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87 Cards in this Set
- Front
- Back
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The cohabitation of normal flora and human body is an example of ___.
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symbiosis
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Symbiosis in which both parties benefit is ___.
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mutualism
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Symbiosis in which one party gains and the other is unaffected is called ___.
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commensalism
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Symbiosis in which one party gains and the other is harmed is called ___.
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parasitism
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What is the difference between 'infection' and 'disease'?
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Infection = invasion or colonization of the body by a pathogenic microorganism
Disease = damage or injury to body that impairs function |
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Define pathogenic.
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disease causing
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The naming convention for bacteria is ___ ___ or _ ___.
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Genus species or G. species
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Define strain.
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A population of bacteria descended from a single cell in clonal fashion.
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What does pathogenicity refer to? Is it qualitative or quantitative?
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The ability of an organism to cause disease. It is qualitative.
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A ___ is capable of harming a normal host (an example being ___ ___). An ___ ___ harms a compromised host (an example being ___ ___).
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pathogen: Mycobacterium tuberculosis
opportunistic pathogen: Pseudomonas aeruginosa |
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What does virulence measure? How can it be expressed? Is it qualitative?
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Virulence is a measure of pathogenicity. It can be expressed as the cell number that will elicit a pathogenic response in a host in a given time period. No,it is QUANTITATIVE.
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What are the four classifications of bacterial infection?
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1) primary infection
2) secondary 3) subclinical 4) nosocomial |
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Define secondary infection.
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Infection caused by an opportunistic parthogen after a primary infection.
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Define subclinical infection.
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No apparent symptoms.
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Define nosocomial infection.
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Acquired as a consequence of hospitalization.
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What are the three classifications of bacterial infection that pertain to location?
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local, systemic (generalized), focal
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What are the 6 key factors influencing the outcome of a bacterial infection?
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1) underlying disease or infection (eg AIDS)
2) stress 3) poor nutrition 4) age 5) immunosuppressive therapy 6) genetics of the host defence system |
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What is the most numberous and obvious microbial component of the normal flora?
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Bacteria
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What does the normal flora contain besides bacteria?
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come methanogenic Archaea and a few eukaryotic fungi
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How do bacteria of the normal flora benefit from us?
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nutrients, stable environment / protection, mode of transport
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In what three main ways do we benefit from the normal flora?
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- inhibits bacterial infection
- pH, nutrients, O2 levels - nutritional synergisms - synthesis of vitamins - steroid metabolism - organic acid production - stimulation of immune system - glycosidase reactions |
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What are two disadvantages of the normal flora?
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pathogenic potential when introduced into other locations
- ie E. coli production of intestinal gas |
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What 5 vitamins do the normal flora produce?
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thiamin
riboflavin pyridoxine vitamin B12, K |
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What gases do the normal flora produce?
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CO2
CH4 H2 |
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What odor-causing molecules are produced by the normal flora?
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skatole
butyric acid H2S NH3 amines indole |
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What organic acids are produced by the normal flora?
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butryic acid
acetic acid propionic acid |
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Is the fetal environment stable before birth, or are babies born with normal flora?
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It is sterile. Normal flora acquired shortly after birth
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What factors affect the composition of the normal flora?
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Diet
Infection Oral antiobiotic therapy |
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What is colitis caused by?
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The overgrowth of Clostridium difficile
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What determines the location of the normal flora?
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Bacteria's tissue preference for colonization
Interaction with human receptors expressed at specific locations Biofilms tend to attract large amounts of bacteria to one site |
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What are the three classifications of bacterial infection that pertain to location?
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local, systemic (generalized), focal
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What are the 6 key factors influencing the outcome of a bacterial infection?
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1) underlying disease or infection (eg AIDS)
2) stress 3) poor nutrition 4) age 5) immunosuppressive therapy 6) genetics of the host defence system |
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What is the most numberous and obvious microbial component of the normal flora?
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Bacteria
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What does the normal flora contain besides bacteria?
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come methanogenic Archaea and a few eukaryotic fungi
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How do bacteria of the normal flora benefit from us?
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nutrients, stable environment / protection, mode of transport
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In what three main ways do we benefit from the normal flora?
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- inhibits bacterial infection
- pH, nutrients, O2 levels - nutritional synergisms - synthesis of vitamins - steroid metabolism - organic acid production - stimulation of immune system - glycosidase reactions |
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What are two disadvantages of the normal flora?
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pathogenic potential when introduced into other locations
- ie E. coli production of intestinal gas |
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What 5 vitamins do the normal flora produce?
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thiamin
riboflavin pyridoxine vitamin B12, K |
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What gases do the normal flora produce?
