TBL 11 Bacteria Flashcards
Lymphocytes and lymph return to the blood via the ______ duct.
thoracic duct
The first line of host defence is the ______ mechanism, which prevent the bacteria/pathogen from infecting the body.
barrier mechanism
The first stage of infection by pathogens involve _______ to the epithelium, followed by local infection and _______ of the epithelium.
adherence and penetration of epithelium
First line of defence:
The ____ acts as a physical barrier and contains antimicrobial peptides.
Skin
First line of defence:
The gastrointestinal tract has (low/high) pH, intestinal motility and intestinal ______ which acts as a biological barrier as it competes with the pathogens for nutrients.
low pH; intestinal motility and intestinal flora
First line of defence:
The neurological tissues have a ______ barrier.
blood-brain barrier
The second line of host defence is the _____ immunity, which helps to clear most infective organisms, and only those with ________ may survive.
Second line of host defence is the innate immunity.
Only those with virulence factors
The innate immunity involves recognition of ______ using pattern recognition receptors which recognise conserved microbial structures such as fimbriae, dsRNA, peptidoglycan.
_____ can also be used as a recognition signal, and this includes inflammation and necrotic cell death.
PAMPs and DAMPs
The third line of defence is the _______ immunity, which is mainly mediated by ___ and ___________.
adaptive immunity; mainly mediated by B and T lymphocytes.
In the presence of _______ released by CD4+ T cells, B cells can switch their antibody class to provide a more specific immune response, and undergo affinity maturation to increase affinity of antibodies.
cytokines
The memory B and T cells formed in response to an infection remain circulating in the _________ and ______, or reside in the ___________, waiting for re-exposure to the same antigen/pathogen.
Memory cells remain circulating in the bloodstream and lymph, or reside in the secondary lymphoid organs.
Memory cells allow for:
1) Faster
2) Stronger
3) More specific
secondary response?
All
Faster - sensitive to antigens
Stronger - more cells
More specific - undergone affinity maturation
Some pathogens are ________. This can be further divided to being on the epithelial surface, or existing in interstitial spaces, blood or lymph.
extracellular
Some pathogens are _________. This can be further divided into cytoplasmic or vesicular.
Intracellular
For extracellular pathogens within the interstitial spaces, blood and lymph, the typical immune response includes:
1.
2.
3.
4.
- Complement activation
- Antibodies
- Neutrophils and macrophages
- Inflammatory reaction
Pro-inflammatory mediators released by macrophages causes the (dilation/contraction) of local small blood vessels and expression of adhesion molecules.
(More/less) white blood cells are produced and enter the bloodstream, then move to the site of infection.
Pro-inflammatory mediators cause the dilation of local small blood vessels. More white blood cells are produced.
Innate immunity causes the (increased/decreased) production of chemokines which attract white blood cells to site of infection via _________.
increased production of chemokines which attract WBCs to the site of infection via chemotaxis.
________ refers to the leakage of plasma proteins, which occurs due to (increased/decreased) vascular permeability.
Plasma exudation; occurs due to increased vascular permeability
Blood clotting may occur in the microvessels to prevent microbial spread in the blood.
-
Th17 cells release cytokine _____, which act on fibroblasts or epithelial cells to secrete neutrophil chemotactic proteins to recruit neutrophils and induce production of ______.
Th17 release cytokine IL-17; induce production of defensins
Large extracellular parasites trigger _______ and _______ responses.
(like allergic reactions)
eosinophils and mast cells
Upon recognition of parasite antigen presented on APCs, ____ cells become activated and secrete cytokines.
IL-4 and IL-13 induce B cell development and differentiation to produce specific anti-parasitic antibody ____ which bind to antigens on the parasite.
Th2 cells; antibody IgE
Parasite:
Cytokine ____, which is produced by Th2 cells, will induce terminal differentiation of eosinophils by binding to CCR3 receptor, causing the eosinophil to express specific Fc receptors which recognise the IgE antibodies on the parasite.
