Identifying And Identify Two Unknown Bacteria From A Mixed Culture

There are many reasons for identifying an unknown bacterium. The reasons range from medical purposes, such as determining if the unknown could cause ailments in living things or knowing what microorganisms are needed to make antibiotics. The experiment was done by applying methods in order to identify an unknown bacterium.

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 I have been learned so far in the microbiology laboratory class for the identification of an unknown bacterium.

Many tests were completed on the unknown such as gram staining and inspection under microscopes to find whether the bacterium is gram positive or gram negative. Chemical resistance tests were also performed to see if certain chemicals affected the unknown growth or if it didn’t affect the bacteria at all. Each biochemical test

The purpose of the Unknown Project is to help microbiology students learn to identify an unknown bacterium in a mixed culture by performing different types of tests in a lab. The student must be familiar with the tests and should be able to analyze and interpret the results. Based on the results attained, an organism may be proposed. But what is a mixed culture? A mixed culture contains either two or more different types of identified microorganisms in a container, like a test tube for example. The culture may carry either organisms from the same bacterial family or it may contain a mixture of fungi and bacteria or other combinations. Being able to identify different types of organisms is essential for us to know if by any case, risks are presented. These cultures are performed mainly in hospitals. They are obtained from different parts of a patient’s body, depending on the suspected infection. Registered Nurses can perform certain cultures like blood, urine, sputum, etc. and send them to the lab. A mixed culture has been helpful in previous medical research by helping determine whether a patient has a bacterial infection or not. For example, “Sputum samples often give mixed cultures. Since the patient coughs up the sputum from the lungs, the sample can become contaminated by normal mouth bacteria, resulting in multiple types of bacteria in the culture.” (http://www.ask.com/science/mixed-culture-microbiology-af200d033ce00db0) Many tests may be performed on this mixed

Whenever there is an unknown disease caused by microorganisms, tests are usually made in order to identify the organism causing the disease. There are several tests that need to be made and they include tests such as performing a gram stain, streaking a plate to isolate colonies, inoculating a broth culture, inoculating API strip, and performing oxidase and catalase tests. Having knowledge on how to identify these tests are of high importance in the medical field so it would be to the advantage of those individuals who know how to examine microorganisms and be able to identify it by correctly performing tests on organisms.

Staphylococcus aureus is a gram positive cocci that forms grape like clusters, produces catalase, has a peptidoglycan and teichoic acid cell wall, and has a G + C content of DNA ranging from 30-40 mol%. An estimated 20% of the human population is long-term carriers of S. aureus, appearing in the nares of the nasal passages and also part of the natural skin flora which is the most common species of Staphylococcus to cause Staph infections. S. aureus is a successful pathogen due to a combination of nasal carriage and bacterial immuno-evasive strategies. S. aureus can cause minor skin infections, pimples, impetigo, boils or furuncles, cellulitis, folliculitis, carbuncles, scalded skin syndrome, and abscesses. Life-threatening diseases such as pneumonia, meningitis, osteomyelitis, endocarditis, toxic shock syndrome, bacteremia, and sepsis are also caused by pathenogenic S. aureus. Its extent ranges from skin, soft tissue, respiratory, bone, joint, and endovascular to wound infections. Nosocomial infections and often postsurgical wound infections are a commonly caused by S. aureus. S. aureus is also a prominent cause of food poisoning in the US, and can be transmitted by different foods, including milk and

Staphylococcus aureus is a type of bacteria. It stains Gram positive and is non-moving small round shaped or non-motile cocci. It is found in grape-like (staphylo-) clusters. is one of the five most common causes of infections after injury or surgery. It affects around 500,000 patients in American hospitals annually. It is abbreviated to “S. aureus” or “Staph aureus” in medical literature. S. aureus was discovered in Aberdeen, Scotland in 1880 by the surgeon Sir Alexander Ogston in pus from surgical abscesses. (Mandal, 2012).

