bacterial infect, GI tract, Lect 5 Flashcards
(56 cards)
1
Q
cholera is due to what organism
A
vibrio cholerae infection
2
Q
where do cholera colonize?
A
- Bacteria colonize the small intestine mucosa with the colonized mucosa showing NO change in physical integrity
3
Q
what is the main clinical feature of cholera
A
- Acute and massive watery diarrhea (1 liter/hour) is the main feature of this disease.
- “rice water” stools
- Rapid depletion of fluids and electrolytes leading to hypo-volemic shock, metabolic acidosis, death
4
Q
cholera has abrupt onset of what symptoms
A
- watery diarrhea
- Muscle cramps, poor skin turgor, wrinkle skin over fingers, (“washerwoman hands”), sunken eyes, missing pulse in extremities.
5
Q
the watery diarrhea in cholera is created by
A
cholera toxin
6
Q
cholera toxin has identical toxin in what organism that causes traveler’s diarrhea
A
enterotoxigenic E-coli
7
Q
describe the cholera agent: gram status
A
- gram negative
8
Q
describe the cholera agent: shape, does it form spores
A
- bent rod shape
- nonspore-former
9
Q
can the cholera agent live in aerobic environement? is it motile?
A
- facultative anaerobe
- motile, polar flagellum
10
Q
identify V. Cholerae serogroups
A
- serogroup O-1: classic epidemic cholera
- serogroup O-139
11
Q
cholera treatment
A
- For the majority of patients, successful therapy usually only requires replacement of fluids and electrolytes.
- Provide by IV route if patient cannot take oral fluids
12
Q
causative cholera microbes are found naturally in what environments
A
The causative microbes are found naturally in marine coastal areas and estuaries, including the United States Gulf Coast region.
13
Q
how is cholera spread
A
- This disease is spread through contaminated drinking water and food.
- Not easily spread by person-to-person route
14
Q
who are important reservoirs for cholera
A
- Asymptomatic human carriers important as reservoirs
- carrier rate 1-20% in endemic regions
- a carrier may have initiated the current cholera epidemic in Haiti
15
Q
are vaccines available for cholera
A
- two killed organism vaccines
- Shanchol: O-1 killed whole cells plus toxoid
- Dukoral: bivalent O-1 and O-139 killed whole cells
16
Q
primary prevention for cholera
A
proper control of sewer
17
Q
travelers to cholera endemic regions can take
A
Prophylactic tetracycline treatment
18
Q
what is the most common cause of food-borne illness in Japan.
A
Vibrio. parahaemolyticus
19
Q
Vibrio. parahaemolyticus causes
A
gastroenteritis to a mild cholera-like illness
20
Q
V. parahaemolyticus normal habitat
A
This organism is normal inhabitant of coastal ocean and estuary waters
21
Q
US cases with V. parahaemolyticus is most frequently associated with
A
mishandling infected seafood
- improper refrigeration
22
Q
vibrio vulnificus normal habitat
A
Also a normal inhabitant of coastal marine and estuary waters.
23
Q
vibrio vulnificus infection is associated with
A
Infection is frequently associated with oysters
-
Wound infections
- Through direct contact of open wound with seawater or oysters.
-
sepsis
- Due to consumption of raw oysters
- Acute self-limiting diarrhea associated with raw oyster consumption
24
Q
clinical presentation
- Eruption of bullous skin lesions, shock.
- History of oyster consumption with suspicion of liver dysfunction (alcoholism commonly)
A
sepsis from V. vulnificus
25
treatment of sepsis caused by V. vulnificus
tetracycline
26
E-coli have two means by which to cause disease
* **O antigen** (LPS) = serogroup
* At least 160 serogroups exist
* **H antigen** (flagella) = serotype
27
MOA of Enterotoxigenic E. coli (ETEC)
* adheres to mucosa of small intestine and produces symptoms by elaboration of toxinds that induce diarrhea
28
Enterotoxigenic E. coli (ETEC) causes what condition
traveler's diarrhea
* afebrile, watery
29
Enterotoxigenic E. coli (ETEC) can be fatal in what patient population
ETEC disease is like cholera, but far less severe. **May be fatal in infants**
30
clinical presentation
* primarily in developed world
* diarrhea that becomes bloody after 1-3 days with cramps, vomiting
* fever in 50% patients
Enterohemorrhagic E. coli (EHEC)
31
Enterohemorrhagic E. coli (EHEC) express what toxin (key virulence factor)
Shiga-like toxin (SLT)
32
Enterohemorrhagic E. coli (EHEC) complications
1. develop **hemolytic uremic syndrome (HUS)**: can be fatal.