IL-5
Parasite:
Upon binding to the parasite, mast cells release _______, TNF-a and enzymes. _________ release major basic protein, peroxidases and eosinophil cationic protein.
Mast cells release histamine, TNF-a and enzymes.
Eosinophils release…, causing cellular lysis and death of parasite.
The typical immune responses against intracellular pathogens include:
- 2.
- Hyperactivation of macrophages
2. Cytotoxic T cells
For macrophage hyperactivation,
the activated Th_ cells will express CD__ ligand on its surface, which binds to CD__ on the macrophage, and secretes ____, hyperactivating the macrophage.
Activated Th1 cells express CD40 ligand which binds to CD40 on the macrophage, and secretes IFN-y, hyperactivating the macrophage.
If the immune system is unable to destroy the intracellular pathogen, it attempts to wall it off and prevent the infection from spreading via _________ formation.
granuloma formation
Granuloma formation is an (active/passive) process.
Active process; since the constant death of macrophages in the granuloma core require constant turnover by addition of new cells
Viruses often act (intracellularly/extracellularly).
intracellularly
Typical immune response against viruses include: 1. 2. 3. 4.
- Interferons
- NK cells
- Cytotoxic T cells
- Antibodies
_________ help microorganisms to cause disease and may include toxins or mechanisms for adhesion, uptake, mobility, survival and immunomodulation.
Virulence factors
Immune evasion for pathogens:
________ involve pathogens possessing surface structures resembling human molecules, so the immune system mistakes them as “self” and does not attack.
Molecular mimicry
Immune evasion:
Many pathogens have different variations of a single antigen, immune system unable to recognise.
-
Immune evasion:
Some bacteria living on mucosal membranes cleave antibody ___ using ______ (enzyme) to prevent its activity.
Cleave antibody IgA using IgA proteases
_________ contains several pathogenicity islands (SP1/SP2), which encode type III secretion systems used to inject effector molecules into host cells.
Salmonella
___ of Salmonella is used to force macrophages to engulf the bacterium, whereas ___ is used to avoid killing within the macrophage.
SP1 - force macrophage to engulf bacterium
SP2 - avoid macrophage killing
The type III secretion system is encoded for by (SP1/SP2)
SP2
The salmonella bacterium contained within the vacuole can inject different effector molecules into the cytoplasm of the host cell using the type III secretion system to:
- Block the intracellular trafficking of ______ and docking to the phagosome, reducing phagolysomal fusion.
- Block assembly of _________ such that no oxygen radicals are produced and no macrophage killing.
- _________ of MHC class II molecules, tagging them for degradation, causing less antigen presentation by MHC II.
- Block intracellular lysosome trafficking, reducing phagolysosome formation
- Block NADPH oxidase
- Ubiquitination of MHC Class II
Shigella is often ingested with food, and are first taken up by __ cells above the Peyer’s patches in the intestine.
M cells (designed to take up specific antigens from the gut)
______ (bacterium) rapidly escapes from the phagosome into the cytoplasm, evading the macrophage killing.
Shigella
Shigella will replicate and kill the macrophage, becoming released on the ______ surface of the epithelium, leading to massive inflammation induced by macrophages.
Shigella is released on the basolateral surface of the epithelium
Shigella can spread laterally from cell to cell without exposing themselves to the immune system, by inducing ____ polymerisation to propel themselves into the next cell.
actin polymerisation
Actin tail formation
Immunomodulation by microorganisms include:
- Killing of _______ (cells) by leukocidins
- Production of _______ which bind TCRs and MHC molecules in the non-variable regions, linking them together and distorting the T cell response
- Production of VacA toxin and y-glutamyl transferase to inhibit (cell) activation and proliferation by acting on IL-2 and IL-2 receptors
- Induce ____ cells to suppress the immune response
- Killing of neutrophils by leukocidins
- Production of superantigens to distort T cell response
- T cell inhibition
- T reg cell activation
The _______ in the brain regulates the core temperature of the body using temperature sensors to monitor temperature.
hypothalamus
The ________ (POA) and ________ (DMH) are the two important structures in temperature regulation.
