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Testing Antibotics On Bacteria Essay, Research Paper



To find the consequence of 10 different antibiotics on two different types of bacterium. I will prove six antibiotics on Escherichia coli, and six

antibiotics on Bacillus subtilis. On Escherichia coli I will prove Achromycin, Chloromycetin, furadantin, nalidixic acid, ternary sulpha, and Kantrex. On Bacillus subtilis I will prove streptomycin, Erythrocin, novobiocin, Achromycin, Chloromycetin, and penicillin. As a side observation, I would besides wish to see if Bacillus subtillis shows opposition to penicillin. The usage of penicillin is being reduced because of the opposition many types of bacteriums are developing against it.


My hypothesis is that penicillin will suppress the most growing against Bacillus subtilis, and that Achromycin will halt Escherichia coli more efficaciously than the others.


I feel that this experiment is valid because it shows how different antibiotics react to different types of bacterium. It besides points out the fact that non all antibiotics work the same or that they work at all on all types of bacteriums.


1 bottle of tryptic soy agar

1 civilization of Escherichia coli

1 civilization of Bacillus subtilis

4 unfertile petri dishes

1 battalion of trial phonograph record

2 unfertile pipettes

2 tubings of physiological saline

1 forceps

1 wax pencil

2 unfertile swabs


1. Loosen the cap of the tryptic soy agar to let it to vent. Put the bottle in a H2O bath at 100 grades Centigrade so that the H2O degree reached the degree of the medium. The agar will run in approximately 20 proceedingss.

2. Gradually cool the medium to about 45 grades Centigrade by allowing the H2O bath cool. Then allow the medium sit for 10 proceedingss.

3. Pour two home bases for each species of bacteriums. The agar should be about 5 mm deep. Cover each petri dish instantly after concentrating to forestall taint.

4. After pouring the home bases, let the agar a few proceedingss to solidify. You can look into this by leaning the home base. If the agar flows to one side, more cooling clip is needed.

5. Add a tubing of physiological saline to each of the bacteria civilization tubings. Replace the top on the saline tubing. Twirl the civilization tubing to scatter the bacteriums in the saline.

6. Using a unfertile pipette, reassign 0.25 milliliter of saline from one bacterial tubing onto each of the two home bases. With a unfertile swab, spread the saline in a thin bed over the full agar surface. Repeat with the other bacterial tubing and home bases, utilizing a pipette and swab. Let 5 to 10 proceedingss for the liquid to be absorbed into the agar.

7. Use the wax pencil to label each dish so that you will cognize what species it contains.

8. When the agar has solidified, the antibiotic trial phonograph record can be added. Using a forceps flamed between each operation place one of each type of trial phonograph record on the surface of each agar home base. The phonograph record should be placed about 3 centimeters apart. The antibiotic on each phonograph record should be identified by the undermentioned abbreviations:

S=Streptomycin, E=Erythromycin, N=Novobiocin, T=Tetracycline, C=Chloramphenicol, P=Penicillin, F=Furadantin, Na=Nalidixic acid, Ts=Triple sulpha, K=Kanamycin

9. After the civilizations have been in the brooder for 48 hours. Remove them and look into around each phonograph record for an country where the bacteria could non turn. Measure each grow country in millimetres and enter them on a tabular array ( see table 1 ) .

Literature Search

Escherichia is a genus of bacillar bacteriums, in the household Enterobacteriaceae. Named for Theodor Escherich ( 1857-1911 ) , a German bacteriologist, the lone species, Escherichia coli, is found in big Numberss as a normal dweller of the big bowel of warm-blooded animate beings. Whenever they leave their usual home ground, these beings can do urinary-tract infections, peritoneal inflammation, endocarditis, and other diseases. Some strains cause terrible stomach flu. E. coli has been widely used as a theoretical account in molecular biological science surveies.

Certain rare strains of the bacteriums Escherichia coli can do nutrient toxic condition in immature kids, the aged, and people with impaired immune systems. E. coli 0157: H7, usually found in the bowels and faecal affair of worlds and animate beings, can last in meat if the meat is non cooked past 155 grades F. A 1993 U.S. eruption of this type of nutrient toxic condition, which affected over 450 people, was attributed to contaminated beefburgers that were cooked rare.

