Exam 1 Flashcards
what is rational antimicrobial use?
the use of antimicrobial agents aimed at maximizing therapeutic efficacy while minimizing risks associated with development of resistance
what are the 3 ways to optimize dosage regimens?
- shoot high
- shoot regular
- shoot fast
what does it mean to shoot high
use the highest possible dose, to enhance therapeutic efficacy and prevent resistant mutants
what does it mean to shoot regular?
administer the drug at regular intervals
what does it mean to shoot fast?
treat the earliest and for the shortest time possible
what is antimicrobial stewardship?
coordinated interventions 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.
the discipline concerned with preventing nosocomial or healthcare-associated infection
Hospital infection control
what are 3 management tools every veterinary clinic should posses?
- formal infection control program
- written manual
- infection control practitioner
how long should soap be in contact with your hand before rinsing?
minimum 20s
what does AST stand for
antimicrobial susceptibility testing
why do we need AST
- guidance to antimicrobial therapy
- surveillance of antimicrobial resistance
- antimicrobial drug discovery
what are the 2 methods for AST
- Dilution method
2. agar diffusion method
what are thession E-test 2 dillution methods for AST
- broth dilution tests (quantitative)
2. agar dilution tests (quantitative)
what are the 2 agar diffusion methods of AST
- disk/tablet diffusion test
2. gradient difffu
Explain what MIC is
Minimum inhibitory concentration
the lowest concentration that inhibits complete
Explain what MBC is
Minimum bactericidal concentration.
the lowest concentration that kills the test strain
when is agar dilution primarily used
research purposes like when many strains have to be tested with one drug
What is a breakpoint?
a drug specific value to interpret the results of susceptibility testing and determine if an antibacterial is potentiall useful in the treatment of bacterial infection
what is the susceptible strain in AST
the strain is inhibited at blood concentrations achieved by standard dosage of the drug
what is the intermediate strain in AST
clinical efficacy is possible if the strain infects body sites where the drug concentrates or if the dosage can be increased compared to standard dosage
what is the resistant strain in AST
the strain is not inhibited at blood concentrations achieved by standard dosage of the drug
what are the 3 most frequent bacterial contaminants in AST
coagulase-negative staphyilococci, bacillus spp., Enterococci
why are surrogate antimicrobials used in AST
to predict susceptibility to other drugs belonging to the same class.
what are the two drugs used for detection of MRSA/MRSP
oxacillin and cefoxitin
what is the MRSA expert rule?
strains resistant to oxacillin/cefoxitin should be regarded as resistant to all B-lactams irrespective of their susceptibility to penicillins and cephalosporins in the report
why are oxacillin and cefoxitin used for the detection of MRSA/MRSP
because the methicillin resistance gene mecA is poorly expressed in laboratory media
ESBLs confer resistance to third generation cephalosporins shuch as ______, ______, and ______
cefpodoxime, cefotaxime, ceftazidime
name the 2 superbugs that infect both hospitals and the cummunity
Meticillin-resistant S. aureus (MRSA) and ESBL-producing E.coli
What is intrinsic resistance
resistance due to structural or functional traits present in all members of a given bacterial species or group
name the two ways bacteria acquire resistance?
mutation and horizontal gene transfer
what are the 3 mechanisms in which horizontal gene transfer occures in bacteria
- transformation (uptake of free DNA)
- transduction (transfer mediated by phage delivery)
- conjugation (transfer cell to cell contact)
what is the resistant gene in MRSA
mecA
what is the penicillin binding protein of mecA
PBP2A
which type of antibiotics does MRSA have a low affinity for
B-lactams (penicilins and cephalosporins)
most common strain of MRSA in companion animals
CC22
Most common strain of MRSA in horses and pigs
CC398
Most common strain of MRSAQ in just horse=
cc8
Most common strain of MRSA in just swine
CC9
what is MRSP
Methicillin Resistant Staphylococcus Pseudintermedius; it is a S. Pseudintermedius that has acquired mecA
what is ESBL
Extended Spectrum Beta Lactamase; it is an enzyme hydrolizing/inactivating most B-lactams produced by Gram Negative Bacteria
what are teh 3 main classes of ESBLs
CTX-M
SHV
TEM
what is the most common type of ESBL in animals
CTX-M-1
Name a common false ESBL found in europe
CMY-2
what is virology
the study of viruses and viral diseases
what is a virologist
someone who studies viruses
T/F viruses are living entities
F
Viruses contain a _____ Genome surrounded by a _______ coat
Nucleic acid (DNA or RNA); Proteiin coat (Capsid)
T/F Viruses contain mitochondria but do not have golgi apparatuses
F, no organelles
Where do viruses get their proteins and energy
host cell, cannot make on own
T/F viruses are facultative intracellular parasites
F obligate intracellular parasites
T/F viruses do not have the genetic capability to multiply by Division
T
What is a capsid
the protein shell of a virus that envelopes the viral nucleic acid/genome
what is the capsid of a virus made of
capsomeres held together by non-covalent bonds
what is a nucleocapsid?
