Micrococcus Luteus: Alexander Fleming

The purpose of this experiment is to investigate the effects of various household products may have on bacterial growth. The bacteria that was chosen as a test subject is Micrococcus luteus, which is generally considered a harmless bacterium unless the host has a weakened immune system. Among the household products that a set of groups will test are common cleaning and disinfecting products such as rubbing alcohol, Betadine, Germ-X, Neosporin, liquid hand soap, and Lysol cleaner. In the experiment, the bacterium, Micrococcus luteus, is to be swabbed and grown in a Petri dish divided into four sections with agar in each. After that, a small circle of thin paper is soaked in the four household items. Then, a piece of parafilm

The unknown bacteria plate chosen was plate #2. It was identified to be Micrococcus luteus. It is a gram positive, Coccus bacteria that is commonly found in dust, water, soil, and the air. M. luteus also thrives in the human mouth and upper respiratory tract. Sir Alexander Fleming discovered it in 1928 before he identified penicillin. It is part of the normal flora on human skin as well as other mammals. Since it is part of normal flora it is normally not pathogenic, but can become opportunistic in an immune-deficient person. It has been known to cause septic shock, UTI’s, and even pneumonia. Micrococcus luteus is both urease and catalase positive. It does not utilize tryptophan for indole production. It is a facultative anaerobe. Mobility is not present for this bacterium. Starch is also not hydrolyzed and oxidase is not present.

The first result of importance was the result of the Gram stain. The observations of the unknown bacteria from the slant culture after Gram staining showed that the unknown bacteria were Gram negative bacilli (Image 1). After determining the unknown bacteria was Gram negative, an oxidase test was conducted on a sample from the slant culture. The cotton swap with the sample of bacteria did not change color when the oxidase reagent was applied, thus providing a negative result. With a negative oxidase test, further tests were conducted to determine various characteristics of the unknown bacteria. A MR-VP broth was inoculated with a sample from a slant culture of unknown bacteria. After incubation, the methyl red reagent was added to the broth, and the broth turned red, providing a positive result (Image 2). An EMB agar streak plate was inoculated with a sample from a slant culture of the unknown bacteria, and after incubation, growth was found on the plate, providing a positive result (Image 3). A Citrate agar slant was inoculated, and after incubation, growth was found on the media, providing a positive result (Image 4). A Urea agar slant was inoculated, and after incubation, the agar had changed from a peach color to a bright pink color, providing a positive result (Image 5). Using the flowchart (Figure 1) developed from the Table of Expected Results, the lab partners started at the oxidase test. Given the negative result of the oxidase test, the flowchart is

Often scientists work with bacteria that do not come in a labeled test tube— for example, bacterial samples taken from infected human tissue or from the soil—and the scientist must then identify the unknown microorganism in order to understand what behavior to expect from the organism, for example, a certain type of infection or antibiotic resistance. However, because of the relatively few forms of bacteria compared to animals and because of the lack of bacterial fossil records due to their asexually reproductive nature, the taxonomy used to classify animals cannot be applied to bacteria (Brown 275). In order to classify unknown bacteria, a variety of physiological and metabolic tests are available to narrow a sample down from the fathomless number of possibilities into a more manageable range. Once these tests have been performed, the researcher can consult Bergey’s Manual of Determinative Bacteriology, a systematically arranged and continually updated collection of all known bacteria based on their structure, metabolism, and other attributes.

This particular bacterium is not one that inhabits a specific geographical region as it colonizes within the human body. The disease is

The two bacteria from sample number 118 I have identified to be Streptococcus mitis and Klebsiella pneumoniae. When taking a class like Microbiology it is understood that most individuals will progress further into the medical field. In the medical field it is important to know as much about as many different bacteria as possible.

