Susceptibility to antibacterials and compared metabolism of suspended bacteria versus embedded bacteria in biofilms

Bacterial adhesion to conventional hydrogel and new silicone-hydrogel contact lens materials

“…Indeed, oxygen is necessary for growth of aerobic bacteria and thus for adhesion and biofilm formation. In addition, inside a biofilm, the reduction of oxygen transport in deeper layers explains the reduction of metabolic activity [5,34,35], suggesting the importance of oxygen availability. It has been recently shown that ultrasound was able to increase the growth rate of planktonic Staphylococcus epidermidis, Pseudomonas aeruginosa, and Escherichia coli cells attached to surfaces [36].…”

“…Usually the number of CFU is calculated from the amount of ATP through a linear regression curve using logarithmic values of ATP and CFU [15], and quantification of cellular ATP corresponds to a valuation of cell activity [11,16]. However, inside a biofilm, not all the bacteria have the same metabolic activity, since bacterial metabolism is qualitatively modified when bacteria are fixed [5]. The bacteria located within deeper layers of the biofilm expressed reduced metabolic activity [5].…”

“…However, inside a biofilm, not all the bacteria have the same metabolic activity, since bacterial metabolism is qualitatively modified when bacteria are fixed [5]. The bacteria located within deeper layers of the biofilm expressed reduced metabolic activity [5]. For that reason, results were expressed as pM of ATP per lens instead of CFU per lens.…”

“…ATP is the key "fuel" molecule for many types of cells, including bacteria, and each type of viable cell has been reported to contain a reasonable amount of ATP. Bacterial counting, another method of quantification of adherent bacteria, cannot detect and count viable but noncultivable bacteria, which are always present in any biofilm [5,6]. On the other hand, bioluminescence can detect all living bacteria whether they are cultivable or not [7].…”

Dynamics of drinking water biofilm in flow/non-flow conditions

“…Authors studying wastewaters and industrial waters are divided between those who defend that the activity of sessile and planktonic bacteria is similar (Bakke et al, 1984;Characklis and Marshall, 1990) and those who reached opposite conclusions (Plas et al, 1994;Le Magrex et al, 1994). Quantitative data on bacterial growth kinetics in drinking water systems is scarce (Pedersen, 1990;Block et al, 1993;Boe-Hansen et al, 2002b), although such data would seem important for the proper design of distribution networks and reservoirs.…”