Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Outline made by: Caleb Richards Checked by: (insert secondary author name after checking) • • Define commensal organisms, opportunistic pathogens, strict pathogens and the different types of relationships that organisms have with their hosts. • Normal flora are frequently found in the body of healthy persons, and while it tends to remain constant for a given person, pretty much everybody has a different set of normal flora • Flora can be transient (deposited from environment or shed from mucous membranes or residential • Commensal intestinal bacteria are able to do: ( I.S.S.S.) • I- Infection resistant (out- compete pathogenic bac. Due to size. • S-source of nutrients ex. digest vitamin k, and help make vitamin B • S- Stimulate tissue turnover ex. Help turn over gut epithelia. • S- Stimulate immune system to produce antibiotic substances. • Obligate pathogens are almost always associated with disease in humans • Opportunistic pathogens are normally harmless, but can be dangerous if the pt is immunocompromised (cancer tx, antibiotics, transplants) • Most ideal type of symbiosis is mutualism • Anaerobes typically outnumber aerobes by 100:1 Describe the normal flora that is present in the different parts of the human body. • Normal flora are always present in skin, respiratory tract, digestive tract, urinary tract, and reproductive tract ( weird memorize tip SUDRR-Mouth • SUDRR-Mouth: Skin, Urinary tract, Dig. Tract, Respiratory Tract, Reproductive tract, & Mouth) • Internal flora is typically gram negative, while skin flora is usually gram positive (most commonly coagulation-negative staphylococci) • When you get old, the original skin bacteria gets replaced with yeasts • Microbial density in skin goes: surface<intrafollicular<under occlusive dressing • Skin microflora can make acids by metabolizing sebaceous secretions • • Most common vaginal bacteria: lactobacillus (post-menopausal, replaced by gramnegative bacilli) • Most common large intestine bacteria: eschericha coli • Propionibacteria is the flora present on our faces that caused most of us miserable acne as teenagers. • In the respiratory tract, the trachea, bronchi, and lungs have low or nonexistent flora populations. • Fetus is initially sterile; lactobacilli multiply in vagina before birth, and newborn intestine is initially colonized with lactobacillus as well, and additional organisms are introduced thru breathing and feeding • Staphylococcus species are most common cause of skin and wound infections Explain the qualities and roles of normal flora (location, infectious potential, contribution to health of host through competition, maintenance of environmental conditions). • Benefits of bacteria: germ-free animals have been found to have lower levels of Igs and were more often overweight. Bacteria can also help us digest complex carbs. • We have 10x more microorganism cells than human cells (10^13:10^14) • Toxic compounds can be released if normal flora find their way into the wrong part of our body by reacting dangerously with certain biochemical molecules. • The heavy amount of anaerobic bacteria on our skin is encouraged by our hair follicles and sebaceous fluids (it’s a good environment for them) • Medical implant infections are most commonly caused by p. acnes and p. granulosum • Tooth enamel is most often decayed by anaerobic bacteria metabolism going on between your teeth (germ-free animals don’t get cavities) • Oropharynx flora is most commonly found in teeth and gingivial surfaces, and less often found in nasal washings. • Trauma from oral cavity can cause s. sanguis to enter bloodstream, adhere to heart valve, and cause endocarditis • Helicobacter pylori can cause peptic ulcer disease, gastritis, and gastric cancer, although most carriers are asymptomatic • Largest intestinal flora categories are bacteroidetes (gram -) and firmicutes (gram +). Bacteroidetes have been associated with weight loss. • • • • Flora are absent from brain, blood, lymph, muscles, cerebrospinal fluid, synovial fluid, deep tissue, and solid organs (heart/kidney/liver) • Small numbers of mostly transient microorganisms can be found in lungs, stomch/small intestine, bladder, and uterus Explain human defenses against infectious disease. • The mucociliary system traps bacteria in mucus and uses cilia to push it into the throat for swallowing. • Alveolar macrophages guard the lower respiratory tract. • Lysozyme degrades cell walls in nasal mucus • The highest concentration of microbes in the entire body is found in the colon (the ileum has similar types of bacteria, but less of them) • The colon flora are mostly anaerobic, and almost all are either gram negative or sporeforming gram positive Describe the interaction of the bacterial cell with the immune system. • Becomes Pathogenic in 3 ways: 1. Invasion, 2. Release Toxins, 3. Opportunistic infec. • Local invasion can occur; for example, staph from skin can get in wound and cause infection. • Bacterial translocation occurs when viable bacteria from the GI tract pass to normally sterile tissues. • For example, if normal colonic bacteria invade the small intestine, you can get bowel overgrowth syndrome. • On mucous membranes, IgA can prevent attachment and opsonize bacteria • Few bacteria leave the stomach due to its low pH • Duodenum has few bacteria due to bile salts, pancreatic enzymes, and impact of low stomach pH Discuss methods of bacterial adaptation to host immunity. • Gram + bacteria have lipotechoic acid wall and are immune to complement lysis • Gram – bacteria have LPS/lipoprotein wall; the LPS is immunogenic, and complement activation causes macrophage lysis • • Mycobacteria have a glycolipid wall and are eliminated via cell-mediated immunity (CMI) • Spirochetes have no organized cell wall, and are subject to elimination by complement and antibodies • Commensals limit pathogenic organisms by: displacement, mucin secretion to prevent attachment, metabolic products (fatty acids, lower pH), compete for nutrients, and create antibiotic substances Explain the role of bacterial adaptation to host immunity in development of disease. • In antigenic variation, a pt is infected, immune response clears the infection, then a subsequent infection of a different type occurs, and the immune response clears this one. • To successfully infect, bacteria must gain entry, adhere, invade immunity, and cause tissue damage • Some bacteria can escape phagosomes and live safely in the cell cytosol. Not included in outline: Lists of specific names/pathogenesis of normal flora typically found in each area of the body. This seemed too detailed for this particular lecture, and I’m pretty sure this is discussed in detail in another lecture…