capsid+DNA/RNA
some viruses have an additional layer that covers the capsid known as
The Lipid Envelope
what is the lipid envelope made of?
lipid bilayer from host cell
what are present on the surface of the envelope that often have spike like appearance
Glycoproteins
Term for virus that have only a protein capsid enclosing nucleic acid, no lipid envelope present:
Naked Viruses/ Non-Enclosed Viruses
term for viruses that have an additional lipid layer enclosing the protein capsid enclosing Nucleic Acid
Enveloped Viruses
what is pleomorphism
the ability of some viruses to alter their shape and size
what are the 6 stages of virus replication
- Attachment
- penetration
- uncoating
- synthesis of viral nucleic acid and protein
- Assembly and maturation
- release in large numbers
what are the 4 outcomes of the host cell after viral infection
- cell death
- No apparent change
- transformation of cell to malignant cell
- fusion of cells
what are the 3 types of cell death
- lysis
- alteration cell membrane
- apoptosis
what is the name of the body charged with the task of developing, refining, and maintaining a universal virus taxonomy
The international committee on taxonomy of viruses (ICTV)
what are the 7 types of viral transmission
- direct contact
- indirect contact
- common vehicle
- Airborne Transmission
- Vector borne transmission
- zoonotic transmission
- vertical transmission
type of viral transmission where animal becomes infected by physical contact with host
direct contact transmission
tye of viral transmission where animal becomes infected by fomites
indirect contact transmission
type of viral transmission where animal becomes infected by eating or drinking contaminated food
common-Vehicle transmission
type of viral transmission where infection if transferred from mother to embryo, fetus, or newborn before, during, or after parturition
vertical transmission
3 ways we can grossly diagnose viral infections
- clinical sighns
- necropsy
- histopathology
2 ways we can diagnose viral infections by cultivation
- isolation of viruses in cells/tissue culture
2. inoculation in eggs
the detection of viral antigen or host antibody against virus is known as
serology
what does ELISA stand for
Enzyme linked immunosorbent assay
name the 2 serologic techniques use dto detect a virus
- fluorescent antibody staininog
2. immunohistochemical staining
what technique do we use to detect the nucleic acids of viruses
PCR
what are the 3 ways we can treat viruses
- antiviral drugs
- immune system stimulation
- synthesize antibodies or administration of natural antiserum
_______ are a class of proteins that have antiviral effects and modulate functions of the immune system
interferons
how do we prevent viral infections
- vaccinate
- proper hygiene/sanitation
- eliminate arthropod vectors
- quarantine and culling
what are the 3 types of vaccines we use to vaccinate against viruses
- live-attenuated viruses vaccines
- Non-Replicating virus vaccines
- vaccines produced by recombinant DNA and related technologies
Type of management system where animal houses are cleaned between batches of animals
all in, all out
Name one type of biological control used to eliminate viruses
predatory fish
name one type of chemical control used to eliminate vioruses
use of insecticides
what is pathogenicity
the ability of a virus to cause disease in a host
what is a pathogen
virus that causes disease
what is pathogenesis
the mechanism of development of a disease
what is virulence?
relative measure of the degree of pathogenicity of the infecting virus
what is avirulent?
not virulent/ not harmful to host
T/F virulence is an absolute property
F, Is not absolute
5 Virulence factors related to virus
- genetic variation of virus
- route of entry of virus in host
- affinity of virus to host organs
- dose of infection
immuno evasion
4 Virulence Factors related to host
- host species
- host immunity
- host physiological factors
- fever
2 virulence factors related to the outcome of tug of war
environment and dual infections
how do we measure virulence
lethal dose 50 (LD50)
what is LD50
the dose of the virus required to cause deathin 50% of animals
Name some routs of entry for viruses to enter animal
- cut in skin
- Mucous membrane
- GI tract
- Respiratory tract
how does a virus spread once inside the host
- local spread of virus on epithelial surface
- from local infection of epithelia to subepithelial invasion and lymphatic spread
- to blood stream and then spread via blood
what does viremia mean
presence of virus in blood
what is the difference between primary and secondary viremia?
