EXAM 2 Flashcards
(261 cards)
1
Q
study of bacteria
A
bacteriology
2
Q
study of fungi
A
mycology
3
Q
study of parasites
A
parasitology
4
Q
study of viruses
A
virology
5
Q
prokaryote characterisitcs
A
- unicellular
- lack a membrane-bound nucleus
- lack membrane-bound organelles
- simpler genetic makeup
6
Q
archaea
A
- cell wall lacks peptidoglycan
- dont cause human disease
7
Q
size of bacteria
A
0.2 micrometers to 750 micrometers
8
Q
micrometer
A
1x10^-6 meter
9
Q
coccus
A
sphereical shaped
10
Q
spirochete
A
spiral shaped
11
Q
bacillus
A
rod shaped
12
Q
strep
A
grows in a chain
13
Q
staph
A
grows in grape-like clusters
14
Q
diplo
A
grows in pairs
15
Q
phospholipid head
A
polar-hydrophillic
16
Q
phospholipid tail
A
nonpolar-hydrophobic
17
Q
peptidoglycan
A
rigid, net-like lattice comprised of sugars (glycans/polysaccharides) and amino acids
18
Q
how are peptidoglycans linked
A
2 repeating diasaccahrides crosslinked by short tetrapeptides
19
Q
gram negative stain technique
A
allows classification of bacteria based on cell wall structure
20
Q
gram negative bacteria
A
- stain pink
- THIN peptidoglycan layer in the cell wall
- contains periplasm between inner and outer membranes
- outer membrane present
- LPS present
- NO teichoic acid
21
Q
gram positive bacteria
A
- stain dark purple
- THICK peptidoglycan layer in cell wall
- NO outer membrane
- MINO periplasm
- NO LPS
- contain teichoic acids
22
Q
acid fast bacteria
A
cell walls contain waxy lipid called mycolic acid
- stain weakly as gram positive
23
Q
flagellum
A
a thread-like appendage made up of multiple subunits of the protein flagellin *used for motility
24
Q
chemotaxis
A
movement of an organism in response to chemical stimuli
25
phototaxis
movement in response to light stimuli
26
areotaxis
movement in response to presence or absence of oxygen
27
pilus
hair-like appendage, comprised of the protein pilin, that is found on the surface of many bacteria
*stick to surfaces
28
conjugative pili (sex pili)
used during conjugation to transfer DNA from one bacteria to another
29
conjugative pili steps
1. pilus makes initial contact with recipient bacteria
2. pilus draws in recipient bacteria
3. DNA (mobilized plasmid) transferred from donor to recipient
4. both bacteria now contain DNA in question
30
type IV pili - twitching motility
- movement along a solid surface
- crawling action
- only found at poles of cells
- important host colonization factor in certain pathogens
31
fimbriae
short structures used for attachment to surfaces
32
glycocalyx
viscous, gummy layer surrounding certain bacterial species
- typically polysaccharides, but can be polypeptides
- composition and thickness vary
33
slime layer
loose coating that does not exclude small particles
34
capsule
tight coating that does exclude small particles
35
functions of glycocalyx
- protection from environment
- protection from immune system
- attachment to surfaces
36
cytoplasm
gelatinous solution comprised of water, protein, carbohydrates, lipids, inorganic ions, and low-molecular weight compounds
*also contains nucleoid, plasmids, ribososmes, and inclusion bodies
37
what do prokaryotes lack
- cytoskeleton
- endoplasmic reticulum
- mitochondria
- microsomes
38
nucleoid
- single circular segment of double stranded deoxyribonucleic acid (DNA)
- encodes genetic information for cell function and structure
- smaller than most genomes
39
how many million base pairs is the human genome (haploid)
3,234 Mbp
40
plasmids
circular, extrachromosomal DNA found in many (but not all) bacteria
- replicate independently
41
5 classes of plasmids
- fertility F plasmids
- resistance R plasmids
- col plasmids
- degradative plasmids
- virulence plasmids
42
inclusion bodies
amorphous particles in cytoplasm used as reverse nutrients stored during periods of nutrient abundance
43
endospores
- metabolically inactive structures that preserve the cells genetic information, allowing the cell to survive during times of extreme stress
- highly resistant to environmental stress
- can germinate back into vegetative cell
44
sporulation
bacteria storing genetic information in a pod during times of environmental stress
45
what kind of bacteria produce most endospores
gram negative bacteria
46
how do bacteria grow
binary fission
47
what elements are required in large amounts for bacteria to grow
