Bacterial Structure 1 & Bacteria virulence factors Flashcards

1
Q

Bacteria are present where? (term: ?)
Essential for the existence of ? on Earth

  • Ubiquitous and numerous
  • are bacteria more beneficial or more pathogenic?
  • size ?

**Morphologies - few or diverse?

sphere-shaped - bacteria name?
rod-shaped - bacteria name?

name some other shapes?

A

Bacteria are EVERYWHERE (omnipresence)
Essential for the existence of all life on Earth

  • Ubiquitous and numerous
  • are bacteria more beneficial or more pathogenic? - more are beneficial relative to pathogenic
  • size ? = very small (invisbile to the naked eye)

sphere shaped - cocci
-> coccus, diplococci, diplococci (encapsulated), staphylococci, streptococci, sarcina coccus, tetrad coccus

rod-shaped - bacilli
-> coccobacillus, bacillus, diplobacilli, streptobacilli, palisades

other shapes
- club rod, vibrio, spirillum, helical form, spirochete, filamentous

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2
Q

red ball thing in Clostridium tetani is bacterial spores

majority of arrangement of bacteria is?

A

majority of arrangement of bacteria is diplococci

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3
Q

SIZES

bacteria’s normal range is between #micrometer? to #? micrometer and can be seen through which type of microscope?

In general, bacterial sizes (diameter) range from 1 μm to 5 μm (true range: ? μm – ? cm)

virus, mycoplasma, bacteria, yeasts, eukaryotic cells and mycelia -> arrange smallest to largest

naked eye can see which range of micrometer
light microscopy can see which range of micrometer
electron microscopy can see which range of micrometer

A

bacteria’s normal range 1 micrometer to 5 micrometer and can be seen through both light and electron microscopy

In general, bacterial sizes (diameter) range from 1 μm to 5 μm (true range: 0.1 μm – 2.0 cm)

VMBYEM

virus, mycoplasma, bacteria, yeasts, eukaryotic cells and mycelia

naked eye can see 100 micrometer to 500 micrometer
light microscopy can see 0.3 micrometer to 500 micrometer
electron microscopy can see from 0.05 micrometer to 50 micrometer

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4
Q

Cell structure

  • Prokaryotes (pro – means?; karyote – means?)
  • Unicellular or multicellular organisms?
  • Lack of ? organelles and ? nucleus

All bacteria have: list 5

Some bacteria have: list 4

Some bacteria can produce: ?

A

Cell structure

  • Prokaryotes (pro – before; karyote – nucleus)
  • Unicellular organisms
  • Lack of membranous organelles and true nucleus

All bacteria have:
cell membrane
ribosomes
cytoplasm
complex and rigid cell wall (except mycoplasma - no cell wall)
nucleoid (DNA)

Some bacteria have:
capsule
flagella
pili/fimbriae
plasmids

Some bacteria can produce: endospores

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5
Q

CYTOPLASM: is ? aqueous solution (cytosol)

Functions:?
Contains: ?

label image: what is white thing and black dots

NUCLEOID (DNA)
* The bacterial ?
* single or double-stranded DNA?
* mostly or some? single* (haploid) and circular*
is the circular or straight shape better for protection?

Function
* Contains the ? for the life of the bacteria (core-genome)

A

Cytoplasm: is jelly like aqueous solution (cytosol)

Functions: facilitate major chemical rxns of the cell
Contains: nuceloid (DNA) and ribosomes

label image: white thing is the DNA so 2 chromosomes and black dots are ribosomes

NUCLEOID (DNA)
* The bacterial chromosome
* double-stranded DNA?
* IMP -> mostly single* (haploid) and circular*

is the circular or straight shape better for protection? - circular (other shape more prone to attack by toxins)

Function
* Contains the essential genes for the life of the bacteria (core-genome)

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6
Q

PLASMIDS:

  • DNA molecule -> which shape?
  • single or Double-stranded DNA?
  • Some are ? (able to be passed to other bacteria)
  • Contains additional genes, not ?

