Microbio- bacteriology Flashcards
(318 cards)
1
Q
what are 6 characteristics of bacteria?
A
ubiquitous and numerous more beneficial than pathogenic very small: 0.5-5 micrometer long unicellular single circular chromosome prokaryote= no nucleus, cytoskeleton or histones
2
Q
what are 8 structural components of bacteria?
A
complex and rigid cell wall plasma membrane cytoplasm and ribosomes nucleoid flagella pili capsule endospores
3
Q
what species does not have a cell wall?
A
Mycoplasma
4
Q
what are the three types of bacterial cell walls?
A
gram negative bacteria
gram positive bacteria
mycobacteria
5
Q
what are 3 functions of a cell wall?
A
protection against mechanical damage and osmotic lysis
transport- non selective permeability
differences in structural and chemical composition- pathogenicity and staining properties
6
Q
what is peptidoglycan made up of?
A
chains of alternating subunits crosslinked with short peptides
N-acetylglucosamins (NAG)
N-acetylmuramic acid (NAM)
7
Q
What are the 4 steps of gram staining?
A
Apple crystal violet dye Apply iodine (mordant) Alcohol wash (decolorization) Apply safranin (counter stain)
8
Q
What are the 4 steps of Acid-fast staining?
A
Apply carbolfuchsin (primary stain)
Apply heat (mordant)
Apply acid alcohol (decolorizer)
Apply methylene blue (counter stain)
9
Q
What are 5 characteristics of gram positive bacteria?
A
Thick multilayered peptidoglygan layer
single plasma membrane
high resistance to physical disruption and drying
high susceptibility to ionic detergents
teichoic acids (linked to peptidoglycan) and lipoteichoic acids (linked to plasma membrane)
10
Q
what are 3 functions of teichoic acids and lipoteichoic acids in gram positive bacteria?
A
colonization, infection and immune evasion
protection against harmful molecules and environmental stress
strongly antigenic
11
Q
what are 5 characteristics of gram negative bacteria?
A
thin single layered peptidoglycan layer
inner and outer plasma membrane with periplasmic space
low resistance to physical disruption and drying
low susceptibility to ionic detergents
lipopolysaccharides
12
Q
what are 3 functions of Lipopolysaccharides (LPS)
A
virulence factor
Lipid A component= endotoxin that can activate immune system and exert harmful effects on the host
polysaccharide component= antigenicity
13
Q
What is lipopolysaccharide composed of?
A
O-antigen + core (inner oligosaccharide) + lipid A
endotoxin, released upon cell disruption
14
Q
what are 3 characteristics of mycobacteria?
A
thick waxy hydrophobic cell wall
rich in mycolic acids
Acid-fast: alcohol doesn’t decolorize because of mycolic acids
15
Q
what is another name for acid-fast staining?
A
Ziehl-Neelsen staining
16
Q
4 characteristics of plasma membrane
A
flexible
composed of phospholipids and proteins
no sterols
outer faces hydrophilic, inner faces hydrophobic
17
Q
5 functions to plasma membrane
A
active transport of nutrients
elimination of waste metabolites
electron transport for bacterial respiration
phosphorylation
enzymes and carrier molecule that function in biosynthesis of DNA, cell wall polymers and membrane lipids
18
Q
4 characteristics of nucleoid
A
occupied with nuclear material
single haploid cellular chromosome
double-stranded DNA
plasmids may be present
19
Q
What are two species that are exceptions to the typical nucleoid characteristics?
A
Leptospira= two circular chromosomes
Borrelia burgdarferi= linear chromosome
20
Q
5 characteristics of flagella?
A
present on bacterial surface used for locomotion or motility arrangement by number of flagella or position composed of protein flagellin consist of filament, hook and basal body
21
Q
what is endoflagella and what is an example?
A
flagella in the periplasmic space
ex) spirochetes
allows corkscrew-like motility
22
Q
4 classifications of flagella arrangement
A
monotrichous= one flagella at one end amphitrichous= two flagella, one at each end iophotrichous= multiple flagella at one end peritrichous= multiple flagella all around cell
23
Q
7 characteristics of pili
A
fine, straight, hair-like appendages attached to cell wall
number of pili varies widely
most common on gram negative bacteria
composed of protein pilin
adhesion to host tissues
contribute to antigenicity
connects two bacteria to exchange genetic material
24
Q
What is a capsule made up of?
A
glycocalyx, an extracellular polymeric matrix
mostly polysaccharides
25
4 functions of capsule
nutrient reserve
protection from adverse environmental conditions
facilitate adherence to host cell surfaces
interfere with phagocytosis
26
what is an example of a species that produces a capsule?
Bacillus anthracis- produces defined polypeptide capsule
27
what is a slime layer
non-rigid matrix that is easily deformed
28
what is biofilm?
bacterial populations adherent to each other and/or surfaces and enclosed in a biopolymer matirx
29
What two forms are found with biofilms?
planktonic (free)
| sestile (attached)
30
3 types of attachment of biofilms?
attachment of bacteria to surface and formation of monolayer of cells
clustering of cells and formation of microcolonies
maturation with production of extracellular polymers and hydrated exopolymer matrix
31
what is a factor of biofilms and an example?
virulence factor
| role in persistent infections, plaque formation
32
4 characteristics of endospores
endo= formed intracellularly(eventually released as spores)
cryptobiotic state of dormancy and most durable type of cell found in nature
ensure survival during adverse environmental conditions (for long amount of time)
resistant to extreme adverse conditions (desiccation, high temp, irradiation, strong acids)
33
what 2 genras produce endospores and when do they produce them?
