Final Flashcards
Immunotherapy tests.
Detect pathogen -specific antibody or antigen
Antigens from pathogens can be
Whole pathogen
Molecule produced by pathogen
Pathogen molecule presented on surface of host
What are the common antibodies detected in blood are are common specimens for antibodies
IgG
IgM
(Found at the area of the infection where the pathogen replicates or the antigen is present
What factor is key in accurate immunochemicla diagnosis?
Timing
Acute phase detection may have different antibody presence then further along in disease process
What are indicators of active/recent infection?
Pathogen detection
Present/ recent clinical symptoms of infection
Amount or title of antibodies (number circulating system)
How does an ELIZA immunological assay work?
Antibody is conjugated with an enzyme, the antibody binds to the antigen.
Substrate is added and the enzyme cleaves a reaction to produce a color change (more color means more binding of antigen-antibody binding)
What are the two different ELIZA assays?
Indirect - antibody binding to antibody bound by antigen (antigen coated well)
Sandwich - monoclonal antibody coated well binds antigen and a secondary antibody will bind to the antigen
Describe a lateral-flow immunochromatographic assay
Sample is added to pad
Flow of sample by capillary action
Plate antibody binds conjugate antigen and antibody Second line of anybody’s is to bind conjugate antibody (control line)
What is the basis for IDEXX SNAP test?
Conjugation of antigens to antibody(bound to plate), a congregate antibody(enzyme bound) will bind to antibody- antigen complex.
Color change is produced when substrate is washed across
What is indirect immunofluorescence?
Primary antibody is specific to the antigen (variable region). Binds to antigen
Secondary antibody is specific to the FC portion of the primary antibody -> binds to primary antibody
Secondary antibody is conjugated with fluorophore.
Multiple secondary antibodies can bind and amplify signal
What is agglutination
Particles clump together (antibody and antigen interaction)
Direct or Indirect
What is indirect agglutination
Antigen or antibody coated on beads
Bind bead through an intermediate
What is direct agglutination
Antibody binds directly to antigen.
What are the advantages of immunochemical tests?
ID pathogen when pathogen cannot be cultured
Most have high sensitivity
Most have high specificity
Mid to high-volume testing possible
What are the disadvantages of immunochemical tests?
Detection of antibody may not indicate an active infection
Antibody detection from specimens: very early in infection may not be detected
Possible that antibodies may detect >1 pathogen (different pathogens can have the same antigen)
What is the basis for molecular diagnostics of infectious disease?
Identify makers in the genome or proteome
- determine pathogen ID by characteristic genetic or protein material
- use pathogen-specific genetic sequences to ID pathogen
- use pathogen-specific “protein profile” to ID pathogen
What is MALDI-TOF and how does it work?
Mass spectrometry
Detect part of pathogen (ribosomal peptides) by mass and charge
Signature pattern of fragments
What are the advantages of MALDIVES-TOF?
Rapid ID
High-throughput
ID bacteria/fungi
What are the disadvantages of MALD-TOF
Isolated pathogen analysis
Identification is limited to reference spectra in database
High initial cost
Multiplex PCR/ Microarrays are useful to detect?
Nucleic acid from virus, bacteria, fungi parasite species
Real-time PCR
Pathogen-specific sequence amplification of nucleic acid and measurement
Quantitative for pathogen
Used highly for viral identification and viral load
What are the advantages of molecular diagnostics?
Faster than culture based methods
Highly sensitive
Accurate
High volume testing is possible
What are the disadvantages of molecular diagnostics?
Expensive: equipment and reagents
Requires specialized personnel to run machines
Yes or no answers
Possible false negatives/positives
What phenotypic method cannot be used to clinically diagnose viruses
Culture-based methods
What three things are required for proper specimens collection for diagnostic testing?
Aseptic technique
Collection of a sample specific to the infection
Collection before antibiotic treatment
What are the common specimens collected for a suspected viral infection?
Swabs- nasal, trachea, sputum, and eye
Feces
Blood
Dependent upon suspected viral infection and patient symptoms
Specimen handling is dependent on ?
Pathogen type
Specimen type
What test will be performed
All specimens must be handled to ?
Avoid contamination of other specimens
Avoid contamination of clinic/workers/patient
What are the categories of diagnostics techniques?
Molecular
Immunological and Serological
Phenotypic
What are phenotypic methods of diagnosis
Direct examination
Cytology
Biochemical tests
What are the concentration techniques for direct examination of a sample?
Filtration/ centrifugation
Flotation/ sedimentation
Baermann test for larval identification
Parasite diagnostics are dependent on??
Stage of infection
Animal age and species
Technique used
Severity of infection
False negatives can occur *
What are the advantages of cytology ?
