Chapter 20: Vibrio, Aeromonas, Plesiomonas, and Campylobacter Species Flashcards
1
Q
What causes cholera
A
Vibrio cholera
2
Q
Symptoms of cholera
A
Rice water stools
Large loss of water 10 to 30 movements per day
Dehydration and hypovolemic shock
Toxins causes diarrhea
3
Q
General characteristics of cholera
A
➢Pleomorphic shapes
•Oxidase +
•Reduce nitrate to nitrite
➢Except V. metschnikovii
4
Q
What stimulates the growth of most or all vibrio species
A
Sodium ions
5
Q
What is the name of the antimicrobial disk that vibrio is susceptible to
A
Vibriostat disk
6
Q
List two methods by which vibrios can be distinguished from aeromonads
A
-Vibriostat disk
-6.5% salt broth
7
Q
Most Vibrio are halophiles, T/F and which two are not?
A
True
1) V. Cholerae and
2) V. mimicus
8
Q
Name a test for the vibrio
A
Positive string test
9
Q
What are the two most important Vibrio species.
A
V. cholerae and V. parahaemolyticus
10
Q
Gram stain reaction of Vibrio, Aeromonas, and Plesiomonas
A
Gram negative
11
Q
Oxidase reactivity of Vibrio, Aeromonas, and Plesiomonas
A
Oxidase positive
12
Q
Antigenic structure of V. cholerae and V. parahaemolyticus
A
flagellar H antigen (not useful) and a somatic O antigen of V. cholera
13
Q
How many sero-groups of Vibrio are there and which is most important?
A
Six. O1 are most important
14
Q
O1 vibrio subtypes
A
. Ogawa (A, B)
•Inaba (A, C)
•Hikojima (A, B, C)
15
Q
The six serogroups can be classified as 01 and non-01? T/F
A
True. Non-O1 generally produces milder disease and no cholera toxin
16
Q
V. cholera colonized the
A
Small intestine where they release toxins
17
Q
Cholera toxin is called and causes what symptom
A
choleragen,diarrhea
18
Q
Treatment for V. cholera
A
➢IV and oral fluids containing electrolytes
➢Antibiotics to reduce organisms
19
Q
V. parahaemolyticus facts
A
“Summer diarrhea” of Japan
Limited to areas with 1%-8% NaCl
➢Association with seafood
•Especially raw oysters
20
Q
Symptoms of V. parahaemolyticus
A
Develop after 24-48 hours after eating contaminated seafood
•Watery diarrhea and cramping
•Sometimes vomiting
•Usually no fever
21
Q
Virulence factors of V. parahaemolyticus
A
Heat-stabile hemolysin (Kanagawa phenomenon)
➢Using a high salt mannitol media containing erythrocytes
•Shows hemolysis
22
Q
Are V. parahaemolyticus urease positive
A
Yes!
23
Q
Where is V. vulnificus found
A
the Atlantic, Gulf, and Pacific coasts
24
Q
V. vulnificus is also known as
A
lactose positive vibrio
25
How do you get V. vulnificus
Acquire infection from raw or undercooked seafood
26
V. vulnificus FACTS
Develop septicemia
•Particularly in people with increased serum iron
➢Occasionally found in wounds
27
Least pathogenic of the Vibrio spp.
V. alginolyticus (rarely isolated)
28
Which anatomical site does V. alginolyticus normally infect and who are most at risk?
Mostly external sites
➢Ear infection, wounds, or burns
Sailors or those in constant contact with seawater
29
Most important vibrio spp. are
Cholera and parahaemolyticus
30
If clinical history indicate vibrios, what plate should you culture on and what are the results?
Use TCBS (Thiosulfate, citrate, bile salts, sucrose)
Results:
Yellow- V. cholerae, V. alginolyticus
Green- V. parahaemolyticus, most V. vulnificus
31
Which culture plate works best for growing vibrio and why?
BAP works well since it contains enough salt for most vibrios
32
How do most vibrio behave on MAC agars?
