Ifey Alio (Hamburg / DE), Raphael Moll (Hamburg / DE), Mirja Gudzuhn (Hamburg / DE), Tim Hoffmann (Hamburg / DE), Holger Rohde (Hamburg / DE), Uwe Mamat (Borstel / DE), Ulrich Schaible (Borstel / DE), Kai Papenfort (Jena / DE), Malik Alawi (Hamburg / DE), Roland Thünauer (Hamburg / DE), Wolfgang R. Streit (Hamburg / DE)
Stenotrophomonas maltophilia is an opportunistic pathogen causing various infections. Its prevalence has increased, especially in cystic fibrosis patients, and its multidrug resistance poses challenges in treatment. The bacterium forms multispecies biofilms with other pathogens and is known for its substantial role in pathogenicity in infected lungs
Our goal is to understand the biofilm characteristics of S. maltophilia in single und mixed species biofilms as well as the differential gene expression patterns within these biofilms
In this study over 200 clinical isolates of S. maltophilia as well as chromosomally labeled fluorescent strains of S. maltophilia K279a, P. aeruginosa PA01, S. aureus SH1000 and C. albicans SC5314 were used. Biofilms were formed in flow and static settings and were used for RNA seq analysis. Additionally, reporter fusion constructs of selected genes were generated and were further analyzed.
Results and conclusion
Our analysis revealed a strain-specific variability in biofilm formation and architecture among S.maltophilia isolates. RNA seq. analysis of S. maltophilia isolates identified shared and strain-specific genes, with iron uptake being a key factor in biofilm metabolism. LSM imaging showed that species interactions affect the structural composition of multispecies biofilms leading to a layer formation. S maltophilia showed alteration in lactate metabolism , Propionate degradation and a switch in cytochrome oxidases in our mixed biofilm models.
The expression of virulence factors, QS signaling and cyclic diGMP was decreased in PA01 in coculture with K279a.
Our data show that isolates of S. maltophilia are highly diverse on a phenotypic and genotypic level. Common genes were identified to play a crucial role in the biofilm formation of S. maltophilia. LSM imaging has shown a distinct distribution and layer formation of different species within mixed species biofilms. RNA seq analysis and the application of reporter fusion constructs showed specific and different expression patterns for each species as compared to single species biofilms, suggesting that each species acknowledge and respond to the presence of others in these biofilms.