Reliable Plate Count Bacteria

Hunting the Nightmare Bacteria documentary has had me paranoid. It’s scary to think foreign bacteria can enter your body and shut it down. The most informing information was the NDM-1 wasn’t a bacteria it was a resistance gene that can turn bacteria into superbugs. I do think antibiotics are being over used. I agree with M.D Arjun Srinivasan,” the more you expose a bacteria to an antibiotic, the greater the likelihood that resistance to that antibiotic is going to develop. So the more antibiotics we put into people, we put into the environment, the more opportunities we create for these bacteria to become resistant”.

In the last decade, the number of prescriptions for antibiotics has increases. Even though, antibiotics are helpful, an excess amount of antibiotics can be dangerous. Quite often antibiotics are wrongly prescribed to cure viruses when they are meant to target bacteria. Antibiotics are a type of medicine that is prone to kill microorganisms, or bacteria. By examining the PBS documentary Hunting the Nightmare Bacteria and the article “U.S. government taps GlaxoSmithKline for New Antibiotics” by Ben Hirschler as well as a few other articles can help depict the problem that is of doctors prescribing antibiotics wrongly or excessively, which can led to becoming harmful to the body.

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 unknown bacteria plate chosen was plate #2. It was identified to be Micrococcus luteus. It is a gram positive, Coccus bacteria that is commonly found in dust, water, soil, and the air. M. luteus also thrives in the human mouth and upper respiratory tract. Sir Alexander Fleming discovered it in 1928 before he identified penicillin. It is part of the normal flora on human skin as well as other mammals. Since it is part of normal flora it is normally not pathogenic, but can become opportunistic in an immune-deficient person. It has been known to cause septic shock, UTI’s, and even pneumonia. Micrococcus luteus is both urease and catalase positive. It does not utilize tryptophan for indole production. It is a facultative anaerobe. Mobility is not present for this bacterium. Starch is also not hydrolyzed and oxidase is not present.

This test is used to detect the hemolytic activity in the bacteria. A darkish green color on the media around the bacteria would represent incomplete hemolysis. A transparent media around the bacteria colony represents complete lysis of the red blood cells. If no change is observed around the bacteria colony then the bacteria is non-hemolytic. For my

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).

# of plaques/(volume plated x reciprocal of the dilution factor of the dilution tube used)

Once the lab has obtained the sputum sample, they will begin the process of trying to identify the bacterial pathogen within the infected patient. The quadrant-streak plate method can be used to isolate different bacterial colonies. After obtaining the necessary medium, labeling the petry dish, a small portion of the sputum sample is streaked across the first quadrant of the dish in a "zig-zag" pattern using a sterile inoculation loop. After sterilizing the loop, the step is repeated 3 more times in a clock-wise pattern, dragging part of each quadrant into the next. In all, there will be 4 quadrants. It is important to sterilize the loop in between each quadrant to isolate the individual colonies.

In the 10-3 pasteurized sample, the plate exhibited 71,000 cells/mL. The results of the additional dilution samples contained too few colony forming units to count. However, in the 10-7 dilution, although the plate demonstrated 12 colonies, there should have been no colony forming units on this plate. The reasons for this could have been that this sample was contaminated from “double-dipping” the sample before dispensing it onto the plate or when using the pipette, it mistakenly was inserted in a higher concentration sample and then immediately to a lower concentration sample before it was dispensed onto the plate.

This experiment is about bacterial growth. We will demonstrate a bacterial growth curve using a closed system. Bacterial growth usually takes up to 12-24 hours to get an accurate result so we will be monitoring this growth between two classes. We also used different methods to determine bacterial growth as well as a few different calculations. One way of receiving data is by using a spectrophotometer where we will record the absorption at a given time to create the bacterial growth curve. We also used the plate count method after performing a serial dilution to calculate the actual cell density at different times given. By using this method we can count the population number of the same given and see the maximum cell density

Title Selective and Differential Media, Replica Plating, Rapid Microbiological Systems Andrisha Smith Microbiology 275 Dr.McCann October 20, 2017 Introduction Microbiological media is used to grow microorganisms, select or identify a particular type of microorganism based on aspects of their biochemistry. The two types of medias used in tis lab were selective and differential media. Selective medias are designed to grow some microorganisms and inhibit the growth of others.

Being able to control bacterial growth is something that is important in our everyday lives. As shown in the previous labs, bacteria can grow and create colonies extremely quickly especially in the right environments. By acknowledging this, it is then important to get an understanding of how bacterial growth can be controlled by humans. To control microorganisms it means to inhibit their growth (static) and or kill them (cidal) (Kenneth Todar, 2015); therefore since focusing on bacteria the terms bactericidal and bacteriostatic are both extremely important for this lab. One broad method we will use to control bacterial growth is heat. The amount of heat needed to control bacterial growth is different for different species of bacteria (Kenneth Todar, 2015). Bacteria can also respond differently depending if moist heating method such as an autoclave with steam is used, or a dry heating method such as inoculating a loop over a fire is used (Kenneth Todar, 2015). UV works by damaging the cells DNA, without proper DNA, the cells will die and the object

On each slide a drop of the culture and it was covered with the cover slip. It was made sure that a clean pipette, slide and cover slips were used when sampling that was to avoid contamination. Then the compound microscope was used to examine the live culture under the low magnification that was followed by observing with the medium power. Then each organism that was observed was record in the table that was done for all the slides. Then the percentage abundance for each organism was estimated and recorded for each week.

The purpose of this experiment is to obtain isolation of individual species of particles from the mixed culture. This is completed through the isolation technique of streak plate. The objective of this experiment is to replicate the technique of streak plate but on a much larger scale. Because it is on a larger scale the particles are able to be visually observed as they are isolated using the streaking technique as the experiment is conducted. The benefits of the streaking technique is when a cultures has multiple species they are able to be more easily identified once they have been isolated. This experiment is much like the experiments completed on an agar plate but on one a much larger scale and where techniques

The idea of the experiments is to introduce the concept of bacterial multiplicity of the shapes, forms and species. In addition, the objective of this concept was to recognize, and observe bacterial diversity from three different experiments. The first experiment was to identify differential growth, the second experiment was to calculate bacterial population, and the third experiment was identifying which bacterium was Gram positive or Gram negative. Bacterial diversity has nearly 5,000 species of bacteria that is known, however, it is believed that there are still more types to be discovered. Due to bacteria of being small, it is difficult to culture them and study in precise detail. Although bacteria are small, they are not the smallest living organisms. Let alone, the identification of bacteria is based on a combination of characteristic in cell shapes. The three basic