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101 Cards in this Set
- Front
- Back
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What is Nonselective media?
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Media that permits growth of a wide range of organisms
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What are 3 examples of nonselective media?
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-Chocolate
-LB -TSA |
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What is Selective media?
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Media that inhibits growth of some organisms, but not others.
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What is another name for Selective media?
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Enrichment media
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What are 3 examples of Enrichment media?
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-Mac
-Mannitol Salt -Antibiotic-containing |
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What is Differential media?
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Media that allows distinguishing of organisms based on their metabolic characteristics.
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What makes Differential media different?
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Different dyes
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3 examples of differential media:
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-Mac
-Mannitol Salt -LIA |
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What are 4 main classes of bacteria?
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-Saprophytes
-Commencials -Opportunistic -Pathogens |
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What are Saprophytes?
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Most bacteria
-Not associated w/ disease -Free living |
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Whats a good example of a Saprophyte?
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Bacillus species
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What are Commencials?
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Most bacteria within a host
-They live in association w/ host -Benefit both themself and host |
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What is a good example of a commencial bacteria?
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Staphylococcus
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What are Opportunistic bacteria?
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Those that cause disease in compromised hosts.
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What are 3 ways that hosts can be compromised?
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-Immunosuppression
-Transplantation -Chemotherapy |
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What is a good example of an Opportunistic bacteria?
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Pseudomonas
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What are Pathogenic bacteria?
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Bugs that cause disease in a COMPETENT host
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What is a good example of a pathogenic bacteria?
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Bacillus anthracis
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What is the only time during which a human will lack bacteria and be GNOTOBIOTIC?
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In utero
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What are the body sites that host normal flora?
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All body surfaces exposed to the external environment.
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How many bacteria do we normally have living as normal flora?
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10^14
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WHat are humans MORE; mammalian or prokaryotic cells?
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Bacteria!
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Do we always host the same normal flora?
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No, organisms change based on variations in diet, hygiene, age, etc.
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Where do humans host the largest mass in grams of microflora?
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Intestines
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At what body site is the 2nd largest mass of microflora?
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Skin
(1/5 the amt in the gut) |
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What type of bacteria dominate the skin microflora?
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Gram positive species
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Where are normal flora in the Urinary Tract?
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Only at the DISTAL region; the upper urinary tract is generally sterile.
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What is the dominant microflora in the vagina?
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Lactobacillus
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What part of the resp tract is normally populated by microflora?
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Upper resp tract - the lungs are generally sterile.
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What portion of the GI tract is populated with microflora?
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The colon - the stomach is only very sparsely habitated.
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Why are there predominantly gram pos species on the skin?
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Because they can survive the higher salt concentration due to their thicker cell wall.
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What is the bacterium responsible for odor generation?
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Corynebacterium xerosis
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What is the major route of nosocomial Staph transmission?
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Shedding of squamous cells
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What are the respiratory requirements of skin microflora?
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-Obligate aerobes
-Facultative aerobes |
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What 2 physical features allow microflora to inhabit the skin?
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-Ability to adhere to keratinized epithelial cells
-Ability to tolerate high salt concentration |
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What are 2 skin microflora that are opportunistic pathogens?
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-Staph aureus
-Staph epi |
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What are 3 diseases Staph aureus can cause in immunosuppressed patients?
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-Boils
-Wound infections -Food poisoning |
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What are 2 infections caused by Staph epi?
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-Infective endocarditis
-Infections of prosthetic devices/heart valves |
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How many bacteria are there in the mouth? How many types of species?
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-10^10 bacteria
-500 different species |
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What types of infections can occur on teeth?
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Bacterial aggregates - BIOFILMS (disgusting)
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What are the respiratory requirements of the predominant bacteria in the oral cavity?
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Facultative anaerobes
Obligate anaerobes |
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What are the opportunistic pathogens in the oral cavity normal flora that can give rise to disease?
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-Alpha hemolytic streps
-Nonhemolytic streps |
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What are the alpha/non-hemolytic streps?
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-Strep viridans
-Enterococci |
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What disease do dental pathogens give rise to?
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Bacterial endocarditis
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What are 2 of the respiratory tract mechanisms of defense against bacterial colonization?
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-Hairs in the nares
-Mucociliary escalator |
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What bacteria are capable of colonizing the respiratory tract?
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-Those that resist expulsion
-Those that survive antibacterial factors in mucus |
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What are 6 antibacterial factors in mucus?
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SLLACS
-Secretory IgA -Lysozyme -Lactoferrin -Antibodies -Complement -Superoxide radicals |
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At what level of the resp tract does sterility become the norm?
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Trachea
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What are the microfloral species that inhabit the oropharynx?
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Very complex
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What are 5 typical microflora species in the Nasopharynx?
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-Staph species
-Micrococcus species -Corynebacterium species -Neisseria -Haemophilus |
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What are 3 common microflora in the nares?
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-Staph
-Micrococcus -Corynebacterium |
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What is the predominant species in the oropharynx?
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alpha-hemolytic streps
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What are the predominant GI tract microflora in terms of respiratory requirements?
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Anaerobic
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What is the consequence for GI microflora being in fluid filled cavities?
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Adherence to mucosal surfaces is less important.
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What are the opportunistic pathogenics in the stomach?
