Transcript Vibrio, Aeromonas, Plesiomonas, Campylobacter, & Helicobacter

Vibrio, Aeromonas,
Plesiomonas,
Campylobacter, &
Helicobacter
MLAB 2434 – Microbiology
Keri Brophy-Martinez
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
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
Vibrio species (cont’d)
Gram stain
Curved design
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
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

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
Vibrio species (cont’d)
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.

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
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
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


Vibrio parahaemolyticus:
Laboratory Diagnosis
Halophilic
 Nonfermenters of lactose
 Oxidase +
 Indole +
 Colonies are green on TCBS agar

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
Vibrio vulnificus:
Wound Infections
Vibrio vulnificus:
Laboratory Identification

MacConkey agar


Ferments lactose
TCBS agar
Non-sucrose fermenter
 Appears as clear, blue-green


Oxidase +
Aeromonas
Ubiquitous, motile, curved gramnegative rods widely distributed in
fresh and salt water environments
 Isolated from produce and meat
sources, contaminated food and
water

Aeromonas:
Infections

Gastroenteritis


Wound infections


Usually results from consumption of
contaminated seafood, especially raw
oysters or clams; illness usually selflimiting, except in very young and old
populations
Resulting from traumatic water-related
wound
Septicemia

Targets immunocompromised
Aeromonas:
Skin Infections
Aeromonas:
Colony morphology

SBA


MAC


large, round, raised, opaque
colonies, often mucoid, can be
translucent- white; Β-hemolytic
Ferments lactose
CIN (cefulodin, irgasan, novobiocin)

pink-centered colony
Aeromonas:
Laboratory Diagnosis

Β- hemolytic colonies
• Perform oxidase(+) and indole (+)
• To distinguish between Vibrio use
O/129
• Vibrio= “S”
• Aeromonas =“R”
Plesiomonas

Habitat



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)
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
Plesiomonas:
Laboratory Identification
SBA: shiny, opaque, raised center
with smooth edge; nonhemolytic
 MAC: variable
 TCBS



No growth
Laboratory Diagnosis
Oxidase positive
 O/129 “S”

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
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
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


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
Helicobacter pylori

Tissue Biopsy

Detects urease production
 14C-labeled

urea breath test
Traditional culture generally not
used
Helicobacter pylori
References







Engelkirk, P. G., & Duben-Engelkirk, J. (2008). Laboratory
Diagnosis of Infectious Diseases: Essentials of Diagnostic
Microbiology . Baltimore, MD: Lippincott Williams &
Willkins.
http://explow.com/Vibrio_parahaemolyticus
http://www.pharmaceuticaltechnology.com/projects/sbl_vaccin/sbl_vaccin4.html
http://ridingrickshaw.wordpress.com/2011/08/21/cholera-cotsbeware-of-graphic-pictures/
http://safeoysters.org/medical/symptoms.html
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.