Exam 2 Enteric Bacteria Flashcards
(178 cards)
1
Q
Enteropathogenic bacteria - gram stain/shape?
A
Gram negative rods
2
Q
Enteropathogenic bacteria - order and family
A
Order: Enterobacteriales
Family: Enterobacteriacae
3
Q
The Enterobacteriaceae are able to cause infection through being both _____ and ______
A
Pathogens and opportunists
4
Q
Which species are considered Enterobacteria pathogens? (5)
A
- Eschericia coli
- Shigella
- Salmonella
- Yersinia pestis
- Y. enterocolitica
5
Q
Which species are considered Enterobacteria opportunists? (5)
A
- Klebsiella pneumoniae
- Proteus mirabilis
- Enterobacter
- Serratia
- Pseudomonas
6
Q
Proteus mirabilis is often associated with what infection?
A
Urinary tract infection
7
Q
What bacteria is this, and what are some of its characteristics?
A
E. coli; very mobile (peritrichous flagella) and covered with fimbrae so great for attachment
8
Q
Pseudomonas is often associated with what infections?
A
Cystic fibrosis, burn patients
9
Q
General characteristics of Enterobacteriaceae: what virulence factors do they have?
A
- Endotoxin/LPS (O antigens)
- Exotoxins (Enterotoxins)
- Flagella (H antigens)
also have adhesion factors and capsules
10
Q
Enterobacteriaceae metabolism
A
Facultative anaerobes; dif species have characteristic fermentation patterns so can be used to tell them apart
11
Q
What are coliforms and which species are considered coliform bacteria?
A
Bacteria that shed a lot in our feces
- E. coli
- Klebsiella
- Citrobacter
- Enterobacter
Think “ICKY” (ECKE)
12
Q
Coliform bacteria provide indices for:
A
Fecal contamination of drinking water (potability)
13
Q
Regulatory standard for drinking water
A
<500 CFU/mL of water
14
Q
Why is it important to consider CFU in drinking water standards?
A
CFU is live bacteria
live bacteria cause disease
15
Q
Dental water quality: for routine dental treatment, meet _______
A
Regulatory standards for drinking water
16
Q
E. coli is a ____ fermenter
A
Lactose
17
Q
E. coli metabolism
A
Facultative anaerobe
18
Q
E. coli makes tryptophanase to produce ____
A
Indole (organic compound)
19
Q
E. coli can be cultured on what type of agar?
A
MacConkey agar (due to ability to ferment lactose, color will change to hot pink)
20
Q
Indole test can be used to detect presence of:
A
E. coli
21
Q
E. coli virulence factors
A
- Adhesion factors
- Enterotoxins (Heat labile toxin and Heat stable toxin)
- Shigatoxin (verotoxin)
- Hemolysins
- Capsule
E. coli will CHASE me away
22
Q
What enterotoxins does E. coli have?
A
- Heat labile toxin (LT-I and II) –> similar to cholera
- Heat stable toxin (ST), causes increase of intracellular cGMP
23
Q
Which E. coli enterotoxin causes cGMP to increase?
A
Heat stable toxin (ST)
24
Q
Most common cause of uncomplicated UTI in women
A
E. coli
25
UTI's can have an ______ route of infection, leading to:
Ascending (urethra --> kidney) ; cystitis and pyelonephritis
26
What is cystitis?
Bladder inflammation
27
Cystitis strains have specific ____ adhesion factors
O antigens adhesion factors
28
What is pyelonephritis?
Kidney inflammation
29
Pyelonephritis strains have unique ____ antigens
P fimbrial antigens
30
E. coli UTI symptoms
Flank pain, turbid (cloudy) urine
31
Methods of E. coli UTI prevention
- wash before and urinate after sex
- wipe genitals from front to back
32
WBC casts are often a symptom of:
**Pyelonephritis**; produced by damaged kidneys and found in urine
33
Pyruria
Pus in urine
34
Diagnosis of UTI
**Often diagnosed by symptoms**; also 100,000 CFU/mL of urine, PMN, WBC casts
35
What strains of E. coli produce intestinal infection?
- EHEC
- STEC
- ETEC
(6 pathotypes in total; there are others but they're not in red or blue)
36
What is EHEC and what does it cause?
Enterohemorrhagic E. coli; causes bleeding in the gut
37
What is STEC?
Shiga Toxin producing E. coli
38
Shigatoxin (Stx) is encoded by:
Lysogenic phage
39
Shigatoxin can be acquired by eating ____
undercooked beef
40
What infections can intestinal shigatoxin lead to?