Primary= initial entry of virus into blood
Secondary= virus has replicated in organs and once more entered into circulation
what is a disseminated infection?
infection spreads beyond the primary site of infection
what is systemic infection
if a number of organs or tissues are infected
what are the 3 ways viruses are spread through nerves
- through peripheral nerves
- through receptor neurons in the nasal epithelium
- BBB and infect CNS
what is a neurotropic virus
viruses that can infect neural cells. infection may occur by neural or hematogenous sporead
what is a neuroinvasive virus
viruses that enter the CNS after infection
what is a neurovirulent virus
viruses that cause disease of nervous tissue, manifested by neurological symptoms and often death
what is tropism
the specificity of a virus for a particular host tissue
what are pantropic viruses
can replicate in more than one host organ
what are the 5 ways that viruses interact with the host cell
- inhibition of host cell nucleic acid synthesis
- inhibition fo host cell RNA synthesis
- inhibition of host cell protein synthesis
- cytopathic effects of toxic viral proteins
- interference with cellular membrane function
what is an oncoviruse
a virus that can cause cancer
type of infection usually characterized by intensive shedding over a short period of time
acute infection
type of infection characterized by shedding at lower titers over months or years
persistent infections
what is a vesicle
fluid filled sac
The name for benign skin growths that appear when a virus infects the top layer of the skin
Warts
what is erythema
reddening of the skin
a viral infection of the respiratory tract causes _____
inflammation, obstruction of air passages, and hypoxia and respiratory distress
when the CNS is infected with a virus what 4 side effects are typically seen?
- lytic infections of neurons
(destruction) - neuronal necrosis (death of body tissue)
- neuronophagia (killing of neuronal cells by phagocytic cells)
- perivascular cuffing (inflammatory cells around blood vessels in CNS)
Viral infections of the hemopoietic system cause what 2 things
- damage to endothelium (hemorrhages)
2. clots form throughout body
viral infection of the fetus are known as ______
Teratogenic viruses
how do prokaryotic cell replicate
binary fission
how do eukaryotic cells replicate
mitosis
How do you name Bacteria?
Genus and species
Genus: capitialized and italicized
species: italicized
subspecies: italicized
Serovar: not italicized, Capitalized
what is included in the nucleoide of bacteria?
DNA, RNA, NAPs, DNA gyrase, topoisomerase 1
T/F the plasmid of a bacterial cell is not part of the nucleoid
T
what is the importance of the plasmid
contains genes for resistance of virulence factors
how do bacterial plasmids transmit their genes
conjugation
what is the importance of the bacterial envelope
provides protection, energy, and adhesion
what is the importance of the bacterial capsule
helps bacteria evade immune system, tolerance to drugs
Gram Negative bacteria will stain ______ whereas gram positive bacteria will stain ______.
Pink; Purple
what is the LPS present in the gram negative cell wall
endotoxin
T/F gram positive bacteria contain lipoteichoic acid and a thick peptidoglycan layer
T
what does monotrichous mean?
singular flagella
what is the term for multiple polarized flagella
lephotrichous
what is the term for multiple flagella spread around the entire organism?
peritrichous
what is the term fro two flagella polorized at opposite ends
amphitrichous
what is the difference between antimicrobial and antibiotic?
antimicrobial is any substance that kills or inhibits the growth of microorganisms
antibiotics- any substance produced by a microorganism that kills or inhibits the growth of other microorganisms
T/F all antimicrobials are antibiotics, but all antibiotics are antimicrobials
F, all antibiotics are antimicrobials but not all antimicrobials are antibiotics
what are 3 ways we can classify antimicrobials
- mode of action
- effect on bacteria
- spectrum
which category of drugs are good against gram + cocci? Bad?
Penicillin
Metronidazole
Which category of drugs are good against gram - Rods? Bad?
G
- amoxicillin + CA
- Cephalosporins
- Sulfonamides
- Aminoglycosides
- Fluroquinolones
B
- Metronidazole
- Penicillin
- Macrolides
which category of drugs are good against Staphylococci? Bad?
G
- Amoxicillin + CA
- Cephalosporins
- sulfonamides
- aminoglycosides
- Fluroquinolones
B
- Metronidazole
- penicillin
which category of drugs are good against Anaerobes? Bad?
G
- Metronidazole
- Penicillin
B
Aminoglycosides
T/F there are more pathogenic bacteria than non-pathogenic bacteria
F
what is the MoA of B-lactams
inhibit cell wall synthesis
what are the 5 ways antibacterial agents are classified
- chemical structure
- origin
- effect on bacteria
- spectrum of activity
- mode of action
Name the 3 types of B-lactams discussed
- penicilins
- carbapenems
- Cephalosporins
Bactericidal drugs _____ whereas bacteriostatc drugs ________
kill; inhibit growth
what is co-resistance
refers to the co-existance of multiple genes or mutations encoding resistance to different drugs within the same strain or genetic element
what is co-selection
the selection of multiple resistance genes when one of these genes is selected
what is commensalism
good for one, no effect on other
two types of pathogenic organisms
- Facultative pathogenic
2. obligate pathogenic
