Glossary of Microbiology video 1
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- what is the unique aspect of fungi that makes them succeptable to many antibiotics?
- What is the normal flora found on our skin?
- Skin: Staphlococcus epidermidis
Nose: Staphlococcus Aureus
Oropharynx: Viridans Streptococci incl. Strep. mutans and Strep. Salivarius
Colon: Bacteroides (predominant organism)
- What microorganisms make up the normal flora of the gingival crevices? (4)
- Aneerobes: Prevotella, fusobacterium, Streptococcus, and Actinomyces
- What are the some adherence factors of both gram positive and negative bacteria?
- Gram (-): pili/fimbriae - adherence to cell surfaces
Gram (+): teichoic acids - adherence to cell surfaces
Adhesins: colonizing factor aadhesins, pertussis toxin, and hemagglutinins.
IgA proteases: cleaved Fc portion may coat bacteria and bind them to cellular Fc receptors.
- Which organisms secrete biofilms to attach to inert materials?
- Staph. epidermidis, and strep. mutans
- What is the numanic and organisms that have capsules?
- Some Killers Have Pretty Nice Capsules
- What are two microorgaisms which are able to live within phagocytic cells?
How do they do this?
- M. tuberculosis (inhibits phagesome-lysosome fusion.
Listeria (escapes the phagosome into the cytoplams before phagosome-lysosomal fusion.
- What organisms steal (chelate) and import iron?
- What is an invasin?
- invade non-phagocytic cells, thus excaping the immune system.
- What is the chemical in the gram negative organism that is toxic?
- LPS, it is actually the LIPID A portion of the LPS that is toxic.
- Usually endotoxin is not release until the gram negative organism dies. What is the one exception to this rule?
- N. Meningitidis, which over-produces outer membrane fragments
- What does this release of LPS cause, and what is each due to?
- LPS activates macrophages which damages tissues.
bradykinin-induced vasodilation leads to SHOCK
activation of HAGEMAN FACTOR leads to COAGULATION (DIC)
- What are exotoxins?
- Very toxic released from living bacteria.
- Can endotoxins or exotoxins be moeified to a toxoid?
- Endotoxins cannot but exotoxins can be modified by chemicals or heat to produce a TOXOID that still is immunogenic, but no longer toxic and thus can be used as a vaccine.
- How does an A-B toxin work?
- The B part of the toxin attaches to the cell and allows the A part to enter the cell. The A part of the toxin is the toxic part (often an enzyme)
- What are two examples of cytotoxins and
- Cl. perfringens has the ALPHA TOXIN (enzyme) which is a lecithinase.
Staphylococcus aureus also has an ALPHA TOXIN which inserts itself to into a cells membrane to form pores in the membrane
- What does Cl. Perfringens cause?
- What is the toxin and how does it work?
- Toxin is DIPHTHERIA TOXIN and it works by ADP RYBOSYL TRANSFERASE; WHICH INACTIVATES EF-2, thus stopping protein synthesis.
- What is the toxin and how does it work?
- Toxin is EXOTOSIN A and it works by ADP RYBOSYL TRANSFERASE; WHICH INACTIVATES EF-2, thus stopping protein synthesis
- What are the primary targets for diphtheria toxin?
- heart, nerves, and epithelium
- What is the primary target for Exotoxin A and what organism secretes it?
- Secreted by Pseudomonas aeruginosa, the primary target for exotoxin 2 is the LIVER.
- What organism secretes Shiga toxin and what does it do?
- Secreted by Shigella dysenteriae and it interferes with the 60S ribosomal subunit, thus inhibiting protein synthesis in eukaryotic cells.
- What organism secretes Verotoxin and what is it's mechanism?
- Secreted by Enterohemorrhagic E. Coli (EHEC). It interferes with the 60 S ribosomal subunit, thus inhibiting protein synthesis in eukaryotic cells.
- What organism secretes Tetanus toxin and how does it work?