Hemorrhagic colitis, hemolytic uremic syndrome (HUS)
41
ETEC is known as:
Traveler's and infants watery diarrhea
42
True or false: ETEC watery diarrhea is non-invasive
True - doesn't spread from gut to rest of body
43
ETEC includes what toxins?
Heat labile toxin, Heat stable toxin
44
What is the most common strain of STEC in the US?
O157:H7
O = LPS antigen
H = flagellar antigen
45
Hemorrhagic colitis incubation time
3-4 days
46
Where/how does STEC colonize the gut to cause hemorrhagic colitis?
Invades colon epithelial cells causing acute inflammation
47
Hemorrhagic colitis symptoms
Severe abdominal pain, **bloody diarrhea**, mucus, PMN
48
True or false: Fever is reported as a common symptom of hemorrhagic colitis
False - little or no fever (usually lasts a week)
49
STEC transmission
Fecal-oral
- through ground beef
- contaminated water, **unpasteurized** milk and juice
- sprouts, lettuce, spinach, salami (animal waste can be found in fertilizer)
50
Hemorrhagic colitis therapy
Mainly **rehydration**. Don't need antibiotics unless it spreads to rest of body (**extra-intestinal**)
51
Hemolytic uremic syndrome is caused by:
EHEC/Shiga Toxin
52
How does EHEC cause HUS?
- toxin damages capillary lining
- platelets clump to initiate healing
- platelets form mesh in capillaries --> damages RBCs and prevents adequate blood flow
- leads to organ dysfunction or failure
53
Most common cause of acute renal failure in children
Hemolytic Uremic Syndrome
54
HUS leads to what 3 outcomes?
1. Microangiopathic **hemolytic anemia/schistocytes (destroyed RBC)**
2. **Thrombocytopenia (low blood platelets)**
3. Renal insufficiency (**acute renal failure**)
55
What toxins are associated with HUS?
Shiga toxin and LPS
56
True or false: treatment of HUS involves the use of antibiotics
False - could make the infection worse by releasing more LPS
57
What bacteria is this/characteristics?
Shigella; no flagella so is not mobile, but lots of fimbrae for attachment
58
True or false: Shigella can ferment lactose
False - No color change on MacConkey agar
59
____ is thought to be biogroups within E. coli
Shigella
60
Shigella sp. to know
1. Shigella dysenteriae
2. Shigella sonnei
61
____ causes most serious of bacillary dysentary
Shigella dysenteriae
| epidemic in developing countries
62
Shigella dysenteriae is epidemic in:
Developing countries
(not found in US because we treat our drinking water)
63
Shigella sonnei (and flexneri) dominate in what country?
U.S.
64
What is dysentery?
Diarrhea with visible blood
65
Causes of dysentery
Bacterial - Shigella and STEC O157:H7
66
Most common cause of dysentery
Shigella sp.
67
Virulent strains of Shigella contain:
Large virulence/invasion plasmid
68
Shiga toxin is produced by which Shigella strain?
Shigella dysenteriae
69
Shiga toxin is derived from:
Phage
70
Structure of Shigatoxin
AB structure
71
What is the function of the A subunit in Shigella dysenteriae?
Inactivates ribosomes to **stop protein synthesis**, causes cell death and **enterotoxic dysentery**
72
What is the function of the B subunit in Shigella dysenteriae?
Binds to vascular endothelial cells (gut, kidney, lungs)
73
Shigella enters small intestine through:
M cells
74
Shigellosis is transmitted via:
Fecal-oral
- contaminated food and water
75
True or false: Shigella has a very high infectious dose
False - very low (doesn't take much to cause infection)
76
What happens in the early/second stages of Shigellosis?
Early:
- **colonization** of small intestine, profuse watery diarrhea
Second:
- invasion of colon, fever, cramps, **blood** and pus in stool
| earlystage MAY progress to second stage
77
Shigellosis is usually self-limiting unless caused by:
Shigella dysenteriae
78
Shigellosis may progress to _____
Hemolytic uremic syndrome (HUS)
79
Shigellosis diagnosis
Culture feces, **PMN in feces (indicates invasive infection)**, enzyme immunoassay, ELISA, PCR
80
Shigellosis tx
**Supportive - fluid replacement**
Amoxicillin, ampicillin
81
What is the bacteria/characteristics?
