Vibrio: Gram Negative Bacteria - Essay Example

"Vibrio: Gram-Negative Bacteria" is a great example of a paper on infections.
Vibrio happens to be a kind of Gram-Negative bacteria that has a curved rod shape like a comma. Vibrio comprises of a few species such as vibrio Parhemolyticus, Vibrio Cholera which grows without salt, and Vibrio Vulnificus.  Such vibrio species may lead to diseases that are foodborne, mostly associated with the consumption of seafood that is undercooked. Specifically found within salty water, the species of vibrio are facultative anaebros which test oxidase-positive as well as do not form spores. All the members of its kind are motile as well as have polar flagella with enveloping tabular structures (Nicholas, Daniels, & Shafaie, 2000).

A). common contamination sources for Vibrio cholera include shellfish that is undercooked or raw, rice, ice, food that has been left out for a few hours at room temperature, and beverages as well as foods from street vendors. Uncooked vegetables and fruits are other contamination sources for the bacterium.

b). Common sources of contamination for Vibrio vulnificus include particular oysters as well as eating undercooked or raw shellfish (Nicholas, Daniels, & Shafaie, 2000).

The most significant pathogenic Vibrio, among the three vibrio SPP in the United States, is the Vibrio Vulnificus. This is due to vibrio vulnificus’ invasiveness as well as the high rates of fatality that are associated with the infection. It has come to be a leading cause of deaths associated with seafood within the US and it is a salt-loving organism with no known infectious dose (Nicholas, Daniels, & Shafaie, 2000).

Cholera toxin contains two subunit types i.e. subunit A and Subunit, where subunit A does contain A1 domain that involves an enzymatic active site, while domain A2 has a, α- helix tail. Subunit B has 5 chains forming the pentameric ring around the in structure central pore. The major vulnerable factor for the pathogen vibrio cholera and brings about key infection symptom. The enzymatic part has some globular area (CTA1) AS WELL AS a long helical field (CTA2). The CTX connects to the ADP- ribosylation factor 6(Arf6) making it possible for its catalytic activity.

The pre-enrichment step is performed during isolation of Vibrio spp due to the fact that it gives V. Vulnificus improved recovery on selective agars when compared to direct plating. There are four factors that are considered in choosing to include the pre-enrichment step: V. Vulnificus’ expected concentration within the samples if there is need for the quantitative or qualitative results, the cells’ conditions and the background flora’s level and composition.

 Characteristic colonial morphology on agar is shown below:

1. parahemolyticus – blue and green centred colonies
2. cholera – large yellow colonies
3. alginolyticus – mucoidal colonies that are large and yellow
4. harveyi/ v. ficheri – bluish-green to greyish-green colonies showing luminescence in dark