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-Streptococcus species
-Helicobacter pylori |
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What are opportunistic pathogens in the Duodenum?
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-Streptococcus species
-Bacteroides species |
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What are the opportunistic pathogens in the Jejunum?
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Streptococcus species
Bacteroides species (same as in duodenum) |
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What are the opportunistic pathogens in the Ileum?
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Enterococcus faecalis
Bacteroides Clostridium Enterobacteriaceae |
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What are the opportunistic pathogens in the colon?
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Bacteroides
Enterococcus Clostridium |
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What are 2 opportunistic pathogens that survive the very acidic environment of the stomach?
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-Streptococcus species
-Helicobacter pylori |
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What are 2 opportunistic pathogens that survive the duodenum/jejunum?
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-Streptococcus species
-Bacteroides species |
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What are 4 opportunistic pathogens that survive the neutral pH and bile/digestive enzymes of the ileum?
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-Enterococcus faecalis
-Bacteroides -Clostridium -Enterobacteriacae |
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What are 3 opportunistic pathogens that survive the neutral pH and anaerobic environment of the colon?
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-Bacteroides
-Clostridium -Enterococcus |
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Why is the urethra sterile except for the distal portion?
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Because of constant flushing by sterile urine
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What is the pH of vaginal secretions prior to puberty and after menopause? What are the predominant microflora then?
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pH: alkaline
Microflora: staph/strep |
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What is the pH of vaginal secretions during puberty? Why?
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Acidic - due to glycogen fermentation in epithelial cells due to estrogens
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What is the predominant vaginal microflora during puberty and childbirth years?
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Lactobacillus
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What are 3 bacteria that are encapsulated and predominantly extracellular?
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-Staphylococcus
-Streptococcus -Clostridium |
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What are the 3 host defenses against Extracellular microbes?
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-Complement
-Antibodies -Phagocytosis |
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What are 3 bacteria that are predominantly cytoplasmic within cells?
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-Listeria monocytogenes
-Shigella -Francisella tularensis |
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What are the 2 host defenses against cytoplasmic bacteria?
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-CTLs
-NK cells |
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What are the 3 microbes that are predominantly found within phagosomes within cells?
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-Legionella
-Salmonella -Mycobacteria |
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What are the 3 host defenses against phagosomal bacteria?
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TH1 cells
IgG antibody Lysosomes |
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What bacteria is particularly capable of colonizing nonbiological surfaces like catheters?
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Pseudomonas aeruginosa
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What bacteria is particularly capable of adhering to human oropharyngeal cells?
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Haemophilus influenzae
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What are the 2 main steps in bacterial adherence?
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1. Pre-adhesion
2. Adhesion |
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What are 3 pre-adhesion forces?
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-Vanderwalls
-Electrostatic -Hydrophobic |
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Is pre-adhesion specific or nonspecific?
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Specific
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What do the adherent structures on microbes contain that allow for direct binding to host cell proteins?
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Adhesins
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What are 4 possible consequences of microbes binding and adhering to host cells?
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-Tropism
-Change in morphology -Cytokine release -Apoptosis |
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What bacteria uses a Type 3 secretion system to invade epithelial cells?
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Salmonella typhimurium
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How does that type 3 secretion system work?
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S. typhi pumps proteins from itself into the target cell's cytoplasm that allow for S. typhi to be ingested.
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What is the result of the S. typhi type 3 secretion system?
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Membrane ruffling and invagination of the membrane.
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What occurs in fermentation?
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Conversion of Pyruvate to Acids, Alcohols, or Gases
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What bugs do we think of when we think of fermentation?
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Enterobacteriaceae
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What are the final electron acceptors in Anaerobic respiration?
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-Nitrate
-Sulfate -Carbon dioxide |
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What are 2 main bugs we think of as being Anaerobes?
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-Clostridium
-Bacteroides |
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What is the final electron acceptor in Aerobic respiration?
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Oxygen
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What are 2 predominant aerobes? How are they identified?
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-Pseudomonas
-Haemophilus -Oxidase positive |
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What are 4 exchangeable elements in bacterial genetics?
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-Plasmids
-Transposons -Pathogenicity islands -Bacteriophage |
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What bacterium uses a plasmid to encode antibiotic resistance?
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Enterococcus - against Vancomycin
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What bacterium uses transposons to undergo fimbriae switching?
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UPEC
(uropathogenic) |
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What bacterium uses Pathogenicity islands to encode its virulence?
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Salmonella
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What bacterium uses bacteriophage to store its toxin genes?
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Vibrio
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What are the 3 mechanisms of DNA transfer in bacteria?
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-Transformation
-Conjugation -Transduction |
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What are the 2 toxins that are bacteriophage mediated?
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-Shiga toxin
-Cholera toxin |
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What are 2 things that toxins are important for?
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-Pathogenesis
-Vaccines! |
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What host cells are very important in controlling bacterial infections?
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Macrophages
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What are the steps in phagocytosis?
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RUMKA
-Recognition -Uptake -Maturation -Killing -Antigen presentation |
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What are the 2 main strategies that bacteria have developed for disrupting intracellular trafficking?
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-Survival within phagosomes
-Escape from phagosomes |
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What causes a constitutive macrophage response?
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Tuberculosis
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