It metabolizes by either respiratory or fermentative processes classifying it as a chemoorganotroph 4. Ubiquitous in nature, S. In particular, food sources that provide a nutrient rich environment include starchy variants The bacterium propels itself in these different environments using peritrichous flagellum 4.
Species Serratia marcescens on an XLD agar plate. Obtained from the CDC Public Health Image Library Description and Significance Serratia marcescens is a motile,short rod-shaped, Gram-negative, facultative anaerobe bacterium, classified as an opportunistic pathogen.
It was discovered in by Bartolomeo Bizio in Padua, Italy. Bizio named the genus Serratia in honor of and Italian physicist named Serratia, and chose marcescens for the species name after the Latin word for decay .
Serratia marcescens was first thought to be harmless non-pathogenic. Due to its ability to produce red pigmentation, it was first used in as a marker in order to trace bacterial activity or transmission .
A study using Serratia marcescens was carried out to determine the possibility of biological weapons being transmitted by wind current.
Serratia marcescens was chosen because it was easily tracked due to its pigment production. However,there was an increase in the number of pneumonia and urinary tract infections  reported in the region shortly after the experiment was conducted.
Although Serratia marcescens was classified as a human pathogen in the s, scientist still used it as a bacterial tracer well into the s . They grow in pH levels that range from 5 to 9 . Serratia marcescens is well known for the red pigmentation it produces called prodigiosin.
The red pigment production is not present in all strains but in those that it is present, it can resemble blood . This and the fact that Serratia marcescens typically grows on bread and communion wafers stored in moist places, has led scientists to suggest Serratia contamination as a possible explanation for transubstantiation miracles the conversion of bread to the body and blood of Christ.
After speaking the words of consecration, blood began to drip from the consecrated Host onto his hands and the altar . This event was depicted by Raphael on the walls of the Vatican . Genome Structure The genome of the Serratia marcescens strain Db11 was sequenced by the Sanger Institute with the collaboaration of Dr.
Cell Structure and Metabolism Serratia marcescens is short and rod shaped. It is a facultative anaerobe, meaning that it can grow in either the presence of oxygen aerobic or in the absence of oxygen anaerobic.
Primarily it uses fermentation as the means of gathering energy and has enzymes superoxide dismutase, catalase or peroxides that protect it from reactive oxygen species, allowing it to live in oxygenated environments.
Serratia marcescens is a gram negative bacterium. Gram negative bacteria have a thin cell wall made of a single layer of peptidoglycan that is enclosed by an outer membrane.
The outer membrane has lipopolysaccharides LPSwhich are a special kind of phospholipid composed of fatty acids that are attached to a glucosamine phosphate dimer. One glucosamine is then attached to a core polysaccharide that extends to the O polysaccharides.
The outer membrane also serves as a means to regulate the uptake of nutrients and the exclusion of toxins. The protein pores and transporters found in the envelope layers vary in selectivity . Serratia marcescens is motile and travels by several different means.
A single Serratia marcescens bacterium can swim with the use of its flagellum . As a group they can swarm together on agar of lower concentrations 0. Serratia marcescens have about — flagella per swimmer cell .
Serratia marcescens can also form a biofilm complex structure made of secreted mucilaginous matrixto form a protective coating in which they are encased . Hydrolysis of casein is not a common trait and is therefore useful in the differentiation of Serratia marcescens from the strains of Enterobacteriaceae and Pseudomonadaceae families .
Serratia marcescens has the reproducible capability to break down casein producing a clearing on milk agar plates. Casein is a protein precipitated from milk that forms the basis of cheese and certain plastics . Serratia marcescens uses extracellular enzymes called proteases to break down the peptide bonds CO-NH in casein .
Similarly, an extracellular enzyme called gelatinase breaks down gelatin, an incomplete protein that lacks tryptophan. There are other biochemical tests that help to identify Serratia marcescens in the lab. Serratia marcescens is negative for acid production on lactose, but positive glucose and sucrose with gas production fermentation.
Nitrate tests are positive since nitrate is generally used as the final electron acceptor rather than oxygen .
Citrate positive test is used by Serratia marcescens to produce pyruvic acid.Antimicrobial action of tea tree oil (Melaleuca alternifolia) on five common bacteria 6 each plate with at least cm clearance between discs to avoid confusion in zone of inhibitions. A small piece of fresh garlic purchased from a local grocer was used rather than a disc to test its inhibitory efficacy.
Serratia marcescens is motile and travels by several different means.
A single Serratia marcescens bacterium can swim with the use of its flagellum . As a group they can swarm together on agar of lower concentrations (%) . In the early part of the 20 th century, Serratia marcescens was considered a nonpathogenic organism and was used in medical experiments and as a biological warfare test agent.
Since the mids, however, Serratia species have been recognized to cause a full spectrum of human clinical disease. 25°C = S. marcescens 2. A) I did not expect this result for the S.
marcescens, because in the first experiment testing pigmentation production, there was more pigment production during the 25°C incubation process. So, I would imagine there to be more growth at the same temperature due to that reason.
Calorimetric and growth data are reported for the anaerobic growth of a strain of Serratia marcescens in a glucose-limited medium over the temperature range from 20 to 32°.
• To learn the effects of UV irradiation on different bacterial species. • To learn if there is a correlation between the length of exposure to UV irradiation and the number of bacteria killed. • To learn the different techniques used to .