Gastrointestinal Pathogens Quiz

V. cincinnatiensis and Grimontii hollisae have very poor growth in TCBS.

Vibrio is a genus of bacteria that can have various shapes, including comma-shaped, straight rods, and pleomorphic forms. These bacteria are also Gram-negative, meaning they do not retain the crystal violet stain in the Gram staining process. Therefore, the correct answers for this question are comma-shaped, straight rods, pleomorphic, and Gram-negative rods.

Aeromonas can have rounded ends or appear as coccobacilli, meaning they have a shape that is between a rod and a sphere. They can occur singly, in pairs, or in short chains. Additionally, Aeromonas are Gram-negative rods, which means they stain pink when subjected to the Gram stain test.

Vibrio is a genus of bacteria that includes both susceptible and resistant strains to Agent O/129. However, the given information states that Vibrio is susceptible to Agent O/129. Additionally, Vibrio is known to test positive in the string test, which is a diagnostic test used to identify certain bacteria. Moreover, Vibrio is capable of growing in a high concentration of salt, specifically 6% NaCl. Therefore, the correct answers are Agent O/129 susceptible, String test positive, and Growth in 6% NaCl.

Aeromonas is resistant to Agent O/129, as mentioned in the answer. This means that it is not affected by or susceptible to Agent O/129. Additionally, the String test is negative for Aeromonas, indicating that it does not produce strings when tested. Lastly, Aeromonas does not grow in 6% NaCl, as stated in the answer.

0.05% sodium deoxycholate is the correct answer because it is a reagent that can lyse cells and release nucleic acid material. Sodium deoxycholate is a bile salt that disrupts the cell membrane, causing the cells to break open and release their contents. The concentration of 0.05% is sufficient to achieve cell lysis without being too harsh and damaging the nucleic acids. The other reagents listed, such as 0.5% sodium deoxycholate, sodium taurocholate, and 0.5% deoxycholic acid, may also have the ability to lyse cells, but they are not the best options for releasing nucleic acid material.

DNA is the correct answer because DNA is a viscous substance that can form into a mucoid "string" when teased. DNA is a long, coiled molecule that carries the genetic information in all living organisms. When DNA is extracted and stretched, it can form a string-like structure due to its double helix shape. This property of DNA allows scientists to manipulate and study it in the laboratory. mRNA, tRNA, and rRNA are all types of RNA molecules that play different roles in protein synthesis and are not known to exhibit the same viscous and string-like properties as DNA.

V. cholerae and V. mimicus can grow in 0% NaCl because they are both halophilic bacteria, meaning they can tolerate and grow in environments with low salt concentrations.

Photobacterium damsela is the correct answer because it is the only organism listed that is known to be indole negative. Indole is a compound produced by certain bacteria during the breakdown of tryptophan, and the indole test is commonly used to differentiate between bacterial species. In this case, all the other organisms listed are Vibrio species, which are typically indole positive. Therefore, Photobacterium damsela is the only indole negative organism among the options provided.

V. furnissli is the correct answer because it is known to produce gas from glucose.

V. vulnificus is a delayed/late lactose utilizer because it takes longer to utilize lactose compared to the other organisms listed.

The organisms listed, V. cholerae, V. mimicus, V. vulnificus, V. parahaemolyticus, V. alginolyticus, and V. harveyi, are all positive for Lysine decarboxylase.

V. cholerae, V. mimicus, and V. metschnikovii are the organisms listed that have variable growth in 6% NaCl. This means that their growth can vary in the presence of a 6% NaCl (sodium chloride) solution. The other organisms listed may not exhibit variable growth in this specific condition.

Chromobacterium violaceum is the only organism listed that is OXIDASE variable. This means that it may or may not produce the enzyme oxidase, which is used in the oxidase test to identify certain bacteria. The other organisms listed are not OXIDASE variable, meaning they consistently produce the oxidase enzyme.

The organisms listed in the answer, A. jandaei (A. veronii complex), A. veronii biovar sobria, and A. veronii biovar veronii, are all capable of producing gas from glucose. Gas production from glucose is a characteristic used in microbiology to differentiate between different bacterial species. Therefore, these organisms have the ability to ferment glucose and produce gas as a byproduct.

The organisms A. caviae complex and A. veronii biovar veronii are positive for esculin hydrolysis.

The organisms listed in the answer (A. caviae complex, A. veronii biovar sobria, A. veronii biovar veronii) are capable of fermenting sucrose. This means that they can break down sucrose into simpler compounds, such as glucose and fructose, through a process called fermentation. Fermentation of sucrose is a common metabolic activity in certain bacteria, allowing them to obtain energy and produce byproducts. Chromobacterium violaceum, on the other hand, does not ferment sucrose.

The organisms listed, A. caviae complex and Chromobacterium violaceum, are lysine decarboxylase (negative). This means that they do not have the ability to decarboxylate lysine, which is a process that involves removing a carboxyl group from lysine to produce cadaverine.

A. veronii biovar veronii is the correct answer because it belongs to the A. veronii complex and is known to be negative for arginine dihydrolase.

The correct answer is A. veronii biovar veronii because it is the only organism listed that is positive for ornithine decarboxylase.

The organisms listed that have GREEN colonies in TCBS are V. mimicus, V. vulnificus, V. parahaemolyticus, Photobacterium damsela, and Grimontii hollisae.

The organisms V. cholerae, V. alginolyticus, V. cincinnatiensis, V. fluvialis, V. harveyi, V. metschnikovii, and V. furnissli have yellow colonies in TCBS.

Campylobacter exhibits darting motility. This means that the bacteria move rapidly in a jerky, darting motion. This type of motility allows Campylobacter to navigate through its environment and colonize different surfaces. Swarming motility refers to a coordinated movement of bacteria, usually on a solid surface, while falling leaves motility is not a recognized term in relation to bacterial motility. Non-motile bacteria are unable to move on their own.

Campylobacter is the correct answer because it is a genus of bacteria that are known to have long spirals or S or seagull wing shapes rods or coccobacilli. This characteristic can be observed in old cultures of Campylobacter. Vibrio, Aeromonas, and Helicobacter are other genera of bacteria, but they do not typically exhibit the same rod or coccobacilli shapes as Campylobacter.

Helicobacter can be presumptively identified if found in gastric biopsies because it is commonly associated with gastric infections and can be detected in biopsy samples taken from the stomach. Additionally, it is urease positive, meaning it produces the enzyme urease, which can be detected through laboratory tests. The other options, long spirals or S or seagull wing shapes rods or coccobacilli (in old cultures) and darting motility, are not specific to Helicobacter and can be observed in other bacteria as well.

The organisms C. fetus subsp. fetus, A. butzleri, and A. cryaerophilus can grow at 25C.

The organisms listed that cannot grow at 42C are C. hyointestinalis, A. butzleri, A. cryaerophilus, and H. fennelliae.

C. jejuni subsp. jejuni and C. jejuni subsp. doylei are the organisms that test positive for Hippurate hydrolysis.

C. concisus, C. curvus, and C. rectus are all catalase negative organisms. This means that they do not produce the enzyme catalase, which is responsible for breaking down hydrogen peroxide into water and oxygen. This can be determined through a catalase test, where hydrogen peroxide is added to a bacterial culture and if bubbles of oxygen are produced, it indicates a positive result for catalase. Since these three organisms do not produce bubbles, they are considered catalase negative.

The organisms C. concisus, C. curvus, C. hyointestinalis, C. rectus, and C. sputorum are H2S positive in TSI.

C. jejuni subsp. doylei cannot reduce nitrate to nitrite. H. fennelliae also cannot reduce nitrate to nitrite.