a. Using table 12.9 as a reference, find and explain the differences between the results for Staphylococcus and Pseudomonas. Are any of these drugs broad spectrums?

b. Explain the difference in the MIC of E. coli for penicillin versus ampicillin.
c. Refer to figure 12.18 a, take measurements, and interpret the results.
Figure 12.18 a

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TABLE 12.9 Bacterium Staphylococcus aureus Enterococcus faecalis Neisseria gonorrhoeae Escherichia coli Pseudomonas aeruginosa Salmonella species Clostridium perfringens Comparative MICs (ug/ml) for Common Drugs and Pathogens Penicillin G Ampicillin Sulfamethoxazole Tetracycline Cefaclor 4.0 60.0 2.0 3.0 4.0 0.8 12.0 4.0 3.6 0.5 100.0 >500.0 12.0 0.05 1.6 0.5 12.0 3.0 100.0 5.0 3.0 0.3 0.3 0.8 1-4.0 100.0 1.0 3.0 >200.0 >100 10.0 NA 6.0 0.16 NA Kirby-Bauer Disk Diffusion Test Enrofloxacin 5 ug (R 17 mm; S 2 22 mm) Oxytetracycline 30 ug (R < 17 mm, S 2 22 mm) Gentamicin 10 ug (R 17 mm, S 221 mm) 2 4 30 Cefotaxime 30 ug (R 14 mm, S 22 Ampicillin 10 3 mm) (R 14 mm, S 2 22 mm) Chloramphenicol 30 ug (R < 21 mm; S 21 mm) - Zone of Inhibition Antibiotic carrier (disc) imprinted with abbreviation and concentration - Region of bacterial growth Disk Diffusion Test (schematic) Example and evaluation of a sensitivity test, agar diffusion method R resistant, I- intermediate, S sensitive