Block 1 Flashcards
Veterinary diagnostics assist on determining (5) which improves knowledge on (3)
a. Assist on determining:
i. Etiologic agent
ii. Risk of pathogen transmission
iii. Appropriate treatments for infectious diseases
iv. Prognosis of clinical syndromes
v. Preventative and control measures of infectious diseases
b. Improves:
i. Knowledge on pathogens involved in clinical syndromes
ii. Knowledge of pathogens of public importance
iii. Economic losses due to infectious diseases in production animals
Pre-analytical phase of bacteriology and fungal diagnostics include what?
i. Clinical evaluation of the patient
ii. Sample collection, storage, transportation
analytical phase of bacteriology and fungal diagnostics include what?
i. Laboratory processing and analysis
ii. Biosafety levels (BSL)
Post-analytical phase of bacteriology and fungal diagnostics include what?
i. Data reporting and interpretation
ii. Diagnosis and treatment
Types of samples (pre analytic phase) collection of Transudates, exudates, pus, discharges is done by?
Syringe or sterile container
Anaerobic transport medium in anaerobic infection is suspected
Types of samples (pre analytic phase) collection of Lovage or washes is done by?
Syringe, material in saline and LRS
Types of samples (pre analytic phase) collection of Feces is done by?
- 2-3mg in leak proof container
- Repeated sampling for intermittent shedding/chronic
catheterization
Types of samples (pre analytic phase) collection of Urine is done by?
Cystocentesis preferred over catheterization
Or MID STREAM free catch
Types of samples (pre analytic phase) collection of Blood is done by?
- Culture → use appropriate tubes for testing
iv. Urine - Serology→ red top tubes, repeated sampling needed over time
- PCR → EDTA tubes
Types of samples (pre analytic phase) collection of Tissue from necropsy is done by?
- Collect samples for culture first during necropsy
- Collect a good amount of tissue in leak proof containers
- Refrigerate
Adequate transport conditions must be kept to maintain the viability of the microorganism (temp., pH, moisture, oxygen, etc.). Transportation can be in what? (3)
i. Swabs, syringes, sterile tubes
ii. Leak proof sterile containers
iii. Use transport media
b. Be aware of transportation safety and packaging regulations for public transport
Choosing a diagnostic method Depends on: (4)
- Infection type
- Test availability
- Sensitivity and specificity
- Time and costs
Detection of the agent. Direct detection of the bacteria/fungi Staining options include (6)
a. Giemsa/Diff quick → mycoplasma
b. DCF → campylobacter
c. Polychrome methylene blue → Bacillus anthracis
d. Modified Ziehl-Nielsen → Brucella abortus
e. Ziehl-Nielsen → Mycobacterium
KOH, Giemsa → Fungi
Culture media→ contain essential nutrients for growth of
non-fastidious bacteria (for bacteria that grows easily). Examples are (3)
nutrient broth, peptone broth, trypticase soy
agar
Selective media → for growth of only selected bacteria. Examples are? (3)
i. Phenylethyl alcohol agar (PEA) → for Gram +
ii. Mac Conkey agar → for Gram -
iii. Sabourad’s dextrose agar → for fungi
Differential media → distinguish 1 bacteria growing on the
same plate from another. Examples are? (2)
Blood agar → recognition of hemolysin production (differentiates staphylococcus)
ii. Mac Conkey agar → nutrient utilization (lactose fermentation vs. gram neg)
Plate inoculation technique for obtaining isolated pure cultures like Bacterial colony, which is what?
Bacterial colony: visible ma of bacteria all originating
from a single mother cell. Definitive identification of a potential pathogen involves
subculture of an isolated colony to obtain a pure growth
which can be subjected to biochemical or other tests
Results of detection of the agent could be determined by (4)
a. # of colonies isolated (light, moderate, heavy)
b. Accept results = what was expected, known cause,
consistent cytology
c. Don’t accept results = it will be specified why (ex:
contamination, normal microbiota, inflammation)
d. Further information or testing required
What does PCR aid in identifying?
- Aids in identification → tests for DNA
- Conventional (qualitative) → positive or negative
- Real time PCR (quantitative) → gives amount
Detection of microbial components Can be done by? (3)
- Antigen detection: ELISA, agglutination, fluorescent antibody staining, SNAP tests
- Chemical detention: MALDI-TOF → analysis of total protein
- Biological detection: Limulus amoebocyte assay test for LPS of
the bacteria
Detection of host immune response by Serology will detect what? Examples could be? (4)
detection of humoral immunity
1. Ex: agglutination, precipitation, ELISA, immunofluorescence
2. Quantitative → measurement of antibody titer
a. Tells you if the patient has an active infection or not
b. Paired serum titers → compare acute and convalescent
phase samples
i. 4 fold increase in serum titers = infection
c. IgM to IgG conversion for T cell dependent responses
Detection of cell-mediated immunity Example could be?
