Invasive bacteria

Stool may also be analyzed for mucus, fat, osmolality, fecal leukocytes, and pH. The presence of mucus suggests colonic involvement. Fat in the stool may be due to a malabsorption disorder. Fecal leukocytes can be found in inflammatory diarrheas including infections caused by invasive bacteria (e.g., E. coli, Shigella, and Campylobacter species). Stool pH (normally greater than 6) is decreased by bacterial fermentation processes. 

Although theoretically safe, poorly absorbed antimicrobials could become absorbable in the presence of mucosal inflammatory or ulcerative changes [100], like those occurring in IBD or when invasive bacteria colonize the intestine. To verify whether the presence of intestinal lesions would affect rifaximin absorption, the drug was given to rats with experimentally induced colitis [101]. The indomethacin-induced enteropathy did not affect intestinal absorption of rifaximin. However, under the same experimental conditions, systemic bioavailability of neomycin did increase [101]. 

The presence of S. mutans and other cariogenic bacteria contributes towards the formation of a biofilm known as dental plaque, and their metabolism of fermentable carbohydrates in the diet leads to the formation of acids [12]. Dental caries has been described as a complex imbalance in physiologic equilibrium between tooth mineral and biofilm [13]. Biofilms imply the involvement of microbiological species [14], but the key concept included within this definition is that the bacteria involved are native to the body, not a group of specific invasive bacteria causing infection [14]. 

INVASIVE BACTERIA ENCOUNTER HOST DEFENSE ( PHAGOCYTES, COMPLEMENT, ANTIBODIES )... 

Figure 2. Counteracting strategies of invasive bacteria against unspecific host defense.

One of the roles of the BBB likely involves protection of the brain from invasive bacteria, viruses, and fungi. However, when under BBB disruption any of these parasites invades the brain, the immune system must respond. This implies that under certain conditions, lymphocytes cross the BBB and reach those sites in the brain where their protective functions are needed. The existence of tight junctions between endothelial... 

Fig. 1. Salmonella enterica serovar Typhimurium invasiveness is growth phase dependent. Salmonella grown to late log/early stationary phase (dotted line) are hyper-invasive (solid line). The gray bar illustrates the subculture time required to obtain hyper-invasive bacteria.

Forward Genetics with BAC Technology and Invasive Bacteria. 12... 

Ziegler D, Mariotti A, Pfluger V, Saad M, Vogel G, Tonolla M, Perret X. In situ identification of plant-invasive bacteria with MALDI-TOF mass spectrometry. Plos ONE. 2012 7(5) e37189. 

Bacteria cause disease of the gut as a result of either mucosal invasion or toxin produchon or a combinahon of the two mechanisms as summarized in Table 6.4. Treatment is largely directed at replacing and maintaining an adequate intake of fluid and electrolytes. Anhbiohcs are generally not recommended for infechve gastroenterihs. 

Brannstrom, M. Vojinovic, O. (1976). Responses of the dental pulp to invasion of bacteria around three filling materials. Journal of Dentistry for Children, 43, 83-9. 

Returning to bacteria, PC also appears to play a role in infection of humans by pathogenic strains/species by allowing colonization and invasiveness due to interaction with appropriate receptors on host endothelial cells (reviewed by Harnett and Harnett, 1999). This may act as a double-edged sword, however, as the PC on the surface of the bacteria can be targeted by both the innate and adaptive immune responses and indeed such responses appear to play a role in the control of H. influenzae and S. pneumoniae, respectively, in humans (reviewed by Harnett and Harnett, 1999). 

EPEC causes a degeneration of the microvillus brush border, with cupping and pedestal formation of the plasma membrane at the sites of bacterial attachment and reorganization of cytoskeletal proteins [43, 44], Invasion has been observed in some clinical specimens, but the mechanism of how this bacteria produces diarrhea is not fully understood. Some possibilities include an increase in permeability and loss in microvilli leading to malabsorption. 

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