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Effects of household cleaners on Escherichia coli

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									  Effects of household
cleaners on Escherichia
               coli
           Presented by:

            Brian Agee
 Undergraduate Microbiology Major
 Tennessee Technological University
       Cookeville, TN 38505
                Introduction
   “An increase in food-borne illnesses has
    been observed in many countries recently,
    with a high proportion of these outbreaks
    occurring in the home.” (Rusin 1998)

   The most notable area where bacteria were
    found was in the kitchen, where large
    numbers of Escherichia coli was found.
    (Josephson 1997)
                     Introduction
   Recent outbreaks of Escherichia coli have brought the
    issues of hygiene and disinfection to the public’s
    attention. (Cogan 2002)
   Because of public attention, antibacterial agents
    marketed for the home have increased from only a
    few dozen in the mid-1990s to more than 700 today.
    (Levy 2001)
   In order to determine the efficiency of these
    antibacterial products, their use in a household setting
    must be considered. (Kusumaningrum 2002)
                   Introduction
   Objective: Determine if Escherichia coli is susceptible
    to common household cleaners and which cleaners
    are the most effective at inhibiting and killing the
    bacteria.

   Hypothesis: Escherichia coli will be susceptible to all
    of the cleaning agents and therefore will not be able
    to survive in their presence.

   Null Hypothesis: Escherichia coli will not be
    susceptible to all of the cleaning agents and
    therefore grow in their presence.
              Methods and Materials
        Assay 1: Disc Diffusion Assay (Goss 2005)
   Determines the effectiveness of the
    cleaning agent at inhibiting Escherichia coli.
   Cleaning agents used for this assay
    included Clorox bleach, Ajax, vinegar,
    Germ-X, Lysol, and 409.
   Each cleaning agent was applied to a disc
    and placed on a TSA plate with Escherichia
    coli.
   TSA plates were then incubated for 48
    hours at 35.6°C.
   After the 48 hour incubation, the zone of
    inhibition was measured in millimeters.
   As the size of the zone of inhibition
    increased, so did the cleaning agents
    ability to inhibit Escherichia coli.
           Methods and Materials
     Assay 2: Tube Growth Assay (Goss 2005)
   Determines the effectiveness of the cleaning agent as a
    bactericidal agent.
   Cleaning agents used for this assay included Clorox bleach,
    Ajax, vinegar, Germ-X, Lysol, and 409.
   Escherichia coli was placed into a test tube with each of the
    cleaning agents and incubated for 48 hours at 35.6°C.
   Samples from each test tube were streaked on TSA plates
    and also placed in the incubators for a period of 48 hours.
   If growth occurred on the TSA plate, then the cleaning
    agent was ineffective at killing Escherichia coli.
                              Results
             Assay 1: Disc Diffusion Assay (Goss 2005)
Table 1: Zones of Inhibition for common household cleaning agents.
                                                   Size of Zone of Inhibition
Cleaning Agent       Zone of Inhibition (+ or -)   (mm)


 Clorox Bleach                   +                             60
   Germ-X                        +                             13
     Ajax                        +                             25
     409                         +                             15
     Lysol                       +                             20
   Vinegar                       +                             15


    Average Zone of Inhibition for Common
             Household Cleaners                                25
                                                      Results
       Assay 1: Disc Diffusion Assay (Goss 2005)
                                      60
            Zone of Inhibition (mm)
                                      50

                                      40

                                      30

                                      20

                                      10

                                      0
                                           Clorox Germ-X    Ajax    409     Lysol   Vinegar
                                           Bleach
                                                           Cleaning Agent


Figure 1: Zones of inhibition against Escherichia coli for household cleaning agents
   Of the six cleaning agents tested, Clorox bleach was determined to be the best at
    inhibitor of Escherichia coli.
   The zone of inhibition of Clorox bleach was approximately 3-4 times larger than
    any of the other cleaning agents. (Figure 1)
   The average zone of inhibition for all of the cleaning agents tested was 25mm.
    (Table 1)
                                  Results
                Assay 2: Tube Growth Assay (Goss 2005)
  Table 2: Results from tube growth assay, which determined the effectiveness of
     the cleaning agents at killing Escherichia coli
  Cleaning Agent        Cloudiness in Test Tube (+ or -)   Growth on TSA Plate (+ or -)
None (Broth+Bacteria)                  +                                +
   Clorox Bleach                       -                                -
Clorox Bleach (50%)                    -                                -
      Germ-X                           -                                -
   Germ-X (50%)                        -                                -
        Ajax                           -                                -
     Ajax (50%)                        -                                -
        409                            -                                -
     409 (50%)                         -                                -
        Lysol                          -                                -
     Lysol (50%)                       -                                -
      Vinegar                          -                                -
   Vinegar (50%)                       -                                -
                           Results
      Assay 2: Tube Growth Assay (Goss 2005)