Tuberculin skin test
a. Tests for bovine tuberculosis
b. Caudal fold test and comparative cervical test
What are some limitations to testing ? (4)
i. Negative microscopy does not rule out infection
ii. Negative result on serology does not discard infection
iii. Positive PCR in a healthy animal does not mean active infection or need to treat
IV. A positive growth on a culture could just be host- associated microbiota
Pros and cons of direct mircoscopy
Pro
-Fast, cost effective (cheap)
-Provides immediate information on number, characteristics, and host response
Con
-Expertise (need to be trained) -Low sensitivity
-Usually cannot identify species
Pro and con of culturing
Pro: gold standard
Con: time consuming 2-10 days, supplies and expertise
Pro and con of PCR
Pro: fast, identifies isolates
Con: +PCR does not always mean active infection or need to treat
Pro and con of serology
Pro: Widely used, rapid test’s available, some useful for chronic and carrier state
Con -False negatives (recent exposure, immunosuppression)
-False positives (vax, cross-reactions, past infection)
Define antimicrobial?
any substance of natural, semisynthetic, or synthetic origin that kills or inhibits the growth of microorganisms/bacteria but causes little or no damage to the host
Define Therapeutic use
when diseased animals are treated to cure infection
Define prophylactic use
: when healthy animals are treated to prevent infection
Define metaphylactic use
when diseases herds are treated to cure infection in
some individuals and prevent infection in others
Growth promotion use
when healthy animals are treated with low (sub-therapeutic) concentrations in feed to improve growth rate and efficiency of feed utilization and improve reproductive performance
Therapeutic use:
Prophylactic use
Metaphylactic use
1. Not a good idea! Promotes resistance!
Define antibiotic. Produced by, function.
chemical substance that is produced by microorganisms and has
the capacity in dilute solution to selectively inhibit the growth or kill other microorganisms
i. Natural products
1. Produced by microorganisms (mainly soil dwelling)
- Function:
a. Communication between microorganisms
b. Killing/inhibition of potentially competitive microorganisms - Very old molecules
All antibiotics are antimicrobials, but not all antimicrobials are antibiotics
Chemical structure of B-lactams
Examples
All contain a beta-lactation ring
Penicillins, cephalosporins
Chemical structure of Aminoglycosides
Examples
All contain amino sugar substructures
Gentamycin, streptomycin
Chemical structure of tetracyclines
Examples
All contain 4 adjacent cyclic hydrocarbon rings
Tetracycline, doxycycline, oxytetracycline
Chemical structure of macrolides
Examples
All contain a 14, 15 or 15-membrane macrolide ring
Erythromycin, azithromycin
Chemical structure of sulfonamides
Examples
All contain the sulfonamide group
Sulfadiazine, prontosil
Chemical structure of (fluoro)Quinolones
Examples
All contain fused aromatic rings. With a carboxylic acid group
Ciprofloxacin, enrofloxacin
Define bactericidal?
Death and disruption of bacterial cell.
Reduce number of viable cells
Preferred for serious and/or life threatening infections or immunocompromised patients
Act on cell wall synthesis, cell membranes and DNA synthesis
Define Bacteriostatic
Inhibit growth and multiplication of bacteria.
Requires the immune system to further clear the infection
Inhibit protein synthesis and pathways
How can we reach the desired antimicrobial effect in the body, at the infection site?
ADME principle of drug delivery
(Absorption, distribution, metabolism, and excretion)
Host factors (age, genetics, pregnancy)
Combination therapy of drugs (increase efficacy, increase spectrum, synergic effect
How can we reach the desired antimicrobial effect inside the body of the host, at the infection side?
Pharmacokinetics/ pharmacodynamics (PK-PD) modeling
MIC - minimally inhibitory concentration.
Narrow-spectrum antimicrobials act against what?
A limited group of bacteria and are used against a particular subset of microorganisms
Broad-spectrum antimicrobials act against what?
A large group of bacteria and are active against both gram-positive and gram-negative organisms
Rational antimicrobial use means what?
It comprises any actions that prevent or minimize development of resistantance in the strain causing infection as well as in the patient’s commensalism microbiota without impacting efficacy
Antimicrobial stewardship means what?
