Vibrio, Aeromonas, Plesiomonas, and Campylobacter Flashcards Preview

Microbiology > Vibrio, Aeromonas, Plesiomonas, and Campylobacter > Flashcards

Flashcards in Vibrio, Aeromonas, Plesiomonas, and Campylobacter Deck (33):
1

- found in water
- usually involved in epidemics
- causative agent of cholera

Vibrio species

2

rice water stool, large loss of electrolytes, dehydration and hypovolemic shock, diarrhea caused by toxin, fecal-oral transmission

cholera

3

rise in isolation of Vibrio

associated with water and water areas (seafood, coastal regions, tsunamis, etc.)

4

- facultative anaerobes, straight rods (can be curved on Gram stain)
- catalase and oxidase positive, reduce nitrate to nitrite (except V. metschnikovii)
- susceptible to Vibriostat disk (0/129), positive string test, halophilic

Vibrio

5

Vibriostat disk (0/129)

0/129 = 2,4-diamino-6,7-diisopropylpteridine
susceptibility differentiates Vibrio from Aeromonas

6

String test

emulsify 2-3 colonies in a drop of sodium desoxycholate
colonies can be picked up like a string

7

Vibrio Antigens

H antigen - all have it
O antigen - V. cholerae

8

O1 antigen

- O1, O139 are associated with epidemics (classic and El Tor)
- Non-O1 are milder, don't produce cholera toxin

9

Cholera infection

- bacteria colonize small intestine and release toxin
- cholera toxin causes diarrhea (toxin has A and B subunits) which causes electrolyte and water loss

10

Treatment for cholera

IV fluids and electrolytes, antibiotics if significant infection

11

Vibrio parahaemolyticus

- cause of "Summer diarrhea of Japan"; associated with seafood; causes diarrhea and cramping
- heat-stable hemolysin (Kanagawa phenomenon); some strains are urease positive

12

Vibrio vulnificus

- atlantic, gulf and pacific coasts; from raw or undercooked seafood or wounds
- known as "lactose positive vibrio"; causes septicemia (serious infection)

13

Vibrio alginolyticus

mimics cholera; most frequently isolated; least pathogenic; mostly external (ears, wounds, burns)

14

Vibrio specimen collection

aspirates or tissue

15

Vibrio culturing

- greenish colonies on SBA
- BAP because of salt
- Mac (NLF except V. vulnificus)
- TCBS (thiosulfate, citrate, bile salts, sucrose)

16

TCBS (color change)

yellow (cholera, alginolycticus)
green (parahaemolyticus, vulnificus)

17

Vibrio susceptibility

susceptible to doxycycline and ciprofloxacin

18

- oxidase positive, glucose fermenting
- straight gram-negative rods
- mesophilic and psychophilic groups
- infection associated with contaminated water

Aeromonas

19

Mesophilic Aeromonas

motile
A. hydrophila complex
A. veronii complex
A. caviae complex

20

Psychrophilic Aeromonas

A. salmonicida; non-motile; grows best at 22-25C

21

Aeromonas (clinical infections)

- Gastroenteritits (contaminated water, Traveler's diarrhea)
- Wound infection (A. hydrophila)
- Septicemia (A. veronii -liver disease, ICP most susceptible)
- osteomyelitis, pelvic abscesses, otitis, cystitis, etc.

22

Aeromonas identification

beta hemolytic
oxidase positive
indole positive
string test negative
resistant to Vibriostat disk
grow well in 0% NaCl
inositol negative

23

Aeromonas antimicrobial susceptibility

susceptible to trimethoprim, sulfamethoxazole (SMZ), aminoglycosides and quinolones

24

Plesiomonas

- gram-negative rods (part of enterobacteriaceae)
- similar to Shigella, but lower virulence
- soil and aquatic environments

25

Plesiomonas shigelloides

oxidase positive
ferments glucose
facultative anaerobe
motile (polar flagella)
susceptible to Vibriostat disk

26

Plesiomonas shigelloides (clinical infections)

- gastroenteritis (undercooked seafood - diarrhea, subacute or chronic)
- extraintestinal infections (found in snakes, lizards, newts - zoo keepers at risk)
- mostly self-limiting

27

Plesiomonas shigelloides (culturing)

- grow quickly on most media
- nonhemolytic colonies with raised center
- inositol brilliant green bile salts (IBB) - white or pink

28

Differentiating Plesiomonas shigelloides

- oxidase + rules out Enterobacteriaceae
- sensitivity to Vibriostat disk rules out Aeromonas
- no growth in high salt rules out Vibrio
- Inositol fermentation confirms Plesiomonas
- lysine and ornithine decarboxylase positive
- arginine dihydrolase positive

29

Campylobacter

- microaerophilic (5% O2)
- non-spore forming rods (seagull-wing shape)
- oxidase and catalase +
- darting motility
- nonfermentative

30

Campylobacter (clinical infections)

- transmission by contact with animals, contaminated food/water, person to person
- C. jejuni: #1 cause of diarrhea world-wide, self-limiting, associated with Guillain-Barre syndrome
- C. fetus: isolated from blood, causes abortion in animals

31

Helicobacter pylori

- colonizes 20-40% of adults; causes gastritis (type B)
- lives in mucus covering of stomach (doesn't invade tissue)
- produces urease (urea --> ammonia) to neutralize stomach acid
- causes gastric carcinoma (stomach cancer)

32

Culturing Campylobacter and Helicobacter

- Campy blood agar plates (10% sheep blood)
- Skirrow media (lysed horse RBC's)
- V media
- grow in capnophilic or microphilic environment
- organism exhibits corkscrew motility

33

Presumptive ID of Helicobacter

- Inoculate Christensen's urea medium - (rapid color change in 2 hours)
- biopsy stomach specimen
- urea breath test