   All cleaners were effective
    at killing Escherichia coli,
    even when reduced to 50%
    concentration. (Table 2)

   The only growth occurred
    where the control, which
    consisted of nutrient broth
    and Escherichia coli, was
    streaked. (Table 2)
                 Discussion
 The main cause of the spreading of Escherichia
  coli is primarily the result of poor hand and
  surface hygiene. (Cogan 2002)
 According to Tsai, sodium hypochlorite
  cleaners are effective at inhibiting and killing
  surface germs. (Tsai 1999)
 The findings from my research seem to agree
  with these previous findings because Clorox
  bleach, a hypochlorite cleaner, was discovered
  to be the most effective at inhibiting and killing
  Escherichia coli.
                      Discussion
   The main purpose of cleaning agents is to prevent
    transmission of disease causing microorganisms. (Levy
    2001)
   Disinfection products used in combination with a regular
    cleaning schedule can greatly reduce the amount of bacteria
    found in the household. (Rusin 1998)
   In a study conducted by Cole, he found that more target
    bacteria are found in homes that don’t use antibacterial
    products than homes that use these products. (Cole 2003)
   These previous studies seem to agree with my research
    because all of the cleaners tested seemed to inhibit and kill
    the bacterium tested.
                      Conclusion
   Hypothesis: Escherichia coli will be susceptible to all of
    the cleaning agents and therefore will not be able to
    survive in their presence.
   Null Hypothesis: Escherichia coli will not be
    susceptible to all of the cleaning agents and therefore
    grow in their presence.
   My hypothesis was confirmed because Escherichia
    coli was susceptible to all of the cleaning agents and
    was not able to survive in their presence.
   Therefore, my null hypothesis was rejected.
                      Conclusion
   All cleaning agents that were tested were proven to
    be effective at inhibiting and killing Escherichia coli.
   Clorox bleach was found to be the most effective
    cleaning agent, producing a zone of inhibition
    approximately 3-4 times greater than any of the
    other cleaning agents tested.
   In order to keep our society healthy, household
    cleaners must be used on a regular basis in order to
    help eliminate the chances of becoming infected by
    a bacterium, especially Escherichia coli.
                                    References
   Besser, R. E., S. M. Lett, J. T. Weber, M. P. Doyle, T. J. Barrett, J. G. Wells, and P. M. Griffin. 1993.
    An outbreak of diarrhea and hemolytic uremic syndrome from Escherichia coli O157:H7 in Fresh-
    pressed apple cider. Journal of American Medical Association 269: 2217-2220.
   [CDC] Centers for Disease Control and Prevention. 2005 Oct. 6. CDC homepage, Escherichia coli.<
    http://www.cdc.gov > Accessed 2005 Oct. 23.
   Cogan, T. A., J. Slader, S. F. Bloomfield, and T. J. Humphrey. 2002. Achieving hygiene in the domestic
    kitchen: the effectiveness of commonly used cleaning procedures. Journal of Applied Microbiology 92:
    885-892.
   Cole, E. C., R. M. Addison, J. R. Rubino, K. E. Leese, P. D. Dulaney, M. S. Newell, J. Wilkins, D. J.
    Gaber, T. Wineinger, and D. A. Criger. 2003. Journal of Applied Microbiology 95: 664-676.
   Goss, Susan. 2005. Biology 3230: Health sciences microbiology laboratory manual. Cookeville, TN.
    Tennessee Technological University. P 62-66.
   Josephson, K. L., J. R.Rubino, and I. L. Pepper. 1997. Characterization and quantification of bacterial
    pathogens and indicator organisms in household kitchens with and without the use of a disinfectant
    cleaner. Journal of Applied Microbiology 83: 737-750.
   Kusumaningrum, H. D., M. M. van Putten, F. M. Rombouts, and R. R. Beumer. 2002. Effects of
    Antibacterial Dishwashing Liquid on Food-borne Pathogens and Competitive Microorganisms in
    Kitchen Sponges. Journal of Food Protection 65: 61-65.
   Levy, Stuart B. 2001. Antibacterial Household Products: Cause for Concern. Emerging Infectious
    Diseases; 2001 June; Boston, MA. Boston: Tufts University School of Medicine. P 512-515.
   Rusin, P., P. Orosz-Coughlin, and C. Gerba. 1998. Reduction of faecal coliform, coliform and
    heterotrophic plate count bacteria in the household kitchen and bathroom by disinfection with
    hypochlorite cleaners. Journal of Applied Microbiology 85: 819-828.
   Tsai, C., and S. Lin. Disinfection of Hospital Waste Sludge using hypochlorite and chlorine dioxide.
    1999. Journal of Applied Microbiology 86: 827-833

								
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