Coordinated interventions/program designed to improve and measure the appropriate use of antimicrobials by promoting the selection of the optimal antimicrobial drug regimen, dose, duration of therapy, and route of administration
Prokaryote:
describe?
how is it like bacteria?
what does it contain?
are there exceptions? what are they?
are they big/small? what is the surface to volume ration? why?
***Prokaryote: smaller, unicellular, lacks nucleus (DNA floats around),
single haploid circular chromosome
* Think bacteria: wide range of morphology
* Contain: ribosomes, cytoplasm, nucleoid (DNA), cell wall
* Exceptions: Leptospira (2 circular chromosomes), Borrellia burgdorferi (linear
chromosome), Mycoplasma (no cell wall)
* Small in size with a large surface to volume ratio so nutrients quickly reach all
parts of the cell
Eukaryote:
describe
what do they contain?
how are the chromosomes arranged?
how do they replicate?
Eukaryote: larger, organelles (mitochondria, Golgi, lysosomes, ribosomes),
linear chromosomes (DNA inside), replicate by mitosis
* Think fungi
Bacteria structures and cell wall
what is the capsul?
what is it associated with?
what does it help with?
Capsule: usually polysaccharide, associated with virulence, helps with survival and attachment
Bacteria structures and cell wall
Cell wall describe?
used for what?
what does it determine?
Cell wall: PEPTIDOGLYCAN, for shape and structure, used to determine if gram pos. or gram neg.
Bacteria structures and cell wall
Cell wall, Gram pos:
describe
does it have an outer membane?
more resistent to what?
what color gram stain?
Gram pos: thick peptidoglycan layer, no outer membrane, lipoteichoic and teichoic acids, strong antigenic properties
* More resistant to drying and disruption
* GRAM STAIN: purple=positive
Bacteria structures and cell wall
Cell wall, Gram neg:
describe:
does it have an outer membrane?
More prone to what?
what color gram stain?
Gram neg: thin peptidoglycan layer, has outer membrane, lipopolysaccharides (aka LPS)
* More prone to drying and disruption (because more lipids)
* Polysaccharide chain: antigenic portion
* Lipid A: endotoxin that will cause toxic effects (harm) and activate immune system
* GRAM STAIN: pink=negative
Bacteria structures and cell wall
All bacteria have this except ?
They have a what?
All bacteria have this except **mycobacterium **(mycolic acid virulence factor) = acid fast stain
* **ACID FAST STAIN: **pink=positive, blue=negative
Bacteria structures and cell wall
Cytoplasmic membrane
what is it?
Cytoplasmic membrane: phospholipid bilayer (very selective membrane)
Bacteria structures and cell wall
Flagella
what is it?
Flagella: motility
Bacteria structures and cell wall
Pilus/pili/fimbriae
explain
what are the 2 kinds called and what do they do?
Pilus/pili/fimbriae: attachment pili (attach to host and invade), conjugation pili (exchange DNA/plasmid)
Bacteria structures and cell wall
Endospore
what are the 2
describe
Endospore (Clostridium spp. and Bacillus spp.): extremely durable dormant state
Bacteria structures and cell wall
In a gram positive photo, name the 3 structures from outside to inside.
are any thick/thin?
Capsule-thick
cell wall-thick
cytoplasmic membrane-thin
Bacteria structures and cell wall
In a gram negative photo, name the 6 structures from outside to inside.
are any thick/thin?
capsule
outer membrane
periplasmic space
cell wall
periplasmic space
cytoplasmic membrane
all thin
Bacteria structures and cell wall
on the slides….
Which one looks like a dark hotdog with a tail?
which one looks like a skinny worm with a tail on both ends?
which one looks like a short white hotdog with all kids of curly tails on one end?
which one looks like a short work with curly tails all over it?
Monotrichous
amphitrichous
lophotrichous
Peritrichous
Bacterial growth
How does it replicate, what is another word for this?
Replication by binary fission (asexual replication)
Bacterial growth
4 phases of growth
what are they?
Lag phase
Exponential/Logarithmic phase
Maximal stationary phase
Decline/death phase
Bacterial growth
4 phases of growth
what happens during lag phase?
Lag phase: increase in cell size but no division
Bacterial growth
4 phases of growth
what happens during Exponential/Logarithmic phase
Exponential/Logarithmic phase: cells multiple at the highest rate
Bacterial growth
4 phases of growth
what happens during Maximal stationary phase
Maximal stationary phase: balance between multiplication and
growth rate (bacterial is growing & bacteria is dying)
Bacterial growth
4 phases of growth
what happens during
Decline/death phase
Decline/death phase: decrease in numbers due to cell death
Bacterial growth
what 2 things might some bacteria require?
