Microbiology II Flashcards
1
Q
What is the gram type and shape of the major flora in the gut?
A
Gram negative rods
2
Q
What are the 5 F’s that infect the gut with the bacilli Enterobacteriaceae?
A
food fluids fingers flies feces
(but really it’s just feces)
3
Q
What are two pathologically important features of Gram negative rods?
A
Sharing of virulence factors
(through conjugation, etc)
Antibiotic resistance
4
Q
Where are gram negative rods found?
A
ubiquitous
dirt, water, GI flora
5
Q
T/F
Gram negative bacteria can cause cancer
A
True
6
Q
How many species of Enteric Gram negative rods are there?
What is their metabolic category?
A
over 500
Facultative anaerobes
7
Q
T/F
Enteric Gram negatives are highly fastidious.
A
False
they are non-fastidious but sensitive to drying
8
Q
All of the Gram- Enterics are have a _______ cycle.
A
Oro fecal
9
Q
What type of infection is Campylobacter?
A
Zoonotic
10
Q
Where can Helicobacter live?
A
Stomach
*causes cancers and ulcers
11
Q
What are the Serotype terms for:
Flagella
Capsules
Endotoxins (LPS)
A
H-antigens
K-antigens
O-antigens
*these are determined by agglutination
12
Q
What is meant by Antigen Variation?
A
Bacteria evade adaptive response by changing epitopes
*referring to Gram- Enterics
13
Q
How does Phase Variation in Gram- Enterics protect them from Antibody-mediated death?
A
They change the expression of major features (Antigens), like capsule and flagella.
14
Q
Name 6 virulence factors for Gram- Enterics.
A
Adhesive factors Endocytosis (invade cells) Macrophage Taxi Capsules (phagocytic resistance) Phase variation Antibiotic Resistance Toxins
15
Q
T/F
All Gram- Enterics have endotoxin, and some have exotoxin.
A
True
16
Q
What are the specific adhesion molecules on Fimbrae called?
A
Adhesins
17
Q
T/F
All Gram- Enterics initiate actin assembly and internalize into attached cells
A
False
some do
*Bacterial-directed endocytosis
18
Q
Which Gram- Enterics enter mucosal epithelium?
Which of these use macrophage taxis?
A
E. coli (EIEC)
Shigella
Salmonella
Yersinia
(these two taxi)
19
Q
How do macrophage taxi Gram- Enterics survive?
A
Block endosome-lysosome function and escape the death chamber
20
Q
E. coli (EPEC variant) does what to intestinal cell walls?
A
Attaches to brush border and causes malabsorption
21
Q
What 4 things does LPS directly activate?
this is our innate immune response
A
Macrophage
Hageman Factor (coagulation)
Platelets (coagulation)
Complement (mast cell degranulation/pro-inflammatory mediators)
22
Q
TNF-alpha stimulated endothelial cells to produce:
A
NO
23
Q
Gram - bacteria can, in large numbers, cause sepsis, which entails:
*this is caused especially by what bacteria?
A
Hypovolemic shock (CV) Intravascular coagulation (causing internal bleeding) then, Multiple organ shutdown ARDS
*bacteriamia
24
Q
What are the 3 major classes of A-B Exotoxins produces by Gram - Enterics?
A
2 Robosylation of regulatory proteins (gut)
1 cleave rRNA and block protein synth
25
What is the equation for disease causing potential?
Virulence x Dose / Host resistance
26
Why is Shigella's infectious dose very small?
Very acid resistant
27
How does Shigella infect the colon?
By invading epithelial "M" cells and dividing inside.
28
How does Shigella move laterally once inside these epithelial cells?
Actin-directed pseudopodia
29
What is the result of a local Shigella infection of the colon?
dysentery
30
What type of toxin do some strains of Shigella dysenteriae produce?
Shiga toxin
(A-B cleaves rRNA)
*damages intestinal epithelial cells
31
What can Shiga toxins do if they get into blood?