Functions:
* Provide ? factors (genes)
* ? resistance (genes)
* & other genes…

Ribosomes:
* The cellular ? factory
* Composed by ? & ?
* Two subunits = large (?) and small (?)
* ? genetic code
* Applications = therapy + phylogeny

for therapy bc stop the production of proteins then u die so good target for therapy and
2. if its conserved then we can build bullet (not a specific one tho)

phylogen: if we read how its composed then we can organize that we can understanding of microbes

A

PLASMIDS:

  • DNA molecule -> circular
  • Double-stranded DNA?
  • Some are conjugative (able to be passed to other bacteria)
  • Contains additional genes, not essential

Functions:
* Provide virulence factors (genes)
* antibiotic resistance (genes)
* & other genes…

Ribosomes:
* The cellular protein factory
* Composed by proteins & rRNA
* Two subunits = large (50s) and small (30s)
* conserved genetic code
* Applications = therapy + phylogeny

for therapy bc stop the production of proteins then u die so good target for therapy and
2. if its conserved then we can build bullet (not a specific one tho)

phylogen: if we read how its composed then we can organize that we can understanding of microbes

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7
Q

Bacterial envelope:
1. plasma membrane is aka what membrane?
2. ? proteins
3. do they have a cell wall and what is in it?
4. Allows the ? of the two main groups of bacteria which are ?

A

Bacterial envelope:
1. cytoplasmic or plasma membrane
2. membrane-associated proteins
3. cell wall (peptidoglycan layer)
4. Allows the characterization of the two main groups of bacteria which are gram + and - (- always have 2 cytoplasmic membranes)

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8
Q

Bacterial envelope:

  1. Plasma membranes or ? have:
    list 4 characteristics
  2. Membrane-associated proteins:
    list 4 characteristics
  3. Cell wall (peptidoglycan layer)
    Peptidoglycan = chain of alternating subunits of ?
    Functions
    - Protection against ? and ?
    - ? transport
    - differences in ? and ? - pathogenicity and ? properties
  4. Allows the characterization of the two main groups of bacteria
    Gram staining technique:

step 1: “ ? “
primary stain added to specimen

step 2: “ ? “
mordant makes dye more or less? soluble so it adheres to cell walls

step 3: ?
decolorizer washes away stain from gram (-) cell walls

step 4: ?
counterstain allows dye adherence to ? cell walls.

stays purple due to the presence of a ? layer of peptidoglycan in whose cell walls? which retains the crystal violet these cells are stained with

A
  1. Cytoplasmic membrane
    ■ Flexible structures
    ■ Layercomposedofphospholipidsandproteins
    ■ No sterols (presentineukaryoticcells)
    ■Outer faces are hydrophilic, interior hydrophobic
  2. Membrane-associated proteins:
    ■ Stabilization of membrane
    ■ Transportof molecules
    ■ Electron transport for bacterial respiration
    ■ Enzymes
  3. Cell wall (peptidoglycan layer)

Peptidogly”can” (reverse: NAC -> NAG NAM nag nam nag nam…) = chain of alternating subunits of N- acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) crosslinked with short peptides

Functions
- Protection against mechanical damage and osmotic lysis
- non-selective transport
- differences in structure and chemical composition - pathogenicity and staining properties

  1. Allows the characterization of the two main groups of bacteria
    Gram staining technique:

step 1: “crystal violet”
primary stain added to speciment

step 2: “iodine”
mordant makes dye less soluble so it adheres to cell walls

step 3: Alcohol
decolorizer washes away stain from gram (-) cell walls

step 4: safranin (pink in color)
counterstain allows dye adherence to gram (-) cell walls.

stays purple due to the presence of a thick layer of peptidoglycan in the gram + cell walls, which retains the crystal violet these cells are stained with

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9
Q

Bacterial envelope:

Outer membrane
* Only in Gram-? bacteria

(things happen in which space? where what is present?)

Contains:
* Lipopolysaccharide: ?
Porins: ?
Transporter proteins: ?

Alternative structural bacterial envelopes:

Mycobacteria
* Bacterial envelope contains ** ? **
* ? cell wall
* ? staining for identification

Mollicutes (Mycoplasma)
* ** ? ~ no ? layer **
* Highly ? and ? unstable
* The ? bacteria described
(- need which microscope to see them)

A

Bacterial envelope:

Outer membrane
* Only in Gram-negative bacteria

(things happen in periplasmic space where peptidoglycan is present)

Contains:
* Lipopolysaccharide: a strong immunologic molecule called endotoxin
Porins: protein channels that allow small hydrophilic molecules
Transporter proteins: enable transport of large nutrients

Alternative structural bacterial envelopes:

Mycobacteria (note myco - bacteria; myco - lic acids)
* Bacterial envelope contains ** mycolic acids **
* thick waxy hydrophobic cell wall
* acid-fast staining for identification

Mollicutes (Mycoplasma)
* IMP!!! ** no cell wall ~ no peptidoglycan layer ** (all other bacteria have cell wall)
* Highly pleomorphic and osmotically unstable
* The smallest bacteria described
- need electron microscope to see them

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10
Q

Capsule:

  • ?, an extracellular polymeric matrix
  • in ? bacterial species

Functions: list 3

what is green thing in pic?