Clostridium and Bacillus
| when exposed to adverse conditions (nutrient depletion)
34
```
Morphology- Cocci
coccus
diplococci
streptococci
staphylococci
```
```
round
one
two
chain
cluster
```
35
```
morphology-bacilli
coccobacillus
bacillus
diplobacilli
streptobacilli
pallisades
```
```
rod
rounded rod
one
two
chain
lined vertically
```
36
morphology- budding and appendaged bacteria (2)
hypna
| stalk
37
morphology- other (3)
corkscrew form
filamentous
spirochete
38
What are the two main factors required for bacterial growth?
sources of metabolic energy
| environmental factors
39
what are the 3 sources of metabolic energy?
fermentation (anaerobic)
respiration (aerobic)
photosynthesis
40
What are the 6 environmental factors for bacterial growth?
```
nutrients
pH
Temp
Gaseous requirement
ionic strength and osmotic pressure
light
```
41
environmental factors-nutrients (7)
```
C
N
H
minerals
growth factors
vitamins
trace elements
```
42
environmental factors- pH (optimal)
pathogenic= 7.2-7.4
43
environmental factors- temp (optimal)
mesophilic 30-37C
44
environmental factors- gas (2)
oxygen and carbon dioxide
45
what are the 4 types of gas requirements
aerobes= require oxygen
facultative anaerobes=grow with or without oxygen
anaerobe= can't live in oxygen
microaerophile= oxygen required in lower levels
46
how do bacteria reproduce?
binary fission
47
definition of generation time
length of time required for a single bacterial cell to yield two daughter cells (30 min to 20 h)
48
what are the 4 phases of the bacterial growth curve?
lag phase
exponential phase or logarithmic phase
maximal stationary phase
decline phase or death phase
49
growth curve- lag phase
increases in cell size, active metabolism of cells but no division
50
growth curve- exponential phase/logarithmic phase
cells multiply at maximum rate
51
growth curve- maximal stationary phase
due to exhaustion of nutrients or accumulation of toxic products, growth is ceased, balance slow multiplication and death rate
spore formation in this phase
52
growth curve- decline phase/death phase
progressive death of cells
53
What is the phylogenetic tree of life?
diagram representing evolutionary relationships among organisms
54
what is phylogeny based on?
comparative sequences analyses of conserved genes
55
What is taxonomy?
study of bacterial identification, nomenclature and classification
56
what is polyphasic taxonomy?
classification of bacteria as evaluated by both genotypic and phenotypic properties
57
What are 5 properties used for classification in polyphasic taxonomy?
morphology and motility
metabolism and pysiology
biochemical characteristics (FA composition
AND profiling, GC ration, multilocus sequence typing (MLST)
16S rRNA gene and whole genome sequencing
58
what is the role of species in taxonomy and what is its definition?
basic taxonomic unit
group or pop composed of similar individuals that are capable of interbreeding naturally and are reproductively isolated from other groups
59
what is the issue with bacteria in the species definition and how is the problem solved?
interbreeding= sexual reproduction, bacteria reproduce asexually
ICBN determine the species classification of bacteria
60
What are 3 classifications of beneficial bacteria?
symbionts= commensalism and mutualism
| free-living (planktonic)
61
what are 3 classifications of harmful bacteria?
obligate pathogens
facultative pathogens
opportunistic pathogen
62
definition of symbiont
two different organisms living in symbiosis
63
definition of mutualism
two different species in symbiotic relationship in which both benefit from it
64
definition of commensalism
relation between two species in which one benefits from the other without harming or benefiting it
65
pathogen definition
infectious agent
| microoganism that can cause disease upon colonization of the host
66
obligate pathogen definition
microorganism which must infect a host and cause disease in order to multiply and be transmitted from one host to another
67
facultative pathogen definition
microorganism which can infect and multiply in host but is also capable of multiplying in the environment
68
opportunistic pathogen definition
microorganism which does not ordinarily cause disease but which, under certain conditions, becomes pathogenic
69
infection definition
the invasion and multiplication of pathogens in an individual or population
70
disease definition
a disorder of structure or function in the host that adversely impacts the host and is not simply a direct result of physical injury
71
definition of pathogenesis
biological mechanisms that lead to a disease
| how do bacteria cause disease
72
definition of pathogenicity
ability of microorganism to damage a host
73
definition of virulence
relative capacity of a pathogen to damage a host
74
definition of infectious disease
disease caused by pathogens and transmittable to other hosts
75
what does infectious diseases represent?
interactions between host, pathogen and environment
76
host factors for disease (3)
breed, age, sex, genotype
physology and damage
immuity
77
pathogen factors for disease (4)
genotype
virulence, resistance, survival
route, vector tropism
inoculation dose
78
environment factors for disease (2)
housing, management, hygiene
| nutrition, disease control
79
what 4 things must a microbe do to act as a pathogen?