Pre-optic area and dorsomedial hypothalamus
The maintenance of body temperature relies on sensing the external environment and responding to it, using warmth and cold sensors.
Warmth sensors are unmyelinated __________, whereas cold sensors are _______ and decreased input from ______.
Warmth sensors: unmyelinated C-fibres
cold sensors:
A-delta fibres and decreased input from C-fibres
The temperature sensation detected by the sensors enter the spinal cord via the _________, which passes signals to the _________ and finally the hypothalamus.
Enter the spinal cord via the A) Lissauer’s tract, which passes signals to the B) lateral spinothalamic tract and finally the C) hypothalamus
Temperature signals from temperature sensors are processed in the ______ and _______
POA and DMH in the hypothalamus
When (warmth/cold) sensors in the skin detect increased skin temperature, afferent signals are sent to the POA and DMH which will transmit efferent signals to effector organs to effect a response:
- Peripheral (vasodilation/vasoconstriction) of skin arterioles to allow greater blood flow to the surface.
- (Constriction/Dilation) of shunt vessels to force blood to move through the surface of arterioles for cooling.
- (Increased/decreased) production of sweat
- Peripheral vasodilation of skin arterioles
- Constriction of shunt vessels
- Increased sweat production
When (warmth/cold) sensors in the skin detect decreased skin temperature, afferent signals are sent to the POA and DMH which will transmit efferent signals to effector organs to effect a response:
- Peripheral (vasoconstriction/vasodilation) of blood arterioles to prevent blood flow to the surface
- (Dilation/constriction) of shunt vessels to allow blood to bypass the surface of arterioles
- __________ of hairs to trap a cushion of heat-insulating air
- Metabolism of ___ to help generate heat
- ________ due to intense muscular spasms to produce heat
Warming up:
- Peripheral vasoconstriction of blood arterioles
- Dilation of shunt vessels
- Piloerection of hairs
- Metabolism of fat
- Shivering
Temperature variation of core body temperature in humans is primarily regulated by the __________ which project into the POA, allowing for circadian modulation of body temperature.
suprachiasmatic nucleus (circadian pacemaker)
Lying down can (increase/decrease) distal skin temperatures, causing a (increase/decrease) in core body temperature.
Lying down can increase distal skin temperatures, causing a decrease in core body temperature.
Melatonin is a sleep-related neurohormone that causes peripheral (vasodilation/vasoconstriction) and radiation of heat causing heat (loss/gain).
Peripheral vasodilation causing heat loss.
A (increase/decrease) in body temperature and its maintenance overnight is integral to a normal circadian rhythm.
decrease
The gold standard for measuring body temperature is to measure the temperature of the blood within the __________.
pulmonary artery
Temperature is generally measured at four peripheral sites:
Oral, tympanic (ear), rectal, axillary
Fever is when body temperature is raised in the presence of an _________.
infective agent
________ fevers are characteristic to TB, abscess, schistosomiasis.
Spiking
_______ (diurnal variation) fevers are characteristic to Kawasaki disease, malaria and amoebiasis.
Remitting
________ fever (i.e. fever for 7 days then 3 days normal) is characteristic to dengue, Legionnaire’s disease.
Saddleback
Longer periodicity fever is characteristic to Pel-Ebstein fever in ________.
lymphoma
Infections lead to the release of ______ that will cause the increased production of _____ which will bind to EP3 receptor within the ___ of the hypothalamus, which signals to the DMH, causing a sympathetic activation of non-shivering thermogenesis.
Infections lead to the release of pyrogens that will cause the increased production of prostaglandin E2 (PGE2), which bind to EP3 receptor within the POA of the hypothalamus, which signals to the DMH.
