1. Laboratory strains of Staphylococcus aureus (S. aureus is Gram +), Escherichia coli (E.coli is Gram-), and Bacillus cereus (B. cereus is Gram +) were exposed to three I different antibiotics (bacitracin, penicillin G, and tetracycline) using the Kirby-Bauer technique. Below are the results. Values represent the zones of inhibition: Organism S. aureus E.coli Tetracycline 40 mm (S) Bacitracin Penicillin G 10 mm (R) 40 mm (S) 10 mm (R) 3 mm (R) 30 mm (S) right 25 mm (1) B. cereus 4 mm (R) 5 mm (R) Use the table on the next page to determine which bacteria were sensitive (S), resistant (R) or intermediate (I) to the antibiotics. For your answer you can simply put S, R or I into the table above next to the appropriate zone of inhibition numbers. 2. Referring to question 1, on the basis of these results which antibiotics were narrow spectrum? Broad spectrum? Explain your answers.

Below, you can see a picture of an antimicrobial drug. Regarding semi-synthetic antimicrobial drug development to try to avoid development of antibiotic resistance, use 1 sentence to address what is the significance/value of the presence of the various R-groups (e.g. R4, R5, R6, etc.)?

The following results were obtained from a disk diffusion test for a strain of Escherichia coli.   Chemotherapeutic Zone of inhibition (mm) A 7 B 10 C 18 D 3   Which drug above (A, B, C, or D) is most effective against this E. coli strain?             ***Which drug above (A, B, C, or D) is most effective against Staphylococcus aureus?  Explain your answer.

A relatively large zone of inhibition surrounding an antimicrobial disk on a Kirby-Bauer test plate would most likely be interpreted as: a. sensitive reaction b. intermediate reaction c. resistant reaction

E. coli O157:H7 is an organism of concern in contaminated foods. How can the use of MacConkey agar and Sorbitol-MacConkey agar be used to screen for E. coli bacteria in general and E. coli O157:H7 in particular?

What does the zone of inhibition imply? Does the measurement of the zone ofinhibition imply that one antibiotic is better than the other? Support your answer.

12:28 TABLE 1 Disk Symbol A B Today 10:42 AM INTERPRETING INHIBITION ZONES OF TEST CULTURES CHEMICAL METHODS OF CONTROL: ANTIMICROBIAL DRUGS Antimicrobial Agent Ampicillin when testing gram-negative bacteria Ampicillin when testing gram-positive bacteria Chloramphenicol Ceftazidime Carbenicillin Carbenicillin when testing Pseudomonas Cephalothin Ciprofloxacin Erythromycin Cefoxitin Sulfisoxazole Bunnsoxazo Gentamicin Conca companion Imipenem Penicillin when testing staphylococci Penicillin when testing other bacteria Polymyxin Rifampin Streptomycin Trimethoprim- Sulfamethoxazole (TMP-SMZ) Tetracycline Vancomycin when testing Staphylococcus spp. Vancomycin when testing enterococci PROCEDURE Second Period 1. Measure the zones of inhibition in millimeters, using a ruler on the underside of the plate (see Figure 3b). If the diameter is difficult to measure, measure the radius from the center of the disk to the edge of the zone. Multiply the radius by 2 to get the diameter of the zone. Disk…

The world is facing a Corona Virus (COVID-19) Pandemic and as a potential scientist and a microbiology student, you have been required to prepare the easiest and most affordable hand sanitizer that can be utilized by students in various microbiology laboratories. Each student in your class has been given 96% ethanol and you are required to prepare 70% ethanol hand sanitizer in a 2L spray bottle. Describe clearly the method you will use in order to achieve the aim of the practical.

State the principle that underlies the following biochemical tests: a) Methyl red test b) Voges-Proskauer test.

What is your personal comment on the relevance of this application? Refer to the study below https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7824784/ Riboswitches as Drug Targets for Antibiotics Vipul Panchal* and Ruth Brenk*