N2, H2, CO2, Carbon, PO4, Iron, Sulfur, Potassium, Calcium, Magnesium and energy
48
what elements are required in trace amounts for bacteria to grow
Mn, Zn, Cobalt, Molybdenum, Nickel, Copper, Selenium
49
prototroph
a microorganism that can derive all nutritional requirements for growth from the micronutrients and macronutrients supplied
50
fastidious
microorganisms that have complex and special nutrient requirements
- might require special vitamins or amino acids to grow
51
obligate aerobe
absolute requirement for O2
52
facultative aerobe/anaerobe
grow either aerobically or anaerobically
53
obligate anaerobe
ideal growth in absence of O2
54
4 phases of bacterial growth
1. lag phase
2. exponential (logarithmic) phase
3. stationary phase
4. death
55
lag phase
initial or beginning of growth
56
exponential phase
great increase in numbers
57
stationary phase
no increase in number of bacteria
58
heterotrophic bacteria
- essentially all pathogenic bacteria
- obtain energy from organic compounds
59
photosynthetic bacteria
- synthesize their own glucose
- less apt to be pathogenic
60
autotrophic bacteria
- no sunlight
- no organic compounds
- use inorganic compounds
- less apt to be pathogenic
61
what are the ways bacteria can generate energy
- aerobic respiration
- anaerobic respiration
- fermentation
- photosynthesis
62
bacteria producing energy through aerobic respiration
- major energy producing mechanism for aerobes
- consists of 3 major pathways: glycolysis, krebs cycle, and electron transport chain
63
how much ATP does 1 molecule of glucose yield
38 molecules
64
what is the primary substrate in the glycolytic pathway
glucose
65
what is the primary end product of the glycolytic pathway
pyruvate
66
what happens in the investment phase of glycolysis
2 ATPs are spent
67
what happens in the payoff phase of glycolysis
4 ATPs and 2 NADHs are gained
68
summary of glycolytic pathway
- 1 glucose --> 2 pyruvates
- net gain of 2 ATPs
- NADH generated (converted to ~3 more ATP)
69
initial step of krebs cycle
2 NADH are produced for energy
70
krebs cycle overview
- net gain of 2 ATPs
- 6 more NADH produced
- 2 FADH2 produced
71
what is electron transport + oxidative phosphorylation
- a series of electron transfers within the cytoplasmic membrane
- generate ADP and ATP from NADH and FADH2
- accomplished with cytochromes and enzymes
72
bacteria producing energy through anaerobic respiration
- utilizes the same three pathways as aerobic respiration
- but O2 is not the terminal electron acceptor (NO3, SO4, CO3, and Fe3+ are instead)
- produce energy by reducing substrate
- LESS ATP is generated **
73
bacteria producing energy through fermentation
- generates energy primarily using the glycolytic pathway
- simple organic end-products formed from anaerobic dissimilation or metabolism of glucose
- LESS ATP generated**
74
bacteria producing energy through photosynthesis
- converts light to ATP
- not a feature of pathogenic bacteria
75
final electron acceptor in aerobic respiration
oxygen
76
what determines phenotype
genotype
77
genome
entire collection of genetic material in a cell or virus
78
gene
heritable unit of genetic material that define a particular trait
79
genotype
genetic makeup
80
phenotype
physiological or physical traits
81
chromosomes
- genome organized into packaged strands of DNA
- number does not influence organism complexity
82
prokaryotic chromosomes
- 1-3 chromosomes
- circular
83
eukaryotic chromosomes
- numerous linear chromosomes
- histones to package
- mitochondria and chloroplasts
84
plasmids
circular and extracheomosomal
85
nucleic acids
- built from nucleotides
- phosphate
- sugar (deoxy or ribose)
- nitrogen base (purine or pyrmidine)
- in RNA: ribonucleotides
86
structure of DNA
antiparallel
87
central dogma
DNA-->RNA-->proteins
88
DNA replication
- process by which a cell copies its genome before division
- Bidirectional
- typically very fast and accurate
- few mutations
- proofreading mechanisms
- enzymes
- unwind DNA, copy DNA, rewind parent and new DNA
89
leading strand
- continuous replication by DNA polymerase III (5' to 3')
- DNA polymerase I replaces RNA primer with DNA
- ligase
90
lagging strand
- discontinuous replication by DNA polymerase III
- okazaki fragments
- DNA polymerase I and ligase remove and replace primers
91
eukaryotic DNA replication
- takes longer, involves more protein factors
