E. coli biofilm formation and its susceptibility towards T4 bacteriophages studied in a continuously operating mixing – tubular bioreactor system

Abstract

Summary A system consisting of a connected mixed and tubular bioreactor was designed to study bacterial biofilm formation and the effect of its exposure to bacteriophages under different experimental conditions. The bacterial biofilm inside silicone tubular bioreactor was formed during the continuous pumping of bacterial cells at a constant physiological state for 2 h and subsequent washing with a buffer for 24 h. Monitoring bacterial and bacteriophage concentration along the tubular bioreactor was performed via a piercing method. The presence of biofilm and planktonic cells was demonstrated by combining the piercing method, measurement of planktonic cell concentration at the tubular bioreactor outlet, and optical microscopy. The planktonic cell formation rate was found to be 8.95 × 10−3 h−1 and increased approximately four‐fold (4×) after biofilm exposure to an LB medium. Exposure of bacterial biofilm to bacteriophages in the LB medium resulted in a rapid decrease of biofilm and planktonic cell concentration, to below the detection limit within < 2 h. When bacteriophages were supplied in the buffer, only a moderate decrease in the concentration of both bacterial cell types was observed. After biofilm washing with buffer to remove unadsorbed bacteriophages, its exposure to the LB medium (without bacteriophages) resulted in a rapid decrease in bacterial concentration: again below the detection limit in < 2 h.

Novel T4 bacteriophage and royal jelly infused disinfectant versus E. coli compared to QACs

“…In a study conducted by Dissanayake et al, a bacteriophage solution was able to decrease pathogenic viable E. coli counts in selected mice by up to 54%, which was a similar efficacy as ampicillin, a type of β-lactam antibiotic [18]. In another study conducted by Lisac et al, the introduction of the T4 bacteriophage resulted in a rapid decrease of the biofilm and cell concentrations to the point where detection was not possible [19]. This indicates that the utilization of the T4 bacteriophage serves as a potentially effective way to inhibit the growth of E. coli, thus serving as inspiration for this current experiment.…”

Emerging investigator series: the role of phage lifestyle in wastewater microbial community structures and functions: insights into diverse microbial environments

“…2 There have been several reviews on the impact of phages on biological wastewater systems that include methods and potential impacts of phages on microbial ecology. 3,4 Examples of studies on phages that are not explicitly covered in this review are the application of phages to manage sludge bulking, 5 control biofilms, 6,7 or enhance disinfection; 8,9 and the use of phages as surrogates for viral pathogens. [10][11][12] There are relatively fewer studies on phages in activated sludge compared with the wealth of literature available on phages in natural environments.…”