What is the morphology of Serratia marcescens?
MICROSCOPIC APPEARANCE
| Gram Stain: | Gram-negative. |
|---|---|
| Morphology: | Straight rods with rounded ends. |
| Size: | 0.5-0.8 micrometers by 0.9-2.0 micrometers. |
| Motility: | Usually motile by peritrichous flagella. |
| Capsules: | None. |
Does Serratia marcescens grow on EMB agar?
Eosin methylene blue agar (EMB) is a differential and selective media that supports the growth of gram-negative bacteria, including Escherichia coli and S. marcescens.
At what site S is Serratia normally found?
It is commonly found in the respiratory and urinary tracts of hospitalized adults and in the gastrointestinal systems of children. Due to its abundant presence in the environment, and its preference for damp conditions, S.
What are the characteristics of Serratia marcescens?
Serratia marcescens (S. marcescens) is a gram-negative bacillus that occurs naturally in soil and water and produces a red pigment at room temperature. It is associated with urinary and respiratory infections, endocarditis, osteomyelitis, septicemia, wound infections, eye infections, and meningitis.
What is the texture of Serratia marcescens?
For comparison purposes, after 3 days of incubation at 30°C, the S. marcescens MG1 parental wild-type colonies were ∼4 mm in diameter, had a “non-sticky-to-touch” colony texture, and had a rough or grainy appearance (Fig.
What does Serratia marcescens look like on agar?
Serratia marcescens. Medium-sized colonies that appear buff in colour on Blood Agar. The bacteria produce a red pigment which is easily seen when grown on blood-free media such as nutrient agar or Kings agar B. This culture has been incubated at 30°C.
Is Serratia marcescens EMB positive or negative?
Biochemical Test and Identification of Serratia marcescens
| Basic Characteristics | Properties (Serratia marcescens) |
|---|---|
| Tartrate | Negative (-ve) |
| Trehalose | Positive (+ve) |
| Xylose | Negative (-ve) |
| Enzymatic Reactions |
What does Serratia marcescens look like under a microscope?
Now, Serratia marcescens has a thin peptidoglycan layer, so it doesn’t retain the crystal violet dye during Gram staining. Instead, like any other Gram-negative bacteria, it stains pink with safranin dye. And since it’s a Gram-negative bacillus, it looks like a little pink rod under the microscope.
What is the arrangement of Serratia marcescens?
Serratia marcescens is a gram-negative rod-shaped facultatively anaerobic bacterium that is extremely motile. An S. marcescens gram stain shows short, pink-colored dots, as seen below. Rod-shaped bacteria, bacilliform bacteria or bacilli describe the typical shape of Serratia marcescens.
What is the colony morphology of Staphylococcus epidermidis?
Cellular morphology and biochemistry S. epidermidis is a very hardy microorganism, consisting of non-motile, Gram-positive cocci, arranged in grape- like clusters. It forms white, raised, cohesive colonies about 1–2 mm in diameter after overnight incubation, and is not haemolytic on blood agar.
What does colony morphology tell you?
Colony morphology is a method that scientists use to describe the characteristics of an individual colony of bacteria growing on agar in a Petri dish. It can be used to help to identify them. A swab from a bin spread directly onto nutrient agar. Colonies differ in their shape, size, colour and texture.
Is S. marcescens Gram-positive or negative?
gram negative
Serratia marcescens is an opportunistic, gram negative, nosocomial pathogen which belongs to family, Enterobacteriaceae. It was discovered by Bizio, an Italian pharmacist, in 1819, when he identified it as a cause of the bloody discolouration on cornmeal mush.
Why is S. marcescens red?
Serratia marcescens is a gram-negative, facultatively-anaerobic bacterium and opportunistic pathogen which produces the red pigment prodigiosin.
What is the margin of Serratia marcescens?
Table 2
| Bacterial isolates | Colour on nutrient agar | Margin |
|---|---|---|
| B. cereus | Off-white | Entire |
| Escherichia coli | Mucoid | Entire |
| Serratia | Mucoid | Entire |
| Leuconostoc | Light yellow | Entire |
What does Serratia marcescens colonies look like on blood agar?
On blood agar and some other media, S. marcescens produces red colonies. On CT agar, colonies of Serratia spp. are small and slightly bluish-white. On Tween 80 agar, colonies are large, pinkish, and surrounded by a white zone of precipitate.
What is Serratia found in?
The plant types with highest Serratia prevalence are vegetables, mushrooms, mosses, grasses, and decaying plant material. Serratia has been consistently found in figs and coconuts. S. marcescens and S. ficaria are often found in Calimyrna figs. Several species related to Serratia have also been identified on Smyrna figs and its fig wasps.
What is the shape of Shigella flexneri?
Shigella flexneri it is a short bacillus, 0.7–1.5 µm long, as well as 0.3–0.8 µm in diameter. Its cell wall is represented by a thin layer of peptidoglycans, without teichoic and lipoteichoic acids. It also does not present a capsule.
How to study the epidemiology of Serratia marcescens (Serratia)?
Several methods can be used to study the epidemiology of S. marcescens. Usual enrichment strategies involve the use of media containing antibiotic and antifungal substances. A caprylate-thallous media seems to be highly preferred for the selective growth of genus Serratia, as it can use caprylic acid as a carbon source.