Determine cell and tissue morphology Cellular association of bacteria/ parasites/ fungi Morphology Impression of disease stage/severity Immediate analysis
Disadvantages of Cytology
Mild/chronic infection may not be readily detected
Mot all samples are appropriate for cytology of bacterial infections
Difficult to distinguish normal flora from pathogenic bacteria
What type of infections can you culture?
Bacteria or fungal
What types of infections are not cultured for diagnosis?
Parasites or viruses
What are the different culture options?
Agar
Broth
Biochemical
What type of media is used for general growth of a culture?
Nutrient agar
What type of medial is important for growth of a single suspected pathogen type?
Selective media
What type of media are used to ID a pathogen?
Differential media
Most are also selective medias
An enrichment broth is used for what?
To increase the number of a specific bacteria type and inhibit growth of others
What is a fastidious bacteria?
Requires specific nutrients and culture conditions
Use environmental/nutritional characteristics to select growth of specific organisms => selective media
How can biochemical tests be used to ID a pathogen?
Different bacteria produce different enzymes-> enzymatic or fermentation tests to determine differences in bacterial profiles
What is an antibiotic?
Chemical substance that is produced by a microorganism and has the ability to inhibit growth/ kill another microorganism
What is the difference between an antibiotic and antimicrobial/antibacterial?
Antibiotics are compounds that are produced by microorganisms
Antimicrobial/antibacterial can be any substance (natural/synthetic/semi-synthetic) that inhibits or kills and microorganism
All antibiotics are antimicrobial but not all antimicrobials are antibiotics
What are the uses of antibiotics in animals?
Therapeutic - treat the sick
Prophylactic - prevention
Metaphylatic -treat sick and healthy in a heard for prevention
Growth promotion - healthy animals treated
How can antibacterial agents be classified?
Chemical structure Origin Effect on bacteria Spectrum of activity Mode of action
What compounds are penicillins?
Penicillin G/V
Ampicillin/amoxicillin
Amoxicillin/ Clavulanic acid
What compounds are tetracyclines?
Tetracycline
Oxytetracycline
Doxycycline.
What compounds are Quinolones ?
Oxolinic acid
Erirofloxacin/ Marofloxacin
Pradofloxacin / Norfloxacin
What compounds are Sulfonamides ?
Sulfadiazine
Sulfadiazine/ Trimethorprim
What compounds are phenicols?
Chloramephenciol
Florfenicol
What compounds are cephalosporins?
Cefalexin/Cephadroxil
Cefpodoxime/Ceftiofur
Cefovecin, Cefquinome
What compounds belong to the macrolides?
Erythromycin
Tiamulin, Tilmicosin
What compounds belong to the group Lincosamides
Lycomycin/ Clindamycin
Used for skin infections in dogs
What compounds belong to animoglycosides?
Streptomycin
Gentamicin/ Neomycin
Amikacin
What compounds belong to the polypeptide group?
Colistin/ Polymixin
What drug targets anaerobes?
Metronidazole
What compounds belong to the carbapenems?
Imipenem/meropenem
Ertapenem/ doripenem
What compounds are glycopeptides ?
Vancomycin/ Teicoplanin
What compounds belong to Oxazolidones?
Linezolide
What two antibacterials are synthetically made?
Quinolones and sulfonamides
What is a semi-synthetic compound?
A natural compound that is chemically altered
What is the difference between a bacteriocidal and bacteriostatic drug?
Bactericidal- kill
Bacteriostatic- inhibit growth
Drugs can vary depending on concentration, bacterial species, and combinations of drugs
What classes of antibiotics are bateriostatic?
Lincosamides Macrolides Phenicols Sulfonamides Tetracyclines
What drug will have no effect against a non-penicillase producing staphylococci?
Metronidazole
What group of B-lactams will have no effect on penicillase-producing staphylococci?
Penicillins
Aminopenicillins
Metronidazole
What drugs will have no effect on glucose fermentative gram-negative rods?
Metronidazole
Penicillins
Lincosamides
Macrolides
What drugs will have no effect against anaerobes ?
Aminoglycosides
What drugs have low/variable activity against Non-penicillase-producing gram-positive cocci ?
Lincosamides Macrolides Tetracyclines Aminoglycosides Floroquinolones Cephalosporins Sulfonamides
What drugs have low/poor activity against penicillase-producing staphylococcus?
Linosamides
Macrolides
What drugs have low/variable activity against glucose-fermentation gram-negative rods?
Aminopenicillins
Tetracycline
What drugs have low/variable activity against anaerobes?
Cephalosporins
Tetracyclines
Sulfonamides
Flouroquinolones
What modes of action can B-lactams have against bacteria?
Inhibit cell wall synthesis, protein synthesis, DNA synthesis, metabolic processes, and cell membrane integrity
Co-resistance
Co-existence of multiple genes/mutations encoding resistance to different drugs within the same strain/genetic element
Co-selection
Selection of multiple resistance genes when one of these genes is selected
What is a vaccine?
