Antimicrobial Lab Report

Antibiotics either stop the bacterial cell from reproducing or kill the cell. They can disrupt the bacteria by deterring

For the temperature test each bacteria was placed on a nutrient agar and incubated for either 10, 20, 30, 40, or 50 degrees Celsius for 48 hours. During the pH test, each organism was placed on four agars varying in pH level from pH 2, 4, 6 and 8 and incubated near 37 degrees Celsius for 48 hours. For the osmotic pressure test, each organism was placed on four agars one each containing 2%, 5%, 8%, and 11% NaCl concentration levels. These were incubated near 37 degrees Celsius for 48 hours. The results of the tests are recorded in Tables 1, 2, and 3. All tests were performed according to the instructions provided in Leboffe & Pierce(1). The biochemical tests used on both unknowns and the ubiquity are:

E.coli outbreaks have steadily grown over the last few decades. An expansion in big farming has led to E. coli not only being found in meat, but vegetation as well, due to waste runoff. This has increased our need for adequate antibiotics that can fight bacteria, like E. coli. The best way to pinpoint which antibiotics work is by measuring their ability to create antimicrobial agents or zones of inhibition. When a paper disc that has been saturated in an antibiotic is inserted in a solution of E.coli and medium, the zone of inhibition will be noted as the clear ring that forms around the disk. The antibiotics efficacy is then determined by measuring each disk zone of inhibition, and comparing these measurements to the zone measurements of an untreated specimen. If an antibiotic is to be deemed sufficient for treating E. coli it should show a zone of inhibition that is at least double the size of the untreated specimen.

According to a trial trying to determine bacterial resistance within the Enterobacteriaceae family “E. cloacae has been proven resistance to ampicillin, amoxicillin-clavulanic acid, first-generation cephalosporins, cephalothin, cefoxitin, broad-spectrum cephalosporins, as well as third generation cephalosporins.”1 The trial also stated that “this vast resistance is due to the bacteria’s

What would explain the phenomenon of a minute growth near a disc that had a clear zone of inhibition is that the agent is bacteriostatic because it is it is inhibiting the growth of the bacteria versus a bactericidal agent which just kills

Chemical antimicrobial agents are chemical compounds capable of either inhibiting the growth of microorganisms or killing them outright. Those which are taken internally to alleviate the symptoms of or promote healing from disease are called chemotherapeutic drugs, and among these is a class of compounds called antibiotics. In order for a chemotherapeutic drug to be classed as an antibiotic, it must be produced by a microorganism such as bacterium or fungus or at least derived from a chemical produced by one. It must also be capable of killing or inhibiting the growth of other microorganisms and of doing so when taken in very small quantities.

The part that would be measured is the diameter of the zone if inhibition. The independent variables would be the substances (P-10, S-10, C-30, and TE-30) and the dependent would be the zone of inhibition which is what would be measured. Some of the standardized variables for this experiment were the bacteria, the petri dish, and the nutrient. A

Penicillin inhibits the enzyme that is the cross link of pepitogylcin within the cell wall. This destroys the cell wall and exposes the inside of the cell to the external environment causing cell lysis. Penicillin is effective against gram-positive for this reason because of their thick cell walls that are full of pepitogylcin, as well as staphylococci and streptococci due to cell structure. Unfortunately, many bacteria strains have built resistance to Penicillin due to excessive use.

The purpose of this experiment is to show how different concentrations of Ampicillin affect Escherichia Coli Growth and how the bacteria become resistant to the antibiotic drug. Through a series of steps, which involves streaking agar plates with E.coli sample and application of ampicillin to the E.coli sample on the agar plate, the experiment yields a result that supports the hypothesis. The hypothesis acclaims that ampicillin would affect the growth of E.coli; measuring the zone of inhibition approves the claim in the experiment. The measurements of the zone of inhibition indicate that the generation of E.coli expands as the radius reduces. The reduction of the radius shows the E.coli population is reducing and becoming resistant. In other

Penicillin, as well as other β- lactams, inhibits the enzyme that places essential cross-links between the individual polymer strings of the cell wall. It does this specifically by using the β-lactam ring to irreversibly block the active site of the enzyme, which catalyzes the reaction, transpeptidase. This inhibition allows the bacteria to newly synthesize a cell wall and to elongate, but not divide. This is due to the lack of cross-linking. The result is disruption of cell wall integrity, making the cell osmotically unstable and susceptible to lysis (Walsh, 2003). Penicillin reacts with the transpeptidase to form a stable acyl intermediate. The β-lactam ring acylates the hydroxyl group of one specific serine residue in the transpeptidase, producing an inactive penicilloyl-enzyme complex (Williams et al.,

faecalis and E. faecium. However, even though tetracycline exhibit clinically significant anti-enterococcal activity, it is generally considered a second-line agent and is seldom used for enterococci treatment nowadays, so these results may not be alarming. Nonetheless, this finding, as well as increasing rifampin resistance in E. faecium urine, although non-significant, should be taken seriously and preventive measures should be taken. More concerning is the emergence of linezolid resistance in both E. faecalis and E. faecium, which remains a crucial therapy for VRE faecium, providing additional evidence of a growing public health crisis. Linezolid resistance in enterococci, although still relatively less common, has been linked with increasing linezolid use previously.18 Our findings could also be related to the involvement of antibiotic selective pressure on changing enterococci resistance, supporting a cautious use of these antibiotics and reinforcing the need for better infection control strategies and alternative therapies to treat enterococci infections. Our findings may explain the linezolid resistance of <30.2% for E. faecalis urine isolates observed in a previous

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

1. Make a wet mount (Ex 12) of a small sample of the alfalfa water. Examine at 1000X total magnification using high contrast. This will illustrate how many organisms, both motile and non-motile, are present in the sample.

Examples of antibiotics that are commonly used in infection treatment include: gentamycin, tetracycline, streptomycin, and carbenicillin

Tetracycline is a common antibiotic that is used to treat many patients that have infections such as urinary and respiratory infections. The objective of this research was to analyze the effects of Tetracycline on E.coli, in order to determine if it would have a dose response to the sensitive strain DH5Alpha. For the experiment, we had to prepare a bacterial Serial Dilution based on our MIC range of 1 µg/ml to 128 µg/ml. First, we prepared a bacterial serial dilution and placed the bacteria on LB agar, and incubated it at 37 degrees Celsius until the next lab period. During the incubation period, we began to calculate our tetracycline serial dilution. Then began preparing the samples by adding them to bacterial plates. We then incubated the bacterial plates that have tetracycline. After a week of incubation, we interpreted our results from the antibiotic plating. The Results showed that any concentration lower than 0.15 µg/ml will show a growth in bacteria compared to a concentration higher than 0.15 µg/ml that showed no growth of bacteria. Therefore, the minimum inhibitory concentration of Tetracycline that would inhibit growth of E. Coli is 0.15 µg/ml.