Birby Bauer Disc Diffusion Report

Abstract-The gram-negative bacteria Serratia marcescens has gained attention in recent years for its tendency to cause nosocomial infections in humans, as well as its development of antibiotic resistance. Antibiotic resistance in a bacterium that is harmful to humans can be concerning as it can result in infections that are difficult to treat. In order to find out more about the growing antibiotic resistance of S. marcescens, this experiment used the disc diffusion method to test the susceptibility of S. marcescens to two varieties of antibiotics that were known to have success against some gram-negative bacterium: streptomycin and ampicillin. These antibiotics were, respectively, an aminoglycoside and a beta-lactam. The experiment tested which of the two that S. marcescens had developed more of a resistance to. The zones of inhibition of the discs were significantly larger for discs treated with streptomycin compared to discs treated with ampicillin. This led to the conclusion that S. marcescens is less resistant to streptomycin than to ampicillin.

5.) Inoculate the plate with a lawn coverage streak and place 1 bacitracin antibiotic disk in the

This is important in the medical field because identification of unknown bacteria can help treat a patient by knowing the contributing source of a disease. Also knowledge of different bacteria helped others make antibiotics used today. This lab was completed by using the methods learned thus far in identification of bacteria.

Microchemlab.com states that a zone of inhibition is a qualitative method used clinically to measure antibiotic resistance and industrially to test the ability of solids and textiles to inhibit microbial growth. Researchers who develop antimicrobial textiles, surfaces, and liquids use this test as a quick and easy way to measure and compare levels of inhibitory activity (“Zone of Inhibition Test for Antimicrobial Activity”). The control of the experiment is distilled water. The independent variable is the different house cleaning products, and the dependant variable is the amount of growth or decline in the bacteria. Time, temperature, and amount of household household item are all constants in this experiment. Time needs to remain the same for all the products because time affects how well the bacteria grows. The temperature is required to stay the same as well because it can directly manipulate the rate of growth in the bacteria, and large amounts of the household item can offset the bacteria’s growth as

The Diffusion and Osmosis Lab determines the molarities of various sucrose solutions based on change in mass. Using table sugar in different amount of molar concentration 0.0M, 0.2M, 0.4M, 0.6M, 0.8M and 1.0M. The molarity of the solution of the sucrose solution in the dialysis tubing determines the amount of water that either move into the bag or out the bag, which also means its mass changed.

2. Which antibiotic was most effective in killing the bacterial lawn on each plate? Which was the least effective?

The Kirby- Bauer method is used to test antibiotics sensitivity to the microbe. Some antibiotics have broad-spectrum effect, which means they inhibit the growth of more than one microbe; while narrow spectrum only have an effective on one group of microbe. In order for this test to be effective a lawn of bacteria has to be made on Mueller- Hinton agar. This agar does two amazing things in the world of science. It contains a starch that makes it test plate transparent (easy to read results) and it control the rate of diffusion of the tested drug. Ampicillin, Gentamicin, Gentamicin, penicillin, and vancomycin are the fours types of antibiotics that were use to test the sensitivity of the microbe to them. The microbe was resistant to Ampicillin;

By making comparisons between the areas with the substances and quadrant A, it could be determined if the bacteria had been exterminated. By making comparisons between the areas with the substances and quadrant B, it could be determined if the growth of bacteria in the affected. Since the bacteria in quadrant B were allowed to grow without being affected by any manipulated variables, it was used as a reference point to determine if the substances had any effect on bacterial growth. Since each group was limited to one petri dish, no replicates were made. All observations in this lab were taken qualitatively (biological drawings) because accurate measurements could not be made due to the petri dish being sealed.

When investigating this experiment I found many different types of antiseptics all with different effects on bacteria and the effectiveness of all these antiseptics varied. I found

What is your conclusion with regard to the effect of the drug on curing the infection? What is the odds ratio using the CMH method?

The minimum inhibitory concentrations (MICs) of antibiotics for strains overexpressing an efflux pump are usually 2 or more folds higher than those strains of that species which didn’t have overexpressing an efflux pump.In this study, we hypothesized that the FQ resistant among P. aeruginosa isolated from burn wound infections (may be due to widespread use of FQ agents to treat burn wounds) could be in corporate with resistance to other existing antipseudomonal agents such as Beta-lactams and Aminoglycosides through FQ selected overexpression of multidrug efflux pumps. The specific aims of our study were to use CCCP as a screening agent to

The original plates were swabbed with defective bacteria that did not grow to show sufficient, so new plates were made in replacement and the following results and conclusions are based off of observations from the new plates. The hypothesis stated earlier was rejected by this experiment because in the hypothesis rubbing alcohol was predicted to have the largest zone of inhibition, but according to the class and overall average, Betadine has the largest zone of inhibition diameter at 42.2 mm for the class average and 39.6 mm for the overall average. As shown in the graph and table, the largest diameter lengths in order from least to greatest was Betadine with a class average of 42.2 mm and an overall average of 39.6

Gold standard procedures should be implemented with the aim of providing timely and accurate results. (Schentag) The culture result should be accompanied by its clinical significance, selective reporting of susceptibility testing results in accordance with hospital antimicrobial therapy guidelines and suggested management. (Schentag) This encourages appropriate prescribing and minimises unnecessary use of antimicrobials. The clinical microbiology team should also provide reports to AMS regarding resistant organisms.

The main objective of this experiment is to investigate the effect of different types of antibiotics on bacteria Bacillus subtilis and Escherichia coli. Some of the main methods used in this experiment

Antibiotic resistant pattern of Anoxybacillus flavithermus and Bacillus pumilus were done using disc diffusion method. Twenty two antibiotic disks were tested. i.e., Ampicillin, Streptomycin, Amikacin, Kanamycin, Chloramphenicol, Tetracycline, Rifampin, Piperacillin, Cephradin, Cefixime, Cefotoxime, Azithromycin, Clarithromycin, Erithromycin, Clindamycin, Fucidic acid, Nalidixic acid, Nitrofurantoin, Vancomycin, Novobiocin, Flumequine and Septrin.