In the laboratory, identification of an unknown bacterium is often necessary. In the lab, a random sample consisting of three different bacteria was selected. The sample contained one gram-positive, one gram-negative paracolon, and one gram-negative coliform. The purpose of the experiment is to identify each of the three species that the mixture contained. After receiving an unknown mixture, the sample was streaked for isolation onto TSA, blood agar, and MacConkey plates. Each plate serves as a first step to identify the unknowns. The TSA (tryptic soy agar) can be used to do a gram stain, which differentiates gram-negatives from gram-positives, based on the structural make up of the cell wall (Carson, 2015). The blood agar plate is used to test for hemolytic activity, which is useful for distinguishing gram-positives. A MacConkey plate is selective by inhibiting the growth of gram-positives and differential due to the fermentation of lactose by certain gram-negative species. In the …show more content…
The gram negative species are apart of the Enterobacteriaceae family. These are gram-negative rods, which are facultatively aerobic - either respiring or fermenting. Most are motile via a flagella (Carson, 2015). Salmonella enterica and Yersinia enterocolitica are both paracolons, which lack the ability to ferment lactose. Conversely, Klebsiella pneumoniae and Escherichia coli are both coliforms, which are able to ferment lactose. Of the Enterobacteriaceae family, there are genera that are in the normal human flora. Some species such as K. pneumoniae and E. coli are opportunistic pathogens which can capitalize on weakened host defenses and cause food poisoning (Baron, 1996). S. enterica secrete proteins that help aid in intracellular invasion and proliferation (Hensel, 2009). K. pneumoniae is a part of the normal human mouth, skin, and intestine flora, but can wreak havoc if inhaled (Ryan,
Hunting nightmare bacteria Answer the following questions Case of Addy (the girl from Arizona ) 1- Based on the pediatrician observations what was Addy’s diagnosis at the Pediatric Hospital intensive care unit ? She had got infected by staff or positive bacteria called Methicillin-resistant Staphylococcus aureus (MRSA). MRSA is a community associated bacteria that infects kids when they are playing in playing ground and getting scabs on their knee. They spread through that wound and it has very high resistance to antibiotics.
The purpose of this lab report is to employ a myriad of skills, tools and, methods learned throughout this semester to perform the appropriate tests for the identification of the assigned unknown bacteria. Add more background information here!!! The most important tools and techniques used during this identification include aseptic technique, microscopic examination and, the use of selective and differential media. Aseptic technique is an important tool for microbiologists. It is imperative that aseptic technique is maintained throughout the length of any test to avoid any cross-contamination that may lead to inaccurate results.
In this experiment, we cultivated an unknown specimen containing two microorganisms. The purpose of this experiment was to use a variety of biochemical test previously learned in the lab to identify the unknown bacteria. The identification of unknown bacteria is a major part of microbiology. Microbiologist observe samples such as blood and sputum in the laboratory for the presence of microorganisms. Identifying unknown bacteria is extremely important in clinical settings because it helps physicians find treatment for infections.
A starch agar plate was inoculated with a streak of the unknown bacteria and then incubated. On the second day of incubation, the plate was removed from the incubator and placed over a hot plate heating Iodine solids. The smoke of the Iodine stained the plate to display the presence or absence of a halo around the bacteria 2.12 Lipid Hydrolysis This test was done by making a single line streak inoculation on a tributyrin agar plate and allowing incubation. After the incubation period, the plate was observed for the presence or absence of a halo around the bacteria.
Enterobacteriaceae - Enterobacteriacaea is a family of gram-negative, anaerobic, rod-shaped bacteria that are usually motile and consist of saprophytes and parasites of worldwide distribution. They can be found in soil, water, plants and animals. Q2I: Mutation - Mutation is an inheritable change in the base sequence of the genome of an organism. Question Set 3: Q3A: The authors hypothesized that colistin resistance was spreading by horizontal gene transfer as opposed to mutation.