find an appropriate niche within a host
compete with normal microbiota to adhere to host tissues
evade or overcome normal host defenses
express genes that encode the factors causing disease
80
definition of inflammation
biological tissue response to harmful stimuli such as pathogens and/or their metabolites
81
4 examples or diseases resulting in inflammation
local tissue damage (due to toxins/ immune response)
toxaemia, with structural or functional alteration of host cells
acute systemic disease
chronic disease
82
definition of virulence factor
bacterial traits that confer pathogenicity
83
what does virulence factor enable pathogenic bacteria to do?
colonize extracellular or intracellular niches in hosts
84
are the majority of pathogenic bacteria intracellular or extracellular?
extracellular
85
what do Obligate intracellular pathogens need to replicate and what are 2 examples?
need host cell to replicate
Rickettsia
chlamydia
86
what are two types of multiplication in facultative intracellular pathogens?
in phagocytes
| in non-phagocytes
87
what is an example of a falcultative intracellular pathogen that multiplies in phagocytes?
Mycobacterium
88
what is are 3 examples of falcultative intracellular pathogen that multiplies in non-phagocytes?
Brucella
Salmonella
Listeria monocytogenes
89
Two types of toxins
exotoxins
| endotoxins
90
Exotoxin characteristics (6)
```
produced by live bacteria (Gr+ and Gr-)
proteins
heat liable
potent toxins, eith specific activity (neurotoxins, leukotoxins, enterotoxins)
highly antigenic
synthesis determined extrachromosomally
```
91
endotoxins characteristics (6)
component of cell wall of Gr- bacteria, released following cell death
LPS complex with lipid A
heat stable
Toxins with moderate, non-specific activity
weakly antigenic
encoded in chromosome
92
what is a superantigen?
exotoxin causing dysfunction of immune system
93
how to superantigens subvert the adaptive immune response?
```
by cross-linking two antigen-regodnition receptors
T-cell receptor (TCR) and major histocompatibility complex (MHC) class 2 molecule
```
94
what do superantigen binding result in?
massive T-cell proliferation and cytokine release
| fever, shock, multiple organ system failure
95
What does the activation of superantigens depend on?
variable region of beta chain of TCR rather than antigen specificity= no immune protection
96
definition of biofilm
mass of bacteria cling to surfaces, producing extracellular polymer matrix and exchange nutrients
97
3 examples of biofilm formation
dental plaques
biofilms in catheters
urinary tract infection
98
definition of quorum sensing
bacteria (in biiofilms) produce small signal molecules (pheromones, autodinducers) by which they communicate
99
What happens when a bacterial population reaches a defined density in a biofilm (bacterial quorum)
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
100
5 examples of quorum sensing species
```
Staphylococcus aureus
Pseudomonas aeruginosa
E. coli
S. epidermidis
Streptococcus spp
```
101
What is a plasmid and 2 examples
small circular DNA
| Tetanus neurotoxin, Staphylococcus enterotoxin (superantigen)
102
what is a bacteriophage and 3 examples
virus that infects and replicates within bacteria
| Diphteria toxin, Botulinum toxin, Shiga toxin
103
Plasmids and bacteriohages carry genes for what? (3)
antibiotic resistance
toxins
other virulence factors
104
what is the role of plasmids and bacteriophages
transfer virulence factors from one bacterium to another
105
What two bacterial structures mediate the transfer of plasmids and bacteriophages
capsules and fimbriae
106
what are three methods of bacterial transfer?
conjugation
transformation
transduction
107
what is conjugation and how does it occur?
plasmid mediated transfer
| transfer of genetic material through direct contact between donor and receptor cell
108
what is transformation and how does it occur?
uptake of naked DNA segment
| alteration of a cell resulting from the direct uptake and incorporation of exogenous genetic material
109
what is transduction and how does it occur?
phage mediated transfer
| foreign DNA is introduces into another cell via a viral vector
110
What are 4 reasons why it is important for clinicians to receive rapid and accurate info about the agent of an infectious disease?
antimicrobial susceptibility
treatment plan
prevention and control plan
zoonosis
111
What 4 things does choosing a diagnostic method depend on?
infection type
test availability
sensitivity and specificity
time and cost
112
What are the two categories to diagnostic methods?
detection of the agent
| detection of the host immune response
113
what are the 4 types of detection of the agent for diagnostic methods?
direct detection of the bacteria
cultural and biochemical characteristics
immunological techniques
molecular techniques to detect bacterial DNA
114
What are two methods of direct detection of the bacterial for diagnostic purposes?
microscopy and differential staining
| fluorescent antibody staining
115
what are two methods of immunological techniques for diagnostic purposes?
direct detection of antigens
| detection of metabolites (toxins)
116
what are two categories of detection of host immune response for diagnostic method?
serology: detection of humoral immunity
| detection of cell-mediated immunity
117
direct microscopic observation definition
examination of stained or unstained preparations (smears) under microscope
118
what are 4 methods of direct microscopic observation?
gram staining
acid-fast staining
fluorescent antibody staining
electron microscopy
119
what is a benefit of direct microscopic observation and what 3 things does it determine in a sample?
