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Chapter 6
were similar at 48 hours. It is important to acknowledge however that
given the number of independent CBR runs (3 at 48 hours and 2 at 168
hours) and the number of coupons counted, the results at 48 hours are
more robust that those for 168 hours.
Another interesting finding from the 168 hour biofilm research was that
the S. Enteritidis strain S09-0717 was a more dense biofilm former than the
S. Typhimurium strains and the S. Agona strain on most surfaces when
biofilm was developed over 168 hours. These findings are in contrast to
what was reported from the studies performed using the CBR over 48
hours as reported in chapter 2. These findings indicate that the S.
Enteritidis strain S09-0717 may be a slower biofilm former but given a
longer period of time, the strain may form a more dense biofilm than most
other strains examined. This interesting finding could have implications on
the settings used for biofilm studies in the future. As most biofilm studies
are based on short time scales, researchers in this area may be missing
some important biofilm properties of the S. Enteritidis strains. Although
caution needs to be exercised when making broad assumptions based on a
small subset of strains as previously discussed. Ideally, to confirm these
findings, more strains would need to be examined over an extended period
of time.
Moreover, had the S. Enteritidis strain not been included in the
experiments performed for 168 hours, it may have been assumed that the
S. Agona outbreak related strain S09-0494 was the only strain that formed
a significantly more dense biofilm in comparison to the other strains
examined. For example, it may have easily been misinterpreted that the
outbreak strain formed a more dense biofilm than the other strains
examined - S. Agona SL483 and the two S. Typhimurium strains. This serves
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