Competitive inter-species interactions underlie the increased antimicrobial tolerance in multispecies brewery biofilms

Abstract

16Genetic diversity often enhances the tolerance of microbial communities against antimicrobial 17 treatment. However the sociobiology underlying this antimicrobial tolerance remains largely 18 unexplored. Here we analyze how inter-species interactions can increase antimicrobial tolerance. We 19 apply our approach to 17 industrially-relevant multispecies biofilm models, based on species isolated 20 from 58 contaminating biofilms in three breweries. Sulfathiazole is used as antimicrobial agent 21 because it shows the highest activity out of 22 biofilm inhibitors tested. Our analysis reveals that 22 competitive interactions dominate among species within brewery biofilms. We show that 23 antimicrobial treatment can reduce the level of competition and therefore cause a subset of species 24 to bloom. The result is a lower percentage inhibition of these species and increased tolerance. In 25 addition, we show that the presence of competing species can also directly enhance the inherent 26

Pseudomonas Putida as a Potential Biocontrol Agent Against Salmonella Java Biofilm Formation in the Drinking Water System of Broiler Houses

“…The other P. putida strains also inhibited S. Java signi cantly, albeit to a lower extent, and they formed less bio lm in mixed-than in mono-culture. The observation that all three P. putida strains engage in competitive interactions with S. Java ts with a growing body of recent theoretical and experimental work indicating that competition, not cooperation, dominates interactions among microbial species (Mitri and Foster, 2013;Ghoul and Mitri, 2016;Parijs and Steenackers, 2018).…”

“…This potential for both positive and negative interactions between microbes raises the need for in depth characterization of the sociobiology of candidate BCAs. The cooperation criterion can be used to distinguish between cooperative and competitive interactions (Mitri and Foster, 2013), whereas the biodiversity effect (consisting of a selection effect and a complementarity effect) provides a useful logic to further characterize the level and nature of competition (Loreau and Hector, 2001; Parijs and Steenackers, 2018). Since bio lm-growth capacities of microorganisms strongly depend on several factors, including growth conditions, contact surface and taxonomy (Chia et al, 2009 In previous work (Maes et al, 2019), we identi ed Pseudomonas putida as part of the natural dominant microbiota on several locations on the inside of the DWS in broiler houses, but it is not known as a common contaminant on chickens.…”

Pseudomonas putida as a potential biocontrol agent against Salmonella Java biofilm formation in the drinking water system of broiler houses

“…In this study, the cooperation criterion and the biodiversity effect were calculated to determine social interactions between S. Java and P. putida and to consequently assess the potential of P. putida as BCA. The cooperation criterion requires that the inoculation density in co-culture equals the sum of inoculation densities of the monocultures whereas the biodiversity effect imposes that the inoculation density of each species in co-culture should be its inoculation density in monoculture divided by the number of species in co-culture (Parijs and Steenackers, 2018). A preliminary experiment was conducted growing mono-species bio lms of S. Java in both set-ups but no differences in nal bio lm growth were observed.…”

“…To further characterize the level and nature of competition we calculated the biodiversity effect (Loreau and Hector, 2001;Parijs and Steenackers, 2018). In case inter-species competition is equal to intraspecies competition, the observed bio lm formation in dual-species conditions is expected to be equal to the mono-species bio lm formation, weighed by the inoculum densities (expected bio lm formation).…”

“…This potential for both positive and negative interactions between microbes raises the need for in depth characterization of the sociobiology of candidate BCAs. The cooperation criterion can be used to distinguish between cooperative and competitive interactions (Mitri and Foster, 2013), whereas the biodiversity effect (consisting of a selection effect and a complementarity effect) provides a useful logic to further characterize the level and nature of competition (Loreau and Hector, 2001; Parijs and Steenackers, 2018). Since bio lm-growth capacities of microorganisms strongly depend on several factors, including growth conditions, contact surface and taxonomy (Chia et al, 2009; Elhariry et al, 2012; Schonewille et al, 2012; Lianou and Koutsoumanis, 2013; Wang et al, 2013), assays to evaluate social interactions should be performed under lab controlled conditions that mimic the real situation as much as possible.…”