an E. albertii strain can translocate from the intestinal lumen to Mesenteric Lymph Nodes and liver in a rat model. Based on our finding of bacterial translocation, we investigated how E. albertii might cross the intestinal epithelium by performing infections of M-like cells in vitro to identify the potential in vivo translocation route. Altogether, our approaches allowed us to draft a general E. albertii infection route from the colonization till the bacterial spreading in vivo.