FLAGELLA:
* Anchored to the ?
* ?-protein structure (engine)
* The ? and ? vary between
bacteria

  • Functions:
    ?
A

Capsule:

  • glycocalyx, an extracellular polymeric matrix
  • in some bacterial species

Functions:
1. protection (environment, phagocytosis)
2. cell adherence
3. nutrient reserve

what is green thing in pic? -> glycocalyx

FLAGELLA:
* Anchored to the bacterial cell envelope
* multi-protein structure (engine)
* The number and position vary between
bacteria

  • Functions:
    locomotion or bacterial motility
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11
Q

Pili/fimbriae:
* ? appendages attached to ?
* Known as “?”
* Most common on which type of bacteria?

Function
* Adhesion to ? (specificity)
* Contribute to ?

Endospores:
* Cryptobiotic state of ? and most ? type of cell found in nature
* Produced by some ? bacteria
* Examples of pathogenic genera: ? and ?

Function
* Ensure survival during ? environmental conditions
* ? bodies

A

Pili/fimbriae:
* fine straight hair like appendages attached to cell wall
* Known as “adhesins”
* Most common on which type of bacteria? = gram-negative bacteria which has an outer membrane

Function
* Adhesion to host tissues (specificity)
* Contribute to antigenicity

Endospores:
* Cryptobiotic state of dormancy and most durable type of cell found in nature
* Produced by some gram positive bacteria
* Examples of pathogenic genera: bacillus and clostridium

Function
* Ensure survival during adverse environmental conditions
* dormant highly resistant bodies

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12
Q

which of the following bacterial structures may help for the establishment of animal infection?

capsule
plasmid
flagella

A

ALL OF EM - each’s function will help it in animal infection

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13
Q

Bacterial growth and metabolism

Metabolism: definition?

Metabolism’s currency of energy?

A

Metabolism: is defined as the sum of all chemical rxn needed to support cellular function and hence the life of an organism

Metabolism -> energy transfer/matter transport (molecule to glucose etc.) -> cellular work -> growth and reproduction

Metabolism’s currency of energy = ATP (e.g. ATP helps flagellum move which in turn makes bacteria move; e.g. for protein to be put into the complex structure again need ATP)

ATP: adenine ribose and 3 phosphate group (when break 1 of the 3 phosphate group gives energy i.e., exothermic so gives u energy)

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14
Q

Bacterial growth and metabolism

how do bacteria grow?

generation time: Length of time required for a single bacterial cell to yield ? (? to ?)

bacterial growth: what are required for the process to occur?

EXAM QUESTION:
can bacteria produce their own nutrition (e.g. carbon etc.) and can they survive on their own?
nutrition: depends on what ? they have inside the chromosome to eat; they need mainly 3 things which are ?

A

how do bacteria grow? by binary fission

  1. nucleoid divides; cell wall and membrane begin to form transverse septum
  2. transverse septum becomes complete
  3. daughter cells separate

(1 mother cell divides into 2 daughter cells and make septum where 2 membranes form an invagination -> then divide, smtms they cut but smtms dont and so form chains of bacteria)

generation time: Length of time required for a single bacterial cell to yield 2 daughter cells (30 mins to 20 h) e.g. e coli (most pathogens as well) grow v fast

bacterial growth:
specific environmental factors needed for process to occur
- nutrients (e.g. glucose, nitrates, fatty acids)
- pH
- ionic strength & osmotic pressure
- temp.
- gaseous requirement (oxygen, CO2)

EXAM QUESTION:
can bacteria produce their own nutrition (e.g. carbon etc.) and can they survive on their own? - NO, they must get their nutrition from surroundings including protein, carbs and lipids (glucose can be derived from all 3 sources)

nutrition: depends on what enzyme they have inside the chromosome to eat; they need mainly 3 things which are protein, carbs (EASIEST TO PRODUCE ATP FROM) and lipids.

