A Short Note On Non Pathogen : Streptococcus Thermophilus Essay

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

When you go to the grocery store and pick up a yogurt, some containers stated “live, active cultures”. What does “live, active cultures” mean? Does it mean that there is living bacteria in the yogurt? Isn’t that harmful? Some bacteria can make you sick, but are important because they help your body fight off the bad bacteria.

The unknown bacterium did not produce any spores as was evident by the endospore stain. B. subtilis (positive controls) was capable of producing spores in the NSM agar plate while no spores were formed by E. coli (negative control). The spore-former Sporosarcina was eliminated from the list of the possible genera. In the blood agar test, it was determined that the bacterium was gamma-hemolytic when it was compared to the gamma-hemolytic control S. epidermidis and beta-hemolytic control S. aureus. Since most species of Streptococcus are either alpha or beta-hemolytic, the negative result of the blood agar hemolysins led to the elimination of Streptococcus (8). These tests narrowed the possible genus to

Streptococcus pyogenes, also known as Group A streptococcus (GAS), is a β-hemolytic, Gram-positive bacterium that most commonly causes respiratory disease, including pharyngitis or tonsillitis, as well as skin infections such as impetigo and cellulitis. The organism is transmitted via respiratory droplets or by contact with fomites, and commonly infects young children. In addition to the common clinical presentations associated with S. pyogenes, some individuals develop the postinfectious sequelae of rheumatic fever and glomerulonephritis. Due to the severity of these medical consequences, prophylactic antibiotic use is often recommended for any patients with otherwise mild S. pyogenes infections (21).

S. pyogenes infections may vary from mild to life-threatening with a plethora of symptoms due to the many types of infections it causes. This bacterium is responsible for the diseases of pharyngitis, rheumatic fever, impetigo, erysipelas, cellulitis, necrotizing fasciitis, acute poststreptococcal glomerulonephritis, and toxic shock syndrome, just to name a few. Each of these infections has its own unique set of symptoms as will be explored in depth below.

When reflecting back to experiment 3, Aseptic Technique and Culturing Microbes, I realized the large amount of microorganisms that can be found in everyday life. Many different types are found with in the human body. Theses experiments focused on two types of bacteria. First was Staphylococcus epidermidis, found on the skin, and second was Lactobacillus acidophilus, found in the gastrointestinal tract. Both have similar needs for growth when it comes to temperature, however, different growth environments are used.

Streptococcus pyogenes is a very common bacteria found in humans. It is very transmissible and can be caught through the air via coughing or sneezing. This form of Strep. illness is referred to as Streptococcal pharyngitis, also known as Strep. throat, which can complicate into Scarlet Fever. It is also possible to be infected through abrasions of the skin, which can result in cellulitis, impetigo, or even necrotizing fasciitis. Aside from human to human contact, these bacteria can also be found in unpasteurized milk. There is no vaccine for Streptococcal infections, though antibiotics such as penicillin still work very well against them.

Streptococcus pneumoniae is found worldwide. The common host is the human body, in which it often does not cause disease but at other times it can cause diseses in particular, pneumonia. It also causes otitis media, bacteremia, meningitis, peritonitis, and sinusitis. The route by which this organism is spread is from human to human in the form of aerosol droplets. When inside the host the organism’s primary site of pneumococcal colonization is the nasopharynx. From this site it can aspire to the lungs, eventually spread to the blood and traverse the blood-brain barrier to the meninges, once inside the blood it can cause infections throughout the body. Symptoms of the disease include sudden

Enterococcus cacae isolated from human stool differs because of its inability to produce acid from arabinose, lactose, and mannitol. Enterococcus camelliae was isolate from fermented tea leaves in Thailand; they are unable to produce acid from D-galactose and lactose. Enterococcus canis was isolated from rectal swabs and chronic otitis in dogs; they are unable to hydrolyse arginine or to grow on selective media that contain 0.04% azide. Enterococcus avium Enterococcus pseudoavium differs from their inability to produce acid from lactose. Enterococcus hermanniensis differ from the inability to produce acid from substrates. Enterococcus lactis are atypical and are isolated in raw milk Italian cheeses. Enterococcus quebecensis and Enterococcus termitis are negative for the Voges-Proskauer (VP) test, meaning that as a result of fermentation, acid is not produced. Enterococcus rivorum growth at 45ᵒC or in a 6.5% NaCl broth there is little or no growth. Enterococcus ureasiticus has a urease activity production. Some species found in water or on plants differ because they can produce pigments such as Enterococcus ureilyticus and Enterococcus rotai. The most common species seen in humans are Enterococcus facalis and Enterococcus faecium which through testing has shown a resistance to clindamycin and oxacillin but

Abstract – Yogurt is a product of lactic acid and lactose. In order to produce yogurt, milk is pasteurized (at 45 degrees Celsius) and the inoculum is added followed by incubation. Over a period of 7 days, yoghurt fermentation was attempted using lactobacillus cultures. A liter of milk was supplied and plain yoghurt was used as a starter culture as it contains the necessary bacteria to ferment lactose and produce lactic acid. The milk was added to a flask: then boiled, cooled and inoculated. The milk was incubated for a week and all the while the milk was tested for changes in pH, density, mass and physical changes. The values obtained were then used to determine the growth kinetics of Lactobacillus bulgaricus.

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

Introduction: Through the conduction of numerous experiments, the identity of two bacterial isolates was determined. The tested specimen was an unknown sample of a mixed culture of two different species of bacteria. The first step that was taken was obtaining a pure culture of each species of bacteria by isolating one species from the other. Once isolation was complete, the isolated cultures were tested using procedures that had been performed during previous lab sessions. A gram stain was performed on the two isolates. The isolate which had tested gram negative was then tested for the presence of cytochrome C and lactose fermentation. For the gram positive isolate, cell shape was determined and a catalase test was performed.

For example, Lactobacillus bulgaricus and Streptococcus thermophilus are especially beneficial as active transite bacteria helpful in uptaking nutrients.

A fresh pipette was used to transfer 0.5ml of broth culture of E. coli, to be inoculated, into a tube of molten agar previously boiled to drive off oxygen. The tube was then rolled to distribute the bacteria and allowed time for the agar to harden. The tube was incubated at 37oC for 48 hours. The procedure was repeated for broth cultures of the bacterium Clostridium sporogenes and B. Subtilis.