HUS - Hemolytic Uremic Syndrome
| damage glomerular endothelial cells & renal failure
32
What encodes a Shiga-like Toxin?
Entero-hemorrhagic E. coli (EHEC)
*similar to S. dysenteriae
33
List Shigella species from most pathogenic to least:
S. dyssenteriae
S. flexneri
S. sonnei
34
The Shigella bacteria cause a _____ LPS caused by invasion of bacteria into the endothelium.
Local
35
What is the immune response to M-cell invasion by Shigella?
Ulcers, which causes dyssenteric symptoms
36
What is stool filled with in dysentery caused by Shigella?
mucus
pus
blood
37
EHEC 0157:H7 has _____ toxin and can act _____.
Shiga-like
| Systemically
38
What causes Typhoid Fever?
Salmonella typhi
macrophage taxis rupture and releases lots of bacteria
*systemic
39
Where is Salmonella typhi found in carriers?
Gallbladder (maybe gallstones)
feces
*typhoid Mary
40
How many Salmonella serotypes are there?
over 2000
41
How is Salmonella different from Shigella?
Doesn't tolerate stomach acid as well
| *need large dose for infection
42
How do most Salmonella species act in the gut?
Invade epithelial cells and destroy.
| Usually isolated infection
43
Why is Salmonella typhi particularly infectious?
Evades macrophage destruction by using taxis
44
What is the definition of bacteremia?
Bacteria in blood
45
List Salmonella species from most to least virulent:
S. typhi
S. typhimurium
S. enterica
46
T/F
| Salmonella is acid sensitive
True
47
What type of virulence factors can be transferred to normal Gi flora?
What are 2 types of pathogens that transfer such genes?
adhesions and endotoxins
Shigella and V. cholera
48
Name 4 pathogenic E. coli that have gained virulence factors from Shigella or V. cholera?
(one gained from an unknown source)
ETEC - Enterotoxigenic E. coli
EHEC - Enterohemorrhagic E. coli
EPEC - Enteropathogenic E. coli
EIEC - Enteroinvasive E. coli
49
E. coli outbreak's pts are often hospitalized with what condition?
HUS (hemorrhagic uremic syndrome)
50
What causes most (75%) UTI's?
| What allows them to survive in the urinary tract?
```
E. coli (uropathogenic strains)
Specialized adhesions (fimbrae)
```
51
At what point can a UTI cause systemic LPS?
Once it reaches the kidney
52
Aside from LPS, what do E. coli strains of UTI's secrete?
Cytolytic exotoxin
53
What is a curved Gram- rod and has enterotoxin causing ribosylation (increases cAMP)?
Vibrio cholerae
54
What zoonotic infection has Shiga-like toxin?
Campylobacter jejuni
55
What causes ulcers and is a spiral Gram- rod?
Helicobacter pylori
56
What causes cystic fibrosis and is a big problem in burn victims and has a poor response to antibiotics?
Pseudomonas aeruginosa
57
What's a key periodontal bug that is Gram- rod anaerobe?
Bacteroides
58
What Gram- rod comes through skin, oral mucosa, and grows in macrophage?
Brucella abortus
59
What fragile Gram- rod with a capsule binds ciliated bronchi and is not enteric?
Bordetella pertusis
60
What Gram- rod causes Plague?
Yersinia pestis
61
Mortality rates:
Bubonic plague
Pneumonic plague
75%
| 100%
62
T/F
| Y. pestis uses macrophage taxis
True
63
What are the toxic agents used by Y. pestis?
LPS
| Superantigen
64
What are 2 sources of Passive Immunity?
Mother
| Injection of antibody
65
Why is passive immunity temporary?
IgG half life 21 days
66
What is an important mild antibody?
slgA
(blocks colonization of gut viruses and toxins)
*protects from Vibrio cholerae
67
What Gram- curved rod is Non-invasive, and does not fully penetrate enteric endothelium?