- multiple replication initiation sites
- slower: amount of DNA and packaging
92
how are genes expressed
proteins
93
transcription
DNA--> RNA
94
translation
RNA--> proteins
95
steps of transcription
- initiation
- elongation
- termination
96
RNA polymerase
- binds to promoter
- complementary ribonucleotides (U-A)
- continues until it has its terminator sequence
97
where does protein synthesis take plase
- prokaryotes: cytoplasm
- eukaryotes: nucleus
98
transcription initiation
RNA polymerase binds to the promoter and DNA unwinds, revealing the template strand
99
transcription elongation
RNA polymerase travels down the DNA. The RNA strand is built from 5'-->3' as complementary ribonucleotides are paired with the template strand
100
transcription termination
a terminator sequence at the end of the translated gene signals the RNA polymerase to fall off ther DNA and release the new RNA
101
mRNA
carries genetic messages in triplet codes and is translated to build a protein
102
tRNA
cloverleaf structure shaped molecule serves as an adaptor molecule to usher amino acids into the ribosome during translation
103
rRNA
takes on complex stem and loop structures and combines with proteins to build structures
104
splicing mRNA
1. mRNA contains non-protein coding regions (introns)
2. introns are removed by splicosome creating a coherent protein-encoding mRNA strand
3. processed mRNA with joined exons is ready to be exported to the cytoplasm to be translated
105
translation steps
- initiation
- elongation
- termination
106
location of translation
cytoplasm in both prokaryotes and eukaryotes
107
what carries out translation
ribosomes
- rRNA and proteins
- APE sites
- large and small subunits
108
translation initiation
- ribosome attaches to mRNA and scans until it reaches a start codon (AUG)
- initiator tRNA carrying amino acid methionine then enters the ribosomes P site
- the start codon on the mRNA base pairs with the anticodon on the initiator tRNA
109
genetic code redundancy
- protects versus mutations
- wobble 3rd position
110
translation elongation
- ribosome constructs the protein
- incoming tRNA;s codon pairs with codon in ribosomes A site
- peptide bond forms between amino acids, transferring the growing protein chain to tRNA in A site
- ribosomes translocates down mRNA; tRNA in the A site shifts to the P site
- the tRNA in the P site shifts to the E site, exiting the ribosome
111
translation termination
- ribosome encounters stop codon
- termination factor enters the ribosome
- ribosome releases the protein and detaches from the mRNA
112
translation in eukaryotic cells
most mRNA encodes a single protein
113
translation in prokaryotic cells
- mRNA is commonly polycistronic
- polysome formation
114
post translational modification
- addition of organic and/or inorganic factors
- trimming of AA sequence
- often required for proper protein function
- way to regulate how often mRNA is made into protein
115
regulating protein synthesis
~20% of a cells genes are expressed at any given time
- need mechanisms to turn certain proteins on or off according to cells needs
116
constitutive genes
housekeeping genes; always on
117
facultative genes
not always on
118
pre transcriptional regulation
controlled by operons
119
operons
collection of genes controlled by shared regulatory elements
- promoter
- genes
- repressor
- operator
120
inducible operon
OFF by default; can be turned on
121
repressible operon
ON by default; can be turned off
122
lac operon when glucose is present but lactose is NOT
- no transcription
- repressor is bound
123
lac operon when glucose is NOT present but lactose IS present
- high transcription
- allolactose inactivates repressor; not allowing it to bind
124
arg operon when arginine is low
- insufficient amount of arginine cannot activate the repressor
- repressor cannot bind to operator because it is not associated with arginine
- transcription occurs
125
arg operon when arginine is high
- abundant arginine activates repressor
- activated repressor binds to operator
- transcription is blocked
126
lac operon
inducible operon
127
arg operon
repressible operon
128
mutation
a change in genetic material of a cell or virus
129
substitution mutation
an incorrect nucleotide is added
130
insertion mutation
addition of one or more nucleotides
131
deletion mutation