most important and cost effective procedure
number
bacterial morphology
host immune response (cellular reaction)
120
cultural and biochemical characteristics definition
cultivation of bacteria under selected conditions an identification
121
what is cultural and biochemical characteristics detection based on?
atmospheric conditions
122
what are 3 atmospheric conditions used for detection of bacterial agent through cultural and biochemical characteristics?
oxygen required for growth
oxygen not required or utilized for growth
oxygen not required but can be utilized for growth
123
what 3 categories of bacteria require oxygen for growth?
aerobes
microaerobes
capnophiles
124
what 2 categories of bacteria do not require or utilize oxygen for growth?
anaerobes
| aerotolerant aerobes
125
what category of bacteria don't require oxygen but can utilize it for growth?
facultative anaerobes
126
What are three types of media?
culture media
selective media
differential media
127
definition of culture media
contain essential nutrients for growth of non-fastidious bacteria (nutrient agar)
128
definition of selective media
used for growth of only selected bacteria
129
what are two examples of selective media and what are they selective for?
MacConkey agar= selective for gram- negative bacteria
| Phenylethyl alcohol agar= selective for gram-positive bacteria
130
definition of differential media
distinguish one bacteria from another growing on the same plate
131
example of differential media and what is its use?
blood agar= enriched medium supporting growth of most pathogenic bacteria, allows recognition of hemolysin production
132
What are 5 species that require special cultures?
```
Mycoplasma
Salmonella
Listeria
Campylobacter
Mycobacterium
```
133
what is the plate inoculation technique that is used for obtaining isolated colonies?
quad streaking
134
what are 4 methods for bacterial pathogenesis identification?
```
Biochemical techniques
phage and virulence typing
whole FA analysis
enzyme typing
protein analysis
```
135
what are 3 biochemical techniques for bacterial identification?
biochemical kits (nutrient fermentation)
catalase test
oxidation0fermentatio test
136
define immunological techniques (serotyping) for detection of bacterial agent
immunological identification of surface antigens on pathogens
137
what are 3 categories of serotyping?
antigen detection
chemical detection
biological detection
138
what are three methods of antigen detection?
fluorescent antibody staining
enzyme-linked immunosorbent assay (ELISA)
aggulation tests
139
What is chemical detection of bacterial agents limited for?
use for clinical speciments
140
what is chemical detection and what are 3 examples?
analysis of total cell FA/proteins
| HPLC, GLC, protein analysis
141
what is biological detection for bacterial agents?
limus amoebocyte assay test for LPS
142
What is Limus ameobocyte lysate (LAL)?
aqueous extract of blood cells from Atlantic horseshoe crab
143
how does biological detection work?
LAL reacts with LPS= gel clot formation in sample tube
144
What is the molecular technique for detection of host immune response?
PCR= polymerase reaction= amplification of specific DNA fragments from genes
145
what 4 components are required for PCR?
oligonucleotide primers
RNA nucleotides
taq polymerase
target DNA
146
what are 3 characteristics of PCR
non-culture based technique
detects bacterial specific DNA
you must know what you are looking for in order to use correct primers
147
define serology
diagnostic identification of antibodies in serum
148
what are 3 tests used in serology
agglutination
precipitation
ELISA tests
149
What does serology prove but doesn't confirm?
evidence of exposure to an infectious agent but not necessarily confirmation of etiological role for that agent in the animal sampled
150
A collection of 2 serum samples within 2 weeks apart and a four-fold rise in antibody titer are indicative of what?
indicative of recent exposure to an infectious agent
151
antibody titer definition
measurement of antibody level (quantity)
152
seroconversion definition
antibody development after exposure to a pathogen or antigen
153
how are antibody titers expressed?
as the reciprocal of the highest dilution of serum that postively reacts in a specific test
154
how are antibody titer results interpreted?
the higher the antibody response, the higher the titer
155
What are 2 examples of detection of cell-mediated immunity
Tuberculin skin test
| interferon gamma release assay
156
What does TB skin test for and where is it obligatory? How quick are the results?
tests for bovine tuberculosis (mycobacterium bovis)
obligatory in the EU
results in 4 days
157
what does Intergeron gamma release assay test for? how quick are the results?
whole blood test that can aid in diagnosis of mycobacterium infections
results within 24 h
158
what are 11 methods of limiting microbial growth?
refrigeration, freezing, boiling, drying
pasteurization, acidification
increased osmotic pressure, hydrostatic pressure
gamma irradication, chemical additives
159
definition of sterilization
process to eliminate or kill all forms of living microorganisms ans their pathogenic products (including spores), usually on equipment and for surgical procedures
160
what are 8 methods of sterilization?
```
autoclaving
dry heat
incineration
alcohol flame
gamma irradication
UV-light
membrane filtration
chemical sterilization
```
161
definition of antimicrobial agent
drug that destroys microbes, prevents their multiplication or growth or prevents their pathogenic effect
162
definition of antimicrobial
any substance of natural, semisynthetic or synthetic origin that kills or inhibits the growth of microorganisms but causes little or no damage to the host
163
definition of antibiotic
a low molecular substance produced by a microorganism that at a low concentration inhibits or kills other microorganisms
164
what are three categories of antibiotics?
natural
semi-synthetic
synthetic
165
How are natural antibiotics made and what are 3 examples?
produced by bacteria or fungi (a true antibiotic)
streptomycin
penicillin
tertacycline
166
How are semi-synthetic antibiotics made and what are 2 examples?
chemically-altered natural compound
ampicillin
amikacin
167
How are syntheticantibiotics made and what are 3 examples?
chemically designed in the lab
sulfonamide
enrofloxacin
marbofloxacin
168
what are 5 categories of chemical structures used in classification of antimicrobial agents?
