Question | Answer |
some of the general, common, microscopic morphologic characteristics of the Vibrios and other Gram neg organisms | gram-negative bacilli (rods), that are motile, oxidase positive, and are shaped like commas, “S” shaped, seagull wings, and spirals. |
Where are the organisms discussed in this chapter generally found? | ubiquitous in nature. |
What three major pathogenic genera of organisms were discussed in this chapter? | Vibrio, Campylobacter and Helicobacter |
What major clinical condition is associated with the following organisms that were discussed in your textbook: Helicobacter pylori and Campylobacter jejuni. | Diarrheal diseases |
Define halophilic bacteria | Salt loving |
What are the gram staining reaction and morphologic characteristics of the Vibrio spp.? | curves or comma-shaped gram-negative bacilli (rods). |
What are the general culture requirements for the Vibrio spp.? (media, atmosphere…) | most ordinary artificial media in ambient air. These organisms are oxidase positive and motile.
All species EXCEPT V. cholerae need NaCl to grow, so these organisms are considered “halophilic bacteria” = salt loving. |
With what disease is Vibrio cholerae associated? | cholera |
Where can Vibrio cholerae be found? What of the other Vibrio spp.? | V. cholerae is found in fresh water, the other Vibrios are found in salt water, shellfish, other marine animals and plankton. |
Is Vibrio cholerae a halophilic or nonhalophilic organism? | V. cholerae is a nonhalophilic bacterium. |
What virulence factor(s) possessed by the Vibrios are used to classify these organisms? | Vibrios possess the virulence factors: H and O antigens |
Of the virulence factors listed on the last card, which serogroup do the pathogenic Vibrio spp. (Vibrio cholerae) belong? | 01 serogroup |
How is Vibrio cholerae transmitted to humans? | These organisms are transmitted by food and water, although flies and person-to-person contact with infected individuals has also been implicated |
What is characteristic of the diarrheal disease caused by Vibrio cholerae? | Characteristic of this disease is a rice-water stool. This type of diarrhea is colorless, odorless and contains flecks of mucous, many Vibrios, and epithelial cells. The mucous flecks are what give the stools the appearance of rice water. |
What types of infections are associated with Vibrio parahemolyticus? | V. parahemolyticus can cause acute gastroenteritis that resembles cholera |
How is infection with Vibrio parahemolyticus transmitted to humans? | Ingestion of raw seafood |
What types of infections are associated with Vibrio vulnificus? | V. vulnificus most often appears as skin lesions after handling shellfish or other marine animals or after laceration with seashells. Diarrhea due to this organism can occur after eating raw or undercooked seafood, especially oysters. |
How are infections with Vibrio vulnificus transmitted to humans? | handling shellfish or other marine animals or after laceration with seashells |
What type of specimens can be collected for the isolation of Vibrio spp.?
Do the organisms require any special handling, transporting… | Stool samples,samples from infected wounds suspected of infection with the Vibrios are the usual specimens.To prepare and send these organisms to reference lab,Cary-Blair transport media is used,can be refrigerated until they are sent to a reference lab. |
How are cases of Vibrio infection treated? | Rehydration of the patient is the most important part of treatment for these Vibrio diseases. Then if indicated, treatment with antibiotics would be next. |
What are the gram stain reaction and morphologic characteristic of the Helicobacter spp.? | Helicobacter is a curved, spiral-shaped, gram negative bacilli (rod) that is distributed ubiquitously in nature |
How are infections with Helicobacter transmitted to humans? | No specific route of transmission has been found for this organism, but it is most likely a person-to-person transmission. |
What type of motility do the Helicobacter exhibit? | It moves in a rapid corkscrew motion |
What types of clinical conditions are Helicobacter pylori associated? | This organism is thought to play a significant role in the development of peptic ulcers and the development of gastric carcinomas (cancers of the stomach) |
How is it that Helicobacter pylori is able to survive in the gastric mucosa? | H.pylori can produce an enzyme called urease that can breakdown the metabolic product “urea”, producing large amount of ammonia (which can neutralize “acid” compounds—like the acid of the stomach).This ammonia shields the organism,and allows growths |
How is it that Helicobacter pylori is able to survive in the gastric mucosa? | H.pylori also produces a 2nd enzyme called mucinase that allows the organism to penetrate the mucous layer to the epithelial side of the stomach where the pH is more neutral. The organism can then continue to multiply and grow, |
How is it that Helicobacter pylori is able to survive in the gastric mucosa? | H.pylori lastly can produce a 3rd enzyme: protease that modifies the mucous layer so that acids can no longer diffuse through it as easily. This way the stomach becomes less acidic, and this helps the organism to survive. |
What types of specimens are collected for the isolation of Helicobacter spp.? | Biopsy specimens |
What are the gram stain reaction and morphologic characteristics of the Campylobacter spp.? | Campylobacter is a small, curved gram-negative bacilli (rod) that is arranged quite often in “S” shapes or “seagull wing” shapes. They are motile organisms and they like increased CO2 environments—(almost anaerobic environments) |
What types of infections are caused by Campylobacter spp? | Gastroenteritis is the most common infection seen with this organism. |
How are infections with Campylobacter spp. transmitted to humans? | By contact with infected animals, drinking unpasteurized milk, and oral/anal sexual activity |
What types of virulence factors do the Campylobacter spp. possess that allows them to cause infections in humans? | Campylobacter spp. appear to posses several virulence factors, including a cytotoxin (cell killer), an enterotoxin (intestinal cell killer), a cytotonic (cell inhibitor) and an invasive ability, all which help the organism to survive |
What are the incubation and culture requirements of the Campylobacter spp.? Do they require any special transporting, processing or media to be isolated? | all specimens for Campylobacter are promptly cultured when received in the lab.Cary-Blair transport medium.best viewed with dark field or phase-contrast microscopy.Selective media like Skirrow’s media,Campy BAP are most common,42C in increased CO2 |