Cholera
| Vibrio cholerae
68
What type of toxin does Cholera release?
| What does it do?
A-B exotoxin
pumps salts and water into colon
*rice water stools
69
What is the treatment for Cholera?
Water/electrolyte matching
70
When is the "window of susceptibility" for babies?
3-5 months
71
What are the 2 major pathogenic Neisseria species?
N. meningitidis
| N. gonorrhoeae
72
Neisseria meningitidis and gonorrhoeae are both?
Gram- diplococci
| aerobic or microaerophilic
73
T/F
| Both pathogenic Neisseria species cause purulent infections
True
74
Where is Neisseria meningitidis commonly found in healthy individuals?
What is the medical slang for this species?
nasopharynx
| meningococcus
75
What are the 2 diseases caused by Neisseria meningitidis?
meningitis
| meningococcemia
76
What are the major virulence factors of N. meningitidis?
Fimbrae (nasopharynx)
Capsule
IgA protease (very clever)
77
What two benefits does N. meningitidis get from having a capsule?
Anti-phagocytic
| Antigenic differences between strains
78
How is N. meningitidis spread?
| Natural carriers?
respiratory droplets and prolonged contact
| humans only
79
What percentage are asymptomatic and carrying N. meningitidis?
10%
80
Who is susceptible to N. meningitidis?
Those lacking opsonizing antibodies to anti-phagocytic capsules
*moves from nasopharynx into blood - bacteremia
81
What can bacteremia from N. menigitidis lead to?
meningococcal sepsis (septic shock)
'blebs' - lots of endotoxin from meningococcal outer membrane > cytokine > systemic inflammation > decrease BP > Disseminated Intravascular Coagulation
82
When are the peaks for death by menigococcal sepsis?
```
3 months (vast majority of deaths)
20 yrs
```
83
What is the difference between meningitis and meningococcal septicemia?
Bacteria cross to the brain and local endotoxin causes damage
84
What results in capillary blockage and damage during sepsis?
Disseminated Intravascular Coagulation
85
What are the 3 most serious brain infections in children that cause meningitis?
Are they Gram+/-?
H. influenza G-
N. meningitidis G-
Strep pneumococcus G+
86
T/F
| Viral meningitis is much more severe than bacterial.
False
Viral much more common much less severe
87
On gross examination of CSF, what is indication of bacterial meningitis?
Cloudy
88
The 3 species that cause bacterial meningitis in children (H. influenza, N. meningitidis, S. pneumococcus) all have _____ and live _____
capsules
| back of throat
89
Where does the human reservoir for N. meningitidis reside?
Carrier rate?
Nasopharynx
10%
90
T/F
| N. meningitidis is very hardy.
False
Very fragile, drying kills, hard to grow
91
What are meningits and meningococcemia both caused by?
Systemin LPS
92
Meningococcemia is often accompanied with a.....
rash
93
Both meningitis and meningococcemia are both ultimatley caused by....
Blebbed endotoxin released by N. meningitidis
94
What is the fatality rate for bacterial meningitis?
| % with serious outcomes like brain damage?
15%
| 15%
95
What is the Fatality rate for Meningococcemia?
| Serious outcomes like brain damage?
40%
| 50%
96
Common name for N. meningitidis
| Common name for N. gonorrhoeae
meningococcus
| gonococcus
97
What are the major virulence factors for N. gonorrhoeae?
```
Fimbrae attachment to mucosal epithelium*
Gene conversion and Phase Variation
Incorporates host surface receptors
IgA protease*
LPS*
Penicillin resistance
```
98
Is N. gonorrhoeae encapsulated?
no capsule
99
Why is gonorrhea so difficult to get rid of?
Half women have no symptoms
| less that 10% men have no symptoms
100
What is a consequence of untreated gonnorhea?
PID
| Pelvic Inflammatory Disease
101
Why are newborns routinely treated with anti-microbial eye ointment?
