Micro Flashcards
1
Q
Tranformation
- what is it
- occurs
A
- bacteria is dead and has lysed, a piece of DNA binds to cell wall of live bacteria, DNA gets into cell and incorporates itself into genome
- only occurs w/ closely related bacterial species
2
Q
Transduction
- occurs w
- normal life cycle
- generalized transduction
- specialized transduction (temperate)
A
- bacteriophage; virus that infects bacteria
- phage attaches to bacteria through cell wall -> injects genetic material and enzyme into bacteria -> enzymes break up bacterial DNA and takes over machinery of bacteria to replicate phage DNA -> bacteria becomes full of phages -> bacteria lyses releasing phages
- phage infected bacteria -> bacterial DNA lysed into fragments -> accidentally a piece of bacterial DNA gets incorporated into phage instead of phage DNA -> bacteria is full of phage and lyses -> the phage with bacterial DNA binds and incorporates the DNA into another bacteria -> instead of new bacteria being infected it incorporates the old bacterias DNA into its own DNA
- phage DNA is incorpoarted into genome of bacteria -> sits and lives w/ bacteria for several generations until bacteria starts to die (detects decrease in production of ATP) -> phage DNA extracted from bacterial DNA and takes some bacterial DNA with it -> lyses rest of bacterial DNA and uses machinery to replicate own DNA-> phage lyses bacteria -> phage is released w/ both its own DNA and some small pieces of bacterial DNA
3
Q
Conjugation
- what is it
- what happens
- what is necessary
A
- bacterial sex
- direct transfer of DNA from one cell to another through plasmids
- cell to cell contact, w/ pilli
4
Q
Transposon
- what is it
- cut and paste
- copy and paste
A
- piece of DNA w/ ability to move around
- transposon jumps to new site and gap that is left is filled in
- copy of transposon jumps to new location
5
Q
Virulence Factors of bacteria
- techoic acid
- endotoxin
- capsule
- antiphago surface
- spores
- neurotoxin
- cord factor
A
- gram +
- gram -
- protection
- M protein, protein A
- dormant bacteria releases toxin when exposed to heat
- clostridium
- prevents bacteria from being phagocytosed
6
Q
Gram + vs -
- number layer
- thickness
- oute membrane
- increased permeability
- color
A
- +: one, -: two
- +: thick, -: thin
- +: absent, -: present
- +: more penetrable, -: less permeable
- +: purple, - pink
7
Q
Gram + pep wall
- made of
- linker
- penicillen and cephalosporin
- teichoic acid: purpose, causes
A
- N-AM and N-AG
- D-ala
- mimic D-ala but do not link the N-AM and N-AG -> punches holes into cell wall -> water into cell -> cell swells and lyses
- stabilize peptidoglycan wall by attracting positively charged ions; when released will cause fever and vasodilation but not sepsis
8
Q
Gram - pep wall
- endo toxin: lipid A
- endo toxin: inner and out core
- endo toxin: O antigen
- importance
- how
A
- embedded in cell membrane is lipid A -> fever, septic shock, diarrhea
- inner core connect to lipid A and then connects to outer core, stimulates immune response; different in every bacteria
- connected to outer core; every family has same O antigen
- pts with gram - infections will get sicker after getting the antibiotic because when the bacteria starts lysing it releases the endo toxin and stimulates even greater immune response
- once released LPS binds to LPS binding protein -> LPS transferred to CD14 (on surface of macrophages) -> puts LPS on MD2 (lymphocyte antigen 96)-> associated with TLR4 -> TLR4 is PRR and will activate immune sxs through release of cytokines, NO, immunomodulators
9
Q
Exotoxin
- what is it
- location of damage
A
- extracellular produced toxin produced by bacteria for survival advantage
- non-membrane damaging and membrane damaging
10
Q
Non- membrane damaging exotoxin
- hyaluronidase
- lipase
- IgA protease: which bacterias,
- collagenase
A
- breaks down hyaluronic acid which is component in BM and ECM; allows
- coverts plasminogen to plasmin to break down clot
- allows bacteria to break through subcutaneous tissue
- bacteria that colonize mucus membrane; destroys IgA
- destroys fascia and collagen in muscle to take infection to bone
11
Q
Membrane damaging exotoxin
- hemolysin
- leukocidins
- phospholipase
- lecithinase
A
- lyse RBC
- lyse WBC
- lyse all cells
- lyse all cells
12
Q
Intracellular exotoxin
- ADP ribosyl transferase
- bacteria
A
- inactive NAD and turns it into nicotene and ADR -> stop protein synthesis -> kill cell
- diptheria, psuedomonas, cholera, e.coli, pertusis
13
Q
Bacteria Specific Endotoxin
- shiga toxin
- pseudomonas
- shigella
- staph
- strep pyo
- anthracis
- diptheria
- tetanus
- botulinum
- c perf
A
- binds to 60 s ribosome -> inhibit protein synthesis -> cell death; causes n/v, diarrhea and neurotox
- pyro something -> interferes with electron transport chain
- NAD glycohydrolase -> produced when shigella phagocytosed -> depletes neutrophil of NAD -> w/o NAD cannot have normal cell metabolism and blocks PMN from being able to do normal function
- super antigen will bind MHC 2 protein and T cell receptor -> induce IL1 and 2 causing shock
- strep O hemolyzes RBCs and is used to detect step pyo infection, erythrogenic toxin -> leads to formation of rashes (impetigo)
- edema factor: AC -> cAMP -> edema, lethal factor: inhibits kinases and kills macrophages
- elogation factor 2 -> produces pseudomembrane in back of throat
- inhibits release of glycine -> rigid paralysis
- blocks release of Ach -> flaccid paralysis
- alpha lecithinase and causes gas gangrene -> double zone of hemolysis
14
Q
Bacteria Specific Exotoxin
- E. Coli
- Vibrio
- Bordetella
A
- heat labile, raises cAMP, heat stable cGMP -> cause diarrhea
- heat labile exotoxin -> cause rice water diarrhea
- stimulates AC via ribosylation -> increase histamine production and phagocyte dysfunction
15
Q
Septic Shock
- what is it
- importance
- bacteremia
- sepsis
- septic shock
- COD
- kidneys
- lungs
- brain
- vascular
- coagulation
- tx
- reasoning for tx
A
- deadly response to infection
- main cause of death in ICU
- bacteria in blood stream, can trigger immune system and can cause sepsis, shock, and death
- systemic inflammaroty/ immune response to bacteremia
- dangerous drop in BP and subsequent organ dysfunction (kidney)
- heart failure
- acute renal failure
- ARDS
- encephalopathy
- vasodilation -> decreased BO
- DIC, excessive bleeding
- treat underlying infection, give vaso constrictor (compensate for vasodilation from cytokines)
- bacteriostatic will put into plateau phase and bacterialcidal will put in death phase
16
Q
- maconkey
- chocolate
- blood
- lowenstein jensen
- charcoal yeast
- thayer martin
- bordet-gengou
- cysteine tellurite
A
- e. coli, enterobacter, klebsiella
- hib
- diptheria
- TB
- legionella
- fungus
- nisseria, chocolate agar with vanco, polymixin, nistatin, trimethoprim
- bordatella
- diptheria