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15
Q

Bacteria has mainly 2 diff. production (glucose)?

pH:
bacteria have diff. range of ? where they can live and multiply. Most of bacteria are ? (neutral pH)

Ionic strength & osmotic pressure:
usually ? solution (solutes inside more concentrated than outside so need to control that)

? solution: solutes outside more concentrated than inside

Most pathogenic bacteria grow best at osmotic pressures equivalent to ? (? NaCl).

Temperature:
Temperature requirement for optimal enzyme-catalyzed metabolic reactions.

Most pathogenic bacteria are ? (30-40 C) and why??

their optimal temp. depends on ?

their temp. range:
psychrophiles
psychrotrophs
mesophils
thermophiles
hyperthermophiles

A

aerobic and anaerobic (last molecule receiving is not oxygen and its called fermentation - produce acid and gases out of it)

bacteria have diff. range of pH where they can live and multiply. Most of bacteria are neutrophils (neutral pH)

Ionic strength & osmotic pressure
usually hypotonic solution (solutes inside more concentrated than outside so need to control that)

hypertonic solution: solutes outside more concentrated than inside

Most pathogenic bacteria grow best at osmotic pressures equivalent to physiological saline (0.65% NaCl).

Temperature:
Temperature requirement for optimal enzyme-catalyzed metabolic reactions.

Most pathogenic bacteria are mesophils (30-40 C) as the temp. in our blood is the same range (37 C) so adapted to that and hence can multiply etc.

their optimal temp. depends on enzymes

their optimal. range:
psychrophiles: 10 C
psychrotrophs 21 C
mesophils 35 C
thermophiles 60 C
hyperthermophiles 90 C

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16
Q

Bacterial growth:
Specific environmental factors are required for the process to occurs

Gaseous
requirement (oxygen, carbon dioxide)

Bacteria vary in their need and tolerance for ?.
They are divided into two major groups: ? and ?.
* The carbon dioxide is required for ?.
* The air levels are sufficient for many bacteria (0.04%).
Some require elevated levels of * ? * (5-10%).

obligate aerobes:
obligate anaerobes:
facultative anaerobes:
aerotolerant anaerobes:

A

Bacterial growth:
Specific environmental factors are required for the process to occurs

Gaseous
requirement (oxygen, carbon dioxide)

Bacteria vary in their need and tolerance for OXYGEN.
They are divided into two major groups: aerobes and anaerobes
* The carbon dioxide is required for growth (and to balance oxygen level)
* The air levels are sufficient for many bacteria (0.04%).
Some require elevated levels of * carbon dioxide * (5-10%).

obligate aerobes: oxygen loving bacteria
obligate anaerobes: oxygen hating bacteria

facultative anaerobes: can change their metabolic processes depending on the presence of oxygen, using the more efficient process of cellular respiration when oxygen present and the less efficient process of fermentation in the absence of oxygen, facultative anaerobe E coli. (so present both on top and bottom as seen in image)

aerotolerant anaerobes: bacteria can tolerate oxygen but their first option would be an anaerobic pathway.

17
Q

bacterial growth:

The size of bacteria populations is expressed as the number of cells present.

LAG PHASE:
EXPONENTIAL GROWTH PHASE:
STATIONARY PHASE:
DEATH PHASE:

where does spore formation occur?

The result: (over)multiplication of bacteria in the wrong place → ?

A

LAG PHASE: Increase in cell size, active metabolism of cells but no division
EXPONENTIAL GROWTH PHASE: Cells multiply at maximum rate (optimal environmental conditions such as nutrients, temp.)
STATIONARY PHASE: Nutrient exhaustion
& accumulation of toxic products (SPORE FORMATION)
DEATH PHASE: Progressive death of cells

where does spore formation occur? - stationary phase

The result: (over)multiplication of bacteria in the wrong place → DISEASE

18
Q

Phylogenetic tree

Diagram representing ? among organisms

■ Based on ? analyses of conserved genes (rRNAgenes)

■ Recent development towards whole genome-based phylogeny

(Darwin first used beaks of galapagos to draw phylogenetic tree but now we have gene sequencing)

Applications: through gene sequence we can see if disease outbreaks from 2 diff. places are the same

A

Phylogenetic tree

Diagram representing evolutionary history among organisms

■ Based on comparative gene sequence analyses of conserved genes (rRNAgenes)

■ Recent development towards whole genome-based phylogeny

(Darwin first used beaks of galapagos to draw phylogenetic tree but now we have gene sequencing)

19
Q

Taxonomy
Study of bacterial ?, ? and ?
■ Permits accurate ?
■ Precise naming for efficient communication
■ Groups ? organisms

Species
- Basic ?
- Group or population composed of similar individuals that are capable of ? naturally and are ? isolated from other groups

taxonomy imp. as?

