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101 Cards in this Set

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