Protozoan predation as a driver of diversity and virulence in bacterial biofilms

Abstract

Protozoa are eukaryotic organisms that play a crucial role in nutrient cycling and maintaining balance in the food web. Predation, symbiosis and parasitism are three types of interactions between protozoa and bacteria. However, not all bacterial species are equally susceptible to protozoan predation as many are capable of defending against predation in numerous ways and may even establish either a symbiotic or parasitic life-style. Biofilm formation is one such mechanism by which bacteria can survive predation. Structural and chemical components of biofilms enhance resistance to predation compared to their planktonic counterparts. Predation on biofilms gives rise to phenotypic and genetic heterogeneity in prey that leads to trade-offs in virulence in other eukaryotes. Recent advances, using molecular and genomics techniques, allow us to generate new information about the interactions of protozoa and biofilms of prey bacteria. This review presents the current state of the field on impacts of protozoan predation on biofilms. We provide an overview of newly gathered insights into (i) molecular mechanisms of predation resistance in biofilms, (ii) phenotypic and genetic diversification of prey bacteria, and (iii) evolution of virulence as a consequence of protozoan predation on biofilms.

Making a pathogen? Evaluating the impact of protist predation on the evolution of virulence inSerratia marcescens

“…The MEi isolates produced less biofilms than the PEi and ancestor on average, but individually none of them significantly produced less biofilm than the ancestor. As biofilm production is a natural defense mechanism against predators (74)(75)(76), increasing biofilm production could be beneficial in the constant presence of a predator, whereas it is likely not essential in a nutrient rich mono-culture. Although we did not see a significant increase in grazing resistance in any of the PEi isolates, we did observe a decrease in all three MEi isolates when compared to the ancestor.…”

Unraveling the interplay between unicellular parasites and bacterial biofilms: Implications for disease persistence and antibiotic resistance

“…For instance, bacteria like Vibrio cholera , Pseudomonas aeruginosa , and Legionella pneumophila , which respectively cause enteric disease [ 77 ], opportunistic infections (dermatitis, bacteraemia, and infections of the respiratory and urinary tracts and of other vital organs) [ 78 ], and pneumonia [ 79 ], can adjust to their protozoan predators. This adaptation leads to the selection of virulence-associated traits, enhancing their survival within the predatory host environment [ 80 ].…”

Growth dynamic of biofilm-associated Naegleria fowleri in freshwater on various materials

“…Although the occurrence of this pathogenic FLA has been reported, only a few studies have attempted to identify the factors that promote its occurrence, survival and growth. Only temperature, excluding low salinity conditions and also biofilms has been reported as a key parameter (De Jonckheere and Voorde, 1977 ; Wellings et al, 1977 ; Brown et al, 1983 ; Tyndall et al, 1989 ; Huizinga and McLaughlin, 1990 ; Jamerson et al, 2009 ; Goudot et al, 2012 ; Lam et al, 2019 ; Shaheen et al, 2019 ; Del Olmo et al, 2021 ; Stahl and Olson, 2021 ; Hoque et al, 2023 ).…”