A

Taxonomy
Study of bacterial identification, classification and nomenclature
■ Permits accurate identification
■ Precise naming for efficient communication
■ Groups similar organisms

Species
- Basic taxonomic unit
- Group or population composed of similar individuals that are capable of interbreeding naturally and are reproductively isolated from other groups

Dear - domain
King - kingdom
Phillip - phylum
Came - class
Over - order
For - family
Good - genus
Soup - species

taxonomy imp. as helps us identify which one it is.. even if same genus the species can be entirely diff. than each other in terms of pathogenicity and fatality e.g.

Bacillus subtilis: mostly non-pathogenic
Bacillus cereus: food-poisoning pathogen
Bacillus anthracis: lethal pathogen

20
Q

Bacterial Pathogenesis

Bacterial (biological) mechanisms that lead to a disease

“how do bacteria cause disease?”

HOST
* Breed age, sex, genotype * Physiology and ‘damage’ * Immunity

PATHOGEN
* ? (ability to cause disease)
* ? (measurement of pathogenicity)
* Infection route, tropism like brucella for reproductive tissue of females (they like what these females produce)
* ?
* ? factors (bacterial characteristics that contribute to virulence)

ENVIRONMENT
* Housing, management, hygiene (milking dirty)
* ?
* ?

A

Bacterial Pathogenesis

Bacterial (biological) mechanisms that lead to a disease

“how do bacteria cause disease?”

HOST
* Breed age, sex, genotype * Physiology and ‘damage’ * Immunity

PATHOGEN
* pathogenicity (ability to cause disease)
* virulence (measurement of pathogenicity)
* Infection route, tropism like brucella for reproductive tissue of females (they like what these females produce)
* inoculation dose
* virulence factors (bacterial characteristics that contribute to virulence)

ENVIRONMENT
* Housing, management, hygiene (milking dirty)
* nutrition
* disease control

21
Q

PATHOGEN

Infectious agent: a microorganism that can cause ? upon colonization of the host

  • Obligate pathogen: it must infect a ? and cause disease to multiply and be transmitted from ? to ?
  • Facultative pathogen: it can infect and ? in hosts but is also capable of multiplying in the ?
  • Opportunistic pathogen: microorganism which ? cause disease but which, under certain conditions (e.g., impaired host immunity) becomes pathogenic

Host-Pathogen interaction
Defined as how bacteria (and other pathogens) ? themselves within host organisms on a molecular, cellular, organismal or population level.

A

PATHOGEN

Infectious agent: a microorganism that can cause disease upon colonization of the host

  • Obligate pathogen: it must infect a host and cause disease to multiply and be transmitted from one host to another; it NEEDS a host to complete its life cyce
  • Facultative pathogen: it can infect and multiply in hosts but is also capable of multiplying in the environment without a host; thus it doesn’t ncessarily need a host to complete its life cycle
  • Opportunistic pathogen: microorganism which does not ordinarily cause disease but which, under certain conditions (e.g., impaired host immunity) becomes pathogenic

Host-Pathogen interaction
Defined as how bacteria (and other pathogens) sustain themselves within host organisms on a molecular, cellular, organismal or population level.

22
Q

HOST PATHOGEN INTERACTION

** infection: the ? of pathogens in an individual host **

Until here the infection occurred. The consequence can be:
* ? interaction
* ? relationship
* ?

“imp to understand each step”

expsoure: bacteria present in the exposure site to lumen of intestine

adhesion: bacteria bind to intestine
invasion: enter into intestine

colonization: multiples in cells (NOTE: DISEASE HASN’T YET OCCURED, only multiplication/infection)

toxicity: body doesn’t like bacteria chilling there -> inflammation
tissue damage and disease: NOW ? HAS OCCURED!

The pathogen path…

PATHOGEN

Find a ? host and appropriate ? within the host

Compete ? to adhere to host cells

? host defense

Express ? (? factors) that code for factors causing disease

DISEASE

A

HOST PATHOGEN INTERACTION

** infection: the invasion and multiplication of pathogens in an individual host **

Until here the infection occurred. The consequence can be:
* Commensal interaction
* Mutualistic relationship
* Disease

“imp to understand each step”

expsoure: bacteria present in the exposure site to lumen of intestine
adhesion: bacteria bind to intestine
invasion: enter into intestine

colonization: multiples in cells (NOTE: DISEASE HASN’T YET OCCURED, only multiplication/infection)

toxicity: body doesn’t like bacteria chilling there -> inflammation
tissue damage and disease: NOW DISESAE OCCURED!

