Is Yersinia enterocolitica gram positive?

Yersinia enterocolitica is a gram-negative bacillus shaped bacterium that causes a zoonotic disease called yersiniosis.

Does Yersinia grow on MacConkey agar?

The organism grows well on MacConkey agar, and forms small colorless lactose-negative colonies but if the clinical team is suspicious for Yersinia, a selective growth medium is recommended.

What is the morphology of Yersinia enterocolitica?

Morphology and Appearance in Cultures Yersinia enterocolitica is a small Gram-negative rod. It is actively motile at 22–25 °C but not motile at 37 °C. It produces circular, smooth, low, convex colonies of 1–2 mm diameter with an entire or slightly crenulated edge after incubation at 37 °C for 24 h.

Is Yersinia enterocolitica positive or negative?

Food-borne pathogenic Yersinia (Y. enterocolitica and Y. pseudotuberculosis) is facultative anaerobic, gram-negative Enterobacteriaceae and is isolated frequently from soil, water, animals, and foods [1–4].

Is the plague Gram positive or negative?

Plague is a severe infection caused by the gram-negative bacteria. Gram-negative bacteria are classified by the color they turn after a chemical process called Gram staining… read more Yersinia pestis and often involving the lymph nodes and/or lungs. The bacteria are spread mainly by the rat flea.

Is Yersinia enterocolitica a lactose fermenter?

Yersinia enterocolitica is a Gram-negative, non- lactose fermenting, urease-positive bacillus which is the causal organism of diarrhoeal illness and an appendicitis-like syndrome in man.

What gram-negative rods do not grow on MacConkey agar?

Long, thin, slowly growing, oxidase-positive, catalase-positive gram-negative rods that do not grow on MacConkey agar should suggest DF-2. Although testing of antimicrobial susceptibility is problematic, DF-2 has been found to be resistant to aminoglycosides. The drug of choice is penicillin.

What is the shape of Yersinia?

Yersinia, (genus Yersinia), any of a group of ovoid- or rod-shaped bacteria of the family Enterobacteriaceae. Yersinia are gram-negative bacteria and are described as facultative anaerobes, which means that they are capable of surviving in both aerobic and anaerobic environments.

What are the characteristics of Yersinia?

Yersinia pestis — Key Characteristics

• Gram-negative bacilli, possible bipolar staining and a “safety pin” appearance.
• Nonhemolytic.
• Growth is faster at 25 to 28 degrees C than at 35 to 37 degrees C.
• At 48 to 72 hours the colonies on sheep blood agar have a “fried egg” appearance.
• Catalase positive.

What bacteria causes yersiniosis?

Causes and Symptoms of Yersiniosis. Yersiniosis is an infectious disease caused by enteric bacteria of the genus Yersinia. In the United States, most human illness is caused by one species, Y. enterocolitica.

Does Yersinia ferment sucrose?

Biochemical tests that are important for speciation within the genus Yersinia are fermentation of sucrose, rhamnose, raffinose and melibiose and the utilization of citrate (Table 1).

Is erysipelothrix Gram-positive or negative?

Erysipelothrix rhusiopathiae is a gram-positive, nonsporulating, rod-shaped bacterium that is widely distributed in nature and has primarily been seen as a veterinary pathogen (2, 3, 6, 7).

Is Yersinia pestis heterotrophic?

Y. pestis is a chemoheterotroph, meaning that it must consume organic molecules for energy and carbon.

Does Yersinia enterocolitica ferment sucrose?

Y. enterocolitica ferments sucrose and Y.

Can Yersinia ferment sucrose?

Is Yersinia a lactose fermenter?

What are lactose fermenting Gram-negative rods?

E. coli are facultative anaerobic, Gram-negative bacilli that will ferment lactose to produce hydrogen sulfide.

What does gram-negative mean in bacteria?

Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation.

What is the size of Yersinia pestis bacteria?

Gram negative rod-ovoid 0.5-0.8 µm in width and 1-3 µm in length (safety pin appearance), bipolar staining (Giemsa) facultative intracellular, non-motile.

What is the epidemiology of yersiniosis enterocolitica?

The epidemiology of Y. enterocolitica infections is complex and remains poorly understood. Most cases of yersiniosis occur sporadically without an apparent source. The main sources of human infection are assumed to be pork and pork products, as pigs are a major reservoir of pathogenic Y. enterocolitica.

How do you identify Yersinia enterocolitica?

Identification systems for Y. enterocolitica based on biochemical reactions do not guarantee reliable identification at species level. Members of nonpathogenic Yersinia species can easily be misidentified as Y. enterocolitica. To identify presumptively typed Y.

Is Yersinia enterocolitica 2/o9 a food-borne disease?

Furthermore, Sakai (2005) reported a food-borne outbreak of Y. enterocolitica O:8 in Japan where the same PFGE pattern was obtained from all patient and salad isolates. Recently, Y. enterocolitica 2/O:9 has been isolated from chicken eggshell surfaces in Argentina ( Favier et al., 2005 ).

What is Yersinia infection in humans?

 Yersinioses are zoonotic infection with the human being the incidental hosts who do no contribute to the life cycle for the pathogen. Yersinia are classified based on their biochemical features and of the 6 biotypes, subtypes 2,3, and 4 are most common in humans.