Some bacteria require Carbon and/or Nitrogen
Bacterial growth
are oxygen and temperature requirements the same or different?
There are different oxygen and temperature requirements
Bacterial growth
what is the most pathogenic bacteria?
why?
Mesophiles: most pathogenic bacteria because they
grow at host temperature
Bacterial growth
on the graph depicting the 4 phases…
The lag phase takes how long? According to the logarithem, cells are mostly….
approx up to 6 hours
few live cells
logarithem low at about one
Bacterial growth
on the graph depicting the 4 phases…
The exponential growth phase takes how long?
According to the logarithem, cells are mostly….
approx 6 hours to 15 hours
mostly live cells
logarithem rising from about 1to about 9
Bacterial growth
on the graph depicting the 4 phases…
The stationary phase takes how long?
According to the logarithem, cells are mostly….
approx 15 -30 hours
many live cells
some dead cells
logarithem stable at about 9
Bacterial growth
on the graph depicting the 4 phases…
The death phase takes how long?
According to the logarithem, cells are mostly….
approx 30-40 hours
roughly half alive
half dead
logarithem declining to about 5 where some cells remain viable.
Bacterial growth
on the graph that depicts the rate of growth and the temperature (C)….
which grow at the coldest and for how long (what order)
-10 to 20= psychrophiles
0 to 30=psychrotrophs
10 to 48= mesophiles
40 to 72= themophiles
68 to 110=hyperthemophiles
(just approx based on graph)
Bacterial virulence factors
EXOtoxins:
describe
EXOtoxins: usually produced/released by gram pos. and act on specific organs, heat liable
(celebrities have grammy awards/gram positive and many of them are under a lot of heat/heat liable and do drugs and crack under pressure)
Bacterial virulence factors
EXOtoxins:
Superantigens
what are they
what happens
what are the symptoms?
what relevance Toxic Shock Syndrome?
-
Superantigens: improper binding of MHC II molecules– extreme T cell proliferation and release of
cytokine– nausea, vomiting, fever, shock and possibly death
TOXIC SHOCK SYNDROME: can be seen with Staphylococcus aureus or Streptococcus canis
Bacterial virulence factors
ENDOtoxins:
describe
usually associated with ?
part of what ?
what do they cause?
are they heat stable?
ENDOtoxins: usually associated with gram neg., part of cell wall (LPS), cause an immune
reaction, heat stable
Bacterial virulence factors
Biofilms
what are they?
what purpose?
example?
Biofilms: bacteria mass that sticks to each other and to surfaces, beneficial for bacteria to
exchange nutrients
* Examples: dental plaque, Pseudomonas aeruginosa (loves water, blue/green color)
Bacterial virulence factors
Quorum sensing
what is it?
relevance of low density to high density bacteria?
Quorum sensing: allow bacteria to communicate via small signal molecules
* Low density of bacteria: results in individual behavior
* High density of bacteria: encourages group behavior (can result in biofilm formation)
Bacterial virulence factors
Genetic transfer
name the 3 ways
what relevane plasmids and bacteriophages?
Genetic transfer of virulence factors via transformation, transduction, or conjugation
* Plasmids and bacteriophages carry the genes needed for thing like AB resistance or toxin
production
Bacterial virulence factors
on the graph of Bacterial transformation, what is released from the donor cell to the recipient cell?
release of DNA adn Antibiotic resistence gene
Bacterial virulence factors
on the graph of Bacterial transduction, what is released from the recipient cell to the donor cell?
weird spider thing releases phage from the recipient back to the phage inflicted donor
Bacterial virulence factors
on the graph of Bacterial conjugation, what happens between the donor cell and the recipient cell?
looks like they connect and something called transposon occurs.
Fungi overview
Eukaryotic
what is it?
what can’t it do?
Eukaryotic and non-photosynthetic, heterotroph (cannot make their own food)
Fungi overview
what does the cell wall contain?
Cell wall contains CHITIN
Fungi overview
what are the 2 forms and what do they look like?
2 forms: molds (branching hyphae), yeast (unicellular)
* Reproduce sexually (spores) or asexually (spores, budding, fragmentation)
Fungi overview
Antimicrobial/antibacterial
so they work on fungi?