```
Macrolide
Aminoglycoside
Tetracycline
Beta Lactams
Sulfonamines and dipyrimidine
```
169
Why is mode of action an useful classification of antimicrobial agents?
antibacterial agents must interact with a vital structure or black a metabolic pathway to interfere with bacterial cell growth
170
what type of toxicity is preferred for an antimicrobial agent against a mode of action?
selective toxicity without direct toxicity for hosts receiving treatment
171
what are 5 parts of the bacteria that can be used for mode of action in antimicrobial agents?
```
cell wall
DNA/RNA synthesis
plasma membrane
ribosomes
metabolic pathways
```
172
What is a type of cell wall synthesis inhibitor and what are 5 examples?
```
beta-lactam antibiotics
penicillin
ampicillin
cephalosporin
carbapenem
monobactam
```
173
whata re the 2 modes of action of cell wall synthesis inhibitors?
inhibit the peptidoglycan synthesis by binding to penicillin binding proteins
promote autolysin activity causing cell lysis
174
what determines the bacteria's susceptibility to Beta-lactam antibiotics and why?
differences int he cell wall (Gr+/-)
| some agents can't penetrate the outer membrane of Gr* bacteria
175
What contributes to a bacteria's tolerance to beta-lactam antibiotics?
if they have beta lacatamase enzyme, which can cleave beta lactam ring and inactivate the drug
176
What are the two main functions of protein synthesis inhibitors?
inhibit 30S subunit or 50S subunit of bacterial ribosomes
177
what are 2 categories of protein synthesis inhibitors that inhibit 30S subunit and what are 2 examples of each?
Aminoglycosides- gentamicin, amikacin
| Tetracyclines- oxytetracycline, chlortetracycline
178
what are 3 categories of protein synthesis inhibitors that inhibit 50S subunit and what are examples?
Macrolides= erythromycin, azithromycin
chloramphenicol
Lincosamines- clindamysin
179
what are the 4 categories of DNA synthesis inhibitors?
Quinolones
metronidazole
rifampin
mupriocin
180
What is the mode of action for quinolones and what are 3 examples of drugs?
inhibit enzymes which separate DNA strands (DNA gyrase)
| Nalidixic acid, ciproflocacin, Novobiocin
181
what is the mode of action of Metronidazole and what type of bacteria is it more effective against?
causes breaks in DNA strands
| effective against obligate anaerobic bacteria (clostridia)
182
what is the mode of action of Rifampin and what is it active against?
inhibit RNA polymerase during transcription
| Mycobacterium tuberculosis
183
what is the mode of action for Mupirocin?
inhibit tRNA synthetase during translation
184
What causes resistance against DNA synthesis inhibitors?
due to mutations in the gene encoding for enzyme DNA gyrase
185
What is the main type of inhibitors against bacterial metabolic pathways?
folic acid synthesis inhibitors
186
what are the two groups of folic acid synthesis inhibitors and what are their modes of action?
Suphonamides- interfere with formation of folic acid
| Sulfonamides and trimethroprim- competitive inhibitors of dihydrofolate reductase
187
what is the role of folic acid?
precursor for nucleic acid synthesis
188
What are two categories of spectrum of activity for classification of antimicrobial agents?
Broad-spectrum
| narrow-spectrum
189
What are broad-spectrum antimicrobials active against and what are 4 examples?
```
active against both Gram +/- microorganisms
tetracycline
chloramphenicol
fluoroquinolone
cephalosporin
```
190
what are narrow spectrum antimicrobials active against?
limited activity and primarily only useful against particular species of microorganism
191
what are the two types of agents for antimicrobial activity?
bactericidal
| bacteriostatic
192
What is the role of bactericidal agents?
kill bacteria and reduce the total number of viable organisms
193
what is the role of bacteriostatic agents?
inhibit growth and replication of bacteria, this allowing the host immune system to complete pathogen elimination
194
What will occur if a type of therapeutic agent is not maintained at effective concentrations in the tissues?
dissociation of the drug/cell structure complex can occur, permitting bacterial survival
195
Definition of minimum inhibitory concentration (MIC)
the highest dilution of an antibacterial agent that inhibits growth of an isolate
196
Definition of minimal bactericial concentration (MBC)
highest dilution of a drug that can kill a particular bacterium
197
Definition of susceptibility break point
the drug concentration above which an organism is considered resistant and at or below this value the organism is susceptible to the specific drug
198
what are the three break point values and what do they mean?
```
susceptibility= high likelihood of therapeutic success
intermediate= uncertain therapeutic outcome
resistant= high likelihood of therapeutic failure
```
199
What is another name for a disk diffusion test
Kirby Bauer test
200
what must be used in a disk diffusion test?
a bacterial isolate in pure culture
201
What are the 4 steps of disk diffusion test?
