non - pathogenic GIT

• Genus


  • Aliivibrio
  • Vibrio
  • Grimontia
  • Catenococcus
  • Photobacterium
  • Listonella
  • Salinivibrio
  • Enterovibrio
• Vibrionaceae


  • Inhabitants of fresh or salt water
  • Most bioluminescent bacteria belongs in this family
  • Gram negative
  • Facultative anaerobes
  • Can ferment sugar
  • Oxidase positive
  • Has one or more flagella, which are generally polar
  • Synthesize tetrodotoxin (TTX) - ancient marine alkaloid and powerful neurotoxin
• Vibrio spp.


  • Gram negative, short, curved and non-spore forming (asporegenous) comma-shaped or curved bacillus
  • Facultatively anaerobic
  • Motile through monotrichious organisms except V. metschnikovii
  • Isolated from: algae, plankton, fish and shellfish
  • Found in brackish water, marine water, or salt water
  • Halophilic (high concentration of salt): except V. cholerae and V. mimicus
• Brackish Water - Most Vibrio infections occur during summer and fall when surface waters are relatively warm
• Vibrio culture


  • Colonies are smooth, opaque and iridescent with greenish hue on CAP
  • Colonies are NLF (except: V. vulnificus, w/c is lactose fermenter) on MAC
  • Colonies are Alpha or Beta hemolytic on BAP
• Vibrio biochemical test

  • Catalase and Oxidase positive except V. metschnikovii
  • Glucose fermenters
  • Non-lactose fermenters except V. vulnificus
  • Oxidase (+) and reduce nitrates to nitrite except for V. metschnikovii
• Vibrio cholerae


  • Brackish or marine water habitat
  • Not a normal flora
• Vibrio cholerae transmission


  1. Ingestion of contaminated water or seafood, shellfish, milk or ice cream

  2. Contact on open wound
• Vibrio cholerae virulence factors


  • Cholera toxin (CT) - causes mucosal cells to hyper secrete water and electrolytes into lumen, does not require to penetrate the lumen
  • Accessory cholera toxin (Ace)
  • Zonula occludens toxin (Zot)
  • O1 and O139 somatic antigens (2 of 3 major subgroups)
  • TCP pili - for attachment for release of cholera toxin
  • Mucinase - penetration of mucus membrane
  • Motility and chemotaxis - mediate distribution of cells
• Rice water stool


  Defecate usually 10-30 times per day: can lead to hypotension and later on, can be life-threatening
• Somatic Antigens O1 And O139


  Strains Capable of Epidemic and Pandemic
• Non-O1 And Non-O139


  Non-Epidemic and Extraintestinal
• Haiti Earthquake was Fecal-Oral
• 603,264 - nasiraan ng bahay
• 7436 - infected w/cholera
• Vibrio cholerae organism

  • Fragile but has dormant stages that survive long
  • Dormant stages are viable but nonculturable if in Brackish Water or Saltwater
• Vibrio cholerae manifestations

  • Profuse watery diarrhea (rice watery stool) leading to hypotension/low blood pressure
  • Epidemic and Pandemic if somatic antigens are present
  • Extraintestinal infection such as wound, RT, UT and CNS
• Vibrio cholerae laboratory diagnosis

  • Feces is preferrable, but may use rectal swab on acute phase
  • If Vibrio spp is suspected, use Cary-Blair medium
  • Buffered glycerol saline is toxic for vibrios
  • Rapid darting or shooting-star motility, best if dark-field microscopy is used
  • Broth: alkaline peptone water (pH of 8.4)
  • Thiosulfate-citrate-bile salts-sucrose agar (TBCS): has 1% NaCl and bile salts that inhibits gram positive and sucrose for differentiation
  • Sucrose fermenter - Yellow colonies
  • Non-sucrose fermenter - Green colonies
  • pH indicator: Thymol blue and parathymol blue; starting pH is 8.6 - inhibits other intestinal flora
  • String test positive
• Vibrio chrom agar

  • V. vulnificus - blue
  • V. parahaemolyticus - pink
• How to identify Vibrio cholerae

  1. Check the stool consistency

  2. Activity and recent food intake

  3. Biochemical testing (Enterobacteriaceae VS. Vibrio spp.)

  4. Serological Serotyping

  5. Nucleic Acid-Based Testing
• Inuba and Ogawa


  Common in the PH
• Vibrio cholerae biotype (biovars)

  • Classical - Red Cell Hemolysis (-), Vogue Proskauer (-), Polymyxin B S

  El Tor - Red Cell Hemolysis (+), Vogue Proskauer (+), Polymyxin B R, Agglutination w/ Chicken RBCs (+)
• Vibrio parahaemolyticus