TLDR:
Pyrogens –> Production of PGE2 –> bind to EP3 receptor in POA —> signals to DMH –> Sympathetic activation of thermogenesis
There are two main endogenous cytokine pyrogens: ___ and ___.
IL-1 and TNF-a
IL-1 and TNF-a enhance breakdown of arachidonic acid into _________, enhancing localised inflammation and induces fever.
prostaglandins
____, ____ and ____ may also act as endogenous pyrogens, but to a lesser extent compared to IL-1 and TNF-a.
IL-6, IL-8 and IFN-y
Exogenous pyrogens are typically associated with ______ infections.
_________ (LPS) is a cell wall component of bacteria and it binds to _____ on the macrophage surface, stimulating macrophages to release IL-1 and TNF-a, effectively leading to the production of endogenous pyrogens.
bacterial infections;
Lipopolysaccharides bind to toll-like receptor 4 (TLR4) on macrophages to induce macrophages to release cytokines.
LPS in bacteria cross-interacts with TLR4, resulting in activation of a signalling cascade, leading to transcription factor _____ formation in the nucleus.
____ transcription factor upregulates ______ production.
Transcription factor NFkB formation
upregulates cytokine production
TNF-a and IL-1 are released by immune cells to stimulate other cells to release ____________ proteins which are synthesised by the liver.
acute phase proteins
________ (acute phase protein) binds free iron.
Ferritin
_______ (acute phase protein) downregulates ferroportin expression to prevent release of iron from cells.
Hepcidin
__________ (acute phase protein) oxidises iron to facilitate ferritin action.
Ceruloplasmin
_______ (acute phase protein) binds haemoglobin.
Haptoglobin
Acute phase proteins work to bind ____ to proteins or keep it within cells, so that microorganisms have to excess to them. This starves the bacteria.
binds iron
Bacteria come in three shapes:
Spherical), (Rod-shaped), (spiral-shaped
Cocci (spherical)
Bacilli (rod)
Spirochaetes (spiral)
Gram-positive bacteria is stained (purple/red) due to the exposed peptidoglycan cell wall that retains the iodine dye.
purple
Gram-negative bacteria is stained (purple/red) as the outer membrane resists the first dye, and is decolorised by alcohol before absorbing the counter-stain.
red
Salmonella, Shigella, E. Coli, Vibrio Cholerae and Neisseria are Gram-________ bacteria.
Gram-negative
Mycobacterium tuberculosis is an _______ bacilli that can resist the gram stains.
acid-fast
Listeria is an (intracellular/extracellular) pathogen.
intracellular
Salmonella bacteria is an (intracellular/extracellular) pathogen.
Intracellular *It prevents the formation of phagolysosome and NADPH oxidase. Ubiquitination of MDH class II.
Salmonella bacterium has a ________ (Structure), allowing it to be propelled forward, aiding its movement towards the host cell.
flagella (angular momentum)
The ______ secretion system of Salmonella delivers virulence proteins into the host cells, to trigger uptake into epithelial cells, because they are not naturally phagocytic.
This is done by triggering _____ rearrangement and then engulfment of the bacterium.
Type III secretion system
Triggers actin rearrangement and then engulfment
(actin polymerisation, membrane ruffling and bacterial internalisation)
Listeria (does/does not) possess flagellum. It makes use of the force generated during ____ polymerisation to move.
does not have flagellum; makes use of force generated during actin polymerisation to move
How does listeria bacterium persist/survive in the cell?
Listeria bacteria is able to escape from the endosome into the cytoplasm.
_________ makes use of host cell membrane protrusions to spread to another cell, never remaining extracellular to avoid immune detection.