removal of one or more nucleotides
132
silent mutation
no change in the amino acid sequence
**degeneracy
133
missense mutation
single change in amino acid sequence
134
nonsense mutation
single change in the amino acid sequence that results in a stop codon
135
reversion mutation
restores to the wild type gene sequence
136
frameshift mutation
mutations that result in a shift of the reading fame, changing the way the mRNA transcript is read
137
spontaneous mutation
naturally occurring due to errors in DNA replication; creates evolutionary diversity
138
mutagens
agents that increase rate of mutations
139
carsiongens
mutagens that promotes development of cancers
140
chemical mutagens
- organic or inorganic agents
- arsenic, asbestos, compounds in tobacco
141
physical mutagens
UV light, X rays, radioactive gamma rays
142
biological mutagens
- RECOMBINATION
- viruses, transposons
143
excision repair
- damaged DNA clipped and removed
- DNA polymerase I lays down new nucleotides
- ligase seals
144
vertical gene transfer
cells passing genetic information from parent cell to offspring
145
horizontal gene transfer
passing genetic information between cells independent of cell division
146
examples of horizontal gene transfer
- conjugation
- transformation
- transduction
- transposons
147
conjugation
- bacteria use a cytoplasmic bridge called a pili to copy and transfer a special plasmid known as the F plasmid (fertility factor)
148
high frequency recombination
a bacteria with the F factor integrated into its chromosomal DNA
149
transformation
bacteria take up extracellular DNA
150
Griffiths experiment
conversion of a non-pathogenic pneumococcal bacteria to a virulent strain
151
transduction
viruses transfer bacterial DNA between different bacterial hosts
152
generalized transduction
1. bacteriophage infects a bacterial cell
2. phage replicates in the host. Most phages contain only phage DNA, but occasionally a phage will package a piece of the hosts DNA
3. the transducing phage injects DNA from prior host
153
specialized transduction
1. bacteriophage injects a bacterial cell
2. the bacteriophage's DNA recombines into the host chromosome
3. at some point the bacteriophage DNA excises from the host chromosomes and may take neighboring host genes with it
4. all of the manufactured phage particles will contain phage DNA and the host genes that were excised with the phage DNA
5. the bacteriophage injects its DNA into a new host
6. the bacteriophage integrates into the chromosomal DNA of the new host, which endows the new host with genes from the phages prior host as well as phage DNA
154
antimicrobials
- drugs against microbes
- therapeutic compounds that kill microbes or inhibit their growth to prevent pathogenic action
- categorized based on the type of pathogen they target
155
alexander fleming
- unable to grow staphylococcus aureus near mold at the zone of inhibition
- called the moled penicillin: first antibiotic
156
basic criteria for drugs used as chemo-therapeutic agents in the treatment of infectious disease
1. effective against microbes
2. sufficiently nontoxic to the host
3. able to be purified in high amounts
157
broad spectrum antimicrobial agent
drug is effective agains a broad range of microbes
158
narrow spectrum antimicrobial agent
antimicrobial targets a limited range of microbes
- effective aginst one group or subgroup
- present less disruption to normal microbiota
159
limited spectrum antimicrobial agent
drug is effective against a single organism/disease
160
empiric therapy
a medical treatment with a broad spectrum drug initiation while waiting for culture/ID results
161
criteria of antimicrobial drugs
1. nontoxic to the host and without undesirable side effects
2. nonallergenic to the host
3. not eliminates normal microbiota
4. able to reach the infected part of the body
5. inexpensive and easy to produce
6. chemically stable
7. resistance is unlikely to develop
162
naturally occurring antimicrobials
substances produced by microorganisms that inhibit other living microorganisms
163
synthetic antimicrobials
manufactured by chemical processes
164
semisynthetic antimicrobials
chemical modification of naturally occurring antibiotics
165
modifying antimicrobial drugs
- antimicrobial compounds can be modified by chemical means
- drugs in later generations have expanded capabilities over their predecessors