Antimicrobial/antibacterial DO NOT work on fungi = resistant
Fungi overview
What relevance:Mostly saprophytes?
Mostly saprophytes (live on decaying matter) and non-pathogenic
Fungi overview
how do they grow?
Grow aerobically (sometimes strict aerobe)
Fungi overview
When they are pathogenic: what 3 things happen?
Invasion of tissue
Toxin production
Induce hypersensitivity
Fungi overview
When they are pathogenic
Invasion of tissue is called ?
what is an example?
Invasion of tissue: mycosis, ex. Ringworm
Fungi overview
When they are pathogenic
Toxin production is called ?
what happens?
Toxin production: mycotoxicosis, INGESTION of pre-formed toxins
Fungi overview
When they are pathogenic
Induce hypersensitivity is this common?
Induce hypersensitivity: less common
Fungi overview
on the picture… of yeast, filamentous fungi and bacteria…
which one looks like a weird tree branch?
which one looks like larger round peas?
which one looks like deer poop pellets?
which one looks like a weird tree branch? filamentous fungi
which one looks like larger round peas? yeast (10um)
which one looks like deer poop pellets? Bacteria
Pathogenesis and terms
pathogenic or non-pathogenic?
Less than 5% of microbes are pathogenic (95% non-pathogenic)
Pathogenesis and terms
name the 3 kids of “cellular” pathogens take? what is the majority?
Pathogens can be: extracellular (majority), obligate intracellular or facultative intracellular
Pathogenesis and terms
Pathogen: what is it? what does it do?
Pathogen: what causes the disease, infectious agent
Pathogenesis and terms
Pathogenesis:what is this?
Pathogenesis: mechanisms to generate disease (genesis=generate)
Pathogenesis and terms
Pathogenicity: what is this?
Pathogenicity: ability of microorganism to damage host
Pathogenesis and terms
Infection: what happens?
Infection: invasion and multiplication in the host (population)
Pathogenesis and terms
Virulence: what does this mean?
Virulence: capacity of a pathogen to damage host
Pathogenesis and terms
Virulence factors: what do they do?
Virulence factors: help the bacteria cause disease
Pathogenesis and terms
Events of pathogenesism, what are the 5 events?
Events of pathogenesis: (1)find host, (2)evade host, (3)adhere to host, (4)multiply in host, (5)cause damage to host
Bacterial and Fungal Diagnosis steps
on the graph…
what are the 3 steps and what happens in each step?
pre-analytical phase: clinical evaluation
sample collection, storage and transportation
analytical phase: lab processing and analysis
post-analytical phase:
diagnosis and treatment
data reporting and interpretation
PRE-ANALYTICAL PHASE
what happens first?
Physical exam, collect samples (aseptic), complete submission form, appropriate transportation (triple pack
system!)
PRE-ANALYTICAL PHASE
Sample collection:
what happens first in a necropsy?
when should you collect samples?
what relevance to timing and bacteria in sample collection?
what relevance to fungi and location of bacteria sample collection?
how do you keep the bacteria viable?
Know transport and safety regulations for public transport of diagnostic samples & infectious substances
Sample collection:
* During a necropsy, collect samples 1st
* Collect samples in the acute/early stage of disease!
* Bacteria: collect sample BEFORE starting AM’s
* Fungi: collect sample from **PERIPHERY **of active lesion
* Use transport media to keep the bacteria viable
* Know transport and safety regulations for public transport of diagnostic samples & infectious substances
PRE-ANALYTICAL PHASE
Detection of the agent
4 important steps are?
Detection of the agent: direct (microscopy & staining), isolation/identification, detection of toxins (Ag), molecular
**techniques (PCR) **
*dna bacterial
PRE-ANALYTICAL PHASE
Detection of immune response
name 2
Detection of immune response: serology (IgM- acute, IgG- chronic), detection of cells exposed to Ag’s (cell-
mediated immunity)
ANALYTICAL PHASE
what is the most common stain?
Gram: most common stain
ANALYTICAL PHASE
what is DCF
DCF: Campylobacter spp.
ANALYTICAL PHASE
what is Polychrome Methylene Blue
Polychrome Methylene Blue: Bacillus anthracis
ANALYTICAL PHASE
what is Modified Ziehl-Nielsen
Modified Ziehl-Nielsen: Brucella abortus
ANALYTICAL PHASE
what is Ziehl-Nielsen
Ziehl-Nielsen: Mycobacterium spp.
