1. Vibrio, Aeromonas, Plesiomonas, Campylobacter, & Helicobacter
MLAB 2434 – Microbiology
Keri Brophy-Martinez

2. Vibrio species Habitat
Aquatic environments; fresh water, brackish and marine or salt water
Except for V. cholerae and V. mimicus, all are halophilic (salt-loving)
Tolerates alkaline environments
High pH toxic to other micro-organisms

3. Vibrio species General characteristics
Gram negative rods with polar, sheathed flagella in broth but peritrichous, unsheathed flagella on solid media
Rods are “curved” in clinical specimens, but small, straight rods after culture
Facultatively anaerobic
Possess O and H antigens
Allows serotyping

4. Vibrio species (cont’d)
Gram stain
Curved design

5. Vibrio species: Other Notable Characteristics
Most are oxidase positive and able to reduce nitrates to nitrites
All are susceptible to vibriostatic compound O/129
Ferments glucose
Most exhibit a mucoid “stringing” reaction when colonies mixed with sodium desoxycholate

6. Vibrio species: Clinical Infections
Vibrio species can be isolated from a variety of clinical specimens, including feces, wound, and blood
Major species are V. cholerae, V. parahaemolyticus, V. vulnificus, and V. alginolyticus

7. Vibrio species: Hints to Infection
Best indicators of Vibrio infection is presence of recognized factors
Recent consumption of raw seafood (especially oysters)
Recent immigration or foreign travel
Accidental trauma during contact with fresh or marine water
Medical History important to consider

8. Vibrio species (cont’d)

9. Vibrio cholerae V. cholerae O1 is causative agent of cholera
Also known as Asiatic cholera or epidemic cholera; particularly prevalent in India and Bangladesh
Also seen along the Gulf coast of the U.S.

10. Vibrio cholerae: Clinical Infections
Acute diarrheal disease
Spread through contaminated water, but also improperly preserved foods, including fish and seafood, milk, ice cream, and unpreserved meat
“Rice Water” stools
Caused by cholera toxin or choleragen
Loss of electrolytes & water
Dehydration is usual cause of death
Man is the only host

11. Vibrio cholerae: Identification Methods
Routine media
SBA
Medium-large colonies; smooth, opaque, irredescent with a greenish hue; might see α or β- hemolysis
MAC
NLF
Selective/Differential Media
TCBS (Thiosulfate citrate bile salts sucrose) agar
Yellow colonies indicate acid production
Positive result for V. cholerae

12. Vibrio parahaemolyticus
“Summer diarrhea” in Japan
Gastroenteritis
Most cases traced to recent consumption of raw, improperly cooked, seafood, especially oysters
Gastrointestinal symptoms are generally self-limiting; watery diarrhea, moderate cramps or vomiting
Skin infections associated with salt water exposure

13. Vibrio parahaemolyticus: Laboratory Diagnosis
Halophilic
Nonfermenters of lactose
Oxidase +
Indole +
Colonies are green on TCBS agar

14. Vibrio vulnificus
Found in marine environments along all coasts in the U.S.
Two categories of infections
Primary septicemia following consumption of contaminated shellfish, especially raw oysters; patients with liver dysfunction that results in increased levels of iron are predisposed
Wound infections following traumatic aquatic wound

15. Vibrio vulnificus: Wound Infections

16. Vibrio vulnificus: Laboratory Identification
MacConkey agar
Ferments lactose
TCBS agar
Non-sucrose fermenter
Appears as clear, blue-green
Oxidase +

17. Aeromonas
Ubiquitous, motile, curved gram-negative rods widely distributed in fresh and salt water environments
Isolated from produce and meat sources, contaminated food and water

18. Aeromonas: Infections
Gastroenteritis
Usually results from consumption of contaminated seafood, especially raw oysters or clams; illness usually self-limiting, except in very young and old populations
Wound infections
Resulting from traumatic water-related wound
Septicemia
Targets immunocompromised

19. Aeromonas: Skin Infections

20. Aeromonas: Colony morphology
SBA
large, round, raised, opaque colonies, often mucoid, can be translucent- white; Β-hemolytic
MAC
Ferments lactose
CIN (cefulodin, irgasan, novobiocin)
pink-centered colony

21. Aeromonas: Laboratory Diagnosis
Β- hemolytic colonies
Perform oxidase(+) and indole (+)
To distinguish between Vibrio use O/129
Vibrio= “S”
Aeromonas =“R”

22. Plesiomonas Habitat Warm and cold blooded animals are carriers
Found in soil and aquatic environments; particularly fish and estuarine waters of tropical and subtropical climates
Warm and cold blooded animals are carriers
Occupational exposure is the source of some infections;(fish handlers, vets, zookeepers)

23. Plesiomonas: Infections
Single species is P. shigelloides
Oxidase positive, glucose fermenting, facultatively anaerobic gram negative motile rods
Primarily causes gastroenteritis resulting from consumption of uncooked oysters or shrimp
Also causes bacteremia or meningitis in immunocompromised after animal exposure

24. Plesiomonas: Laboratory Identification
SBA: shiny, opaque, raised center with smooth edge; nonhemolytic
MAC: variable
TCBS
No growth
Laboratory Diagnosis
Oxidase positive
O/129 “S”

25. Campylobacter species
Most common cause of bacterial gastroenteritis worldwide is Campylobacter jejuni
Campylobacter infections attributed to direct contact with animals and indirectly through consumption of contaminated water and dairy products and improperly cooked poultry

26. Campylobacter species
Curved, gram-negative rods appearing as long spirals, S shapes, or seagull-wing shapes
Stains poorly
Microaerophilic and capnophilic environment for growth
Require selective media (CAMPY)
Incubation at 42o for 2-3 days
Exhibit “darting” motility

27. Campylobacter species
Colony Morphology
CAMPY( Brucella agar + 1% sheep rbcs + vancomycin, trimethoprim, polymyxin B, amphotericin B, cephalothin)
Colonies are moist, runny-looking and spreading, nonhemolytic
Will not grow on MAC
Laboratory Diagnosis
Darting motility in hanging drop
Oxidase positive
Catalase positive

28. Helicobacter pylori
Associated with gastric and duodenal ulcers, gastric malignancy, and gastritis
Transmission
Fecal-oral
Oral-oral
Zoonotic
The organism does not invade the gastric epithelium, but the host immune antibody response causes inflammation

29. Helicobacter pylori Tissue Biopsy 14C-labeled urea breath test
Detects urease production
14C-labeled urea breath test
Traditional culture generally not used

30. Helicobacter pylori

31. References
Engelkirk, P. G., & Duben-Engelkirk, J. (2008). Laboratory Diagnosis of Infectious Diseases: Essentials of Diagnostic Microbiology . Baltimore, MD: Lippincott Williams & Willkins.
Kiser, K. M., Payne, W. C., & Taff, T. (2011). Clinical Laboratory Microbiology: A Practical Approach . Upper Saddle River, NJ: Pearson Education, Inc.
Mahon, C. R., Lehman, D. C., & Manuselis, G. (2011). Textbook of Diagnostic Microbiology (4th ed.). Maryland Heights, MO: Saunders.