Listeria
The bacterial genome is made up of ____ genome, which is conserved across the different strains of similar pathogens, and the ________ genome which is obtained from disparate sources.
core genome and accessory genome
=> this leads to unexpectedly high levels of variation between genomes of bacterial pathogens
_________ of bacteria is the process by which a recipient cell takes up small fragments of naked DNA from the surrounding environment, followed by homologous recombination into the genome.
Transformation
There are three main processes which facilitate horizontal gene exchange between bacteria, contributing to sources of accessory genes and therefore genetic variation.
1) Transformation
2) Transduction
3) Conjugation
Only _______ bacterial cells can take up naked DNA from the environment (i.e. undergo transformation) via their ___________ factors.
Competent bacterial cells; competence factors
___________ of donor DNA fragment occurs with homologous section of the recipient cell’s chromosome.
i.e. some sequence must match.
Homologous recombination
Pathogens like ______ and Streptococcus make use of transformation.
Neisseria
Transduction involves the use of _________ to carry bacterial genes from their first host to their second host cell due to errors in the phage reproductive cycle followed by homologous recombination.
bacteriophages
___________ is the process of transfer of the donor cell DNA to the recipient cell via direct contact between the two cells.
Conjugation
The donor cell for conjugation possesses a ________ which is present on the transmissible plasmid, and contains genes responsible for sex pilus synthesis.
fertility (F) factor
Donor cell uses _______ to attach to a recipient cell, forming a temporary cytoplasmic mating bridge, which is the route for DNA transfer.
sex pilus
__________ (horizontal gene trf) is common in drug resistance interactions.
Conjugation
Any horizontally acquired DNA that contributes to the virulence of the bacterium is a __________.
pathogenicity island
Bacteria replicate via ________.
binary fission
Bacteria is able to evolve rapidly and adapt to new environmental challenges due to:
1)
2)
1) High replication rate
2) Mechanisms for horizontal gene transfer
Binary fission:
- Bacterial chromosome is first attached to the __________.
- _________ occurs.
- Cell elongates, membrane growth causes the two chromosomes to grow apart.
- ______ forms and extends as the cell membrane invaginates.
- Invaginating cell membrane and newly formed septum splits the cell into two genetically identical daughter cells. (Cytokinesis)
- Bacterial chromosome attached to plasma membrane.
- DNA Replication occurs.
- Cell elongates.
- Septum formation
__________ of bacteria allows for any new genes mutated/taken up by the cell to be expressed in the phenotype immediately.
Haploid genome
_________ is preventing disease before an infection is acquired, whereas therapy is treating disease after the host is infected.
Prophylaxis
(Active/passive) immunisation is the administration of antigen, to provoke a host immune response.
Active
Passive immunisation is the administration of ________ to provide an immediate protection. This includes transfer of antibodies across the placenta, and in breast milk.
Antibodies
There are mainly two types of vaccines.
Live attenuated vaccines
and
Inactivated vaccines
Dead whole cell vaccines can be inactivated by ______ or ______ treatment.
heating or formalin treatment
Subunit vaccines usually require ______.
adjuvants (to activate the innate immune system) because there are no danger signals provided by the subunit vaccine itself
Attenuation of live viruses is usually done by:
Culturing them for many generations in cell lines which are NOT the primary target of the virus
Examples of live attenuated vaccines:
Oral polio vaccine, BCG vaccine for TB bacterial, measles vaccine, chickenpox vaccine, MMR
New way of attenuating viruses:
- Clone and sequence to identify functions of different genes
- Delete/modify a gene by mutations to construct a vaccine with immunogenic surface molecules but no virulence factors
_______ is an example of a vaccine obtained from the new way of attenuating viruses.
Rotavirus
The Dukoral oral cholera vaccine is a (live attenuated/inactivated whole cell/subunit) vaccine.
inactivated whole cell vaccine containing killed cholera bacteria and the B component of the cholera toxin
There are mainly three types of subunit vaccines.
Toxoids, viral surface antigens and bacterial capsule polysaccharides
Bacterial capsule polysaccharides vaccine alone with trigger the T-cell (independent/dependent) response.