ANALYTICAL PHASE
what is KOH
KOH: fungi
ANALYTICAL PHASE
Ross = BSL 2 lab
what is high risk
what is low risk
Ross = BSL 2 lab (BSL 4 being high risk, BSL 1 being low risk)
ANALYTICAL PHASE
Direct microscopy
what are 4 pros?
what are 3 cons?
Direct microscopy:
* Pros: immediate info, # of bacteria/fungi, morphology, host cellular response (inflammation)
* Cons: expertise (don’t confuse bacteria with “trash”), low sensitivity, usually can’t ID species
ANALYTICAL PHASE
Culture and ID
good? bad?
requirements?
Culture and ID: GOLD STANDARD, but bacteria each have growth requirements, time consuming, need expertise
ANALYTICAL PHASE
Culture and ID
what are the 2 forms and what are they called?
Broth (liquid) media, agar (solid) media
ANALYTICAL PHASE
Culture and ID
Culture media:
when do you use it?
examples?
Culture media: for non-selective bacterial growth
* Ex. soy agar, nutrient broth, peptone broth
ANALYTICAL PHASE
Culture and ID
Selective media/differential media
what is it?
what are 3 types?
Selective media: grows bacteria SELECTIVELY
* Ex. PEA (phenylethyl alcohol agar) selects gram pos., (alcohol is a “+” experience) MacConkey agar selects gram neg., (McDonalds makes you fat and is not healthy a “-“ experience)
SDA (Sabourad’s dextrose sugar) selects fungi
* Differential media: distinguishes 2 bacteria from each other on one plate
* Ex. Blood agar: recognizes hemolysin production, differentiates Staphylococcus, Streptococcus & Enterococcus
* Ex. MacConkey: differentiates lactose pos. and lactose neg. (pink if lactose is produced)
ANALYTICAL PHASE
PCR
what is it?
how does it work?
what does it detect?
PCR: non-culture based ID, fast results
* Conventional (is there an pathogen or not), RT-PCR (how many bacteria)
ANALYTICAL PHASE
Detection of microbial components
what test?
what does it detect?
is it common?
Detection of microbial components: ELISA for Ag detection (less commonly used to PCR) (indirect ELISA)
ANALYTICAL PHASE
Serology
what does it detect?
what does it measure?
how is it tested?
what does it ties for?
how do you read it?
when is it primarily used?
what are 3 pros?
what are 2 cons?
Serology: detect humoral response, measure of exposure to the pathogen, ELISA, Antibody titer (paired serum, 4
fold increase=positive for infection), primarily used at the herd level
* Pros: screening populations/herd, rapid, (some) detect chronic carriers
* Cons: false negatives and false positives
ANALYTICAL PHASE
Tuberculin skin test
what does it test?
when is it used?
what are 2 examples of this test?
how is it done?
Tuberculin skin test: detect cellular response, primary screening, caudal fold test & comparative cervical test for
TB (Mycobacterium bovis)
ok I can’t really read this, but I think it says “ skin test for m. bovis and m.avian next to each other. if rxn is larger for m. bovis than ps. for m. bovis. distingish between “base levels” non and a pos rxn?”
ANALYTICAL PHASE
Interpreting results:
Neg. microscopy results does NOT ?
Neg. serology does NOT?
Pos. PCR does NOT?
Interpreting results:
* Neg. microscopy results does NOT mean the animal does not have an infection
* Neg. serology does NOT mean the animal does not have an infection
* Pos. PCR does NOT mean the animal is currently infected
ANALYTICAL PHASE
on the graph…
4 pictures:
in each is a Substrate which looks like a sun in the sky…
There is an Ag which looks like a green soccer ball
what do you use if you have one soccer player–a primary antibody conjugate?
what do you use if you have a second soccer player standing on the head of the first soccer player–a secondary antibody conjugate?
what do you use if the secondary antibody conjugate is now fighting for the soccer ball with a third player?
what do you call 2 independant soccer players with their own balls?
what do you use if you have one soccer player–a primary antibody conjugate? Direct ELISA/Unknown Antigen
what do you use if you have a second soccer player standing on the head of the first soccer player–a secondary antibody conjugate? Indirect ELISA/unknown Antibody
what do you use if the secondary antibody conjugate is now fighting for the soccer ball with a third player? Sandwich ELISA/unknown antigen
what do you call 2 independant soccer players with their own balls? competitive ELISA
Antimicrobial vs. Antibiotic
Prevention is better than a cure, explain.
what 4 ways can you achieve this?
