October 21, 2014
Antimicrobial Sensitivity Lab Results
By: Keith Schultz
Subject: Bio 150.15L; Professor Patricia Franklin
PVCC
After each of the 4 inoculated plates were allowed to incubate, bacterial growth appeared to be uniform across each plate, with the exception of the area surrounding each of the antimicrobials used. Each antimicrobial showed a varying propensity towards inhibiting the respective growth of the bacteria in each plate. The diameters of the clearing around each specific antibiotic, or zones of inhibition, were measured and recorded in the charts below. Subsequently, using the chart of Accepted Standards for Zones of Inhibition, each antimicrobial was classified as either resistant, intermediate, or susceptible.
Sample of inoculated agar
plate showing zone of
inhibition:
Plate 1, which was inoculated with E. coli, showed the most significant bacterial growth around the Chloramphenicol and Streptomycin antibiotics. Erythromycin and Ampicillin had significantly larger zones of inhibition.
Plate 1
Bacterium - Escherichia coli
Antimicrobial Used
Zone of Inhibition (mm)
Interpretation
1
Erythromycin
10mm
Resistant
2
Ampicillin
20mm
Intermediate
3
Chloramphenicol
4mm
Resistant
4
Streptomycin
2mm
Resistant
Plate 2, which was inoculated with S. aureus, displayed similar bacterial growth around the Rifampin, Kanacymin, and Trimethoprim. Ciproflaxacin had the largest zone of inhibition.
Plate 2
Plate 2 Bacterium - Staphylococcus aureus
Antimicrobial Used
Zone of Inhibition (mm)
Interpretation
1
Rifampin
8mm
Resistant
2
Ciproflaxacin
15mm
Intermediate
3
Kanacymin
9mm
Resistant
4
Trimethoprim
6mm
Resistant
The third plate had uniform growth of S. aureus bacteria. Erythromycin had the most effect on the bacteria whereas Ampicillin had the lease effect.
Plate 3
Plate 4, with E. coli, showed resistance to the...