Inhibition Of E-Coli

Out of the all the antiseptics being used in this investigation the more well known antiseptics such as dettol and sudocrem will be more effective when stopping the growth of bacteria than natural antiseptics like lemon.

When streaking bacteria and handling mannitol and xylitol solutions, the experimenter wore an apron, nitrile gloves on both hands and plastic protective goggles. After each set of plates were prepared, the experimenter removed the gloves from both hands without skin contact and thoroughly washed their hands for approximately 20 seconds with soap and warm water. Throughout the entire experiment the experimenter was cautious also to avoid contacting bacteria with eyes, mouth, or open wound.

What exactly is E.coli poisoning? What is the origin of e.coli? I always had these question in mind and decided to do this research on this topic because it has always been a subject during these past few years and it's becoming a topic over the news. As I was doing my research on the topic is then when I knew that the name E.Coli that we always see wasn’t the actual name of it. Its name is called Escherichia Coli and that there a few different types of e.coli which I never even knew of. I never thought of what could happen if someone gets infected with e.coli or how cautious we should be trying to stay away from it. Is it also something not just us to prevent it but also the way it gets into the foods we eat. It’s best to know and understand how it could become a big issue even if you are careful with how to handle it. How do actually keep e.coli away from us how should the government make sure the rates of food contamination decrease?

Three of the circles were labelled with the number 1, three were labelled 2 and three were labelled 3, leaving three blank. The swab was removed from the packet and quickly placed into the bottle of e. coli bacteria then quickly being removed with no dripping chemicals. The e. coli bottle was then closed while the swab applied the e. coli onto the base of the agar plate making an ‘s’ shape pattern, and then turned 90 degrees and was repeated. After this was completed the lid was placed on that agar plate while one of the small circles labelled number one was dipped into a small amount of detergent. The lid was removed from the agar plate and the paper was placed onto the top left corner of the agar plate using tweezers. Once it was flat on the base with the number one facing up, the lid was again put on the agar plate to prevent bacteria from the air landing on the surface. Using a new, clean pair of tweezers a piece of paper labelled with the number two was dipped into hand sanitiser, the lid was removed and the paper was placed flat on the top right corner of the base of the plate with the lid then being replaced on the plate. With another pair of

Escherichia coli are bacteria commonly found in the intestines of humans and other animals (Water: Basic Information about Regulated Drinking Water Contaminants 2009). Many strains of E.coli are harmless and contribute to healthy intestinal tracts. However, some strains can cause illness, including abdominal cramps, diarrhea, vomiting, hemorrhagic colitis, and hemolytic uremic syndrome (Tian Ding 2012).

Purpose: To explore the effectiveness of different levels of concentration of antiseptic and antibacterial products’ prevention of bacterial growth.

EMB media is also selective and differential. This media selects for Gram-negative bacteria due to the toxicity of the dyes in it to Gram-positive bacteria. It differentiates bacteria by resulting in a metallic green sheen being produced on the colonies that can ferment lactose. The fact that no significant growth was observed on the 12 EMB plates suggests that there was a problem with the plating method. It would be extremely unlikely to swab a surface and find no Gram-negative bacteria present. The results of the MS and EMB trials led to a shift in swabbing and plating methods in an attempt to maximize bacterial

The lab result was phenomenal. We were able to distinguish which substance was more resistant to the bacteria. Comparing the results to the control disk, P-10 didn’t do as much compared to C-30 which is the most effective substance due to a higher zone of inhibition percentage. The substance disk that proved to be the most effective was C-30 which was then followed by TE-30, S-10, and lastly P-10 (see graph below). However the only two substance disks that were higher than the 10% difference were C-30 and TE-30 and both P-10 and S-10 had less than 10% difference showing errors in

This efficacy can be analyzed via various antimicrobial tests such as E-tests, disc diffusion, agar dilution, and microdilution. E-tests assess antimicrobial properties by applying a concentration gradient using strips on an agar plate inoculated with the microorganism of interest. The inhibition zones can then be assessed surrounding each strip of known antimicrobial concentrations. Disc diffusion uses this same procedure; however, the antimicrobial is applied to small discs rather than a strip. Agar dilution quantifies an effective antimicrobial concentration by using multiple agar pour plates containing increasing concentrations of the inhibitory compound. The minimum inhibitory concentration (MIC) can then be determined by identifying the agar plate with the lowest concentration that did not support growth. Microdilution – the antimicrobial test conducted in this experiment – determines the MIC by filling the wells of a microtiter plate with decreasing concentrations of the antimicrobial. Micrograms are then added to the wells at a standardized concentration and the plate is incubated for 24-49 hours and the optimal temperature. Growth in these wells is then determined by measuring the turbidity (OD600) of the broths. Thus, the MIC identified as the well with the lowest concentration of the antimicrobial that inhibits