Salmonella; lot of flagella (motile) and fimbrae (attachment)
82
Salmonella does not ferment _____
Lactose
83
Salmonella produces _____ from thiosulfate
Hydrogen Sulfide (H2S)
84
Salmonella major virulence factors
- Endotoxin (O antigen)
- Vi antigen (antiphagocytic capsular polysaccharide)
- flagellar phase variation
85
____ has flagellar variation and has 2 alternatively expressed H antigen genes
Salmonella
86
Salmonella transmission
Fecal oral
87
Where does Salmonella invade?
M cells in small intestine
88
Salmonella _____ causes most human infections
Enterica
89
Salmonella infections
- gastroenteritis
- enteric fever
- septicemia/sepsis
- asymptomatic carriage in gallbladder
| Salmonella AGES me
90
Most common salmonella infection; what is it caused by?
Gastroenteritis
- Salmonella enteritidis, Salmonella Typhimurium
91
Enteric fever also known as
Typhoid fever
92
Enteric fever is caused by:
Salmonella Typhi, Salmonella Paratyphi
93
What is septicemia/sepsis
Systemic inflammation triggered by the immune response to an infection
94
Septicemia/sepsis may lead to:
Osteomyelitis, endocarditis
95
Septicemia/sepsis can be caused by:
Salmonella Typhi, Salmonella Paratyphi
96
Most common form salmonellosis
Enteritis
97
Salmonella enteritis is caused by eating ____
Raw/undercooked poultry and eggs
98
Salmonella enteritis symptoms
**Non-bloody diarrhea**, nausea, vomiting, fever, cramps, myalgia, headache
99
Salmonella enteritis treatment
Rehydrate
Abx not recommended
Septicemia should be treated w/ ampicillin, cephalosporins
100
Typhoid fever is caused by:
Salmonella typhi
101
Typhoid fever is ____ infection
Systemic
102
Typhoid fever symptoms
During 2nd week - bacteremia, rash, high fever, tender abdomen, constipation
103
When does S. Typhi colonize the gallbladder?
During 2nd week
104
In the 3rd/4th week of typhoid fever, what happens?
Intestinal hemorrhage, may perforate
105
Typhoid fever rash - rose spots
106
True or false: asymptomatic carriers of typhoid are not infectious
False (Ex. typhoid Mary)
107
True or false: asymptomatic carriers of typhoid should be treated with antibiotics
True - 4-6 weeks
108
Typhoid fever diagnosis
Blood or bone marrow culture
109
Tx of typhoid fever
Antibiotics (Ceftriaxone, azithromycin)
110
When is S. Typhi vaccine given?
To travelers, lab workers, high risk situations
111
What forms of S. Typhi vaccines exist?
Inactivated shot; Attenuated (live) oral
112
Yersinia entercolitica is part of what family?
Enterobacteriaceae (same as E. coli, Shigella, Salmonella)
113
Yersinia entercolitica is distantly related to:
Yersinia pestis
114
Yersinia entercolitica is most common in
Children
115
Yersinia pestis order
Enterbacteriales
116
True or false: Yersinia pestis is an enteric pathogen
False
117
Yersinia pestis is gram ____ and shape ______
Gram negative; coccobacillus (fat rod)
118
Yersinia pestis causes:
Plague (black death)
119
Yersinia pestis is responsible for what types of plagues? (2)
- urban plague (transmitted by fleas/aerosol inhalation)
- sylvatic plague (wild animals)
120
Yersinia pestis is endemic to:
U.S. (rural southwest states)
121
Forms of plague
- bubonic plague
- pneumonic plague
- septicemic plague
122
Bubonic plague is transmitted by ____ and causes ____
flea bite (Y. pestis)
lymphadenopathy, high fever
123
What is pneumonic plague?
Bacteria (Y. pestis) spread to lungs via aerosol --> pneumonia
124
Septicemic plague is spread to
Blood
125
Bubonic plague - where does swelling occur
At lymph nodes
126
Sporatic sylvatic plague is usually:
Bubonic
127
Pneumonia plague can lead to:
Plague gangrene
128
____ causes cholera
Vibrio cholerae
129
Vibrio cholerae is gram ____ and shaped like:
Gram negative; comma shaped
130
V. cholerae _____ epidemic serotypes produce toxin
01 and 0139
131
Vibrio cholerae transmission
Fecal oral
132
Cholera toxin structure
AB structure
133
Is cholera toxin heat labile/stable?