A suspension of antigens that is administered to induce immunity
What is adjuvant?
An additive to a vaccine that enhance the immune response to the Ag
What are the three ways an adjuvant can enhance the immune system
- Delay the release of Ag from the site of injection
- Induce the secretion of chemokines by leukocytes
A. Enhanced cell-mediated immunity
B. Enhanced antibody production
What are the properties of an ideal vaccine?
Inexpensive Consistent in formation-minimal variations Stable Proper type of immune response Range of immunological epitope Long-lived immunity Immunological memory No adverse side-effect
What are the two types of infectious vaccines?
Live attenuated vaccines
Recombinant organism vaccine
Live attenuated vaccine
Attenuated, but an intact and viable organism
Low-level infection
No significant tissue pathology or clinical disease
What are the pros of a live attenuated vaccine?
Rapid onset of immunity
Sustained immunity after a single dose
What are the cons of a live attenuated vaccines?
Potential for reversion to virulence
Virulent in the immunocompromised
Less stable in storage
What is a recombinant organism vaccine?
Viral genes modified and inserted into a carrier
Carrier organisms do not cause disease in vaccinated animals
What is the benefit of a marker vaccine?
A maker vaccine permits the discrimination between a vaccine exposure and a natural immune response
-in testing you can tell the difference
What are the non-infection vaccine types
Killed whole organism vaccine
Subunit vaccine
Naked DNA vaccine
What is a killed whole organism vaccine?
Antigenically intact
Unable to replicate or induce disease
What are the pros to a non-infectious vaccine?
Safe
Doesnt interfere with other vaccines
Stable in storage
What are the cons of a non-infectious vaccine?
Slow onset of immunity
Multiple boosters required
Adjuvant-adverse effects
Reduced degree of protection vs the live
What is a subunit vaccine??
Contains immunological or structural proteins or metabolites of an organism
Eg. Purified protein, synthetic peptides, and recombinant protein
What is a naked DNA vaccine?
Gene of interest is cloned into a plasmid and delivered to animal.
Pathogen gene is expressed and processed in APC for antigen presentation
______________ immunization is performed by administering antibodies
Passive
Protection by passive immunization is _______________ but ______________
Immediate ; temporary
How do you provide active immunization?
Administer an antigen -> induce an immune response in recipient (humoral/cell-mediated response with immunological memory)
What are the protection levels provided with active immunization?
Strong - no infection
Infected - clinically well
Infected- mild form of disease
Failure- no protection
What adverse side effects can result from vaccination?
Type I hypersensitive
Feline injection site sarcoma (FISS)
What are the consequences of antimicrobial resistance on animal and public health?
Increased patient mortality and morbidity
Risks of zoonotic transmission
What are the economic consequences of antimicrobial resistance?
More visits, lab tests, and therapies
Prolonged hospitalization
Reduced weight gain (food animals)
Loss of customers / vet reputation
Cost for hospital and farm decontamination
Cost for surveillance and intervention programmes
What are the mechanisms of antimicrobial resistance?
Blocking of drug binding to protein target
- target modification
- target protection
- drug trapping
Change in concentration of drug in cell (mutation or membrane pores and transport systems)
- increased efflux
- decreased influx
Name three emerging resistant bacteria in animals.
Staphylococcus aureus (MRSA) Staphylococcus pseudintermedius (MRSP) Escherichia coli (ESBL producer)
Resistance to B-lactam
All these bacteria are resistant to cephalosporins and are often multidrug-resistant (MDR)
What is MRSA?
Methicillin resistant staphylococcus aureus
Resistant gene (mecA) encodes a penicillin-binding protein with low affinity to most B-lactams
What is MRSP?
Methicillin resistant staphylococcus pseudintermedius
Resistance gene mecA
70 are skin and wound care post surgical in clinic
Difficult to choose an antibiotic because of multidrug resistance
Human infection usually lower but prevalence higher in dog owners and vet staff -> veterinarians as vectors for animal infection
What is ESBL??
Extended spectrum beta lactamase
Enzyme that can hydrolize/inactivate most b-lactams (produced by gram negative bacteria)
What are the three main classes of ESBL? What makes them true ESBLs
CTX-M , SHV, and TEM
Susceptible to B-lactamase inhibitors (eg clavulanic acid)
What is a false ESBL
resistant to B-lactamase inhibitor
Widespread in Europe in poultry: CMY-2
How can bacteria acquire resistance?
Mutation (usually antimicrobial target gene/protein) Horizontal gene transfer -transformation (free DNA uptake) -transduction (phage delivery) -conjugation (cell to cell transfer)
What three antibiotics are B-lactams
Penicillins
Cephalosporins
Carbapenems
