Effects of Ultraviolet Radiation on Staphylococcus aureus, Pseudomonas aeruginosa, and Deinococcus r

1
Effects of Ultraviolet Radiation on
Staphylococcus aureus Pseudomonas aeruginosa
and Deinococcus radiodurans Amber B.
HoffertBiology Department Tennessee
Technological University Cookeville TN
38505-0001

• Conclusion
• Stphylococcus aureus colonies were affected by UV
  radiation and have a virtual TDT of 80 seconds
• Pseudomonas aeruginosa colonies are affected by
  UV radiation and have a TDT of 80 seconds
• Deinococcus radiodurans colonies were not
  affected by UV radiation.
• Ultraviolet radiation needs to be used more in
  practical settings as a physical method of
  control for S. aureus and P. aeruginosa.
• More research needs to be done with D.
  radiodurans to find out its genetic code that
  allows it to be resistant to ionizing radiation.

• Results
• As shown in Figure 1 the Staphylococcus aureus
  and Pseudomonas aeruginosa growth patterns were
  decreasing as the time exposed increased. Figure
  1 also shows how Deinococcus radiodurans did not
  follow the same pattern but appeared to be
  resistant to UV radiation exposure.
• Table 1 shows the mortality percentages D.
  radiodurans average colony counts that were
  seemingly not affected by the UV radiation levels
  used in this experiment.

• Introduction
• One method to control bacteria is with physical
  methods such as Ultraviolet Radiation (UV)
  exposure.
• UV radiation has been used for air vaccines and
  drinking water disinfection(US Dept Health 2002)
• Research has also been conducted with high
  intensity UV radiation as an antimicrobial
  treatment for dental tools contaminated with
  Staphylococcus aureus. (USEPA 1997)
• Pseudomonas aeruginosa has been shown to be
  sensitive to low-intensity UV when compared with
  other microbes(Golley et al 1986).
• Research shows Deinococcus radiodurans can
  survive very high doses of ionizing radiation
  that are lethal to virtually all other
  organisms(DOE 2006).

• Acknowledgements
• Dr. Morgan for his help in this semester long
  process
• Dr. Goss for her use of the lab guidance and
  advice
• Tenn. Tech. Biology Department for the use of the
  culture media
• Kelly Talent for her help along the way
• Nick Sells for his assistance during the
  experiment
• My husband Will Hoffert for the computer help

• Objective Hypothesis
• The objective of this study was to test the
  effects of ultraviolet radiation exposures on
  Staphylococcus aureus Pseudomonas aeruginosa
  and Deinococcus radiodurans bacteria colonie
  growth in the laboratory.
• Based on the objective this experiment tested
  the null hypothesis that UV radiation has no
  effect on growth and was designed to test the
  effects of ultraviolet radiation on
  Staphylococcus aureus Pseudomonas aeruginosa
  and Deinococcus radiodurans colonies.

• Methods Materials
• This experiment followed the methods outlined by
  Goss(2001) in her study on the Control of
  Microbial Growth UV Radiation
• Exposure responses were observed using six small
  TSA plates per organism one for each of six time
  periods.
• Each TSA plate was streaked with a 1 µL loop of
  108 organism.
• As before control groups were not exposed to UV
  radiation.
• Incubation periods and counting colonies followed
  the protocol of Goss(2006) to acquire statistical
  results.