1. standardized bacteria inoculum spread on agar plate
2. single-concentration antimicrobial disks are placed on the plate and incubated
3. growth inhibition zone diameter is measured
4. compare to published reference breakpoints (zone size)
202
what are the 4 steps of broth dilution test?
1. add multiple dilutions of antimicrobial agents in the wells of a microtiter plate or in tubes
2. add a standardized inoculum of bacteria
3. measure the growth inhibition endpoint (MIC value)
4. compare to published reference breakpoints to interpret the results
203
What does the gradient diffusion test use and how are the results obtained?
uses diffusion and dilution
| MIC values are obtained at the point of intersection between the strip and the ellipse of the zone of inhibition
204
What does antimicrobial resistant impact the most?
developing countries
205
What are the three main ways to prevent antimicrobial resistance?
providers: don't over prescribe or use broad-spectrum drugs
patients/clients: follow orders and finish meds
industry: don't over use drugs
206
what are the two categories of mechanisms of antimicrobial resistance?
innate resistance= preexisting genomic property
| acquired resistance= acquired by mutation or horizontal gene transfer
207
what are 4 types of the mechanisms or acquired antimicrobial resistance?
1. modified cell wall protein= inhibition of drug uptake
2. activation of drug efflux pumps= pump drugs out
3.inactivation of drug by enzymes
alteration of drug target
208
What are 7 problematic bacteria resistance and examples?
- organisms with innate resistance: enterococcus, enterobacter, pseudomonas, acinetobacter
- vancomycin resistance: Enterococcus (VRE)
- Methicillin resistance: staphylococcus aureus (MRSA)
- extended spectrum beta lactamase producers: E.coli, Klebsielle
- Fluoroquinolone resistance: Campylactobacter jejuni
- Multiple drug resistant: E.coli, Salmonella (MDR)
- MDR and extensively drug resistance (XDR): Mycobacterium tuberculosis
209
definition of pathogen
infectious agent
| microorganism that can cause disease upon colonization of the host
210
definition of obligate pathogen
must infect a host and cause disease in order to multiply and be transmitted from one host to another
211
what are the 3 virulence genes for obligate pathogens?
adherence
invasion and evasion of immune system
toxins
212
definition of facultative pathogen
can infect and multiply in a host but is also capable of multiplying in the environment
213
definition of opportunistic pathogen
does not ordinary cause disease but under certain conditions, become pathogenic
214
definition of obligate intracellular pathogens
can only reproduce inside the infected host cell
215
what are 3 examples of obligate intracellular pathogens?
Rickettsia
Mycoplasma
Chlamydia
216
definition of facultative intracellular pathogens
can survive intra and extracellular
217
what is an example of a facultative intracellular pathogen?
Mycobacterium
218
what is a genus of gram-positive cocci?
staphylococcus
219
where is staphylococcus found and 3 examples, and what does it cause?
commensals on skin and mucus membranes
upper respiratory tract, lower urogenital tract, gastrointestinal tract
infections with puss-filled lesions (abscess)
220
what are 3 important staphylococcus pathogens and what species do they infect?
S. aureus (humans and animals)
S. pseudintermedius (dogs & cats)
s. hyicus (pigs)
221
what does S. pseudintermedius cause and what are two examples of these diseases?
local skin diseases
pyoderma
otitis externa
222
what are 3 causes of Otitis externa and what do they combine with?
parasites, food allergies, foreign bodies
| with staph as secondary infections
223
What is pyoderma triggered by?
overgrowth of normal skin microbiota when the skin changes from dry to moist
224
what disease is caused by S. aureus?
Bovine staphylococcal mastitis- contagious mastitis in cattle
225
what is the range of disease cause by S. aureus?
peracute gangrenous mastitis to chronic mastitis
226
what disease is caused by S. hyicus?
greasy-pig disease
227
What is greasy pig disease and who does it affect?
highly contagious exudative epidermitis
| in suckling and weaned pigs up to 3 months old
228
what is the morbidity and mortality % of greasy-pig disease?
```
Morbidity= 20-100%
mortality= up to 90%
```
229
where can S. hyicus be found and how does an individual become infected?
vaginal mucosa and skin of healthy sows
| entry of skin through minor abrasions
230
what are two diseases in humans caused by S. aureus?
Toxic shock syndrome
| food poisoning
231
what is toxic shock syndrome caused by the effectof?
effect of superantigens entering the bloodstream
232
what is food poisoning cause by?
eating food which S. aureus has multiplies and produced enterotoxins
233
what is a resistant form of S. aureus and what is it mediated by?
methicillin resistant
| mediated by mecA gene resulting in altered penecillin binding proteins
234
where is streptococcus found and two examples?
commensals on mucus membranes
upper respiratory tract
lower urogenital tract
235
what is an important characteristic of streptococcus?
have a capsule to evade phagocytosis
236
what are 4 important streptococcus pathogens and what species do they affect?
