Chapter 21 Vibrio, Aeromonas, Plesiomonas, & Campylobacter

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Chapter 21 Vibrio, Aeromonas, Plesiomonas,
Campylobacter

• MLAB 2434 Clinical Microbiology
• Keri Brophy-Martinez

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Chapter 21 Vibrio species

• Habitat
• Aquatic environments fresh water, brackish and
  marine or salt water

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Chapter 21 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
• Asporogenous ( no reproduction by spores)

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Vibrio species (contd)

• Gram stain of V. cholerae showing slightly curved
  rods

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Vibrio species (contd)

• 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
• Except for V. cholerae and V. mimicus, all are
  halophilic (salt-loving)
• Some strains can be serotyped

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Vibrio species (contd)

• 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

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Vibrio species (contd)

• Best indicators of Vibrio infection is presence
  of recognized factors
• Recent consumption of raw seafood (especially
  oysters)
• Recent immigration or foreign travel
• Gastroenteritis with cholera-like or rice-water
  stools
• Accidental trauma during contact with fresh or
  marine water
• Medical History important to consider

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Vibrio species (contd)
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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.

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Vibrio cholerae (contd)

• Clinical Infection
• 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
• Dehydration is usual cause of death
• Man is the only host

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Vibrio cholerae (contd)

• Colony morphology
• SBA/CA
• Medium-large colonies smooth, opaque,
  irredescent with a greenish hue might see a or
  ß- hemolysis
• MAC
• NLF

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Vibrio cholerae (contd)

• V. cholerae on TCBS (thiosulfate citrate bile
  salts sucrose) agar Colonies are yellow
• TCBS is specific for V. cholerae and
  parahaemolyticus.

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Vibrio parahaemolyticus

• Second most common Vibrio species involved in
  gastroenteritis
• Summer diarrhea in Japan
• Most cases traced to recent consumption of raw,
  improperly cooked, or recontaminated seafood,
  especially oysters

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Vibrio parahaemolyticus (contd)

• Gastrointestinal symptoms are generally
  self-limiting watery diarrhea, moderate cramps
  or vomiting

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Vibrio parahaemolyticus

• Laboratory Diagnosis
• Colonies are green on TCBS agar
• Halophilic
• Nonfermenters of lactose
• Oxidase
• Indole

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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
• http//safeoysters.org/medical/symptoms.htm

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Vibrio vulnificus

• Wound infections with V. vulnificus

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Vibrio vulnificus

• Minor wound infection with V. vulnificus

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Vibrio vulnificus

• Laboratory Diagnosis
• Isolate on TCBS agar
• Oxidase
• Treatment
• Tetracycline

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Chapter 21 - Aeromonas

• Ubiquitous oxidase-positive, glucose-fermenting,
  motile, curved gram-negative rods widely
  distributed in fresh and salt water environments
• Isolated from produce and meat sources
• Seasonal pattern of isolation May- October

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Aeromonas (contd)

• Aeromonas 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 usually from A. hydrophilia
  resulting from traumatic water-related wound
• Septicemia targets immunocompromised

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Aeromonas (contd)

• Aeromonas hydrophilia wound infections, after
  exposure to contaminated salt water

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Aeromonas (contd)

• Colony morphology
• SBA large, round, raised, opaque colonies, often
  mucoid, can be translucent- white ?-hemolytic
• MAC LP
• CIN (cefulodin, irgasan, novobiocin) pink

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Aeromonas (contd)

• Laboratory Diagnosis
• ?- hemolytic colonies
• Perform oxidase() and indole ()
• To distinguish between Vibrio use O/129
• Vibrio S
• Aeromonas R
• Treatment
• Trimethoprim sufamethoxazole, aminoglycosides,
  quinolones

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Chapter 21 - 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)

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Chapter 21 - Plesiomonas

• 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

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Chapter 21 - Plesiomonas

• Colony Morphology
• SBA shiny, opaque, raised center with smooth
  edge nonhemolytic
• MAC LP
• Laboratory Diagnosis
• Oxidase positive
• O/129 S

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Chapter 21 - Plesiomonas

• Treatment
• Self-limited
• If antibiotics needed quinolones,
  cephalosporins, carbapenems

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Chapter 21 Campylobacter and Campylobacter-like
species

• Campylobacter
• Curved, gram-negative rods appearing as long
  spirals, S shapes, or seagull-wing shapes stains
  poorly, so safranin counterstaining should be
  extended to 2 to 3 minutes
• Exhibit darting motility
• Require selective media (CAMPY)
• Microaerophilic and capnophilic environment for
  growth
• Incubation at 42o

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Campylobacter species (contd)

• 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 may also be transmitted sexually

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Campylobacter species (contd)

• 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, and catalase positive

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Campylobacter species (contd)

• C. fetus on Campy plate C. jejuni shown on gram
  stain

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Chapter 21 - Helicobacter pylori

• Strongly associated with gastric and duodenal
  ulcers low grade inflammatory process
• The organism does not invade the gastric
  epithelium, but the host immune antibody response
  causes inflammation
• Can be cultured, but it is so strongly urease
  positive that presumptive identification often
  made from biopsy specimen by testing for urease
  production
• 14C-labeled urea breath test

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Chapter 21- Helicobacter pylori (contd)