T-cell independent response => No immunological memory and no Ig class switching (only IgM produced)
Bacterial lipopolysaccharide LPS vaccine is usually conjugated with a protein to create a _______ vaccine. This can activate T-cell (independent/dependent) response, and therefore form immunological memory and facilitate Ig class switching.
conjugate vaccine;
to activate T-cell dependent response
There are two main routes of delivery for vaccines.
Mucosal or Systemic
Vaccines delivered using the mucosal route include two ways.
Oral and intranasal
For mucosal vaccines, resulting effector cells will home back to mucosal sites, and induce antibody ____ production.
IgA
For systemic vaccines, there are two ways to deliver it.
Intramuscular and Subcutaneous
Systemic vaccines result in responses in draining lymph nodes, giving rise to serum antibodies and __________.
Circulating cytotoxic T cells
Adjuvants are used to activate _______ cells to make them more effective at presenting antigens to T-cells.
It therefore targets the innate immunity to activate the adaptive immunity.
Dendritic cells
Adjuvants need to be structurally similar to ______ or ______ to activate the innate immune response.
PAMPs or DAMPs
For systemic (parenteral) vaccines, common adjuvants use include (A) \_\_\_\_\_\_\_\_\_\_ to fake necrotic cell death signals, (B) Oil in water emulsions with surfactants and squalene to induce \_\_\_\_\_\_\_\_\_ and used for antigen retention within injection site, (C) Bacterial products that act directly on PRRs
(A) Aluminium salts to fake necrotic cell death
(B) Oil to induce inflammation and used for antigen retention
(C) Bacterial components to act on PRRs
__________ is the sum of individual immunities and the effect of lower transmission rate.
Herd immunity
____ herd immunity in the UK uses vaccination in young children to protect older age groups.
HIB (Haemophilus influenza type B)
There are two types of polio vaccines. State each type as well as its type of vaccine.
Oral polio vaccine (live, attenuated)
Inactivated systemic polio vaccine
The disadvantage of inactivated systemic polio vaccine is:
It does not give any intestinal immunity as polio is a faeco-oral disease which may replicate asymptomatically in carriers.
Bacterial infections arise from ______ (carried by the host) or ______ (External) sources and enter through different portals of entry.
Intrinsic VS. Extrinsic
Infections targeting the upper respiratory tract are usually (intrinsicially/extrinsicially) acquired from respiratory tract droplets or airborne.
extrinsically acquired
How does the following bacteria enter the body?
Strep pneumoniae, strep pyogenes, neisseria meningitidis, MRSA, MSSA (S. aureus)
Upper respiratory tract infection
Urogenital tract infections may enter the body through the urogenital tract, and may be extrinsicially or intrisincially acquired.
-
Intrinsic infections of the urogenital tract can come from either the __________ and or the _______.
large intestine or throat
Strep Group A is intrinsically acquired in the _______ and may enter the body through the __________ during pregnancy.
Strep Group A is intrinsicially acquired in the throat and may enter the body through the urogenital tract during pregnancy.
E. coli and Strep group B are intrinsically acquired in the _________ and may enter the body through the ________.
Strep group B and E.coli are intrinsicially acquired in the large intestine and may enter the body through the urogenital tract.
______ infections refer to the infections derived from the hospital.
Nosocomial
Neisseria gonorrhoeae and treponema pallidium are sexually-transmitted infections that can enter the body through _________.
urogenital tract
The gastrointestinal tract, also known as the _________ route, is a common portal of entry for many pathogens which are usually extrinsicially acquired via contaminated food and water.
faeco-oral route
How does the following bacteria enter the body?