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CO2
CH4 H2 |
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What odor-causing molecules are produced by the normal flora?
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skatole
butyric acid H2S NH3 amines indole |
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What organic acids are produced by the normal flora?
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butryic acid
acetic acid propionic acid |
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Is the fetal environment stable before birth, or are babies born with normal flora?
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It is sterile. Normal flora acquired shortly after birth
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What factors affect the composition of the normal flora?
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Diet
Infection Oral antiobiotic therapy |
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What is colitis caused by?
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The overgrowth of Clostridium difficile
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What determines the location of the normal flora?
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Bacteria's tissue preference for colonization
Interaction with human receptors expressed at specific locations Biofilms tend to attract large amounts of bacteria to one site |
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Average area of human adult's skin
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2 m^2
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What areas of skin are microorganisms associated with?
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sweat glands, armpit, genital region, between toes, upper region of hair follicles
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What microbial nutrients do the sebaceous glands secrete?
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urea, amino acids, salts, lactic acid, lipids
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Give two examples of commensal skin flora
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Staphylococcus epidermidis
Micrococcus sp. |
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Give an example of a potentially pathogenic skin flora
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Staphylococcus aureus (around nostrils)
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What affects skin flora?
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weather,
age, hygiene diet |
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Why is saliva not a good culture for bacteria?
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Few nutrients
lysozyme lactoperoxidase |
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What does lysozyme do to bacteria?
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Weakens cell wall by cleaving glycosidic linkages in peptidoglycan
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What does lactoperoxidase do to bacteria?
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kills bacteria, creating singlet oxygen
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What makes the mouth a good site for flora?
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food particles
epithelial debrees |
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As the teeth appear in an infant, there is a shift toward ___ bacteria
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anaerobic, adapted to gingival crevices and tooth surface
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Define plaque
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a type of complex biofilm on tooth surfaces
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What is the name given to the adherent substances produced by organisms in plaque?
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glucans
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Define 'dental caries' (cavities)
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destruction of enamel, dentin, or cementum of teeth caused by acid-producing bacteria in plaque
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What organism is most associated with dental caries
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Streptococcus mutans
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Define periodontal disease. What is the most common form?
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bacterial infection that affects supporting structure of teeth. Ginvitis
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What are the most common infectious diseases in the world?
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periodontal diseases and caries
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What does the GI tract consist of?
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stomach, small and large intestine
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The majority of GI tract flora are __robic bacteria. Three examples.
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anaerobic
E. coli Bacteroides Lactobacillus |
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E. coli has what type of respiration?
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facultative anaerobe
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Bacteroides has what type of respiration?
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strict anaerobe
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Lactobacillus has what type of respiration?
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aerotolerant anaerobe
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How high is bacterial count in stomach? Why?
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Low. Acidic
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One example of a bacteria colonizing stomach wall
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Helicobacter pylori (gastric ulcers)
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What does the small intestine consist of?
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Duodenum
Jejunum Ileum |
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What does the large intestine consist of?
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Colon
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What major physiological process occurs in stomach? pH?
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Secretion of acid
Digestion of macromolecules pH=2 |
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What major physiological process occurs in small intestine? pH?
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Continued digestion
Adsorption of monosaccharides, amino acids, fatty acids, water pH=4-5 |
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What major physiological process occurs in large intestine? pH?
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Adsorption of bile acids, vitamin B12
pH=7 |
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What bacteria inhabit small intestine?
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Enterococci
Lactobacilli |
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What bacteria accounts for 90% of intestinal flora within a week of infant feeding?
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Bifidobacteria
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Describe nostril flora
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- always heavily colonized
- predominantly Staphylococcus epidermidis - sometimes Staphylococcus aureus (potential pathogen) |
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describe sinus flora
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normally sterile
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describe LRT flora
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virtually free. Cilia sweep bacteria upward, then expelled by sneezing
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describe URT flora
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- large number
- around mucous areas |
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Give two diseases that can damage resp tract epithelium
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bronchitis or viral pneumonia
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What causes whooping cough?
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Bordotella pertussis colonizing the tracheal epithelium
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Is urine normally sterile?
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yes
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What does Lactobaciluus sp. do?
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Colonizes vagina, lowers pH, confers protection
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What produces yeast infection?
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antibiotic therapy removing natural bacteria, leading to colonization by candida
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Define gnotobiotic
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germ-free
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Give six characteristics of gnotobiotic animals
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abnormal anatomy/physiology
underdeveloped lymphatic tissue poor immune system thin intestinal wall low antibody titer higher susceptibility to pathogens reduced susceptibility to certain disease processes (ie dental caries) |