Being able to identify unknown microbes from systematic testing is what makes the field of microbiology so important, especially in infectious disease control. Using the testing procedure laid out by the microbiology field we are able to identify unknown bacteria present in our everyday lives, and along the way learn a lot about their characteristics that separate them from other types of bacteria. Being able to do this is vital in order for us to understand why microbes are present in certain places, how they are able to grow and what restricts their growth, that way they can be combatted if necessary. These techniques for determining unknowns are also important for isolating and testing infectious disease microbes in order to prevent spreading. Another important aspect of being able to identify unknown microbes is the
The unknown bacteria was then tested on multiple selective and differential media. Growth was present on the MacConkey Agar and the colonies were the same color as the plate, which told me my bacteria was gram negative and did not ferment lactose. There was no growth on the Mannitol Salt Agar, and this told me the unknown was not salt tolerant and did not
Good and bad bacteria exist in our environment, depending on which one enters the body the immune system these bacteria can either compromise or aid the immune system’s illness fighting capabilities. In class we learned that the skin aids in fighting infection by acting as a protective barrier. In addition, we discussed how normal flora is found on the skin and aids in the defense mechanism because it fights off potential threats by competing with them. The normal flora consists of microorganisms such as protozoa, fungi and bacteria.
By Gram staining alone, it was safe to eliminate the three Gram positive bacteria that could have been assigned: S. epidermidis, M. luteus, and B. megaterium. The second step was to streak plate Unknown #10 to observe its macroscopic
Microorganisms are everywhere; organisms that are so small to be seen with the human eye cover the entire planet, including humans. Some of these microbes help with digestion of food other actually protect humans and other organisms from harm. Some however are deadly. Botulism for example is a deadly assassin hiding until the time is right to strike. Botulism is so good at its job that it can be easily misdiagnosed as other medical disorders.
After a gram stain was done unknown #257 was identified as a gram positive organism because when observed under the microscope the organism appeared purple with cocci in clusters. The organism was also catalase positive which means that it produced enzyme catalase and bubbled when hydrogen peroxide was added to it. Three test were conducted based on the result of the gram staining procedure. Blood agar with a Novobiocin disk was chosen as well as DNase (DNA) and Mannitol Salts (MSA) agar. The Blood agar is a bright red, opaque plate and the streaking or the inoculation technique was a modified streaking for isolation with a heavy quadrant one.
Introduction : The genus Salmonella belongs to the family Enterobacteriaceae (bacteria living in the intestine) and consists of two species, Salmonella enterica and Salmonella bongori (CCFH June 2007). Over 2500 Salmonella enterica serotypes are recognized, and all are regarded as capable of producing disease in humans. Worldwide, salmonellosis is a leading cause of enteric infectious disease attributable to foods. Salmonella cause serious systemic or enteric diseases in animals and humans, Illnesses caused by the majority of Salmonella serotypes range from mild to severe gastroenteritis, and in some people, bacteraemia, septicaemia and a variety of associated longer-term conditions.
Bacteria that causes disease are called pathogens. The disease is caused by a poison called exotoxin and endotoxin produced by the bacteria. Another microbial life are protist. They are unicellular eukaryotes. Types of protist includes protozoans and slime molds.
The genus Streptococcus belongs to the family of Streptococcacaea. It is a type of prokaryote that lacks a nuclear membrane, organelles (except for the ribosomes in the cytoplasm), and has its genetic material arranged in single continuous strands that form loops or coils. They are classified as bacteria because they meet the conditions needed to be classified as one. They are associated with the class of Bacilli, which is a classification of cocci or rod shaped bacteria. Lactobaccillales are the order of gram positive bacteria that can produce lactic acid.
Other bacteria reproduce inside the body and cause different infections - sore throats, ear infections, cavities, and pneumonia, to name a few. Other bacteria are used in labs to make things like medicine and vaccines. Is it amazing that some bacteria are vital to the survival of living things, while others cause