166
next generation drugs
result from each successive round of chemical modification
167
selective toxicity
goal is to inhibit or kill the pathogen with little or no toxic effect on the patient
168
how is selective toxicity achieved
exploiting vulnerable targets
169
hepatotoxic
toxic to liver
170
nephrotoxic
toxic to kidneys
171
oral administration
- preferred antimicrobial route
- convenient and cost effective
172
parenteral administration
- any route not involving the GI tract
- usually an injection or infusion
- faster onset of drug
173
half life of drug
time it takes for half of a dose to be eliminated or deactivated by the body; determines frequency of adminstration
174
bacteriostatic drugs
- prevent/inhibit bacteria from growing
- target bacterial protein synthesis and metabolic pathways
- patients own immune system eventually kills off latent bacteria
175
batericidal
- kills bacteria
- targets bacterial cell walls, cell membranes, or nucleic acids
- does NOT rely on patients immune system to eliminate bacteria
- kill normal microbiota
176
antiviral drugs
- do not destroy their target pathogen but inhibit viral development
- viruses use the host cell to replicate to antiviral drugs are difficult to make
- aim to target and disable essential virus-specific proteins
- effective when viruses are actively replicating
177
1st category of antiviral drug targets
target viral replication cycle
178
2nd category of antiviral drug targets
stimulate the hosts anti-viral immune responses
179
what is the most effective way to reduce significant viral infection
vaccination
180
anti-fungal drug targets
- target fungal-specific compounds not in host cells
- interfere with cell wall synthesis --> lysis
- interfere with cell membrane stability and structure causing death
- interfere with nucleic acid synthesis
181
anti-parasitic drug
- target intracellular components
- difficult to develop
- limited by their toxicity
182
assessing susceptibility to antibiotics (AST)
determine the organism causing the specific infection and which antimicrobials will inhibit the growth of the infecting microbe; will identify and report drug resistance in pathogens
183
aga diffusion tests
- determine a basic antimicrobial susceptibility profile
- relatively inexpensive and can be used to determine pathogen susceptibility
184
kirby-bauer disk diffusion test
- agar diffusion test
- determines susceptibility only
185
epsilometer test (E-test)
- agar diffusion test
- determines susceptibility and minimum inhibitory concentration assays
186
minimum inhibitory concentration (MIC) assays
determine the lowest concentration of an antimicrobial agent that inhibits growth
187
minimum bactericidal concentration (MBC) assays
determine the lowest concentration of an antimicrobial agent required to kill the organism
188
antimicrobial resistance (AMR)
occurs when a microbe is not affected by a drug therapy that is intended to inhibit or eliminate the pathogen
189
intrinsic antimicrobial resistance
- natural resistance to microbial drugs based on inherent microbial structure/function
- makes certain pathogens/infections harder to treat/eliminate
190
acquired resistance
- acquired by genetic mutation or acquisition of resistance genes
- resistance occurs when drug concentration levels within the cell are kept below the MIC
191
types of acquired resistance
1. alter drug's target
2. inactivate drug
3. reduce drug concentrations inside the cell
192
superbugs
strains of bacteria, viruses, parasites and fungi that are resistant to the antimicrobials commonly used to treat the infections they cause
193
superinfections
result when superbugs emerge from the initial infection resistant to the treatment and become the primary cause of a second infection
194
emergence of drug resistance
- antibiotic resistance is fueled by natural selection
- noncomplicance with prescribed dosing parameters
- antimicrobial misuse
195
antimicrobial stewardship
coordinated program that promotes the appropriate use of antimicrobials to promote patient outcomes, reduce and combat microbial resistance and decrease the spread of infections caused by multidrug resistant organisms
196
staphylococcus characteristics
- gram positive
- cocci
- form irregular clusters
- non-spore formers
- non-motile
- typically lack a capsule
197
where is staphylococcus found?
