The Best-Practice Organism for Single-Species Studies of Antimicrobial Efficacy against Biofilms Is Pseudomonas aeruginosa

Anti-biofouling efficacy of three home and personal care product preservatives: Pseudomonas aeruginosa biofilm inhibition and prevention

Due to increasing water scarcity, it is essential to determine cost-effective and efficient methods of producing potable water, especially ones that utilize non-traditional sources. Although reverse osmosis (RO) shows promise as a key-player in mitigating water scarcity, it is limited by biofouling. It is therefore integral to identify effective antifoulants that also do not damage the membrane, cause resistance, or negatively impact human health and the environment. Potential antifoulants include preservatives used in home and personal care products. It is hypothesized that safer preservatives can be applied to RO systems to remove or prevent biofouling. Three preservatives including methylisothiazolinone (MIT), phenoxyethanol (PE), and sodium benzoate (SB) were tested via antimicrobial susceptibility tests against P. aeruginosa biofilms grown in 96-well plates to investigate both biofilm prevention and biofilm removal. Data were collected in the form of minimum biofilm inhibitory concentration (MBIC) and minimum biofilm eradication concentration (MBEC), respectively. MIT was the most effective of the three preservatives but also poses the highest hazard to human health and the environment. Due to efficacy and safety concerns, MIT, PE, and SB are not the final solution; however, a process was demonstrated for determining the efficacy of novel, safer antifoulants. Ultimately, further investigations into safer antifoulants, paired with a greater understanding of biofilm removal and prevention doses will help make RO a better solution for water scarcity.

Biofouling detection methods that are widely applicable and useful across disciplines: a mini-review

Biofouling, or the build-up of microorganisms in a biofilm at the solid-water or water-air interface, is an interdisciplinary problem. Biofouling causes various issues including clogging systems, contaminating devices, and creating infections that are extremely difficult to treat, to name but a few. Therefore, engineers, pharmacologists, microbiologists, wastewater treatment operators, chemists, food preservative formulators, home and personal care product formulators, and toxicologists all play a role in studying and have an interest in solving biofouling. High-throughput studies on biofilm prevention and removal can take the form of biofilm antimicrobial microdilution susceptibility (BAMS) tests. Due to vested interests of many disciplines, the results from these tests should be applicable and useful to each discipline. This critical review analyses the focuses, biological implications, and metrics required by each discipline. The possible detection methods that could satisfy each desired metric are then summarized. The detection methods were analysed in order to recommend two methods of biofilm detection, Crystal Violet stain and the LIVE/DEAD BacLight stain, which correspond with three metrics including total biomass, log reduction, and the MIC, BPC, MBIC, MBC, BBC, and/or MBEC values. Determining these three metrics for each BAMS test will allow this type of research to be widely applicable and useful across many disciplines.