The pathogen path…

PATHOGEN

Find a susceptible host and appropriate niche within the host

Compete microbiota to adhere to host cells

Overcome host defense

Express genes (virulence factors) that code for factors causing disease

DISEASE

23
Q

INFECTIOUS DISEASE

A disease (a disorder of structure or function in the host) caused by ? and ? to other hosts

reservoir species: the bacteria accumulates in them however it doesn’t make them ? but when transmitted to other species it can make them sick.

Intermediate species act like parasites in this case, e.g. pigs, humans eat pigs so a pig that has got the bacteria from reservoir species when eaten by a human, it gets transmitted to the human thus, bat -> monkey (intermediate/amplifier species) [there’s also vector species = musquitoes] -> human

A

INFECTIOUS DISEASE

A disease (a disorder of structure or function in the host) caused by pathogens and transmittable to other hosts

reservoir species: the bacteria accumulates in them however it doesn’t make them but when transmitted to other species it can make them sick.

Intermediate species act like parasites in this case, e.g. pigs, humans eat pigs so a pig that has got the bacteria from reservoir species when eaten by a human, it gets transmitted to the human thus, bat -> monkey (intermediate/amplifier species) [there’s also vector species = musquitoes] -> human

24
Q

Latent period is from when to when?

Infectious period is from when to when?

incubation period is from when to when?

A
25
Q

Infection outcomes

No colonization: (does exposure to bacteria occur in this?)
Infection → disease → recovery
Infection → subclinical disease
Infection → disease → death/disability
Infection → disease → persistence (carriers)

A

Infection outcomes

No colonization: exposure occurs (in all of the ‘em below actually)
Infection → disease → recovery
Infection → subclinical disease (no symptoms but infection occuring inside the host so will have to search for the bacteria)
Infection → disease → death/disability
Infection → disease → persistence (carriers)

26
Q

Inflammation

Biological host response to ? such as ? and/or their metabolites.

A defensive response governed primarily by the immune system, which dispatches ? to the affected sites, resulting in ? and ? or symptoms such as fever.

Results:
* Local ? damage (due to toxins and/or immune response)
* ?
* ? systemic disease
* ? disease

A

Inflammation

Biological host response to harmful stimuli such as pathogens and/or their metabolites.

A defensive response governed primarily by the immune system, which dispatches WBCs to the affected sites, resulting in redness and swelling or symptoms such as fever.

Results:
* Local tissue damage (due to toxins and/or immune response)
* toxemia
* acute systemic disease
* chronic disease

27
Q

bacterial pathogenesis

  • ? concept of disease *

severse diseases and death
mild death

BELOW THESE TWO - INSIDE WATER - hence iceberg

subclinical disease => asymptomatic infection (individual infects others, seroconverts, resists re-infection), v low impact

A
28
Q

VIRULENCE FACTORS

Virulence factor ->

Bacterial traits that confer ?.
Virulence factors enable processes such as ? ->

Allowing bacteria to ? (extracellular and/or intracellular) ? in hosts and produce disease.

(they aren’t virulence factor if they don’t produce ?)

A

VIRULENCE FACTORS

Virulence factor ->

Bacterial traits that confer pathogenicity
Virulence factors enable processes such as adhesion, motility, toxin secretion, immune evasion, bacterial cell-cell communication, colonization ->

Allowing bacteria to colonize (extracellular and/or intracellular) niches in hosts and produce disease.

(they aren’t virulence factor if they don’t produce ?)

29
Q

VIRULENCE FACTORS

Surface-associated proteins:
Host cell ? and ?
? acquisition
Cell ? and ? evasion
? formation

Pili
* ?
* ? uptake
* ? transfer
* ?

Quorum-sensing:
? communication
Virulence ?

Flagella: (note flagella less functions than pili)
?
Host cell ?