- everywhere in nature
- part of normal human microbiota
- typically an opportunistic pathogen
198
how are staphylococcus infections transmitted
- direct transmission (skin, hands, sputum, pus)
- enter through respiratory route, hair follicles, or breaks in the skin
199
how are staphylococcus different from other gram positive cocci
- they are facultative anaerobes
- grow in the presence of bile salts
- produce catalyase; breaks H2O2 into H2O and O2
200
how to tell difference between different staphylococcus species
- coagulase test: production of coagulase
- genomic/DNA based ID
- culture media: mannitol salt agar, blood agar
201
coagulase test with S.aureus
coagulase +
202
coagulase negative staphylococcous
S.epidermidis and S. saprophyticus
203
how to tell the difference between the coagulase negative staphylococcous
susceptibility to antibiotic novobiocin
204
S. aureus
- major pathogen of staphylococcus genus
- coagulase positive
- most common causes of bacteremia and infective endocarditis
- spreads through direct contact
- significant cause of chronic BIOFILM infections
205
cell wall associated virulence factors
- peptidoglycan
- teichoic acid
- capsule (microcapsule)
- clumping factor
- protein A
206
protein A
- binds to host antibodies (IgG) at the Fc region
- blocks opsonization
207
extracellular enzymes virulence factors
- coagulase
- staphylokinase
- hyaluronidase
- lipase
- thermonuclease
- catalase
- proteases
- beta-lactamase
208
coagulase
- plasma clotting protein
- converts fibrinogen to fibrin
- detected by tube free coagulase test
209
staphylokinase
- activates plasminogen to form plasmin (digests fibrin)
- cleaves IgG and particular complement proteins
210
hyluronidase
- spreading factor
- digests hyaluronic acid
211
beta-lactamase
resistance to beta-lactam class of antibiotics
212
toxin virulence factors
- hemolysin
- leukocidin
- enterotoxin
- toxic shock syndrome toxin
- exfoliative toxin
213
hemolysin
- lyse host red blood cells
- alpha hemolysin: causes beta hemolysis on blood agar plates
214
leukocidin
lyse white blood cells
215
super antigens
- binds to TCR outside of normal region
- nonspecific activation of T cells
- activates 20-30% of T cells
- excessive activation of T cells
- massive cytokine release--> inflammatory response in entire body
216
toxic shock syndrome
- toxigenic infection
- inflammation in entire body; full body cytokine response
- in menstruating or postpartum women
- treatment: replacement of fluids, ICU, antibiotics
217
enterotoxin
- superantigen
- food poisioning
- ingestion of preformed toxin
- heat stable
- increased intestinal peristalsis
218
toxic shock syndrom toxin-1
stimulates production of interleukin by macrophages
219
exfoliative (epidermolytic) toxin
- protease that causes peeling of superficial skin layers
- dissolves intracellular bridges
220
infections caused by S.aureus
1. superficial infections
2. toxigenic infections
3. systemic infections
221
superficial infections
- cutaneous infections-pyodermic
- pus formation
- sebaceous glands, hair follicles, wounds
- self resolve or topical antibiotics to treat
222
staphyloccoal scalded skin syndrom (SSSS)
- toxigenic infection
- neonatal disease
- exposure to exfoliative toxin A and B (separates epidermal layer from dermis)
- starts as an erythema around mouth and neck
- treatments: antibiotics, rehydration of skin
223
gastrointestinal disease
- toxigenic infection
- food poisoning - gastroenteritis
- **enterotoxin: disrupts gastrointestinal lining
- route of infection: food handlers, lesions on skin, unrefrigerated foods
224
systemic infections
- septicemia (sepsis)
- pyaemia (pyemia)
- osteomyelitis
- pneumonia
- endocarditis
- meningitis
225
septicemia (sepsis)
- bacteremia: bacteria in the blood
- infection of multiple sites within the body
- bacteria spread from initial site of infection
226
pyaemia
- type of sepsis caused by staphylococcus
- widespread, distinctive abscesses
227
nosocomial infections
- infections acquired from a hospital
- S.aureus is leading cause of HAI