Prevent gonococcal eye infections
| if bad can lead to blindness
102
N. gonorrhoeae is very hardy
False
103
Name 3 important Virulence factors for N. gonorrhoeae.
Fimbrae
LPS
IgA protease
104
Inflammation from gonorrhea is local/systemic and leads to _______
Local LPS
| Pus (pyogenic)
105
Gonorrhea in women:
% asymptomatic
% untreated
50
10-20
*leads to PID 1 million/yr
106
Where does adhesive scarring occur in PID?
Fallopian tubes
107
Is there a vaccine for gonorrhea?
NO
extreme antigen variation makes it difficult
108
What are the 3 very small Gram- bacteria that cause human disease?
Rickettsia
Chlamydia
Mycoplasma
109
What are Rickettsia and Chlamydia's effects on tissues?
```
Obligate Intra-cellular (invaders)
Attacks endothelium
Energy parasites (steal ATP)
```
110
What are Mycoplasma's effects on tissue?
Extra-cellular
| Attacks epithelium
111
What toxins does Mycoplasma have?
Super Antigen
and no LPS
112
What are 2 results of a Rickettsia infection?
Spotted Feve
| Typhus
113
What are 2 results of a Chlamydia infection?
Eye infection
| STD
114
T/F
| Rickettsia is an obligate intracellular parasite.
True
115
Why must Rickettsia live inside cells?
Lack enzymes required to produce AA's
116
What is the main reservoir for Rickettsia?
Arthropods
117
What is the mechanism of Rickettsia infection from vector to host?
Infected arthropod defecates while biting, bacteria enter blood
118
What can many of the pathologies associated with Rickettsia be traced to?
LPS flooding bloodstream systemically
119
What is the most common and important Rickettsial disease worldwide?
Typhus
120
What is the only Rickettsial Typhus that can cause explosive epidemics?
How is it spread?
Louse-born
R. prowazekii > lice > clothes
121
What is the most common Rickettsia in the United States?
R. rickettsii, species of bacteria transmitted by ticks causing Rocky Mountain Spotted Fever
122
```
Organism and Vector causing the following:
Rocky Mountain Spotted Fever
Scrub typhus
Epidemic typhus
Murine typhus
```
R. rickettsii ticks
O. tsutsugamushi mites
R. prowazekii Louse
R. typhi fleas
*skip scrub/murine
123
What do all the arthropod transmitted Rickettsia's have in common?
small
G-
Obligate intracellular parasites
124
Rickettsia is an obligate _______ bacteria.
Gram?
Shape?
Intracellular
G-
coccobacilli
125
What kind of parasite is the Rickettsia bacteria?
Energy parasite
Steals AA's and ATP
*Chlamydia also does this
126
What does Mycoplasma steal from its host?
lipids and cholesterol to strengthen its membrane
127
Ticks are both the _____ and the ______ for Rickettsia.
reservoir
| vector
128
LPS in Rickettsia is systemic and causes what symptoms?
Headache, fever, chill
| Rash
129
What are the 3 biotypes in the serological taxonomy of Rickettsia?
Spotted fever group
Scrub typhus group
Typhus group
130
How does Typhus differ from Typhoid?
Typhus - caused by Rickettsia
Typhoid - "typhus like" caused by Salmonella typhi
(typhoid mary)
*typhus/typhoid - think fever/rash
131
What does Rickettsia prowazekii cause?
| What is its reservoir?
epidemic typhus in close quarters via lice
humans (and some rodents)
*DDT extremely effective against
132
Describe Chlamydia
```
Obligate intracellular parasite
no cell wall
two lipid bilayer/LPS
G-
energy parasite
```
133
What are the 3 major species of Chlamydia that affect humans?
C. trachomatis (STD)
C. pneumoniae (bronchitis & pneumonia)
C. psittaci (pneumonia)
*psittaci is mostly bird pathogen, occasionally human
134
What 2 diseases does Chlamydia trachomatis cause?