In 1928, Alexander Fleming noticed that growing of the pus-producing bacteriums, Staphylococcus aur

Eu, had stopped around an country in which an airborne cast contamination, Penicillium notatum, had begun to turn. Fleming determined that a chemical substance had diffused from the cast, and named it penicillin. The little, impure sums he ab initio extracted lacked authority, giving dissatisfactory consequences in early efforts to handle human infections with penicillin. In 1939, Ernst Boris Chain, Howard Walter Florey, and Edward Penley Abraham at Oxford University began to analyze the possibility that purer, more stable penicillin readyings might be effectual. In 1941 the partly purified stuff was administered to a police officer enduring from osteomyelitis. Dramatic betterment ensued, but the supply was exhausted before a remedy could be effected, and the patient died. Nonetheless, the affair evidently deserved farther geographic expedition, and the eruption of World War II added an component of urgency. The war, nevertheless, interfered with efforts to do penicillin in England on a big graduated table. Chain hence hand-carried a phial of the cast to the United States, where the necessary industrial capacity was available for mass production. Application of beer-brewing engineering yielded big sums of cast spirits, from which partly purified penicillin could be laboriously recovered for clinical usage. The first batches became available for military usage in 1943. The stuff was so scarce that patients’ piss was collected and the excreted penicillin recrystallized to be used once more.

Meanwhile, Rene Dubos at the Rockefeller Institute had been prosecuting Pasteur & # 8217 ; s original train of idea. Detecting that microbic populations in dirt held one another in cheque, he isolated and purified an antibiotic from a dirt bacteria in 1939. It and similar substances later isolated were effectual when applied to superficial lesions but proved excessively toxic for systemic disposal. By 1944, Selman Abraham Waksman and his co-workers had isolated streptomycin from a dirt bug and proved its effectivity against the tubercle B. Between 1945 and 1960, a systematic hunt was carried on for antibiotics derived from bacteriums and casts found all over the universe. Many 100s of antibiotics were discovered, and tonss were screened for antibiotic activity and toxicity. Many were finally marketed, and prescription usage accounted for 100s of dozenss yearly.

In 1957, penicillin was synthesized in the research lab. Complete synthesis of penicillins proved prohibitively expensive, but reaping the basic molecules of penicillin from Penicillium casts and so tacking on diverse molecules proved executable and led to a big figure of bespoke penicillin discrepancies. The sixtiess witnessed a regular detonation of alleged man-made ( portion mold-made, portion synthetic ) penicillins, each designed to cover with the increasing job of penicillin-resistant bacteriums, to accomplish better soaking up and higher concentrations in the organic structure, or to broaden the penicillins & # 8217 ; effectual antimicrobic spectrum.


My decision is that my hypothesis was merely partly right. In my hypothesis I stated that penicillin would suppress bacterial growing best in Bacillus subtilis. This subdivision of the hypothesis was right. However, I besides stated that Achromycin would suppress bacterial growing best in Escherichia coli. This subdivision was wrong. The antibiotic that worked the best on Escherichia coli was nalidixic acid.


In my experiment I received the undermentioned consequences:

Bacillus subtilis ( gram positive )

Growth Area:

Tetracycline:12 millimeter

Novobiocin:9 millimeter

Chloramphenicol:18 millimeter

Strepomycin:11 millimeter

Penicillin:21 millimeter

Erythromycin:15 millimeter

Escherichia coli ( gram negative )

Growth Area:

Chloramphenicol:17 millimeter

Kanamycin:11 millimeter

Triple sulfa:9 millimeter

Nalidixic acid:17 millimeter

Furadantin:14 millimeter

Table 1

Escherichia coli Bacillus subtilis

Antibiotic Width in mm Antibiotic Width in millimeter

Chloramphenicol 12 Tetracycline 12

Kanamycin 11 Novobiocin 9

Triple sulfa 9 Chloramphenicol 18

Nalidixic acid 17 Strepomycin 11

Furadantin 14 Penicillin 21

Tetracycline 10 Erythromycin 15


United States Pharmacopeia. Complete Drug Reference.Consumer Reports Books, Yonkers, New York. Copyright 1994. pp 45, 970, 1489, 1686

Facts and Comparisons. Drug Facts and Comparisons. Facts and Comparisons Inc, St. Louis. Copyright 1991. pp 120, 1374, 1598, 1895

USP DI. Health Care Provider. United States Pharmacopeial Convention. Rockville, Maryland. Copyright 1985. volume 1, pp 145, 1967