S. pyrogenes (humans)
S. agalactiae (cattle)
S. dysgalactiae (cattle)
S. equi subsp. equi (horses)
237
what is a disease caused by S. equi subs. equi?
strangles
238
what is an important characteristic of S. equi subs. equi?
not a commensal
239
what is strangles?
highly contagious febrile disease involving the upper respiratory tract with abscessation of regional lymph nodes
240
what can swollen lymph nodes cause?
airway obstruction leading to death
241
how does strangles spread?
via direct or indirect contact with purulent exudates
242
what disease is cause by S. agalactiae?
contagious mastitis
243
where does S. agalactie colonize and what does it cause?
colonizes in milk ducts
| persistent infection with intermittent bouts of acute mastitis= chronic mastitis
244
what disease does S. dysgalactiae cause?
Environmental mastitis
245
where does S. dysgalactiae colonize and what does it cause?
colonizes buccal cavity, genitalia and skin of mammary gland
| acute mastitis
246
What are the 4 species of gram-positive rods?
Listeria monocytogenes
Erysipelothrix rhusipathiae
Bacillus anthracis
clostridium
247
What are 3 characteristics of Listeria monocytogenes?
ubiquitous in the environment and carried in wide range of animals
Psychrophilic= growth in fridge
falcultative intracellular bacteria that can persist in macrophages
248
what does Listeria monocytogenes use to travel through cells?
actin filaments
249
what are three clinical symptoms of listeriosis?
septicemia
abortion
encephalitis
250
what disease is caused by listeria monocytogenes?
circling disease, silage disease
251
what is the most readily recognized form of listeriosis in ruminants?
encephalitis
252
what does circling disease affect and what causes it?
affects all ages and both sexes
| winter-spring disease of feedlot or housed ruminants
253
what environment enhances multiplication of L. monocytogenes?
less acidic pH of spoiled silage
254
where is Erysipelothrix rhusopathiae found?
widespread in tonsil and intestines of many species
| up to 50% of healthy pigs have it in tonsillar tissues
255
what are 4 syndromes of erysipelothrix rhusiopathiae?
septicemia
arthritis
endocarditis
dermatopathy
256
what disease is caused by E. rhusipathiae in swine?
diamond skin disease
| diamond shaped lesions= pathognomic for disease
257
what are 4 characteristics of Bacillus anthracis?
aerobes or falcultative anaerobes
obligate pathogen
endospore forming
ubiquitous in soil
258
what is the disease caused by Bacillus anthracis, who does it affect and where is the source of infection?
anthrax
cattle
soil contaminated with spores
259
what are two virulence factors of B. anthracis?
bacillus anthracis capsule
| tripartite anthrax toxins
260
what are 3 parts of tripartite anthrax toxin?
protective antigen: cell-binding factor
edema factor: disturbance of water homeostasis
lethal factor: cell death and hypoxia-induced tissue injury= necrosis and hemorrhage
261
what does anthrax cause in ruminants?
acute septicemia
262
what are 3 characteristics of acute septicemia?
rapidly fatal disease with respiratory distress and shock
bleeding from orfices
postmortem: dark unclotted blood, incomplete rigor mortis, splenomegaly
263
what is anthrax in humans called?
woolsoter's disease?
264
what are 4 modes of infection of anthrax in humans?
direct contact
ingestion
inhalation
injection
265
what are 4 characteristics of clostridium?
obligate anaerobes
toxin producer
endospore forming
eidespread in soil, GI tract and feces
266
what are three groups of clostridium?
neurotoxic
histotoxic
enteropathogenic
267
what is the pathogenic effect of Neurotoxic clostridia?
affect neuromuscular function without inducing observable tissue damage
268
what are two species of neurotoxic clostridia and what disease do they cause?
C. tetani- tetanus
| C. botulinum- botulism
269
what is the pathogenic effect of histotoxic clostridia?
localized lesions in muscle and liver, subsequently causing toxaemia
270
what are 3 species of histotoxic clostridia and what disease do they cause?
C. chauvoei- black leg
C. septicum- malignant oedema
c. novyi type A and B- black disease
271
what is the pathogenic effect of enteropathogenic clostridia?
interferes with protein synthesis in cells
272
what are two species of enteropathogenic clostrida and what disease do they cause?
C. perfringens type A-E= enterotoxaemia
| C. difficile= pseudomembranous colitis
273
what is tatanus?
acute, potentially fatal intoxication with neurotoxic clostridis causing spastic paralysis
274
where does C. tetani grow, and what two things does it produce?
grows in contaminated wounds
tetanospasmin- potent neurotoxin
tetanolysin- haemolysin destructing tissues
275
what is botulism?
serious potentially fatal intoxication by ingestion of pre-formed neurotoxin (food intoxication)
276
what does botulism cause?
flaccid paralysis
277
how is botulism spread?
germination of endospores with growth of vegetative cells and toxin production in rotting carcasses, decaying vegetation and contaminated canned foods
278
what is a gram positive pleomorphic species?
corynebacterium pseudotuberculosis
279
what are two characteristics of corynebacterium pseudotuberculosis?
commensals on mucus membranes and in soil
| facultative intracellular pathogens that survive in macrophages
280
what does C. pseudotubervulosis cause and what is it?
Caseous lymphadenitis= abcessation and enlargement of superficial or internal lymph nodes in sheep and goats
281
Where is Enterobacteriaceae found (3) and what is it known for?
water, soil and GI tract
| Coliforme bacteria
282
what are 3 important major pathogens of Enterobacteriaceae?
