The Host - when a baby begins nursing and eating food more...

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The Host The animal, plant, bacterium, or human infected is termed the host. Infection is an interaction of host and pathogen. Both have factors that ward off the other. Here we will discuss some host factors. NON-SPECIFIC HOST FACTORS: Normal microbiota (normal flora or indiginous flora): These are organisms which normally reside in and on the body. Staphylococcus epidermis, Lactobaccilli in the female urogenital system, Propionibacteria and Corynebacteria on the skin, Streptococcus species in the mouth and so on. These organisms have an inhibitory effect on other organisms by: 1. Competition for nutrients 2. Production of chemicals like bacteriocins which directly inhibit other organisms. Escherischia coli and a number of anaerobes (belonging to Clostridium and other genera) occupy the colon. 3. By tying up receptors that pathogens need to colonize a host. Normal microbiota are added at birth and come from the birth canal. Later,
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Unformatted text preview: when a baby begins nursing and eating food more organisms are added. The development of the digestive system would be abnormal without organisms present. If the normal microbiota gets out of balance due to antibiotic therapy a normal inhabitant may selectively survive and cause problems. Digestive problems after antibiotic therapy are almost always due to Clostridium difficile. Its spores probably resist the antibiotics then germinate after therapy is over. Result = diarrhea and other complaints. Urogenital and Oral Yeast infections also can result from imbalances in host microbiota. The white patches of yeast shown cannot be scraped off because the Candida yeast produces hypae like a mold which invades and anchors the organism to the tissue. Transients are organisms that cause no harm but remain for a short time on the host....
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This note was uploaded on 01/23/2012 for the course MCB MCB2010 taught by Professor Smith during the Fall '09 term at Broward College.

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