However, additional tests can be performed to further differentiate the three bacteria from one another. One example is the BactiStaph test for the Staphylococcus genus (in this case S. aureus) (Summers, Brookings and Waites, 1998). Which relies on the principle of detecting coagulase (clumping factor) using fibrinogen, and detecting protein A with immunoglobulin G. As result of these surface markers present on most strains of S. aureus will test positive for BactiStaph test (Summers, Brookings and Waites, 1998; Harris, Foster and Richards, 2002); Another test to differentiate E. coli and B. cereus from S. aureus is by the basis of motility. Using either MAST motility test or hanging drop method differentiate E. coli and B. cereus from S. aureus, as the two bacteria are motile (Mitchell and Kogure, 2006); Lastly, since neither E. coli nor S. aureus produce endospores, whilst B. cereus under the right conditions does produce endospores. By using techniques such as Dipicolinic acid assay or Schaeffer-Fulton spore stain can be used to assess the presence of spores in B. cereus (Hindle & Hall, 1999).

Current biological research investigations show that both lemon and lime juices have an affect on slowing down and potentially stopping the growth of Escherichia Bacteria by creating an inhibition zone. This can be seen in an experimental report done by Dr. Zahra Muhsin Ali “Antagonism activity of citrus fruit juices on some pathogenic bacteria.” The experiment was conducted in the Biological Department of Science at Kufa University to determine the antagonism activity of both Lemon and Lime juices against various bacterium, one of them being E. Coli. The results of the experiment revealed that each juice concentration had inhibiting effects against bacteria due to the presence of citric acid and some volatile oils. The results also showed a reduction in the value of pH. The investigation was further proved successful due to both juices from lemon and lime were found to have inhibited the E. Coli bacterium parameter with an inhibition zone ranging from 8-29mm which can be seen in figure 4. The antagonism effects of the lemon and lime juice was compared with the antagonism effects of some antibiotics, the results being that the isolated E. Coli was resistant to the majority of antibiotics. Proving that overall the experiment conducted was successful

Antibiotics used in this experiment were Penicillin, Chloramphenicol, Tetracycline, and Erythromycin. Penicillin works by attacking bacteria’s peptidoglycan protein links and breaking down the cell wall. Penicillin works on gram negative bacteria but works better against gram positive bacteria. Chloramphenicol and Erythromycin work similarly by inhibiting bacteria’s protein synthesis, which inhibits overall bacterial growth. Both Chloramphenicol and Erythromycin work on both gram negative and gram positive bacteria. Chloramphenicol inhibits protein chain elongation by interfering with the peptidyl transferase activity of the bacterial ribosome at the 50S ribosomal subunit, that prevents peptide bond formation. Erythromycin also binds at the

coli was seen to have a faster growth rate in the 0.5% garlic extract dilution. The growth rate of the 0.5% garlic extract was 1.358 generations per hour. In contrast, the growth rate for 0% garlic extract was 0.882 generations per hour which was the smallest out of the four garlic extracts. In between the 0% and 0.5% garlic extract, the 0.1% and 0.25% garlic extract had growth rates of 0.907 generations per hour and 0.816 generations per hour respectively. With 0.5% garlic had the fastest growing rate, a E. coli generation forms as fast as 44.181 minutes. The 0% garlic extract developed a generation with a time generation of 68.028 minutes, and the 0.1% and 0.25% garlic extracts had time generations of 54.410 minutes and 48.912 minutes respectively. E. coli in the 0.5% garlic extract dilution had grown quickly and surpassed the other 3 dilutions by hour 8 with an OD600 of 1.735 and remained the second highest at hour 25 with an OD600 of

coli strains. The researchers used 11 essential oils in this study instead. The oils were dispersed at room temperature for two minutes using a homogenizator at 20,000 rpm in a sterile 10% (wt/vol) modified, starch solution to obtain a colloidal suspension (10%, wt/vol) The starch helped the oils disperse and improve the antimicrobial properties. The starch solutions were added into a 15ml molten BHI agar. The final concentrations of the various essential oils were obtained and ranged from 0.25 to 2% (vol/vol). The 15ml of molten agar was placed in a Petri dish and left to solidify. Each bacterium was cultivated in colonies of (2x107cfu/ml) was diluted to obtain 10-4 and 10-5 in peptone water (0.1% wt/vol). Then 40 ¼ L of each colony was added to the molten agar solution. Then cheese and meat exposed to the bacterium in the molten agar solution. The results showed that a percentage of sage and thyme oil ranging from 0.5% to 1% were able to reduce bacteria growth by 2-log cycles for E. coli shown in figure 1 to the left. The research showed that the use of sage is an efficient method to limit the growth of bacteria. Although, figure 1 shows thyme being more effective against E. coli than sage there are greater negative aspects of using thyme regularly then sage. Thyme extract used in abundance can cause heartburn, nausea, vomiting, stomach upset, diarrhea, headache, and dizziness. In addition, the volatile oils present in thyme leaves may promote slowed heart rate and rapid breathing in certain individuals. These negative side effects can be extremely unpredictable in an environment such as the zero gravity cabins of the International Space Station(ISS). On the other hand, sage plants have fewer side effects which can be

Also another contribution of error may have come from bar spreader that was used to allocate the samples evenly onto the agar plate. The bar