Lab+3+Antimicrobials

Antimicrobials: Bacillus & E. coli

Part A: Faculatative anaerobes || Facultative anaerobes ||
 * ** Characteristics ** || ** Bacillus ** || ** E. coli ** ||
 * ** Gram positive or negative? ** || Gram positive || Gram negative ||
 * ** Shape? ** || Rod-shaped || Rod-shaped ||
 * ** Aerobes or anaerobes? ** || Obligate aerobes or

Part B: Bacillus: Because of the characteristics above, they are tolerant of disinfectants but intolerant of antibiotics E. coli: Because of the above characteristics, they are resistant to disinfectants and antibiotics

Part C: Mechanism of each disinfectant/antibiotic
 * ** Antibiotics ** || ** Mechanisms of Action ** ||
 * ** Penicillin ** || Inhibits the formation of peptidoglycan in cell walls of bacteria ||
 * ** Erythromycin ** || Inhibits the growth of bacteria ||
 * ** Tetracycline ** || Inhibits protein synthesis ||
 * ** Chloramphenicol ** || Stops growth of bacteria by inhibiting of protein synthesis ||
 * ** Streptomycin ** || Interferes with the binding of tRNA which leads to the misreading of codons ||

[] || [] || Agar Plates: Week One
 * ** Disinfectants ** || ** Mechanisms of Action ** ||
 * ** Dish Soap ** ||  is seen to target bacteria mainly by inhibiting fatty acid synthesis. ||
 * ** Mouthwash ** || An antiseptic is a chemical which will react with the cell walls of bacteria to break them down. When the cell wall breaks the bacterium dies.
 * ** Hand Soap ** ||  cleaning action of this mixture is attributed to the action of [|micelles] , tiny spheres coated on the outside with polar hydrophilic (water-loving) groups, encasing a lipophilic (fat-loving) pocket that can surround the grease particles, causing them to disperse in water. The lipophilic portion is made up of the long hydrocarbon  chain from the fatty acid. In other words, whereas normally oil and water do not mix, the addition of soap allows oils to disperse in water and be rinsed away [|http://en.wikipedia.org/wiki/Soap#Mechanism_of_cleansing_soaps] ||
 * ** Iodine ** || estabilization of the bacterial cell wall and disruption of the membrane that results in leakage of the intracellular components [] ||
 * ** Hydrogen Peroxide ** ||  works by producing destructive hydroxyl free radicals that can attack membrane lipids, DNA, and other essential cell components. Catalase, produced by aerobic organisms and facultative anaerobes that possess cytochrome systems, can protect cells from metabolically produced hydrogen peroxide by degrading hydrogen peroxide to water and oxygen. This defense is overwhelmed by the concentrations used for disinfection

Agar Plates: Week Two



DATA

These are the measurement results of how much area was effected by the antibiotics and by the disinfectants. Please note that, some were compromised due to the disks falling while in the plates to other areas. So no conclusive data could be extracted to provide an appropriate measurement for those areas. Also N/A means areas of no activity Bacillus Antibiotic- 1. 30 mm 2. 28 mm  3. 32 mm  4. 30 mm  5. 19 mm

Bacillus Disinfectant- 1. 84 mm 2. Compromised 3. Compromised 4. N/A 5. 30 mm

E. Coli Antibiotic- 1. 28 mm 2. N/A 3. 25 mm 4. N/A 5. 20 mm

E. Coli Disinfectant 1. 20 mm 2. N/A 3. 50 mm 4. 34 mm  5. 16 mm