2. acute renal failure
1. 8-10% of O157:H7
33
Enterohemorrhagic E. coli (EHEC): which One form predominates
O157:H7
34
STEC also induces hemolytic uremic syndrome. what does STEC stand for
Shiga toxin producing E. coli
* other forms of E-coli that may produce same disease syndrome
35
Enterohemorrhagic E. coli (EHEC) is more common in what patient populations
elderly and young
36
how is EHEC (O157:H7) Diagnosed
* **MacConkeys’s sorbitol agar** can differentiate this pathogen from normal flora E. coli
* This pathogenic strain cannot ferment sorbitol and appears **white** on MAC sorbitol plates while other nonpathogenic E. coli strains are a bright **red/pink color**.
37
EHEC (O157:H7) treatment
* oral rehydration
* **avoid Abx**
* Risk of HUS induction
* do NOT use antimotility agents in children and infants
38
EHEC O157:H7 is associated with what food source
* reservoir is CATTLE
* beef
* raw milk
39
route of transmission of EHEC O157:H7
* This is an extreme low-dose pathogen
* Person-to-person transmission documented
40
what is E. coli O104:H4
a new form of enterogaggregative E. coli O104:H4 emerged in Europe
41
E. coli O104:H4 traced to what food source
alfalfa sprouts
42
E. coli O104:H4 expresses what toxin
shiga toxin
* ability to produce HUS, high case fatality rate
43
Campylobacter jejuni is widely distributed in what food products
**undercooked chicken**
44
Give the characteristics of Campylobacter jejuni
* gram status
* aerobic?
* what temp it grows best at
* Gram negative
* curved rod (sea gull shaped)
* Motile
* Microaerophilic
* Grows well at 42º C
45
clinical presentation
* Very commonly patient has prodrome with fever, headache, malaise, myalgia **12-24 hours before diarrhea onset**.
* Enteritis with diarrhea
* Loose stools to dysentery (bloody diarrhea)
* Fever
* abdominal pain (cramping)
* Self-limiting (improvement after several days).
* Severe acute abdominal pain in lower right quadrant (**mimics appendicitis**).
Campylobacter jejuni
46
reservoir of Campylobacter jejuni
* intestinal tract of animals
* birds especially
47
Campylobacter has the highest infection rate in what patient population
This GI pathogen is unusual in that the highest infection rate is in young adults (college age)
48
complications of Campylobacter infection
* Reiters syndrome
* HLA-B27 individuals
* Guillain-Barre syndrome
* **C. jejuni** **is the chieg precipitant of Guillain-Barre syndrome**
49
which bacteria has these characteristics
* copious production of urease
Helicobacter pylori
* Urease - Produces CO2 and NH4 + that raises pH and protects H. pylori
50
which bacteria has these characteristics
* **gram negative**
* curved rods
* highly motile
* stain best in tissue biopsy with Giemsa
* copious production of urease
Helicobacter pylori
51
What is H. Pylori's primary target in the host
Epithelial cells of pylorus
52
clinical presentation
* gastritis
* cramps
* halitosis: bad breath
* N/V
* eradication of bacteria is not correlated with relief of symptoms
H. Pylori
53
reservoir of H. pylori
humans
* gastritis has been produced by ingestion of large inoculum
54
which bacteria associated with stomach adenocarcinoma
H. Pylori
55
how is H. Pylori diagnosed
**CLO test** – detection of urease activity in biopsy tissue by pH change
56
treatment for H. Pylori
* The optimal antibiotic therapy has not yet been evolved.
* Combination of antibiotics (**tetracycline**) plus **bismuth-containing drugs** are used
* Patient may be re-infected after antibiotic eradication (by family/contacts)