- there is an increase in antibiotic resistance resistant strains of S. aureus
228
MRSA (methicillin-resistance staphylococcus aureus)
acquisition of resistance genes via horizontal gene transfer
229
methicillin
- narrow spectrum beta-lactam antibiotic
- binds to penicillin-binding proteins causes cell death
230
streptococci
- gram positive cocci
- grow in pairs or chains
- catalase negative (no bubbles)
- fastidious: require complex media for growth
- faculative aerobes
- large heterogenous group of bacteria
231
most common strptococcal pathogens
- streptococcus pneumoniae
- streptococcus pyogenes
- streptococcus agalactiae
232
lancefield group
a serologic system based on the reaction of specific antisera with surface carbohydrate antigens
233
hemolytic pattern
RBC lysis on blood agar plates
234
phenotypic trains
biochemical reactions and antibiotic senstivities
235
molecular studies
designating species and sub-species genetically
236
alpha hemolytic
colonies surrounded by green
237
beta hemolytic
clear transparent
238
gamma hemolytic
no notable sones around the colonies
239
S. pneumoniae
- alpha hemolytic
- encapsulated, found in pairs
- commonly colonizes the human nasopharynx
- significant global cause of illness and death
240
pneumococcal transmission
transmitted from person to person via infected respiratory secretions/droplets
241
pneumococcal colonization
- inhabit the healthy human nasopharynx
- strains are typically carried asymptomatically for weeks to months
- nasopharyngeal colonization does not usually result in disease
- NP colonization is a necessary step for the development of pneumococcal disease
242
pneumolysin
a secreted cytotoxin that lyses cells and damages tissues
**pneumococcal virulence factor
243
polysaccharide (pneumococcal) capsule
a protective, antigenic, carbohydrate layer anchored to the external surface of the cell
**pneumococcal virulence factor
- most important determinant of virulence
- protects agains phagocytosis, antibiotics, and environmental stressors
- basis of pneumococcal vaccines
244
invasive pneumococcal disease (IDP)
infection of a normally sterile body fluid or organ
245
otitis media
- non-invasive pneumococcal disease
- middle ear disease
246
sinusitis
- non-invasive pneumococcal disease
- inflammation of the facial sinus cavity
247
pneumonia
- non-invasive pneumococcal disease
- serious lung infection that inflames the alveoli
248
bacteremia
- invasive pneumococcal disease
- bacteria in the blood stream
249
meningitis
- invasive pneumococcal disease
- inflammation of the meninges, the membranes that cover the brain and the spinal cord
250
S. pyogenes
- group A strep GAS
- beta hemolytic
- bacitracin sensitive
- colonization is infrequent
- pathogenic
- infections begin in throat or skin
251
s. pyogenes transmission and pathogenesis
- person to person contact
- mild to life threatening
- large # of virulence factors
252
M protein s. pyogenes virulence factor
- major protein coating the cell surface
- contributes to phagocytosis evasion
253
hyaluronic acid capsule s. pyogenes virulence factor
- protects against phagocytosis
- not produced by all strains
- weak immunogen
254
streptolysins s. pyrogenes virulence factor
damage cell membranes, cause beta hemolysis phenotype
255
streptococcal pyrogenic exotoxins s. pyrogenes virulence factor
linked to rash, TSS, and severe invasive infections
256
s. pyrogenes GAS pharyngitis
- sterp throat
- scarlet fever
257
s. pyrogenes GAS skin and soft tissue infections
- superficial skin and progressively deeper tissue infections occur following breach in protective skin layer
- impetigo
-erysipelas and cellulitis
- necrotizing faciitis
258
s. pyrogenes GAS infection complication: non-supportive sequelae
- rheumatic fever
- glomerulonephritis
- PANDAS
259
S. agalactiae
- group B strep: GBS
- beta hemolytic
- part of normal human GI and GU tract microbiota
- major cause of potentially fatal sepsis, pneumonia, and meningitis in newborns
260
S. agalactiae virulence factors
capsule and beta hemolysin
261
S. agalactiae GBS treatment
prompt diagnosis and intiation of antimircobial therapy