STD
| blindness (trachoma)
135
What is the primary reservoir for Trachoma?
| What is the pathological progression?
children
| eyelids turn inward and scar
136
How is Chlamydia symptomatically similar to Gonorrhea?
symptomatic in men
asymptomatic in women
(generally)
* also a cause of PID
137
T/F
| Chlamydia and Rickettsia are energy parasites
true
138
T/F
| Chlamydia has a peptidoglycan wall and LPS
False
No peptidoglycan, but has LPS
139
What does Chlamydia infect and what type of inflammation does it cause?
Mucosal epithelium
| Local (and chronic)
140
Chlamydia pneumonia has an association with atherosclerosis, is community acquired, and is very rare.
False
More than 50% population has serologic evidence of previous infection
141
What is the common route of infection for C. psittaci?
Birds to dust to lung
*generally only affecting immunocompromised
142
T/F
| There is a vaccine for C. trachmatis
False
143
What is the most common bacterial STI in the USA?
Chlamydia trachmatis
144
What are the smallest known self-replicating organisms?
Mycoplasma and Ureaplasma
145
Describe Mycoplasma
```
No LPS
Gm+
Very common
No cell wall
sterols
```
146
What is the major Mycoplasma pathogen?
M. pneumonia
147
Where does M. pneumonia live?
Surface of respiratory epithelium
*destroys ciliated cells
148
What type of inflammation does M. pneumonia elicit?
| How?
Local
| super antigen
149
What is "walking pneumonia"?
atypical, mild
150
T/F
| Mycoplasma species have been implicated in genitourinary tract diseases, PID, and STI's
True
151
What are Koch's 4 postulates to determine causality of agent?
1. Found in all cases
2. grown
3. cause disease when introduced
4. reisoloation from inoculated host and identified as identical to original causative agent
152
What causes diphtheria and where is it found?
Corynebacterium diphtheriae
skin, upper respiratory, GI
153
What are 3 defining characteristics of C. diphtheriae?
G+
non-spore forming
Rods (bacilli)
154
What kind of toxin does C. diptheriae make and how is it spread?
A-B exotoxin
(inhibits protein synth)
only spreads when lysed by virus
(the infection has an infection)
155
Where does the A-B exotoxin of C. diptheriae preferentially spread systemically?
Where is it locally?
B-subunit binds heart and nerve cells
Throat
156
How is C. diptheriae usually transmitted?
Respiratory droplets of asymptomatic, immune carriers
157
What is the distinctive thick, grayish white exudate caused by C. diphtheriae that adheres firmly to tissue?
What does this cause in advanced cases?
Pseudomembrane
Suffocation
*difficult to dislodge without making underlying tissue bleed
158
How is diphtheria treated?
| How avoided?
anti-toxin
| toxoid (modified immunogenic toxin)
159
Besides C. diphtheriae, what causes a pseudomembrane to form?
Candidiasis
160
T/F
| Diphtheria is non-invasive.
True
*toxin invades
161
Two major ways to die from diphtheria?
Suffocation
| Heart
162
Why does Corynebactirum diphtheriae infections increase when vaccination rates go down?
Bacteria is found everywhere
USSR - Russia breakup lag in public health
163
What type of bacteria form spores?
```
Gram positive (some)
NEVER Gram negative
```
164
T/F
| A minimum amount of metabolism goes on in endospores.
False
NO metabolic processes
165
Structure of endospore:
Dehydrated core with DNA
thick Peptidoglycan
Keratin-like protein
166
What are 2 of the most common and important spore forming bacteria?
Bacillus
| Clostridium
167
```
Describe Clostridium:
metabolism
Gram
Shape
spore forming?
where found
```
```
Obligate anaerobe
G+
Bacilli (rods)
spore forming
ubiquitous
```
168
What are the 4 Clostridium human pathogens?