  • Second most common Vibrio species associated with gastroenteritis
  • Etiologic agent of "summer diarrhea" in Japan
  • Leading cause of pandemic: V. parahaemolyticus serotypes O3:K6
  • Ingestion of contaminated seafood: oysters, scallops, crabs, lobsters, shrimps and sardines
  • Heat stable hemolysin - lyses RBC
  • May use Wagatsuma agar (high mannitol content)
  • Non-sucrose fermenter: green colony on TCBS
• Vibrio vulnificus

  • "Lactose positive" Vibrio species
  • Uses iron for growth; people with elevated iron levels are at higher risk for infection
  • Ingestion of contaminated food: oysters and fish
  • Lactose fermenter
  • Non-sucrose fermenter: green colony on TCBS
  • No special consideration
• Vibrio alginolyticus


  • Ingestion of contaminated food: oysters and fish
  • Unknown virulence factors
  • No special consideration
• Grimontia hollisae


  • Formerly V. hollisae
  • Found naturally in marine environments
  • Ingestion of contaminated food: oysters and fish
  • Unknown virulence factors
  • Only pathogenic species in the Vibrionaceae family that DO NOT grow on thiosulfate-citrate-bile salts-sucrose agar (TCBS)
• Photobacterium damselae


  • Ulcerative lesions in skin and hemorrhage in mouth, eyes and muscles
  • One of pathogenic members of this family which is originally found in damselfish in 1981
  • Digestion of raw seafood and urinary tract infection after being exposed to seawater
  • Cytolysin
  • Gram negative
  • Facultative anaerobe
  • With flagella
• Signs of infection on fishes
• Genus


  • Aeromonas
  • Oceanimonas
  • Oceanisphaera
  • Pseudaeromonas
  • Tolumonas
  • Zobellella
• Aeromonadaceae


  • Gram-negative bacteria, rods or bacilli
  • Facultative anaerobe
  • Mostly found in estuarine waters and fresh water, also in soil and sewage
  • Some are pathogenic for humans and other animals such as fishes and frogs
• Aeromonas spp.


  • Two groups: Mesophilic (A. hydrophila, A. veronii complex, A. caviae complex) and Psychrophilic (A. salmonicida)
  • Habitat: Found in fresh, estuarine and chlorinated waters
  • Motile with single polar flagellum
  • Facultatively anaerobe
  • Manifestation: Traveler's Diarrhea, Septicemia, meningitis, keratitis and wound infections
  • Worst Manifestation: Necrotizing Fasciitis
• Aeromonas laboratory diagnosis

  • Gram negative; curved bacillus
  • Glucose fermenter
  • Grows at 4C to 42C
  • Oxidase (+) and Catalase (+)
  • BAP: large, round, raised, white and opaque
  • MAC: pink color (LF)
  • CIN: "bull's eye" appearance
• Differentiating Vibrio and Aeromonas

  1. Biochemical Test

  2. String test

  3. Activity and Recent Food Intake
• Genus


  • Campylobacter
  • Sulfurospirillum
  • Arcobacter
• Campylobacteraceae


  • Motile
  • Gram-negative curved, occasionally straight, rods which may appear as spirals
  • Non-spore forming
• Campylobacter spp.

  • Habitat: contaminated water, poultry and dairy products; zoonotic disease
  • Motile with single polar flagellum
  • Facultatively anaerobe
  • Does not multiply in food unlike Salmonella and Staph
  • Most recognized antecedent cause of Guillain-Barré syndrome
  • Also an animal pathogen (cattle and swine) that causes sterility and abortion
• Campylobacter species


  • Campylobacter jejuni
  • Campylobacter coli
  • and 15 other species and 6 subspecies
• Campylobacter manifestations


  • Febrile systemic disease
  • Periodontal disease
  • Gastroenteritis (in C. jejuni only)
• Campylobacter laboratory diagnosis


  • Faintly staining, Gram (-) , small, curved or S-shaped rods
  • Old culture: coccobacilli
  • Enteric campylobacters: long spirals or are seagull wing-shaped
  • Motile: Single polar flagellum and oxidase (+)
  • Non-spore forming
  • Hanging drop prep: darting motility
  • Counterstain - Carbolfuchsin; If safranin - 2-3 minutes
  • Optimal growth for C. jejuni and C. coli: 42-43°C; the rest at 37°C
  • Campy-BAP, Butzler agar, Modified Skirrow's medium and charcoal cefoperazone desoxycholate agar (CCDA)
  • Microaerophilic (5-10%), except for C. rectus and C. curvus, which are both strictly anaerobes
  • Capnophilic
• Arcobacter spp.


  • Habitat: untreated water, chicken, pork, lamb and poultry
  • Manifestation: Gastroenteritis, bacteremia, endocarditis, peritonitis
  • Collection: No special requirement; feces, rectal swab & blood
  • Microscopy: Gram negative bacilli/rods; catalase + Oxidase +
  • Culture: Campy-CVA (Cefeporazone, vancomycin and amphotericin B)