LACTOSE NEGATIVE (non fermenter)
***MacConkey agar is a selective and differential culture medium for bacteria. It is designed to selectively isolate Gram-negative and enteric bacteria and differentiate them based on lactose fermentation. Lactose fermenters turn red or pink on MacConkey agar, and nonfermenters do not change color
33
Which species of Vibrio are lactose positive on MAC agar
Vulnificus
34
TCBS plate knowledge
Thiosulfate–citrate–bile salts–sucrose agar, or TCBS agar, is a type of selective agar culture plate that is used in microbiology laboratories to isolate Vibrio species. TCBS agar is highly selective for the isolation of V. cholerae and V. parahaemolyticus as well as other Vibrio species.
35
AEROMONAS
36
Biochemistry, gram stain, and morphology of AEROMONAS
Oxidase +
Glucose Fermentation +
Gram (-) negative bacillus (rods) straight not curved like vibrios!!
37
Where are AEROMONAS found
Generally found in most environments similar to vibrios
➢Can be found in cold-blooded animals
•Snakes, lizards, newts
38
Clinical Infections of Aeromonas
Gastroenteritis
➢Various types of diarrhea
•Acute secretory diarrhea with vomiting
•Acute dysenteric form with blood and mucus
•Chronic diarrhea lasting more than 10 days
•Cholera-like disease with rice-water stools
•Traveler’s diarrhea
Wound infection due to:
➢Various injuries while working in tainted water
39
Use of leaches transmit which AEROMONAS and causes what?
➢A. hydrophila from:
•Use of leaches during plastic surgery to relieve congestion and swelling; Serious infections can result.
40
Which AEROMONAS causes septicemia.
Septicemia
➢A. veronii (sobria)
➢Immunocompromised, liver disease, traumatic injury
41
Which media does Aeoromonads grow on and and what type of hemolysis do they exhibit?
Beta-Hemolysis on SBA and Growth on MacConkey (fermenters).
42
Plesiomonas biochemistry and features
Oxidase positive
•Glucose fermenting
•Facultatively anaerobic
•Motile
43
Clinical Infections of Plesiomonas and how do you get it?
Gastroenteritis.
From raw or undercook seafood or tainted water
•Dysenteric form: One of these accompanied by fever and abdominal pain
* Subacute or chronic disease
44
Who are most at risk for Plesiomonas?
Vets and zookeepers especially for extra-intestinal Infection.
45
Which type of animals are Plesiomonas found in?
Cold blooded
46
Which test differentiates AEROMONAS from Enterobacters
AEROMONAS oxidase +
47
Confirmation test for Plesiomonas
Inositol fermentation
48
CAMPYLOBACTER
49
Biochemical features of Campylobacter
Oxidase +
Catalase +
Microaerophilic
Non-fermentative
50
Campylobacter are motile T/F
T. Darting motility
51
Are Campylobacter spore forming and what are their gram stain morphology?
No. Gram negative rods
*hallmark seagull wing appearance
52
Two important species of Campylobacter
C. jejuni and C. fetus
53
Clinical infections of C. Jejuni
➢Most common diarrheal illness worldwide
➢Diarrhea with mild abdominal pain
•Cramps and bloody diarrhea may follow with fever, chills, and rarely nausea and vomiting
➢Self-limiting lasting 2-6 days
•May remain carriers for several months
54
Which other Campylobacter species are similar to C. jejuni
C. coli and C. lari
55
Clinical infections of C. fetus
Most frequently isolated from blood cultures
•Immunocompromised and elderly patients
•Known to cause abortions in cattle, sheep, pigs
56
Heliobacter pylori
57
What does H. pylori cause
➢Major cause of chronic superficial gastritis
➢Damages tissue resulting in ulcers
Associated with type B gastritis
➢Causing gastric carcinoma (stomach cancer)
Produces a low-grade inflammatory response
58
Features of H. pylori
Does not invade the tissue but does live in the mucus covering the surface of the stomach
➢Produces urease to breakdown urea to ammonia and neutralize the stomach pH
59
Presumptive tests for H. pylori
Inoculating Christensen’s urea medium:
Rapid color change in 2 hours
Biopsy specimen of the stomach: Giemsa, gram, or silver stain
Urea breath test:
Drink 14C labeled urea
Degraded by urease activity releasing 14C CO2
60
How are Campylobacter and Heliobacter cultured
Campy blood agar plates:
Brucella agar base with 10% sheep RBCs
Skirrow media:
Blood agar base, lysed horse RBCs
Butzler or improved version V media:
Thioglycolate-based agar media, 10% sheep RBCs:
Grow plates in a microaerophilic, capnophilic atmosphere i.e.