?:
Virulence factor regulation

Secretion systems: (similar 2 function to pili)
? factor delivery
? secretion and transport
? uptake and transfer

LPS:
?
tissue ?

efflux pumps:
? secretion
? secretion
other secretion of ? compounds

Toxin production
- Tissue ?
- ?
- ? immune response

A

VIRULENCE FACTORS

Surface-associated proteins:
Host cell adhesion and colonization
nutrient acquisition
Cell invasion and immune evasion
biofilm formation

Pili
* motility
* DNA uptake and transfer
* adhesion

Quorum-sensing:
bacterium cell-cell communication
Virulence gene expression control

Flagella: (note flagella less functions than pili)
motility
Host cell adhesion

two-component system:
Virulence factor regulation

Secretion systems: (similar 2 function to pili)
virulence factor delivery
protein secretion and transport
DNA uptake and transfer

LPS:
inflammation
tissue damage

efflux pumps:
antibiotic secretion
siderophore secretion
other secretion of toxic compounds

Toxin production
- Tissue damage
- invasion
- impairs immune response

30
Q

Bacterial toxins

endotoxins and exotoxins

  • Exotoxin → secreted by the ?
  • Exotoxins are highly ? proteins.
  • They are different types of exotoxins according to the ? and ?

A-B toxins
Type III toxins (both are ? targets)

Membrane-damaging toxins
Superantigens (? targets)

Extracellular matrix (EM) toxins (? targets)

A

Bacterial toxins

endotoxins and exotoxins

  • Exotoxin → secreted by the bacteria
  • Exotoxins are highly antigenic proteins.
  • They are different types of exotoxins according to the mechanisms and targets

A-B toxins
Type III toxins (both are intracellular targets)

Membrane-damaging toxins
Superantigens (cell-surface targets)

Extracellular matrix (EM) toxins (EM targets)

31
Q

A-B toxins

Type III toxins

A-B toxins are the ? through which type 3 toxins get into the system so AB are the mechanism for type 3 toxins

A-B toxins Type III toxins

The classic type III toxins are A-B toxins that consist of two parts: an “ ? ” or active component that enzymatically ? some host cell protein or ? to interfere with a host cell function; and a “B” or binding component that binds the ? to a receptor molecule on the surface of the host

They usually ? the host cell metabolism

A

A-B toxins

Type III toxins

A-B toxins are the mode through which type 3 toxins get into the system so AB are the mechanism for type 3 toxins

A-B toxins Type III toxins

The classic type III toxins are A-B toxins that consist of two parts: an “ A ” or active component that enzymatically inactivates some host cell protein or signalling pathway to interfere with a host cell function; and a “B” or binding component that binds the exotoxin to a receptor molecule on the surface of the host

They usually modulate the host cell metabolism

32
Q

EXOTOXIN

Membrane-damaging toxins (Cytotoxic = ? the cell)

?-forming toxins

if u open cell then cell dies so dead once open

phospholipid layer together then make a hole and everything goes out and kill the cell

A

Membrane-damaging toxins (Cytotoxic = kills the cell)

Pore-forming toxins

33
Q

Superantigens

Trigger excessive stimulation of ?
Resulting in ? T-cell ? and ? release. Fever, ?, dermatitis, ?.

SHOCK: is a life-threatening condition that occurs when the body is not getting enough ?. Lack of blood flow means the cells and organs do not get enough ? and ? to function properly. Many organs can be damaged as a result (?).

[antigen-presenting cell (attract ? to kill pathogen)

T cell that comes is similar to the ?]

[FOR SUPERANTIGENS: lymphocyte team react - dont care and just react (it doesn’t have antigen like first one - see pic); many cytokines are produced and make a mess]

A

Superantigens

Trigger excessive stimulation of T lymphocytes
Resulting in massive T-cell proliferation and cytokine release. Fever, arthrities, dermatitis, shock.

SHOCK: is a life-threatening condition that occurs when the body is not getting enough blood flow. Lack of blood flow means the cells and organs do not get enough oxygen and nutrients to function properly. Many organs can be damaged as a result (organic failure).

[antigen-presenting cell (attract ? to kill pathogen)

T cell that comes is similar to the ?]

[FOR SUPERANTIGENS: lymphocyte team react - dont care and just react (it doesn’t have antigen like first one - see pic); many cytokines are produced and make a mess]

34
Q

Extracellular matrix (EM) toxins

EM: substances or environment
? cells.

Toxins allow ? of bacteria

A

Extracellular matrix (EM) toxins

EM: substances or environment
between or below cells.

