Intestines adherence mechanism

Enteric bacterial pathogens must maneuver through a lengthy stretch of hazardous terrain before they reach their intended target or infection site within a host. Initially, they must tolerate salivary enzymes having various hydrolytic activities in the mouth, followed by exposure to shedded epithelial cells in the esophagus that may prevent local bacterial adherence (Pearson and Brownlee, 2005). In the stomach, bacteria must endure another severe environment created by the secretion of digestive enzymes and hydrochloric acid (up to 0.1 M concentration and a pH as low as 1.0). Once bacteria reach the intestines, they then encoimter mechanical. 

The proposed mechanism of small bowel damage due to Osmosin is that the tablets adhered to the intestinal wall (or became lodged in diverticula), resulting in much higher local concentrations of indometacin and potassium than usual. 

However, several DFM strains of LAB have been shown to exert beneficial effects in the intestinal tract without possessing this property, so other mechanisms such as colonization of adherence sites could be involved with reduction of the pathogen in the animal. 

Bacteria causing gastrointestinal infection need to penetrate the mucus layer before attaching themselves to the epithelial surface. This attachment is usually mediated by bacterial fimbriae or pilus structures, although other cell surface components may also take part in the process. Adherent bacteria colonize intestinal epithelium by multiplication and initiation of a series of biochemical reactions inside the target cell through signal transduction mechanisms (with or without the help of toxins) (51). 

Most of the microorganisms are bound and/or mechanically removed via discharge of mucus from the upper respiratory tract, or via the urine, saliva, and tears, or by entrapment and elimination in the intestinal contents before they have the opportunity to multiply. Some adhere to inert bodily structures. For example. Streptococcus mutans attaches to the enamel surface of the teeth (tartar, plaque) in order to elicit dental caries [13],... 

Amar, J., Chabo, C., Waget, A., Klopp, R, Vachoux, C., Bermudez-Humaran, L. G., et al. (2011). Intestinal mucosal adherence and translocation of commensal bacteria at the early onset of type 2 diabetes molecular mechanisms and probiotic treatment. EMBO Molecular Medicine, 3(9), 559-572. 

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