Staphylococcus aureus is a gram-positive coccal bacterium that is a member of the Firmicutes, and is frequently found in the nose, respiratory tract, and on the skin. It is often positive for catalase and nitrate reduction. Although S. aureus is not always pathogenic, it is a common cause of skin infections such as abscesses, respiratory infections such as sinusitis, and food poisoning. Pathogenic strains often promote infections by producing potent protein toxins, and expressing cell-surface proteins that bind and inactivate antibodies. The emergence of antibiotic-resistant strains of S. aureus such as Methicillin-resistant S. aureus (MRSA) is a worldwide problem in clinical medicine.

Staphylococcus Aureus, commonly known as “Staph”, is present on most of the population on our skin and in our nostrils and throat. It can live on even the healthiest, cleanliest individuals. The staph bacteria do not cause harm until there is an open area or break in the human’s main defense system, the skin. Once the bacteria enter the wound, an infection may occur.

Staphylococcus aureus is an important and common pathogen in humans. It is found in the nose or on the skin of many healthy, asymptomatic persons (i.e., carriers) and can cause infections with clinical manifestations ranging from pustules to sepsis and death. Most transmission occurs through the contaminated hands of a person infected with or carrying S. aureus. MRSA infections frequently are encountered in health-care settings (Lowy, 1998).

S. aureus is a Gram-positive coccus where the round cells arranged in irregular grape-like (Greek staphyle) clusters.1 They can both have aerobic and anaerobic respiration and most strains ferment mannitol anaerobically. It is distinguished from other staphylococcal species on the basis of golden (Latin aureum) or white colonies on blood agar and positive results of coagulase, mannitol-fermentation and deoxyribonuclease tests.6 S. aureus is one of the major baterial that can be found on people’s skin and in their nose. Usually it does not cause any harm. But if staphylococcus gets into the body, it will causes skin, soft tissue and bone infections. The infections can be minor or serious that may even lead to death. However, there is one-fourth of healthy people who carry it asymptomatically.2 The main treatment of S. aureus infections are antibiotics and surgical drainage, but the emergence of antibiotic-resistance of S. aureus to penicillin, methicillin and other agents has compromised therapy.2

S. aureus is one of the most important amongst Staphylococci species. The species is found primarily on human skin, mucous membranes and can also be found in other areas of human contact including soil, water, and food products. The species is capable of causing a wide variety of diseases, including septicaemia, sepsis, wound sepsis, septic arthritis, osteomyelitis, food poisoning,

Life History and Characteristics: Staphylococcus aureus is a gram positive bacterium that is usually found in the nasal passages and on the skin of 15 to 40% of healthy humans, but can also survive in a wide variety of locations in the body. This bacterium is spread from person to person or to fomite by direct contact. Colonies of S. aureus appear in pairs, chains, or clusters. S. aureus is not an organism that is contained to one region of the world and is a universal health concern, specifically in the food handling industries.

The objective of this report was to identify an unknown microorganism through several differential media tests. Over the course of a couple weeks, ten tests were performed. First, a gram stain was performed, indicating the bacterium was gram negative. An aerotolerance test determined that the bacterium was a facultative anaerobe. Next, a negative result in the methyl red test indicated that no mixed acid fermentation occurred. The DNase test was performed and yielded a positive result. The SIM test provided two outcomes, that the bacterium did not reduce sulfur nor produce indole from tryptophan.

The genus Staphylococcus is a Gram-positive cocci that is commonly arranged in grapelike clusters. They are universally present in large numbers on the mucous membranes and skin of humans and other warm-blooded animals. They are non spore forming, nonmotile, facultative anaerobes. Many species of staphylococcus can be pathogenic. Staphylococcus aureus is the most common pathogen. It can be recovered from skin lesions, abscesses, and wound infections. It can move from these sites to the bloodstream and urine, where it then has the possibility to cause more serious conditions in various organs.