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Chapter 1
biofilm was considered mature based the structural development [151].
Lamfron et al. demonstrated that after 24 hours, a Candida albicans biofilm
was more resistant to fluconazole than 2, 6 and 24 hour biofilm [152]. Xu et
al. detailed how the biomass of a biofilm derived from sludge placed on a
filter membrane increased over time durations of 6-, 12- , 24- hour was
increased to 7.13, 17.49 and 24.43mg and that after treatment with
adenosine triphosphate (ATP) synthesis inhibiter, the biomass was reduced
by 68%, 80% and 34% respectively [153]. Fraud et al. showed that the
activity of amine oxide (antimicrobial used for eradication of dental
biofilm) reduced the bacterial count of Streptococcus mutans by over 5
log 10 within contact with a 16 hour biofilm, however the efficacy of the
antimicrobial agent was significantly reduced with mature biofilms (40-64
hour biofilm) with minimal activity observed [154]. Fraud et al. also
acknowledged that the substratum may affect antimicrobial activity, to
overcome this limitation all these experiments were carried out on
hydroxyapatite disks to imitate the enamel of a tooth surface [154].
However other previously published material has suggested that age of
biofilm does not contribute to a higher biofilm mass or increased resistance
to disinfectant agents over time. Wong et al. found that the age of a
Salmonella Typhimurium biofilm (3-, 5-, 7- day old biofilm) did not
contribute to increased resistance to disinfectant using the MBEC system
[149]. As discussed in chapter three, it may be possible that a smaller
surface area available for biofilm development may have also contributed
to no increased biofilm density or resistance to disinfectant agents over
time.
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