E.coli, Shigella, Vibrio cholera, Listeria, Salmonella
faeco-oral route via the GI tract
Bacteria may be classified as _______ which cause disease, or _______ which do not cause disease.
pathogens - cause disease; commensals - do not cause disease
Pathogens may be further classified into ____ pathogens (infectious agents that cause disease in any host) or _________ pathogens (potentially infectious agents that rarely cause disease in individuals with a healthy immune system).
true pathogens VS. opportunistic pathogens
The _________ of a bacterium is defined as its ability to cause disease.
pathogenicity
Pathogenicity of bacteria is affected by
1)
2)
1) Infectivity (infection)
2) Virulence (features enhancing disease causation)
The higher the infectivity of a bacterium, the (lower/higher) its infectious dose.
lower
infectious dose is the average number of bacteria needed to initiate an infection
The infectivity of the bacterium depends on several factors:
5
- Route of transmission
- Ability to colonise host
- Tropism and motility
- Replication speed
- Immune evasion
________ is when the bacteria enters the bloodstream to cause disease in other parts of the body.
Bacteraemia
Mycobacterium tuberculosis has a low infective dose and very low replication rate, because it can:
survive inside macrophages and resist killing it
Vibrio cholerae has very (low/high) infectivity. Therefore it needs flagella for motility.
low infectivity (high infective dose)
The _________ of a bacteria refers to the features which it possesses that enhance infection and disease causation.
virulence
Strep pneumoniae - 2 virulence factors
1) Toxin production: _________ is a cholesterol-dependent pore-forming toxin which affects lung architecture, making it more porous for bacteria.
2) Degradation of host molecules: _________ degrades host hyaluronic acid matrix for nutrition and spread.
1) Toxin production: Pneumolysin
2) Degradation of host molecules: Hyaluronan lyase
Staph aureus:
1) Interference with host cell function: __________ interferes with normal T cell function, which may cause organ failure.
2) Immune evasion: _________ lead to neutrophil death and abscess formation.
1) Superantigens
2) Leukocidins
Strep pyogenes is a mouth bacteria that will cause _________.
tonsilitis
Neisseria meningidis colonises the nasopharynx asymptomatically before invading the epithelial and endothelial cells to enter the bloodstream, causing ____________.
Meningococcal septicaemia (bloodstream infection)
Pneumonia is caused by bacteria _______,.
Strep pneumoniae
Cholera is caused by pathogen __________, which is transmitted using the ______ route.
Vibrio cholerae; faeco-oral route
_________ colonises the maternal genital tract from the GI tract, which can cause invasive GBS infection in neonates, causing disease _________.
Group B Strep; Neonatal meningitis septicaemia
Strap aureus produces a family of leukocidins which destroy neutrophils, causing ______.
abscess
Vibrio cholerae has a low infectivity, which uses its _____ to penetrate the thick mucus layer in the intestines, and hooks to the intestinal walls.
flagella
Vibrio cholerae:
- Synthesises toxin A and B to bind to the _______ on the gut wall
- Retrograde endocytosis of toxin ___
- Binding of toxin A to ___ proteins stimulate _______ to produce cAMP
- cAMP activates the ________ channels in the membrane, causing…
- Toxins A and B bind to GM gangliosides on the gut wall.
- Retrograde endocytosis of component A
- Binding of toxin A to Gas proteins stimulate adenylyl cyclase to produce cAMP
- cAMP activates CFTR chloride channels in the membrane, causing Cl- efflux from the cell, allowing Na+ and water to leave the cell.
=> Diarrheoa and dehydration
Staph and strep and listeria are (gram-negative/gram-positive) bacteria.
gram-positive
Neisseria, HIB, E.coli, salmonella, Vibrio cholera and Shigella are (gram-negative/gram-positive) bacteria.
gram-negative
Pseudomonas aeruginosa and Acinetobacter baumanii are examples of (Gram-positive/gram-negative) ____________.
Gram-negative opportunistic pathogens
Staph epidermis and Enterococcus faecalis are examples of (Gram-negative/Gram-positive) ____________.
Gram-negative opportunistic pathogens