- Clostribium tetani. Tetanus toxin blocks release of the inhibitory transmitters glycine and GABA, thus inhibiting neurotransmission in inhibitory synapses.
- What organism secretes Botulinum toxin and how does it work?
- Botulinum toxin is secreted by Clostridium botulinum. It blocks release of acetylcholine, thus inhibiting cholinergic synapses.
- What organism secretes TSST-1 and how does it work?
- TSST-1 is secreted by Staphylococcus aureus and is pyrogenic, decreases liver clearance of LPS, and is a superantigen...thus it produces fever, increased susceptibility to LPS, rash, shock, and capillary leakage.
- Other than Pseudomonas aeruginosa, what is another organism that secretes Exotoxin A and how does it work?
- Exotoxin A secreted by Streptococcus pyogenes. it has the exact same effects as TSST-1 secreted by staph. aureus (fever, increased LPS), but is also cardiotoxic.
- What organism secretes Heat Labile toxin (LT) and how does it work?
- LT is secreted by Entertoxic Escherichia coli. LT stimulates an adenylate cyclase by ADP ribosylation of GTP binding protein. This promotes secretion of fluid and electrolytes from intestinal epithelium.
- What organism secretes cholera toxin and how does it work?
- Cholera toxin secreted by Vibrio cholerae. It acts similar to the E. coli LT and thus results in a profuse, watery diarrhea.
- What organism secretes Anthrax toxin?
- Bacillus anthracis
- What are the different proteins that make up the anthrax toxin?
- EF= edema factor
LF= lethal factor
PA= protective antigen (B component for both EF and LF)
- What is the effect of the anthrax toxin?
- Decreases phagocytosis; causes edema, kills cells.
- What is the organism that produces Pertussis toxin and how does it work?
- Bordatella pertussis
Pertussis toxin ADP ribosylates Gi, which is the negative regulator of adenylate cyclase. This thus INCREASES cAMP
- What are the effects of pertussis toxin?
- Histamine sensitizing
- What toxin is secreted by Clostridium perfringens and what does it do?
- Alpha toxin is secreted. This Clostridium perfringens alpha toxin is a lecithinase that damages cell membranes.
- What toxin is produced by Staphlococcus aureus and what does it do?
- Staph. aureus secretes alpha toxin which intercalates forming pores, thus making the cell membrane leaky.
- What type of paralysis does tetanus toxin produce?
- Spastic paralysis due to inhibition of inhibitory synapses
- What type of paralysis does botulinum toxin produce?
- Flaccid paralysis due to inhibition of cholinergic synapses.
- What is an important capsule of E. Coli and why is it important?
- If E. Coli has the K1 capsule it is likely to cause neonatal meningitis.
- What antibiotics work on the peptidoglycan layer?
- penicillin and cephalosporins act on the peptidoglycan layers and split the peptidoglycan bonds, thus killing the organism.
- What organism stain with the acid fast stain?
- Mycobacterium and Nocardia (Nocardia is partially stained)
- What organism is identified by it's numerous flagella.
- Salmonella typhi
- What is the M-protein?
- M-protein of Strep pyogenes is a surface protein that is very important in it's virulence factor.
- What is another name for the acid fast stain?
- Ziehl-Neelsen Acid Fast Stain
- What color is mycobactera in the ziehl-neelsen stain?
- What is the Auramine-Rhodamine Fluorescent Stain?
- In the case of mycobacterium TB, because the acid fast stain takes some time to perform, the sputum goes thru the Rhodamine-Fluorescent Stain. If the organism is positive on the Auramine-Rhodamine stain then you will do a Acid Fast stain for confimation
- What is the difference between bacteria and human ribosomes?
- bacteria = 70S ribosomes
human = 80S ribosome
and thus it is a major mechanism of antibiotic action
- What organisms produce endospores?
- Baccillus genus and Clostridium genus
- what does differential media do and what is a good example of a differential media?
