1.1 Plant Samples Collection:
Healthy, fresh and disease free Mint (Mentha), and Coriander (Coriander sativum) were purchased in the month of November 2014, from the Karachi local market Gulistan-e-Johar, Karachi, Pakistan. The plants samples were deposited and identified by Herbarium Department of Karachi University.
1.2 Plant Processing:
Plants samples were washed with tap water for three to four times and removed all dust and soil particles, and finally washed with distilled water. Then leaves of both plants (Coriander & Mint) were plug off and was cut with clean knife and made their small pieces and kept them in tray dryer in open environment for dryness. Both the samples were dried completely after seven days then their homogenized fine powder were obtained (60-80 mesh), by using a commercial electric grinder. The powdered material was stored in air tight sterilized bottles in refrigerator at 4°C for further use.
1.3 Test Microorganisms:
Four different bacterial strain were used as indicator microorganisms for testing antibacterial activities were following: Two Gram-Positive bacterial strains (Staphylococcus aurus ATCC 25923 & Staphylococcus ATCC25923) and two Gram-Negative bacterial strains (Escherichia coli ATCC25922 & Salmonella enteritidis ATCC14028). All were American Type Culture Collection. These strains were provided by the Food Microbiology laboratory University of Karachi and commercial laboratory (Food Microbiology) SGS, Karachi. Stock cultures were
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
The purpose of this study project was to carefully isolate and identify two unknown bacteria from a mixed culture. The ability to properly evaluate biochemical test results is also necessary for the identification to be successful. The goal was to apply all of the methods and techniques that have been learned in the microbiology laboratory course for the proper identification of unknown bacteria. A certain amount of bacteria that were used throughout the course were possible bacteria that could be found in a mixed culture. The bacteria that were identified in the mixed culture were Staphylococcus Aureus and Kocuria Rhizophila.
AIM – The aim of the experiment is to determine the relative effectiveness of several anti-microbial substances on developing pathogens. (E. coli)
I inoculated a T-Soy agar with bacteria number 118, for this I used a streak isolation method. Next, in order to distinguish between Gram positive and Gram negative I used a streak isolation technique on a CNA plate, then performed the same exact procedure on a MacConkey plate. The results from the CNA plate showed the Gram Positive bacteria was an Alpha hemolyzer. Next, I used a P Disc on a T-Soy agar inoculated with bacteria 118 and determined the Gram Positive bacteria was not sensitive to P Disc antibiotics. This revealed the Gram Positive bacteria to be Streptococcus Mitis. The results from the MacConkey plate proved the Gram Negative bacteria to be a lactose fermenter. With the Gram Negative bacteria I performed a lysine test with positive results. Next, I performed an ornithine test on the Gram Negative bacteria, with negative results, therefore I concluded the Gram Negative bacteria was Klebsiella pneumoniae.
The purpose of this lab was to identify two unknown bacteria cultures using various differential tests. The identification of these unknown cultures was accomplished by separating and differentiating possible bacteria based on specific biochemical characteristics. Whether the tests performed identified specific enzymatic reactions or metabolic pathways, each was used in a way to help recognize those specifics and identify the unknown cultures. The differential tests used to identify the unknown cultures were oxidase, catalase, lactose and sucrose fermentation, Kugler/iron agar, nitrate reduction, gelatin hydrolysis, starch hydrolysis, manitol salt, MR-VP, citrate, bile esculin,
The purpose of this study was to identify the unknown bacterium using biochemical tests and various methods that had been learned from previous the microbiology laboratory class. Identifying the unknown bacterium was determined by separating and differentiating possible
The species ID from the Biolog was confirmed to be Staphylococcus epidermidis with a probability of 99.2%. The observed results of utilization of D-Mannitol, citric acid, D-fructose, and α -D-lactose matched the expected results. The bacteria sensitivity to NaCl differ from the expected results; the bacteria should be tolerant to NaCl up to 10-15%. The fermentation results of glucose and lactose from phenol red broth was different from the results observed in the Biolog. The Biolog results matched the expected results for S. epidermidis with a few exceptions. From the citrate slant test, it was observed that the bacteria was unable to utilize citrate; however, the observed results from the Biolog test was inconclusive indicting a positive and negative result. The bacteria was indicated to not be sensitive to Vancomycin, however, the bacteria is expected to be sensitive to the antimicrobial
The sole purpose of this project was to identify an unknown bacteria sample #7. Many tests were carried out to determine what this unknown was. Aside from a microbiology lab, understanding and identifying various organisms are important in disease processes, pharmaceutical arenas, and even in the industrial field. Proper lab techniques, including aseptic technique were used throughout the process of identification.