Heat labile
134
Cholera toxin causes uncontrolled activation of ____ leading to ____
adenylate cyclase; osmotic imbalance
135
Cholera toxin - steps of mechanism of pathogenesis (5)
1. A subunit activates G protein
2. uncontrolled stimulation of adenylate cyclase (cell membrane)
3. stimulates cAMP production from ATP
4. cAMP activates protein kinase A
5. osmotic imbalance
136
Osmotic imbalance in cholera leads to:
Dehydration and electrolytes loss
137
Main symptom of cholera
Profuse watery diarrhea - rice water stools
138
Cholera tx
Rehydration (IV, oral)
139
Cholera prevention
Sanitation
140
____ is acquired through open wounds or eating raw shellfish
Vibrio vulnificus
141
Vibrio vulnificus is associated with ____ wounds
Gangrenous
142
Vibrio vulnificus can cause bacteremia, leading to _____ and a ___ mortality
Septic shock; 50%
143
Vibrio parahaemolyticus can be acquired through>
Ingesting raw/improperly cooked shellfish
144
Campylobacter jejuni
Gram negative curved rods in pairs
145
Campylobacter jejuni is highly associated with:
Poultry
146
Assume that all chicken is contaminated with:
Salmonella and Campylobacter (and others)
147
Helicobacter pylori colonizes the gut via:
Adhesins that mediate attachment to gastric mucosa
148
H. pylori produces ____ which is great for testing, and increases pH of gastric microenvironment
Urease
149
Clinical diseases caused by H. pylori
- chronic gastritis
- duodenal ulcer
- gastric peptic ulcer
- gastric carcinoma
150
H. pylori is found in ___ of duodenal ulcers and ____ of gastric ulcers
95%; 85%
151
H. pylori transmission
Fecal oral
152
H. pylori can be diagnosed using:
Urease tests (gastric biopsy and breath test)
153
What is the H. pylori breath test?
- drink 13C-Urea
- if urease is produced then H. pylori is present because 13CO2 will be breathed out
154
How is H. pylori treated?
- antibiotics (clarithromycin and amoxicillin; clarithomycin and metronidazole)
- Proton pump inhibitors (PPI)
155
What do proton pump inhibitors do (H. pylori)?
- suppresses gastric juice production
- concentrate and stabilize antibiotics
156
Enterobacter are mostly ____ infections
Hospital acquired
157
True or false: antibiotic resistance is a serious problem with hospital acquired infections of Enterobacter
True
158
Proteus mirabilis is a ____ producer
Urease
159
Proteus mirabilis hydrolyzes urea to make ____, which can lead to formation of ____
ammonia; kidney stones
160
True or false: Serratia is a nosocomial infection
True
161
Which bacteria produces a bright red pigment?
Serratia
162
Serratia grows well on:
Moist environments
"Bloody" bread
163
P. aeruginosa produces pigments, which are:
Pyocyanin (blue), fluorescein (yellow)
Together looks green
164
P. aeruginosa virulence factors
- abundant anti-phagocytic capsule (slime)
- multiple antibiotic resistance
165
Why are cystic fibrosis patients more susceptible to P. aeruginosa infections?
Alteration of respiratory epithelium facilitates colonization
166
Klebsiella pneumoniae has a prominent ____
Capsule
167
Where is Klebsiella pneumoniae found?
Normal flora GI tract
168
Klebsiella pneumoniae associated diseases
Lobar pneumonia in compromised patients
169
What is carbapenem?
Group of beta lactam antibiotics
170
True or false: Klebsiella pneumoniae is not known to be resistant to any antibiotics
False - it is a multi-drug resistance Gram-negative bacteria
171
Klebsiella pneumoniae produces _____ which confers resistance to most beta lactam antibiotics
Extended spectrum beta lactamases (ESBLs)
172
Carbapenem resistant enterobacteriaceae (CRE) are resistant to:
Nearly all available antibiotics
173
Family ____ is most common cause of CRE
Enterobacteriaceae
(Most commonly Klebsiella pneumoniae)
174
Some CRE infection cases must now use ____ as an antibiotic, but it is a last resort due to potential kidney toxicity
Colistin
175
True or false: there are many new drugs for gram negative bacilli
False - few new ones
176
______ is the most common bacteria in Class A carbapenemase
Enterobacteriaceae
177
Class A carbapenemase confers resistance to:
All Beta lactams
178
E. coli UTI treatment
septra (trimethoprim-sulfamethoxazole)