Toxins allow free-movement of bacteria

35
Q

ENDOTOXINS

Bacterial envelope:

outer membrane: only in gram-? bacteria
?: a strong immunogenic molecule (called ?)

in picture lipid A making a mess and ENDOTOXIN IS LIPOPOLYSACCHARIDE

A

ENDOTOXINS

Bacterial envelope:

outer membrane: only in gram-negative bacteria
Lipopolysaccharide: a strong immunogenic molecule (called endotoxin)

36
Q

The intravascular release or presence of ? present massive effects on the hosts, and their impact is ?-dependent.

High endotoxin levels can cause ? (organ failure) and ?

Endotoxin in small amounts can induce symptoms of ?, ?, and ?, and ?, finally leading to hypotension.

A

The intravascular release or presence of LPS present massive effects on the hosts, and their impact is concentration-dependent.

High endotoxin levels can cause shock (organ failure) and intravascular coagulation -> THESE TWO WILL USUALLY LEAD TO DEATH

Endotoxin in small amounts can induce symptoms of fever, inflammation, and leukopenia, and damage to blood vessels, finally leading to hypotension.

37
Q

CAPSULES

Capsules have a significant role in determining ? of certain molecules to the cell membrane, mediating ? to surfaces, and ? tolerance of desiccation.

PROTECTION AGAINST:
?
? peptides
? lysis and opsonization
? response

FLAGELLA
* ?
* ?
* Participates in ? formation
* Modulate immune system of
?

A

CAPSULES

Capsules have a significant role in determining access of certain molecules to the cell membrane, mediating adhesion to surfaces, and increasing tolerance of desiccation.

PROTECTION AGAINST:
phagocytosis
antimicrobial peptides
complement-mediated lysis and opsonization
inflammatory response

FLAGELLA
* motility
* adhesion
* Participates in biofilm formation
* Modulate immune system of
eukaryotic cells

38
Q

Pili/fimbriae

Their presence greatly enhances the bacteria’s ability to ? to the host and establish infection.

Quorum-sensing
* ? communication by small signal molecules (pheromones, autoinducers)
* Effect on ? and other metabolic gene ? control

Low density: autoinducers diffuse away from bacteria promoting ? cell behavior

High density: autoinducers bind to receptors and promote ? behavior

When the bacterial population reaches a defined density (a bacterial quorum), the pheromones attain a critical threshold concentration at which they coordinate ? of bacterial genes, so that the colonizing bacteria act as a community rather than as individuals

A

Their presence greatly enhances the bacteria’s ability to attach to the host and establish infection.

Quorum-sensing
* bacterial cell-cell communication by small signal molecules (pheromones, autoinducers)
* Effect on virulence and other metabolic gene expression control

Low density: autoinducers diffuse away from bacteria promoting individual cell behavior

High density: autoinducers bind to receptors and promote group behavior

When the bacterial population reaches a defined density (a bacterial quorum), the pheromones attain a critical threshold concentration at which they coordinate expression of bacterial genes, so that the colonizing bacteria act as a community rather than as individuals

39
Q

BIOFILM FORMATION

▪ Clusters of bacteria that are attached to a ? and/or to each other and embedded in a ? matrix
▪ Consists of substances like ?, ? and released ?
▪ ? organization or arrangement

Transfer of virulence factors (VF)
a. Transformation: Bacteria acquire free DNA from the ?.
Some of the acquired DNA may be ? genes.

b. Transduction. ? (viruses of bacteria) transfer bacterial DNA from one bacterium to ?. Some of the transferred DNA may be ? genes.

c. Conjugation. One bacterium can transfer a ? (mobile DNA) to another bacterium. Usually, plasmids contain ? genes.

A

BIOFILM FORMATION

▪ Clusters of bacteria that are attached to a surface and/or to each other and embedded in a self-produced matrix
▪ Consists of substances like proteins, polysaccharides and released DNA
▪ protective organization or arrangement

Transfer of virulence factors (VF)
a. Transformation: Bacteria acquire free DNA from the environment.
Some of the acquired DNA may be VF genes.

b. Transduction. bacteriophages (viruses of bacteria) transfer bacterial DNA from one bacterium to another. Some of the transferred DNA may be VF genes.

c. Conjugation. One bacterium can transfer a plasmid (mobile DNA) to another bacterium. Usually, plasmids contain VF genes.

Emergence and dissemination of Antimicrobial drug resistance Selection of serious pathogenic strains in the clinics (last slide - ask: VIRULENCE FACTORS DR GU..1)