Bacterial Strains : A Study And Their Sources

There are many types of bacteria that can be found in your bathroom. They might also be found on your toothbrush! I have been researching about what bacteria are lurking in my bathroom. I placed 6 petri dishes filled with agar in my bathroom. I left them there for 24 hours to collect bacteria samples.

In the beginning of lab, we were advised to obtain a nutrient agar petri plate, which is used for the cultivation of microbes supporting growth of non-fastidious organisms. Since it contains many nutrients, a wide variety of bacteria and fungi can grow. Taking the plate,

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

(Biology Dept.). 0.1 ml of E.coli K or 0.1ml of E.coli B was added to the 10 fold dilution. Using soft agar technique, the growth media mixture with E.coli was plated and incubated.

In a laboratory setting, it often becomes necessary to identify an unknown organism. In this experiment, researchers classified an unidentified bacterium based on its physical structure, colony morphology, optimal conditions and metabolic properties. A Gram stain using crystal violet, iodine, and safranin and a simple stain using methylene blue characterized the organism’s cell wall. Cultural behavior was classified by inoculating the organism onto nutrient agar and incubating it at 37° C for 48 hours, and observing its behavior, as well as using SIM medium to test for motility. Optimal growth temperature was

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.

Citrobacter Freundii is a species of bacteria that can be potentially harmful to humans. It is known to cause meningitis by protruding into the brain and replicating itself (1). The Citrobacter species has also been found as a cause of some urinary tract infections, diarrhea, and even gastrointestinal diseases and symptoms (3). C. Freundii can be located in a wide variety of soils and water (3). Lastly, it is also the cause of many nosocomial infections due to its presence in water (1).

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.

Different microbes can transmit and produce different types of diseases and infections. Having an unknown bacterium in the body can be a life and death situation. It is very important especially in the healthcare industry that providers are able to differentiate between organisms that are pathogenic and administer the appropriate treatment to their patients. Applying methods that were previously studied in lab, students must be able to isolate an unknown specimen by using laboratory techniques and biochemical tests.

An unknown bacterium 15 was awarded and labeled at the table ready to be identified. Using the skills and test that are taught and learned in microbiology were applied into learning what the unknown bacteria culture was. There were multiple procedures and test done in order to gain all the information needed to determine which bacteria was given. In order to find what the bacteria was the first step was finding the right environment and temperature that would allow the bacteria to thrive and grow. Determining this is one of the most important steps in being able to obtain conclusive results that would allow the results of the test to be accurate and correct. Without the correct temperature and environment the bacteria will give inconclusive results which will alter and skew the end results and may lead to the wrong conclusion. By using the methods that were obtained and learned through the microbiology class allowed the skills and knowledge to determine the bacteria and execute the tests in order to determine the culture.

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.

In the world of microbiology it is vitally important to be able to discern the identities of microorganisms. Not only is it important in a lab setting but as well as in healthcare in general. Properly identify what strain of bacteria a person has will aid in the proper medicine and dose given. Throughout the semester we have learned about different types of bacteria and certain test that can clearly identify them. The purpose of this lab report is to identify a Gram-positive or Gram-negative bacterium. Using all the knowledge of procedures and lab techniques identify the unknown and discuss all the tests you performed.

Bacteria are identified systematically by using various different techniques and narrow down their species present in an unknown bacterial culture. This is highly usefully in identifying infections correctly and in research regarding microorganism. Laboratories use identification techniques based on primary characteristics and gram stains to carefully identify unknown organism in samples collected (faeces, blood, sputum, mucosal swabs), to determine the cause of infection and define a disease.

In this process, I am determined to know my unknown bacteria. So I start by inoculating my unknown bacteria, and spread it on the surface of my EMB medium agar, I take the EMB medium and place it on my incubator chamber. I will get my result on the following day. When the day comes, I walk to the incubator to take out my result, and I found out that it is showing shining green culture on top of the agar. I notice that it is a positive result, and I follow through the dichotomous key, which help me to separate the bacteria from others base on this characteristic. EMB test for Gram-negative bacteria because it has a built-in lactose fermentation that allow them to grow. I make another culture of the unknown bacteria for the following day.

Streptococcus agalactiae also called group B streptococcus (GBS) by Lancefield classification. GBS is gram-positive coccus that tends to form chains, and is part of the normal flora of the genitourinary tract. GBS is a leading cause of newborn early onset disease (EOD)[1, 2], and has highly morbidities and mortality rate[3]. It also associated with invasive disease in adult especially older people over 65 ages[4]. When GBS infects of blood it cause sepsis, infection in the lungs causes pneumonia, infection in the fluid and lining around the brain will cause meningitis[5]. GBS capsular polysaccharide (cps) is the most important virulence factor and now there is ten capsular serotypes have characterized[6], serotypes Ia, Ib, II, III, IV,