PowerPoint Contents
Author: Multiple Authors
Citation: Multiple Authors. 2008. Oxidative-fermentative test.
Publication Date: September 2008
Escherichia coli oxidative-fermentative test (Enlarged view)
FIG. 1. Oxidative-fermentative test with glucose: fermentative result of Escherichia coli after a 24-hour incubation at 37°C. Note acid production and color change in both the oil-covered (anaerobic) tube and open (aerobic) tube. Hazy growth throughout both tubes indicates motility.(Anne Hanson, University of Maine, Orono, ME)
Klebsiella pneumoniae oxidative-fermentative test (Enlarged view)
FIG. 2. Oxidative-fermentative test with glucose: fermentative result of Klebsiella pneumoniae after a 24-hour incubation at 37°C. Note acid production and color change in both the oil-covered (anaerobic) tube and open (aerobic) tube. Note the growth limited to the stab line indicating a nonmotile result. (Anne Hanson, University of Maine, Orono, ME)
Klebsiella pneumoniae oxidative-fermentative test (Enlarged view)
FIG. 3. Oxidative-fermentative test with glucose: fermentative result of Klebsiella pneumoniae after a 24-hour incubation at 37°C. Note acid production and color change in both the oil-covered (anaerobic) tube and open (aerobic) tube. Note the growth limited to the stab line indicating a nonmotile result. (Anne Hanson, University of Maine, Orono, ME)
Pseudomonas aeruginosa oxidative-fermentative test (Enlarged view)
FIG. 4. Oxidative-fermentative test with glucose: oxidative result of Pseudomonas aeruginosa after a 24-hour incubation at 37°C. Note no growth or color change in the oil-covered (anaerobic) tube and acid production and growth in the top portion of the open (aerobic) tube. (Anne Hanson, University of Maine, Orono, ME)
Pseudomonas aeruginosa oxidative-fermentative test (Enlarged view)
FIG. 5. Oxidative-fermentative test with glucose: oxidative result of Pseudomonas aeruginosa after a 24-hour incubation at 37°C. Note no growth or color change in the oil-covered (anaerobic) tube and acid production and growth in the top portion of the open (aerobic) tube. (Anne Hanson, University of Maine, Orono, ME)
Alcaligenes faecalis oxidative-fermentative test (Enlarged view)
FIG. 6. Oxidative-fermentative test with glucose: Alcaligenes faecalis after a 24-hour incubation at 37°C. This result indicates that the bacteria are nonsaccharolytic and unable to use glucose either oxidatively or fermentatively. Note the absence of color change in the oil-covered (anaerobic) tube. The alkaline conditions and growth at the top of the open (aerobic) tube are a result of an increase in pH due to amine production as the bacteria is using the peptones in the media and not the glucose. (Anne Hanson, University of Maine, Orono, ME)
Alcaligenes faecalis oxidative-fermentative test (Enlarged view)
FIG. 7. Oxidative-fermentative test with glucose: Alcaligenes faecalis after a 24-hour incubation at 37°C. This result indicates that the bacteria are nonsaccharolytic and unable to use glucose either oxidatively or fermentatively. Note the absence of color change in the oil-covered (anaerobic) tube. The alkaline conditions and growth at the top of the open (aerobic) tube are a result of an increase in pH due to amine production as the bacteria is using the peptones in the media and not the glucose. (Anne Hanson, University of Maine, Orono, ME)
Uninoculated oxidative-fermentative test (Enlarged view)
FIG. 8. Uninoculated oxidative-fermentative test with glucose. Note the mineral oil layer over one of the tubes to create an anaerobic condition. The mineral oil should be added after inoculation. The bromthymol blue indicator in the media is green at neutral pH. (Anne Hanson, University of Maine, Orono, ME)
Pseudomonas aeruginosa oxidative-fermentative test (Enlarged view)
FIG. 9. Oxidative-fermentative test with glucose: oxidative result for Pseudomonas aeruginosa. Acid production in the open (aerobic) tube and not the oil-covered (anaerobic) tube indicates an oxidative result.
(a). P. aeruginosa incubated for 24 hours at 37°C. Note pH change in the top of the open (aerobic) tube only.
(b). P. aeruginosa incubated for 48 hours at 37°C. Note the diffusion of the acid further down the open (aerobic) tube.
(c). P. aeruginosa incubated for 5 days. Note the diffusion of the acid throughout the open (aerobic) tube.
The result is best if read within 24 to 48 hours. (Anne Hanson, University of Maine, Orono, ME)
Contact Information
ASM Education, education@asmusa.org