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 gram-negative rods widely distributed in fresh and salt water environments Isolated from produce and meat sources, contaminated food and water

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

Aeromonas: Skin Infections

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

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

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)

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 14C-labeled urea breath test 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.pharmaceutical-technology.com/projects/sbl_vaccin/sbl_vaccin4.html http://ridingrickshaw.wordpress.com/2011/08/21/cholera-cots-beware-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.