Gram Negative Unknown Lab Report

My unknown organism #6 is Morganella morganii, which is a gram-negative bacillus rods commonly found in the environment and also in the intestinal tracts of humans, mammals, and reptiles as a normal flora. (3, 5) This bacterium Morganella morganii, was first discovered in the 1906 by a British bacteriologist named H. de R. Morgan. (2) Despite its wide distribution, it is an uncommon cause of community-acquired infection and is most often encountered inpostoperative and other nosocomial settings. (2, 3) Morganella morganii infections respond well to appropriate antibiotic therapy; however, its

According to the “Microbiology Laboratory Manual,” lab 27 focuses on the family Enterobacteriaceae, this is one of the largest families of bacteria (Wong et al., n.d.). Also all of the members are gram-negative, anaerobe straight rods and can commonly be located in mammal’s intestines (Wong et al., n.d.). All the members Enterobacter aerogenes throughout this report will be referred to as, E. aerogenes. There were several examples where E. aerogenes was tested or used, the first example is a One-pot synthesis, the next example is where it is used for dark fermentative biohydrogen production, and the last example is where it is analyzed in groundwater in North Central Nigeria.

There are many reasons for knowing the identity of microorganisms. The reasons range from knowing the causative agent of a disease in a patient, so as to know how it can be treated, to knowing the correct microorganism to be used for making certain foods or antibiotics. This study was done by applying all of the methods that have been learned so far in the microbiology laboratory class for the identification of unknown bacteria. The identification process can be completed with a series of deferential stains and biochemical tests. Creating a dichotomous key helps to limit the amount of biochemical tests done on an unknown organism and by observation

The lipid A palmitoyltransferase pagP is an outer membrane enzyme of the gram-negative bacteria Escherichia coli. Gram-negative bacteria are surrounded by two lipid bilayer membranes, which enclose the periplasmic space composed of peptidoglycan that contains ions and proteins. The two membranes differ in composition and function. With respect to composition, the inner or cytoplasmic membrane is composed of phospholipids, such as phosphatidylethanolamine, phospatidylglycerol and cardiolipin found in both the inner and outer leaflet. The outer membrane is highly asymmetric with its inner leaflet having the same phospholipid composition as the inner membrane and the outer leaflet consisting of lipopolysaccharides.

The first test done for Klebsiella pneumoniae (the gram stain) indicated that this bacteria was rod shaped and therefore, using the dichotomous key the family of bacteria that were ruled out consisted of the genera Neisseria and Rodospirillum. The next tests that were vital to the identification process were the oxygen requirements and glucose fermentation tests. The test results gave us the confirmed family of our species which was Enterobacteriaceae. The negative oxidase test performed confirmed this. Once the lactose fermentation test was performed, many genera were ruled out, including: Salmonella, Serratia, Proteus, Providencia and Marganella. The genera that remained included: Escherichia, Enterobacter, Klebsiella, and Citrobacter. For

On the second day of the unknowns experiment, the TSA plates were observed and their results were recorded. The aerobic TSA plate had a medium amount of growth and the colonies were an off-white color, had irregular shape, undulate margins, and umbonate elevation. The anaerobic TSA plate had less growth, but there was still growth present; the colonies on this plate were transparent, had irregular shape, undulate margins, and raised elevation. The largest colony from each plate was sub-cultured and prepared to be smeared onto a slide for viewing under the microscope. Once the organism had dried, the slide was heat fixed and gram stained. The colony obtained from the aerobic TSA plate showed gram positive bacillus and gram negative bacillus. The colony that was acquired from the anaerobic TSA plate only had the gram negative bacillus. This showed that the gram positive organism was an obligate aerobe and that the gram negative organism was a facultative anaerobe. After the results of the gram stain, the gram negative organism was sub-cultured

Bad bacteria are also known as gram negative gut bacteria. These bad bacteria play an active role in the production of inflammatory metabolites such as lipopolysaccharides or LPS. LPS is made of fats and sugar. Normally, LPS provides structural protection to benign bacteria. However, once leaked from the gut

We conducted this experiment to identify an unknown gram-negative bacteria, the potential unknowns are Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, Salmonella typhimurium and Proteus mirabilis. The unknown bacteria was analyzed with various biochemical test, which are the methyl red test, the citrate test, the gelatin hydrolysis test, the Voges-proskauer test, the urea hydrolysis test, the sulfur indole motility test and the triple sugar iron agar test. It was determined that the unknown bacteria was salmonella typhimurium.

