Is Yersinia enterocolitica oxidase positive?
Yersinia are a group of Gram-negative, non-spore-forming, oxidase-negative, catalase-positive, lactose-negative, and facultative anaerobic rods (or coccobacilli). Y. enterocolitica is one of three human pathogenic species in the genus Yersinia.
How do I know if I have Yersinia enterocolitica?
Yersiniosis usually is diagnosed by detecting the organism in the stool of an infected person. Many laboratories do not routinely test for Yersinia, so it is important to notify laboratory personnel when yersiniosis is suspected so that special tests can be done.
Is Yersinia urease positive?
Yersinia pestis is urease-negative, and Yersinia enterocolitica and Yersinia pseudotuberculosis are both urease-positive. Yersinia spp. grow on simple laboratory media and are tolerant of bile salts. The optimal temperature for growth is 82–86°F (27.8–30°C).
Is Yersinia enterocolitica Gram positive or negative?
Yersinia enterocolitica is a gram-negative bacillus shaped bacterium that causes a zoonotic disease called yersiniosis. The infection is manifested as acute diarrhea, mesenteric adenitis, terminal ileitis, and pseudoappendicitis.
Is Yersinia Gram positive or negative?
Yersinia pestis is a nonmotile, slow-growing, facultative organism classified in the family Enterobacteriaceae. It appears as plump, gram-negative coccobacilli that are seen mostly as single cells or pairs, which may exhibit bipolar staining from a direct specimen if stained with Wright’s or Giemsa stains.
How do you get rid of Yersinia enterocolitica?
First-line drugs used against the bacterium include aminoglycosides and trimethoprim-sulfamethoxazole (TMP-SMZ). Other effective drugs include third-generation cephalosporins, tetracyclines (not recommended in children < 8 y), and fluoroquinolones (not approved for use in children < 18 y).
Can Yersinia come back?
Yersinia enterocolitica and Yersinia pseudotuberculosis are bacterial infections that are uncommon, but can cause problems when they occur. Y enterocolitica causes a condition called enterocolitis, which is an inflammation of the small intestine and colon that occurs, and often recurs, mostly in young children.
Is Yersinia enterocolitica urease test?
This urease test, based on the process involving the hydrolysis of urea, was performed to help identify the Gram-negative enteric bacterium Yersinia enterocolitica. The hydrolysis of urea is confirmed by the formation of ammonia, and CO2, which alkalinizes the medium, and results in a pH shift.
What is oxidase reagent?
The oxidase reagent contains a chromogenic reducing agent, which is a compound that changes color when it becomes oxidized. If the test organism produces cytochrome oxidase, the oxidase reagent will turn blue or purple within 15 seconds.
How does Yersinia enterocolitica reproduce?
Life history/Reproduction: Yersinia enterocolitica being prokaryotic organisms reproduce via binary fission, which is an asexual form of reproduction. This results in two genetically identical bacterial cells. Plasmids are small circular pieces of double stranded DNA that replicate autonomously.
Is Yersinia enterocolitica a cytotoxin?
Pathogenic Yersinia enterocolitica produces two virulence plasmid-encoded cytotoxins, YopE and YopT, that are translocated into target cells where they disrupt the actin cytoskeleton.
What kind of tests are done for Yersinia enterocolitica?
Typically positive results with Yersinia enterocolitica: Ornithine decarboxylase; Urease test (about 25% negative) ONPG; Cellobiose; Sucrose; Mannitol; Methyl red; Motility at 25°C; Typically negative results with Yersinia enterocolitica: Hydrogen sulfide; Lysine decarboxylase; Arginine dihydrolase; Simmons citrate
Are there any animal models of Yersinia enterocolitica?
Numerous animal models have been used to assess virulence of Yersinia species for humans. These models include keratoconjunctivitis in Guinea pigs (Sereny test), enterocolitis to rabbits, lethality to gerbils, and to suckling and adult mice (38).
How is the heat stable for Yersinia enterocolitica?
The heat-stable enterotoxin (ST) produced in vitro by some strains of Y. enterocolitica and related species can be detected by intragastric injection of cultural filtrates in suckling mice and is very similar to Escherichia coli ST (12). However, Yersinia spp. produce ST in vitro only at temperatures below 30°C.
What are the biochemical characteristics of Yersinia pestis?
Biochemical Test and Identification of Yersinia pestis Basic Characteristics Properties (Yersinia pestis) Indole Negative (-ve) Motility Non-Motile MR (Methyl Red) Positive (+ve) Nitrate Reduction Positive (+ve)