C. tetani
C. botulinum
C. perfringens
C. difficile
*these are all G+ spore formers and strict anaerobes
169
What is special about the A-B exotoxin secreted by C. tetani and C. botulinum?
They are the most potent toxins known
170
T/F
| Botulism causes "true" food poisoning.
True
171
T/F
| Perfringens is an infection food poisoning
True
172
What is the worldwide mortality rate for tetanus?
| For infants?
20-50%
| 90%
173
What is the mechanism of the Clostridium tetani toxin?
Blocks neurotransmitter release of Inhibitory Synapses
174
What is the main way we contract C. botulinum?
spores in Food
*infants and honey, home canning ("true")
175
What is the mechanism of the Clostridium botulinum toxin?
Blocks RELEASE of neurotransmitter acetylcholine at the NMJ
*this prevents contraction (flaccid paralysis)
176
T/F
| The immune system can respone to C. tetani and C. botulinum.
False
they are so powerful immune system never sees it at lethal dose
177
Why do infants have less tolerance for C. botulinum?
Stomachs higher pH
178
What two pathologies do Clostridium perfringens cause?
Gas gangrene
| Food poisoning
179
What type of exotoxin does C. perfringen produce?
mostly Cytolytic
*huge number
180
What is the mode of most C. perfringens food poisoning?
left out meat
181
What Clostridium is associated with broad spectrum antibiotics?
C. difficile
*has 2 exotoxins
182
What is another G+ spore forming pathogen other than Clostridium species?
Bacillus anthracis
*this is a HUGE G+
183
What are the 3 types of pathologies caused by Bacillus anthracis?
Mortality rates?
```
Cutaneous anthrax (20%)
Pulmonary anthrax (90%)
GI anthrax (50%)
```
184
What type of toxin is released by Bacillus anthracis?
two potent A-B exotoxins
Edema Toxin
Lethal Toxin
*uses Macrophage taxis
185
What is the Bacillum species that causes true food poisoning, mostly by re-heated fried rice?
Bacillum cereus
186
What are the 2 most important species of Mycobacterium affecting humans?
M. tuberculosis
| M. leprae
187
Why is B-cell immunity no good against Mycobacterium?
Because they get INTO cells
188
Describe the pathology/immune response in M. tuberculosis.
```
Infects macrophage (mostly)
Immunity isolates into lung granulomas
```
189
Describe the pathology/immune response of M. leprae.
Infects Schwann cells
```
Immunity only slows disease progression
either Tuberculoid (strong) or Lepromatous (weak)
```
190
T/F
| 1/3 of the world is infected with TB
True
191
Where does Mycobacterium tuberculosis usually live?
Man, cows, birds, soil, milk, deer, etc.
192
What is unique about the membrane of M. tuberculosis?
High lipid content
| 60% dry weight
193
T/F
| TB grow fast
False
194
T/F
| TB is an Obligate Aerobe
True
195
Why is milk pasteurized?
TB is sensitive to heat
196
What are some morphological features of M. tuberculosis?
Poor staining Gram+
lipid rich
Acid Fast
197
What is the infection rate of TB in US and worldwide?
10 million US
| 2 billion world
198
What does it mean to be Infected Latent?
Infected but not infectious
199
How many die/yr from TB?
1.2 million
200
What are 3 major problems in wiping out TB?
complacency
poor compliance
multi-drug resistance
201
What is THE virulence factor in TB?
Lipid (waxy) membrane
| *has Mycolic Acid
relatively impervious barrier to enzymes, etc
202
Why are antibodies of no use fighting TB?
It wants to be in macrophage
*only way to deal is put it in Granuloma jail
203
T/F
| M. tuberculosis has resistance to enzymes, pH, drying
True
204
How is TB detected in the US?
PPD skin test
| IFN-gamma release assay
205
How is the vaccine (BCG) for TB made?
from M. bovis
makes cross reactive immunity
(false + PPD screens)
