Bacterial biofilm cells quantification techniques: where is consensus in over two decades?

Abstract

It is widely accepted that bacterial biofilms are overly resistant to antibiotics, host immunity and disinfectants. Biofilms develop on various food-processing surfaces hence pose major risks in food industries. Biofilms serve as protective niches for pathogens in food and water thus enhance transmission of food borne pathogens. Furthermore, biofilms are implicated in medical implant infections. The serious problems associated with bacterial biofilms in food, biomedical and environmental fields have stimulated active research on biofilms for over two decades. Biofilm cells quantification is important in many research applications especially in anti-biofilm efficacy studies and quality controls in many industries. However, to date there is no consensus on which technique is most suitable for quantifying bacterial biofilm cells. This apparent lack of a standard technique has hindered effective comparison of results from different bacterial biofilm studies since each technique has a unique readout. Furthermore, it appears that the choice of a biofilm cells quantification technique is largely a matter of convenience and availability of a technique. This may introduce biasness. Consequently, this review critically assesses the availability, suitability and limitations of different techniques for quantifying biofilm cells. This could inform better control and management of bacterial biofilms in environmental and clinical settings.