Escherichia coli
Salmonella serotypes
Yersinia spp.
283
what are 3 opportunistic pathogens of Enterobacteriaceae?
Proteus spp.
Klebisella pneumoniae
Enterobacter aerogenes
284
where is E. coli found normally (1) and where is it found in opportunistic infections (2)?
GI tract
| mammary gland, urinary tract
285
What are 3 diseases caused by E. coli and who do they effect?
Neonatal colisepticaemia- calves, lambs, poultry
Edema disease- piglets
Coliform mastitis
286
What is neonatal colisepticaemia and what are its symptoms (5) ?
invasion of bloodstream
acute fatal disease
depression, weakness, tachycardia, hypothermia, diarrhea
287
What is edema, what age does it affect piglets and what are its effects to the body?
Toxin produced in the blood= toxaemia
1-2 weeks after weaning
damage endothelial cells with perivascular edema
288
What is the source of coliform mastitis and what is its result?
fecal contamination of the mammary gland
| mammary secretions waters with white flecks
289
What does the majority of salmonella strains belong to?
S. enterica supsp. enterica
290
What species does salmonella affect and where?
mammals, birds, reptiles worldwide
291
What are 4 examples of Salmonella serotypes?
Typhimurium
Newport
Enteritidis
Dublin
292
How is Salmonella secreted?
in feces
293
What does S. Enteritidis infect and where can it be isolated?
ovaries of chicken
| isolated from eggs
294
Who does S. Dublin infect and what does it cause?
cattle
| wide range of diseases: septicaemia, abortion, osteomyelitis
295
what are two forms of carriers for S. Dublin?
```
subclinical decal extretors (intermittently in feces)
latent carriers (in gal bladder, no excretions)
```
296
What is Actinobacillus pleurupneumoniae and what does it cause in what species?
highly contagious disease and increasing in prevalence due to intensive rearing practices
Fibronecrotic pleuropneumonia in pigs
297
What does Pasteruella multocida & Mannheimia haemolytica cause in what species and what are the symptoms (4)?
shipping fever pneumonia in cattle (severe bronchopneumonia and pleurisy)
fever, depression, tachypnoea, nasal discharge
298
What is the predilection for Brucella and what do infected animals serve as, and why?
both female and male reproductive organs
| serve as reservoirs, bacteria survive in macrophages
299
what are 4 important pathogens for Brucella and what do they cause in what species?
B. abortus- abortion in cattle
B. melitensis- abortion in sheep
B. canis- abortion, epididymitis, sterility in dogs
B. suis- aboriton, orchitis, arthritis, infertility in pigs
300
what is an important feature of Brucella and what are risk factors because of it?
Zoonotic
contact with secretions or excretions of infected animals (skin, inhalation, ingestion)
raw milk and dairy products made with unpasteurized milk
301
What are two diseases caused by Bordetella bronchiseptica in what species?
Kennel cough in dogs
| Atrophic rhinitis in pigs
302
What is kennel cough, and what are the symptoms?
canine infectious trachobronchitis
| coughing, gagging, oculonasal discharge
303
what is kennel cough a co-infection with and what to intranasal vaccines induce?
Canine adenovirus
| local protective immunity
304
what may colonize during atrophic rhinitis, and what does it cause?
toxigenic Pasteuerella multocida
| severe atropic rhinitis and distortion of the snout
305
What are two spirochete species?
Leptospira
| Borrelia Burgdorferi
306
what is a spirochete
spiral motile bacteria with endoflagella
307
where are Leptospira found?
labile in the environment, sensitive to desiccation
saprogytes: free living in ponds, rivers, surface waters, moist soil
multiple reservoir animals
308
what is a characteristic of pathogenic leptospires?
persist in renal tubules or genital tract
309
What are two key facts about leptospira?
widespread and underdiagnosed zoonotic disease- St. Kitts
| epidemics following natural disasters
310
What animals are affected by leptospirosis and what are the symptoms, what are the symptoms in humans?
pigs, cattle, dogs, horses
reproductive failure, abortions, still births, acute septiacemic disease
humans: influenza-like illness, occasionally liver or kidney disease
311
What does Borrelia burgdorferi cause, what is the vector, and what are most infections considered?
lyme disease
ticks
subclinical
312
What are the clinical disease symptoms in dogs?
fever, lethargy, arthritis
| cardiac, renal or neurological disturbance
313
what are two characteristics of mycoplasm?
no cell wall
| not susceptible to penicillin
314
What two diseases does mycoplasma cause and in what species?
mastitis, contagious bovine pleuropneumonia and arthritis in cattle
enzootic pneumonia in pigs
315
what are the 3 symptoms of a disease caused by mycoplasma in cattle?
stance with head and neck extended and elbows abducted
| expiratory grunting and mucopurulent nasal discharge
316
what is a main characteristic of Rickettsiales and how is it transmitted?
obligate intracellular bacteria
| transmitted through ticks
317
what type of disease does Rickettsiales cause and how is it defined?
```
systemic diseases (targets blood cells)
defined geographical regions
```
318
what are three examples of diseases caused by Rickettsiales
canine cyclic thrombosytopenia
Ehrilchiosis
heartwater in ruminants