➢5%-10% O2 and 10% CO2
61
Vibrio parahaemolyticus can be serotyped by means of it’s
Somatic and capsular antigens
62
The Vibrio cholera bio group El Tor is
Voges-Proskauer + and inhibited by polymixin B
63
Which species is the most frequently encountered species in the US? (regarding Vibrio)
V. parahaemolyticus
64
Which positive test distinguishes Vibrio spp. from Aeromonas?
String test
65
Which species is a psychrophilic aeromonad?
A. salmonicida
** Psychrophiles or cryophiles (adj. psychrophilic or cryophilic) are extremophilic organisms that are capable of growth and reproduction in low temperatures, ranging from −20 °C (−4 °F)[2] to 20 °C (68 °F)[3]. They have an optimal growth temperature at 15 °C (59 °F).[3] They are found in places that are permanently cold, such as the polar regions and the deep sea. They can be contrasted with thermophiles, which are organisms that thrive at unusually high temperatures, and mesophiles at intermediate temperatures.
66
Which species Is most frequently associated with diarrhea in the pediatric population and irritable bowel disease
A. caviae
67
Which of the following traits could be responsible for Aeromonas being overlooked in a stool culture?
Many AEROMONAS appear pink on MacConkey agar
68
Which of the following is not associated with Heliobacter pylori
Dysentery
69
Which of the following is a true statement regarding stool culture incubation at 42°C
Colon microbiota is inhibited
70
Which organism would be most likely given the following results?
Gram negative
Oxidase positive
Growth on thiosulfate, citrate, bile salts, sucrose agar TCBS
Positive lysine decarboxylase
Acid produced from salicin
V. fulnicus
71
A gram-negative rod, isolated from a stool specimen produces CLEAR call Lynn is on MacConkey, agar and yellow colonies on fire sulfate citrate bile salt, sucrose medium TCBS. The isolate is subcultured to a sheep blood agar plate with a O/129 disk. The isolate is sensitive to O/129 and is oxidase positive you should suspect?
V. cholera
72
Which of the following vibrio species would you expect to be most likely isolated from a blood culture?
V. vulnificus
73
Which of the following genera is typically microaerophilic
Heliobacter
74
Campylobacter jejuni is most noted for causing
Gastroenteritis
75
Which of the following is a risk factor for acquiring V. alginolyticus?
Fishing or swimming in ocean water
76
On oxidase positive, indole positive, beta-hemolytic, gram-negative, bacillus resistant to O/129, cannot grow in 6%NaCl broth and is Voges-Proskauer + is isolated from an adult stool culture. You should suspect?
A. hydrophila
77
Darting motility is a characteristic of
Campylobacter
78
Which of the following test is most helpful in differentiating C. Jejuni from Campylobacter spp.
Hippurate hydrolysis
79
When attempting to recover enteric, Campylobacter species which specimen media and incubation conditions should be used?
Appropriate specimens for the isolation of enteric Campylobacter are stool, samples and rectal swabs. Stool samples are preferred. Two categories of media are available for isolation: blood based and charcoal-based. A commonly used blood based medium is CAMPY Dash BAP. This is a Brucella agar-based medium with 10% sheep, red blood cells and a combination of antimicrobials. The addition of antimicrobial agents and incubation of the plates at 42°C inhibits normal fecal biota. Because the Campylobacters require oxygen at a concentration less than room air they must be incubated in a microaerophilic atmosphere.
80
What non-culture methods are used to diagnose H. Pylori
The most commonly used non-culture method for the diagnosis of H. Pylori is the noninvasive carbon 13 or carbon 14 labeled urea breath test. The patient receives an oral dose of labeled urea. Urease activity by H. pylori results in the formation of radioactive labeled CO2, which is absorbed into the bloodstream and then exhaled. Other non-culture methods include microscopic, examination of steam, gastric, tissue, direct fecal, antigen, detection, PCR assay, and determining urease activity of gastric biopsy material
