Question

Antibiotic Susceptibility Test Zone Diameter Interpretation Chart * ** Resistant Susceptible Carbenicillin - CB-100 Enterobacteria and Acitenobacter Pseud. aeruginosa <19 <13 >23 >17 Erythromycin - E 15 Staphylococcus spp. And Enterococci S.pneumoniae and other Streptococci <13 <15 >23 >21 <28 V Penicillin- P 10 Staphylococcus spp Enterococcus spp. Streptococci (non S. pneumoniae) Neisseria gonorrhode <14 V V <26 V Streptomycin - S 10 >15 Tetracycline - Te 30 Enterobacteria, Pseud. aeruginosa, Acitenobacter, Staphylococci, Enterococci and V. cholerae N. gonorrhode S. pneumoniae and other Streptococci <30 >38 Vancomycin - Va 30 Staphylococcus spp. Enterococcus spp. S. pneumoniae and other Streptococci Bacitracin - B 10 >13 * Data taken from interpretation chart on BC BD Sensi-Disc Antimicrobial Susceptibility Test Discs Insel **Measurements between the resistant and sentitive range are considered intermidiate

my question is "how do i even being filling the charts on the worksheet" everything is post in pictures.

Answer 1

From data given only part II can be envisaged

dilution	CFU/plate
undiluted	Can’t be counted
10-1	178
10-2	108
10-3	3
total titer

For calculation of viable titer plate of 10-2 dilution is selected (CFU range 30-150 in a plate)

Dilution factor=1/dilution=100

Missing data is volume of sample poured in the petri plate

Considering the volume of sample poured in each petriplate-= 50 µL

Factor for 50 µL to 1 mL= 20

Viable titer=CFU*factor for µL *dilution factor=108x20x100=2.08 x105