Is Serratia marcescens nitrate positive?

Therefore, nitrate tests are positive since nitrate is generally used as the final electron acceptor rather than oxygen. S.

Is Serratia citrate positive?

Serratia species can be distinguished from other genera by its production of three enzymes DNAase, lipase, and gelatinase. Members of this genus give positive reactions for citrate, Vogues–Proskuer, ortho-nitrophenyl-β-d-galactoside (ONPG) and can ferment mannitol and trehalose.

What are the characteristics 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.

Is Serratia marcescens indole positive?

Serratia marcescens. While all the organisms are gram negative rods, S. marcescens is the only lactose nonfermenter that is motile, oxidase negative and indole negative.

Is Serratia marcescens positive for oxidase?

Serratia marcescens is a motile, non-endospore-forming gram-negative bacillus [1]. This pathogen is an oxidase-negative, DNase-producing bacterium that is capable of growing in extreme conditions.

Serratia Biochemical test results

What is the specific identification test for Serratia?

Miniaturized biochemical detection systems such as BBL™ Enterotube II and API 20E strips have also been used to identify Serratia species. Identification may also be conducted by using automated microbial identification systems. Serratia species that can be identified by the Vitek 2 GN card, from bioMerieux, are S.

How do you identify S. marcescens?

marcescens to produce pyruvic acid, thus it can rely on citrate as a carbon source and test positive for citrate utilization. In identifying the organism, one may also perform a methyl red test, which determines if a microorganism performs mixed-acid fermentation. S. marcescens results in a negative test.

What is Serratia marcescens sensitive to?

Serratia marcescens showed great susceptibility to meropenem (100%), ofloxacin (100%), ciprofloxacin (90.5%) and gentamicin (84.6%), and total (100%) resistance to ceftazidime, cefuroxime, ampicillin and augmentin. The study concluded that occurrence of multidrug resistant S.

Which bacteria is citrate positive?

Klebsiella pneumoniae and Proteus mirabilis are examples of citrate positive organisms. Escherichia coli and Shigella dysenteriae are citrate negative.

Can S. marcescens use citrate?

S. marcescens W225 synthesizes another siderophore, enterobactin, and can utilize ferric citrate as an iron source as well (22).

What bacteria is citrate negative?

What agar does Serratia marcescens grow on?

Growth on Macconkey's agar.

Since the gram stain of Serratia marcescens revealed that the organism was a gram negative bacteria, MacConkey's agar served as a selective media. The organism grew as dark red colonies against the light pink background of the media.

What kills Serratia marcescens?

Once established, the organism usually cannot be eliminated entirely. However, periodic and thorough cleaning of the surfaces where the pink slime occurs, followed by disinfection with chlorine bleach, appears to be the best way to control it.

What covers Serratia marcescens?

Serratia infections should be treated with an aminoglycoside plus an antipseudomonal beta-lactam, as the single use of a beta-lactam can select for resistant strains. Most strains are susceptible to amikacin, but reports indicate increasing resistance to gentamicin and tobramycin.

What makes Serratia marcescens red?

Abstract. Serratia marcescens is a gram-negative, facultatively-anaerobic bacterium and opportunistic pathogen which produces the red pigment prodigiosin.

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.

What Gram stain results for Serratia marcescens?

Serratia marcescens is a Gram-negative, facultatively anaerobic, rod-shaped bacterium belonging to the family Enterobacteriaceae.

Is there a test for Serratia marcescens?

During an outbreak of S. marcescens, both respiratory and gastrointestinal samples should be collected in order to maximize the identification of colonized infants. Broth enrichment adds an additional day to obtaining results but increases the yield of positive results from respiratory specimens.

How do you differentiate Enterobacter and Serratia?

Thus, a rapid test has been needed to differentiate Serratia from Enterobacter. Serratia produces the blue-green indigo color within 5 min., whereas Enterobacter produces the blue-green color in half an hour.

What does Serratia marcescens ferment?

S. marcescens has a complex cell wall and uses peritrichous flagella to move. Its colonies are smooth and moist on non-selective media. The bacterium reduces nitrates, is oxidase negative, and uses acid production to ferment glucose.

Is Serratia marcescens catalase positive?

So, with Serratia marcescens, urease makes urea dissociate into carbon dioxide and ammonia. Ammonia then makes the mixture change color from orange-yellow to bright pink. Also, it's catalase positive which means it can produce an enzyme called catalase.