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Microbio Final Exam Study Guide

Microbio Final Exam Study Guide - Lecture 29 Definitions...

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Lecture 29 Definitions - Pathogen: Any disease-producing organism (can be opportunistic). - Pathogenicity: The ability to produce pathologic changes or disease. - Virulence: Quantitative measure of pathogenicity. - Infection: Colonization and growth of microbes in the host. - Disease: Damage or injury to the host. - Normal flora: Mixture of microbes normally found at any anatomical site in a healthy organism. - Resident flora: Colonizing. Flora consistently found on the skin. - Transient flora: Contaminating. Flora do not colonize or persist, do not survive for extended periods on skin. - Propionibacterium Acnes: Normal inhabitant of skin but is associated with the disease acne vulgaris. The organism thrives in sebum produced by oil glands. Growth of bacteria triggers inflammation. - Immunocompromised host: A host with a weakened immune system (lower resistance to infection). - Bacterial Interference: Most the time, normal flora protect the host from colonization by pathogenic microorganisms. o Lactobacilli in female genital tract. o Corynebacteria on skin. - Gnotobiotic: Literally means “known life” -> known flora. Typically used to mean germ free. Concepts - The most common tissue type for microbial colonization is the mucus membranes. It is found in the mouth, respiratory, urinary and gastrointestinal tract. - The three main kinds of host-microbe interactions are... o Loose association o Adhesion o Invasion - Two major microbial diseases of the oral cavity are… o Dental caries o Gingivitis - Two enzymes found in saliva that protect against microbial infections and how? o Lactoperoxidase: uses hydrogen peroxide to make singlet oxygen, a natural antibiotic. o Lysozyme: cleaves peptidoglycan and kills bacteria. - How does the stomach protect against entry of pathogenic microbes? How does Helicobacter survive? o The stomach has a very acidic pH of 2 which kills most microbes. Helicobacter pylori can survive the acidic conditions by living in the mucosal lining of the stomach. This microbe has urease; hydrolyzes urea (diffusing in from the blood) which results in increased pH (a buffer around the cells) allowing colonization.
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- What type of microbe makes the large intestine an anaerobic environment? Also what are the benefits of intestinal microbes? o Facultative aerobes such as E. coli consume any oxygen present making it anaerobic. o Benefits are… Vitamin synthesis B12, pyridoxine, thiamin, K Glycosidase activity Lots of sugar fermenters Steroid metabolism Bile acids are converted to steroids that are reabsorbed. - What condition prevents pathogenesis of the vagina by microbes? o It is acidic which usually kills microbes. Lecture 30 Vocabulary - Virulence Factor: A pathogen-produced substance (usually a protein, enzyme, adherence factor or toxin) that promotes the establisment and maintanence of a disease.
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Microbio Final Exam Study Guide - Lecture 29 Definitions...

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