As the flowchart shows, a series of tests were conducted to identify the unknown bacterium #65. Microscopic observation of the gram stain indicated a gram-positive coccus bacterium. S. epidermidis was used as the gram-positive control while E. coli was used as the gram-negative control. This observation led to the elimination of all gram negative and rod-shaped genera: Enterobacter, Citrobacter, Klebsiella, Escherichia, Pseudomonas, Serratia, Alcaligenes, Neisseria, Proteus, Salmonella, Shigella, Erwinia, Veillonella, Flavobacterium, Bacillus, Arthrobacter, Lactobacillus, Listeria and Kurthia (2). By performing the catalase test, it was determined that the bacterium was catalase negative and it did not produce bubbles. M. luteus and E. faecalis were used as positive and negative controls, respectively.

The main objective was to identify an unknown organism by utilizing skills we learned in our labs this semester. The purpose was to attain the possible identity of the unknown organism by actually performing biochemical tests and staining techniques we learned in lab. After performing and analyzing the results, we were able to use Bergey’s Manual of Systemic Bacteriology as a guideline to narrow down the genus of our organism test by test.

Unknown lab report# 24 Introduction Microbiology is a study of organisms that surrounds us every day. It requires an educational understanding to identify organisms, and the ability to distinguish different bacteria’s. In applying the learning process of the different bacteria’s, unknown bacteria samples are given to be studied and identified.

The bases of this experiment was to discover the identify of the unknown from three possible specimens: Klebsiella pneumonia, Escherichia coli, and Enterobacter aerogenes. Utilizaing the T streak technique, the bacteria was isolated into pure colonies for further study. The Gram Stain method was used to identity the morhphology of the bacteria such as the shape and whether the bacteria was Gram positive or Gram negative. Biochemical test were also used to help identify the unknown bacteria. The biochemical test used was the Triple Sugar Iron Agar, Sulfur Indole Motility test, Methyl Red test, Voges-Proskauer test, Citrate test, Urease test, and the Gelatin test. After observing the morphology of the bacteria using the Gram Stain method and utilizing all the possible biochemical test, the bacteria was identified to be Enterobacter aerogenes.

After microorganisms enter the patient’s body they can go to the lungs and cause pneumonia. Central line-bloodstream infections occur when microorganism enter the bloodstream by the intravenous line. Microorganisms are transfer into the blood stream by inadequate hand hygiene or improper intravenous fluid, tubing, and site care practice. Multidrug-resistant organisms can cause infections of the blood, skin, or organ systems. These infections can arise due to the overuse or misuse of antibiotics, which can result in the microorganisms becoming more resistant to antibiotic therapy. Methicillin-resistant Staphyloccocus aureus and Clostridium difficile are examples of this kind of infection. Health care employees need to know the different types of hospital acquired infections and how they are spread to be able to effectively prevent them.

A highly conserved gene will be used to identify a prokaryotic species isolated from the body. Fundamental lab techniques will be also explored and utilized, such as amplifying using PCR, cloning, and transforming the gene into a host cell. DNA electrophoresis and specific substrate plating will serve as analysis check points. The final product will be sequenced and compared to similar species to observe phylogenetic relationships.

In a study conducted by Karamoddini et al., antibiotic resistant samples of Klebsiella species were collected from patients at a hospital and treated with bacteriophages isolated from the hospital waste water. Of the species collected, 72 were found to have antibiotic resistance; however, when treated with phages at varying concentrations, not a single strain was left unaffected by antibacterial properties of the phages. These effects were seen in both high and low concentrations, leading Karamoddini et al. postulated that there were two mechanisms at work: an active and a passive mechanism. In the active mechanism, the concentration of phages is low compared that of bacterial concentration, allowing them to replicate inside of and lyse the host cell, while the passive mechanism in which there are significantly more phages than bacteria and the lytic is due to excess primary phages entering a bacterial cell.16 Karamoddini et al.

These are gram positive bacteria which are found in acidic condition of pH 4 to 4.5 – acidophilic.

to the patients.21 For example, BK viral occurs ''in the urine and can cause inflammation and