Other Fermenting GNRs Flashcards
**Compare and contrast the “other fermenters of glucose” and Enterobacterales based on their oxidase reactions, utilization of glucose, and Gram stain reactions and morphologies.
In addition,
Enterobacterales:
Oxidase
Utilization of glucose
GS morphology
Vibrio spp:
Oxidase
Utilization of glucose
GS morphology
Aeromonas spp:
Oxidase
Utilization of glucose
GS morphology
Plesiomonas spp:
Oxidase
Utilization of glucose
GS morphology
Campylobacter spp.:
Oxidase
Utilization of glucose
GS morphology
Helicobacter pylori:
Oxidase
Utilization of glucose
GS morphology
Enterobacterales
Oxidase: Negative
Utilization of glucose: Glucose fermenter
GS morphology: GNR - straight
Vibrio spp.
Oxidase: Positive
Utilization of glucose: Glucose fermenter
GS morphology: GNR - curved/comma shaped
Aeromonas spp.
Oxidase: Positive
Utilization of glucose: Glucose fermenter
GS morphology: GNR - straight
Plesiomonas spp.
Oxidase: Positive
Utilization of glucose: Glucose fermenter
GS morphology: GNR - straight
Campylobacter spp.
Oxidase: Positive
Utilization of glucose: Glucose fermenter
GS morphology: GNR - curved, S-shaped, seagull-wing
Helicobacter pylori
Oxidase: Positive
Utilization of glucose: Glucose fermenter
GS morphology: GNR - spiral shaped
**Describe the Gram stain reactions and any special morphological characteristics associated with the “other fermenters of glucose” organisms (straight rods, curved
rods, spiral rods, S-shaped or gull-winged, etc.).
Vibrio spp: GNR - curved/comma shaped
Aeromonas spp: GNR - straight
Plesiomonas spp: GNR - straight
Campylobacter spp: GNR - curved, S-shaped, seagull-wing
Helicobacter pylori: GNR - spiral shaped
**Identify each organism’s natural habitat.
Vibrio spp: aquatic habitats (coastal areas)
Aeromonas spp: global aquatic ecosystems
Plesiomonas spp: ubiquitous (soil, fresh/brackish water of tropical countries)
Campylobacter spp: GI tracts of a variety of animals (esp. chickens)
Helicobacter pylori: Human gastric muscosa
**Discuss the mediums of choice for isolating these organisms and their recommended incubation conditions. (ex. TCBS, 42°C incubation, etc.)
Vibrio spp: Thiosulfate Citrate Bile Salts Sucrose Agar (TCBS),
35 deg. C, ambient air
Aeromonas spp: CIN or SBA w/ ampicillin, 37 or 22 deg. C (species dependant)
Plesiomonas spp: SBA or Enteric Media
Campylobacter spp: Blood based - Campy-CVA or Charcoal based - Campylobacter selective media (CSM), 42 deg. C in microaerophilic conditions
Helicobacter pylori: Rarely isolated for culture
**Identify key biochemical reactions (ex: Kanagawa phenomenon and V. parahaemolyticus, P. shigelloides and LOA+, C. jejuni and hippurate hydrolysis, rapid urease/CLO test with H. pylori etc.) typical for the identification of the “other
fermenters of glucose” organisms.
Vibrio spp: String Test (presumptive)
-V. parahaemolyticus: Kanagawa phenomenon (beta hemolysis)
Aeromonas spp:
P. shigelloides: LOA+
C. jejuni: Hippurate hydrolysis+
H. pylori: rapid urease/CLO test+
Differentiate the types and symptoms of diarrhea
Osmotic: water retention (drawn away from tissues and into bowel)
Secretory: body releases water into bowel
Exudative: blood and pus in stool
Symptoms
Uncomplicated: frequent bowel movements
Complicated: fever and nausea
Differentiate “gastroenteritis” and “dysentery”
Gastroenteritis: inflammation of the stomach and intestines
Dysentery: infection of the intestines
Recognize the various genera that are considered “other fermenters of glucose”
Vibrio spp.
Aeromonas spp.
Plesiomonas spp.
Camplyobacter spp.
H. pylori
Define the following terms: halophilic, microaerophilic, capnophilic.
Halophilic: organisms that thrive in salty environment
Microaerophilic: organisms that require lower levels of oxygen in environment
Capnophilic: organisms that thrive in the presence of high concentrations of carbon dioxide
Outline the general collection and transportation guidelines for stool cultures
Stool or Rectal swab
Two-hour window (unpreserved)
Preservative:
1. Cary Blair
2. Buffered Glycerol Saline
3. Alkaline Peptone Water
4. Modified Stuart’s
Identify any special collection and transportation requirements of specific pathogens, such as Cary-Blair transport medium for Vibrio, biopsy for H. pylori, etc.
ALL organisms except for H. pylori
Stool/Feces
Two-hour window (unpreserved)
Preservative:
1. Cary Blair
2. Buffered Glycerol Saline (with the exception of Vibrio spp.)
3. Alkaline Peptone Water
4. Modified Stuart’s
Wounds
Sterile Swab
H. pylori: biopsy of stomach