Prevention is better than a cure: consider elements of holistic animal health management to try and prevent antimicrobial
resistance
1. Good animal husbandry: ex. clean water bowls/systems, fresh bedding
2. Effective biosecurity to avoid spread: isolation and quarantine
3. Vaccination: ex. vaccination against Lyme disease, herd immunity
4. Prudent and medically efficient use of antibiotics: antimicrobial stewardship
Antimicrobial vs. Antibiotic
Antimicrobial stewardship and judicious use, explain.
Antimicrobial stewardship and judicious use: consider antimicrobial resistance (AMR) and the one health response to
antimicrobial resistance
What is an antimicrobial?
define
examples
Antimicrobial: any substance of of natural, semi-synthetic or synthetic origin that kills or inhibits the growth of MO while causing little
damage to the host
* Antibiotics, antivirals, antiparasitic agents, antifungals
What is an antibiotic?
define
where are they found
how do they work?
Antibiotic: chemical substance produced by MO’s that inhibits growth or kills other MO’s
* Primarily produced by soil-dwelling organisms and are very old natural molecules
* Communication between different MO’s: MO produce antibiotics to compete with another MO
* OR to inhibit a potential competitive MO
Antibiotics 101
Antibiotic “wish list”- 5
what do they do?
what don’t they cause?
where do they reside?
relevance of stability?
when do they target the pathogen?
Antibiotic “wish list”
* Kill or inhibit growth of MO
* Cause little to no damage to the host and cause no allergic reaction to the host
* Remain in specific body tissues of the host an appropriate period of time to be effective
* Stable when stored (solid or liquid)
* Target a pathogen between it mutates and/or becomes resistant to the antibiotic
Antibiotics 101
Antibiotic development pipeline
how long to develop?
what are the 6 stages?
Antibiotic development pipeline: takes anywhere from 1-20 years!
1. Screening/hit generation
2. Hit-to-lead:
3. Lead optimization
4. Preclinical studies
5. Clinical phases
6. Approval or launch
Antibiotics 101
Antibiotic development pipeline
Screening/hit generation
explain
Screening/hit generation: basic in vitro research to screen molecules
Antibiotics 101
Antibiotic development pipeline
Hit-to-lead
explain
Hit-to-lead: in vivo antibiotic testing against a known pathogen
Antibiotics 101
Antibiotic development pipeline
Lead optimization
explain
Lead optimization: growth of the antibiotic on a large scale
Antibiotics 101
Antibiotic development pipeline
Preclinical studies
explain
Preclinical studies: at this stage, it has been narrowed down to 5-10 molecules
Antibiotics 101
Antibiotic development pipeline
Clinical phases
explain
Clinical phases: occurs with only 1-2 molecules
Antibiotics 101
Antibiotic development pipeline
Approval or launch
explain
Approval or launch: only 1 molecule/antibiotic is commercialized
Classification
Based on mode of action (MOA)
Name 2 structural
name 3 internal
Based on mode of action (MOA)
* Structural: inhibition of cell wall synthesis: Penicillin
* Structural: injury to plasma membrane: Polymyxin B
* Internal: inhibition of nucleic acid replication and transcription: Quinolones
* Internal: inhibition of protein synthesis: Erythromycin, Tetracyclines
* Internal: inhibition of synthesis of metabolites: Sulfanilamide
Classification
Based on antimicrobial effect
what are the 2 types?
Bactericidal
Bacteriostatic
Classification
Based on antimicrobial effect
Bactericidal
explain
how does it work?
when should it be used?
Bactericidal: antimicrobials cause death
* Target binding, cellular process corrupted, +/- metabolic activity = cell death
* Preferred for serious and/or life-threatening infections or immunocompromised patients
Classification
Based on antimicrobial effect
Bacteriostatic
explain
how does it work?
what is required of the host immune system?
Bacteriostatic: inhibits bacterial replication WITHOUT killing the organisms by acting on protein synthesis
* Ribosome binding, translation inhibition, metabolic activity = cell stasis
* Required the hosts immune system to further clear the infection
Classification
can drugs be either Bactericidal or Bacteriostatic?
if so what does it depend upon?
Some drugs can be either bactericidal or bacteriostatic, depending on: drug concentration, presence of other drugs or
bacterial species
Aka some can be both
Classification
see slide 13 to review:
DNA replication
b-lactams
macroclides
tetracyclines
aminoglycosides
translation
transcription
mRNA
polumyxin B
Quinolones
Sulfanilamide
etc.