The purpose of this project was to identify the identities of two unknown bacteria in a mixed broth culture by using several separation methods. To separate the organisms, a four-way streak plate technique was used to isolate the two unknown bacteria into separate visible colonies. Then after each colony were clearly isolated; the two unknowns were processed through Gram staining test to determine the Gram stain and morphology. After Gram staining, a carbohydrate test was performed on each unknown to determine if it had glucose, sucrose, or lactose fermentation. The results of the sugar test help determining which biochemical test should be performed next. The Gram positive organism was tested through a carbohydrate fermentation test, then further tested to confirm its identity through an indole and catalase test. The Gram negative organism was tested through carbohydrate fermentation test, then further tested to confirmed its identity through an indole, and TSIA test. After running four biochemical tests, the results conclude that the Gram positive unknown was Staphylococcus aureus. S. aureus was identified based on the fermentation results of the glucose test, negative indole test, and a positive catalase production. S. aureus is a Gram positive circular shaped bacterium that is very common in the U.S and is normally found in the nose, respiratory tract, and on the skin. This bacterium is usually the most common cause of infections after injury or surgery.
: In the field of microbiology, there are times when a sample will contain more than one species of bacteria. The goal is to separate each bacterium and culture them independently from one another to identify them. This was the objective of this lab. Each stock contained two unknown bacterium, and the possible unknowns were Eserichia coli, Enterobacter aerogenes, Enterobacter cloacae, Serratia marcescens, Proteus vulgaris, Klebsiella pneumoniae, Shigella flexneri, Shigella sonnei, and Salmonella enterica. The tests available were MacConkey agar, Endo agar, Hektoen Enteric agar, Tryptone Soya Agar (TSA), carbohydrate sugar broths, Triple Sugar Iron (TSI) agar, decarboxylase broths (arginine, lysine, and ornithine), Simmon’s Citrate Agar, urease
One person each in a team of four heavily inoculated two Mueller-Hinton agar plates with one of the cultures listed by aseptic transfer from a broth culture using a sterile cotton swab. Each plate was marked off into four segments, a total of eight sectors. One McFarland standard disk containing one of the eight antibiotics tested was placed, using
A total of 13 tests were performed on the unknown bacteria culture #1. Two tests were inconclusive and could not be used. The first test was simply the phenylethyl alcohol agar (PAA) to check for contamination because of its selectivity towards gram-positive bacteria. The alcohol in the agar penetrates the thin peptidoglycan wall of gram-negative bacteria, which results in a slowed and stopped growth. The mannitol salts agar (MSA) is a differential test due to the mannitol sugar. It also has high amounts of salt (7.5% NaCl). If the organism can ferment the sugar, and produce acid as a result, the phenol red pH indicator dye will turn yellow due to the acidic environment. If no change occurred, then it is a negative result meaning that the bacteria
The sterile blank paper disks were coated by the casting of 50 µl of polyacrylic latex modified with 1%T/PANI100:5 additive. Fresh cultures of bacteria were inoculated on nutrient broth and incubated for 24 hour at 37ºC. Definite amount of Muller- Hinton agar was poured into the sterile plate until to be solid. The blank paper disks were impregnated in the inoculated agars. Control disks were prepared using unmodified polyacrylic emulsion. The inoculated plates were incubated at 37ºC under LED lamp light irradiation for 24 h. Antibacterial activity was investigated by measuring the inhibition zones in reference to the test organisms.
2. Introduction: Each student was given unknown bacteria and was instructed to perform a variety of experimental tests that would help to identify their bacteria. During the process of identification, the unknown bacteria was added to many different testing medias using aseptic technique. They are as follows: lactose fermentation on eosin methylene blue (EMB), TSI (Triple Sugar Iron agar), Phenol red sucrose, the SIM test, H2S by SIM, IMViC (indole, motility, voges-proskauer, and citrate), Urease (urea broth), PDase (Phenylalanine Deaminase), Lysine Decarboxylase, and Ornithine Decarboxylase. Colonial morphology on EMB was used to
Each mixed culture that was tested had one gram positive and one gram negative bacterial species. The possible species of bacteria that could have been isolated from the mixtures included the following: Bacillus subtilis, Corynebacterium glutamicum, Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, Enterobacter aerogenes, Salmonella enterica, and Pseudomonas aeruginosa. The identities of the unknown species were determined through comparing the experimental data against data acquired from earlier experimentation.