Remember that while Gram-negative bacteria have no "outer membrane", Gram-negative bacteria do have lipopolysaccharide molecules attached to their bacterial "outer membrane".

TNFa is an endogenous pyrogen, thus is capable of inducing inflammation, fever, apoptotic cell death and, inhibition of tumorigenesis. (Kleef and Hager, 2000) One of the most potent stimuli for TNFa is a bacterial endotoxin (lipopolysaccharide) or (LPS) which is derived from the outer cell wall of gram-negative bacteria. (Verhoef et al., 1999) LPS is a major component of the outer membrane of gram-negative bacteria, and contributes greatly to the structural integrity of the bacteria. (Kaszowska, 2004) Large amounts of TNFa are released in

It turns out microbes don't wait for five seconds, or even 1 second to hop on to your food. Even brief contact with a contaminated floor will contaminate food wet or dry! Bacteria will adhere to food almost immediately, but time does matter. The food left on the floor for five seconds acquired a lot of bacteria, but the food left on the floor for 30 seconds picked up a few colonies more. Imagine if you left it for a full minute, or even 10 minutes... the amount of bacteria would be ten times greater! Furthermore, don't think your food is safe because the floor "looks clean" or the food that you dropped on it does. Floors make great homes for bacteria. Also, floors come in contact with our shoes on a regular basis, and the University of Arizona

I isolated Enterobacter aerogenes from plate number 5. Enterobacter aerogenes is a rod shaped Gram-negative species.

Biochemical tests are used to identify bacteria species based on their differences in their biochemical activities of different bacteria. To differentiate one bacteria from another, each species of bacteria has a well-defined set of metabolic activities. Bacteria can be differentiated in many ways. They can be based on structural differences or metabolic differences. Structurally, the Gram stain is the most fundamental technique in identifying bacterial species and was developed by Christian Gram in 1884. Gram negative bacteria can be distinguished from Gram positive with the presence of LPS, lipopolysaccharide and a thinner peptidoglycan layer which doesn’t retain crystal violet as well. For this experiment, an unknown bacterium was identified from a list of 32 clinically significant bacteria. It was first isolated onto a TSA plate and then through a series of differential and selective tests were performed to determine its identity to be Klebsiella ozaenae.

The hydrophobic anchor which holds the Lipopolysaccharide (LPS) of gram-negative bacteria in the outer leaflet of the outer membrane is Lipid A. This component is produced within the bacterial cell cytoplasm through the Lpx biosynthetic pathway (reference). Lipid A is then transported to the outer membrane (OM) via the Lpt biosynthetic pathway (reference). Lipid A is highly conserved, essential for virulence and bacterial viability. These qualities make it an attractive drug target which could aid in the development of inhibitors of gram-negative bacteria. A recent study of the Lpx pathway has resulted in the identification of a key potential rate-limiting enzyme (reference). That enzyme is tetraacyldisaccharide-1-phosphate 4 '-kinase

Microorganism identification plays a very critical role in the medical significance of modern medicine. One example of reasoning behind it can be for the detection of a disease causing organism in a patient, so it can be certain that it will be appropriately treated. Numerous species of bacteria can appear to share identical morphology (spirilli, cocci, rods), when looking through a microscope. There are many methods and biochemical tests that can be performed to differentiate and determine the genus and species of these morphologically identical unknown bacteria. The purpose of this lab was to identify a mixed pure culture of two unknown bacteria, by applying various differential tests that were learned in the lab thus far. Based upon the Gram-stain reaction and the reactions that occur on the media that they grow on, it is then classified into categories of genus. After each unknown culture has been successfully isolated specific biochemical tests were performed and their metabolic pathways, enzymatic reactions, and byproducts were observed. A single test cannot be used to aid in the identification of a species of an unknown bacteria. From the series of biochemical tests performed in the laboratory, the determination of Unknown #60 (A) was Enterobacter aerogenes and Unknown #60 (B) was Corynebacterium diptheriae.