Classification
if no antibiotics, bacteria…
if Bacteriostatic antibiotics, bacteria….
if Bactericidal antibiotics, bacteria…
if no antibiotics, bacteria… MULTIPLY
if Bacteriostatic antibiotics, bacteria….PREVENT BACTERIA FROM MULTIPLYING
if Bactericidal antibiotics, bacteria…KILL THE BACTERIA
Classification
How to reach antimicrobial effect:
How to reach antimicrobial effect: infection site
Classification
How to reach antimicrobial effect: infection site
ADME Principle of drug delivery
4 STAGES?
ADME Principle of drug delivery: Absorption, Distribution, Metabolism, Excretion
Classification
How to reach antimicrobial effect: infection site
Solubility of the drug at target site, based on ?
Solubility of the drug at target site, based on: chemical properties of the drug and chemical/physiological processing in the
body (related to host factors)
Classification
How to reach antimicrobial effect: infection site
Host-factors ?
Host-factors: age, genetics, lactation
Classification
How to reach antimicrobial effect: infection site
Combination drug therapy
why? what effect?
Combination drug therapy: increase efficacy, spectrum and synergistic effects
Classification
why do
Bacteriostatic drugs need growth?
bactericidal drugs
need growth?
IMPT. NOTE: Bacteriostatic drugs need growth to stop/slow down bacteria metabolism while bactericidal drugs
need growth/metabolism to act
* This causes antagonism or opposite effects if the drugs are used together
Classification
How to reach antimicrobial effect: inside the body
PK-PD modeling
what are they, how are they different?
Pharmacokinetic: what the body does to the drug,
vs
Pharmacodynamic: what the drug does to the body
Classification
How to reach antimicrobial effect: inside the body
PK-PD modeling
Time-dependent antibiotics, explain
Concentration-dependent antibiotics
explain
How to reach antimicrobial effect: inside the body
* PK-PD modeling (Pharmacokinetic: what the body does to the drug, Pharmacodynamic: what the drug does to the body)
* Time-dependent antibiotics: time above the MIC (minimum inhibitory concentration), antibiotics have to be given at regular intervals (ex.
give X every 6 hours)
* Concentration-dependent antibiotics: Cmax (conc.) over MIC ratio & AUC over MIC ratio, antibiotics can have a prolonged effect
Classification & Antibiotic selection
Based on spectrum of activity
explain
what is Narrow-spectrum antimicrobials
what is Broad-spectrum antimicrobials
No single antibiotic can cover all bacteria so they are
divided into narrow and broad spectrum
* Narrow-spectrum antimicrobials: only work against a
limited group of bacteria
* Broad-spectrum antimicrobials: act against a large
group of bacteria, both gram positive and gram negative
organisms
Classification & Antibiotic selection
Based on spectrum of activity
4 Quadrant coverage
what are they?
4 Quadrant coverage: gram positive, gram negative,
aerobes, anaerobes
* There is also a 4 Quadrant coverage chart for special
bacteria and fungi
Classification & Antibiotic selection
Each time an antibiotic is prescribed, what happens?
Each time an antibiotic is prescribed, antibiotic
selection occurs!
Classification & Antibiotic selection
what are anitbiotic resistant organisms?
population of bacteria with a subset of antibiotic resistent organisms
in the presence of an antibiotic, susceptible strains are killed, the resisent strain survives
The resistent strain proliferates and may be capable of causing a new infection.
Rational antimicrobial use
what is it?
what are some critical quesitons?
Rational antimicrobial use: any actions that prevent or minimize development of resistance, without impacting
clinical efficacy
* Critical questions: systemic use, choice of drug, culture, drug dosage???
Rational antimicrobial use
Antimicrobial stewardship, what is it?
Antimicrobial stewardship: the coordinated interventions or programs designed to improve and measure the
appropriate use of antimicrobials
Rational antimicrobial use
Traffic light antimicrobial principle to limit the selection of resistant bacteria
Green antimicrobials ?
Yellow antimicrobials?
Red antimicrobials?
Traffic light antimicrobial principle to limit the selection of resistant bacteria
* Green antimicrobials: recommended against known susceptible organisms, 1st choice antimicrobials
* Yellow antimicrobials: these should NOT be used where efficacy is in doubt, they are relevant to human therapy
* Red antimicrobials: have to have PROPER TESTING as they are the highest importance in HUMAN therapy
Rational antimicrobial use
Antimicrobials that are ranked as the highest priority by all agencies!!!
Name 4
Antimicrobials that are ranked as the highest priority by all agencies!!!
* Fluoroquinolones
* Macrolides
* 3rd generation Cephalosporins
* 4th generation Cephalosporins