- Diff. media helps to differentiate one organism from another. A good example of this is blood agur.
- What does blood agur help you differentiate?
- Blood agur helps you differentiate alpha, beta, and gamma Streptcocci.
- What is the differential medium for Corynebacterium?
- Tellurite agar where the corynebacterium turn black.
- What is the differential medium for Enteric bacteria and what is the significance of this medium?
- MacConkeys agar allows gram negative organisms to grow but not gram positive. Thus it is a selective media, but at the same time it diferentiates lactose from non-lactose fermenters. Lactose fermenters show up as pik colonies.
- What is a good example of a lactose fermenter?
- E. Coli
- What is a good example of a non-lactose fermenter?
- Salmonella Typhi
- What media is used to differentiate Vibrio cholerae?
- TCBS (thiosulfate citrate bile salts sucrose agar)
- What medium is selective for mycobacterium?
- Lowenstein-Jensen medium
- What agar is used for Neisseria?
Which is usually used
- Chocolate agar and Thayer-Martin medium.
The Thayer-Martin medium is usually used because it is selective for Neisseria. It is basically a chololate agar with antibiotics to inhibit the growth of normal flora.
- What is an important test for the identification of neisseria gonnorrhea?
- oxidate test
- What are three good examples of obligate aerobes?
- mycobacterium TB
- What are the three major obligate anaerobes?
- Aerobically or anaerobically, how are most bacteria classified?
- Facultative anaerobes
- What is the mneumonic for the organisms that require cysteine to grow?
- The four sister Ells and the Cysteine chapel.
Flancisella, Brucella, Legionella, and Pasteurella
- What is hte mneumonic for remembering the three obligate anaerobes?
- ABCs of anaerobiosis = Actinomyces, Bacteroides, and Clostridium
- What are the microareophilic organisms and what does each cause?
- Campylobacter and helicobacter
Camplobacter causes gastroenteritis
Helicobacter causes gastric and duodenal ulcers
- What is included in the DTP vaccine?
- Diphtheria: diphtheria toxoid
Tetanus: tetanus toxoid
Pertussis: killed Bordetella pertussisis cells
- When is the DTP vaccine given?
- 2 months, 4 months, 6 months, 18 months, and 5 years old
- What is the vaccine with the new pertussis called and what is the difference?
- The new vacccine is DTaP. The a stands for a cellular b/c it is no longer the dead organism in the vaccine...it is some cellular components. it contains the capsule, toxoid, and hemagluttinin fimbrie
- What is the HIB vaccine and what does it contain?
- Haemophilus influenzae type b
It is an H. influenzae capsular polysaccharide conjugated to protein
- When is the HIB vaccine given and what disease has it helped significantly?
- It is given at 2, 4, 6, 18 months and 5 years old and it has helped neonates fight meningitis.
- Who should get the spreptococcus pneumoniae vacine and what is it composed of?
- elderly people should get the spreptococcus pneumoniae vaccine and it is composed of capsular polysaccharides of 23 different Pneumoncoccus strains.
- Why shouold the spreptococcus pneumoniae vaccine be given to people who lack a spleen?
- The spleen is the major organ that clears capsular proteins.
- What does the neisseria meningitidis vaccine contain.
- Four capsular polysaccharides: Y, W-135, C, and A.
These are the four different types of capsules
- Who should the salmonella typhi vaccine be given to and what does it contain?
- it should be given to travelers to endemic typhoid areas and it is composed of attenuated bacterium
- What is the new salmonella typhi vaccine called?
- What is the vaccine for TB?
- BCG = Bacille Calmette Guerin (BCG)
- What is the BCG vaccine composed of?
- Attenuated (living) strain of Mycobacterium bovis
- What is the bacillus anthracis vaccine composed of and who is it used on?
- composed of a supernatant of partially purified proteins and it is used for military and people around cows and wool a lot.
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