Dataset Information

MacAB-TolC, a determinant of solid-liquid biofilms in Acinetobacter baumannii

ABSTRACT: Acinetobacter baumannii has emerged as one of the most problematic opportunist bacterial pathogen responsible for hospital-acquired and community infections worldwide. Besides its high capacities to acquire antibiotic resistance mechanisms, it also presents high adhesion abilities on inert and living surfaces leading to biofilm development, a lifestyle conferring an additional protection against various treatments, and allowing it to persist for long periods in various hospital niches. Due to their increasing resilience to antimicrobial treatments, A. baumannii biofilms are difficult to control and ultimately eradicate. Overcoming the significant challenges pose by A. baumannii require fundamental insights into mechanisms involved in the development of mature biofilm and thus, may help to develop novel strategies for biofilm prevention and control. To unravel critical determinants of this sessile lifestyle, we compared the proteome profiles of bacteria grown in planktonic stationary phase with those of two A. baumannii strains (ATCC 17978 and SDF), harboring specific features regarding biofilm formation, grown in mature solid-liquid (S-L) biofilm using a proteomic quantitative study. Of interest, among the 69 common proteins determinants accumulated in the two strains at the S-L interface, we sorted out the MacAB-TolC system. This tripartite efflux pump appears to play a role in A. baumannii biofilm formation as demonstrated by using ΔmacAB-tolC deletion mutant. Complementary approaches allowed us to get an overview of the impact of macAB-tolC deletion in A. baumannii physiology. Indeed, this efflux pump appeared to be involved in the envelope stress response occurring in mature biofilm and contributes to maintain WT membrane rigidity as well as tolerance to high osmolarity conditions. In addition, this system is probably involved in the maintenance of iron and sulfur homeostasis. MacAB-TolC might help this pathogen facing and adapting to biofilm architecture which is heterogeneous in space and time, especially in mature biofilm. Increasing our knowledge of A. baumannii biofilm formation will undoubtedly help us develop new therapeutic strategies to tackle this emerging threat to human health.

INSTRUMENT(S): LTQ Orbitrap Elite

ORGANISM(S): Acinetobacter Baumannii

SUBMITTER: Julie Hardouin

LAB HEAD: Emmanuelle Dé

PROVIDER: PXD028619 | Pride | 2022-02-16

REPOSITORIES: Pride

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Publications

MacAB-TolC Contributes to the Development of <i>Acinetobacter baumannii</i> Biofilm at the Solid-Liquid Interface.

Robin Brandon B Nicol Marion M Le Hung H Tahrioui Ali A Schaumann Annick A Vuillemenot Jean-Baptiste JB Vergoz Delphine D Lesouhaitier Olivier O Jouenne Thierry T Hardouin Julie J Potron Anaïs A Perrot Valérie V Dé Emmanuelle E

Frontiers in microbiology 20220113

<i>Acinetobacter baumannii</i> has emerged as one of the most problematic bacterial pathogens responsible for hospital-acquired and community infections worldwide. Besides its high capacity to acquire antibiotic resistance mechanisms, it also presents high adhesion abilities on inert and living surfaces leading to biofilm development. This lifestyle confers additional protection against various treatments and allows it to persist for long periods in various hospital niches. Due to their remarkab ...[more]

PMID: 35095797

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Project description:Background. Desulfovibrio vulgaris Hildenborough is a sulfate-reducing bacterium (SRB) that is intensively studied in the context of metal corrosion and heavy-metal bioremediation, and SRB populations are commonly observed in pipe and subsurface environments as surface-associated populations. In order to elucidate physiological changes associated with biofilm growth at both the transcript and protein level, transcriptomic and proteomic analyses were done on mature biofilm cells and compared to both batch and reactor planktonic populations. The biofilms were cultivated with lactate and sulfate in a continiouslly fed biofilm reactor, and compared to both batch and reactor planktonic populations. The functional genomic analysis demonstrated that biofilm cells were different compared to planktonic cells, and the majority of altered abundances for genes and proteins were annotated as hypothetical (unknown function), energy conservation, amino acid metabolism, and signal transduction. Genes and proteins that showed similar trends in detected levels were particularly involved in energy conservation such as increases in an annotated ech hydrogenase, formate dehydrogenase, pyruvate:ferredoxin oxidoreductase, and rnf oxidoreductase, and the biofilm cells had elevated formate dehydrogenase activity. Several other hydrogenases and formate dehydrogenases also showed an increased protein level, while decreased transcript and protein levels were observed for putative coo hydrogenases as well as a lactate permease and hyp hydrogenases for biofilm cells. Genes annotated for amino acid synthesis and nitrogen utilization were also predominant changers within the biofilm state. Ribosomal transcripts and proteins were notably decreased within the biofilm cells compared to exponential-phase cells but were not as low as levels observed in planktonic, stationary-phase cells. Several putative, extracellular proteins (DVU1012, 1545) were also detected in the extracellular fraction from biofilm cells. Even though both the planktonic and biofilm cells were oxidizing lactate and reducing sulfate, the biofilm cells were physiologically distinct compared to planktonic growth states due to altered abundances of genes/proteins involved in carbon/energy flow and extracellular structures. In addition, average expression values for multiple rRNA transcripts and respiratory activity measurements indicated that biofilm cells were metabolically more similar to exponential-phase cells although biofilm cells are structured differently. The characterization of physiological advantages and constraints of the biofilm growth state for sulfate-reducing bacteria will provide insight into bioremediation applications as well as microbially-induced metal corrosion. Biofilms grown in reactors were compared to reference samples of reactor, planktonic and batch, planktonic. Each sample had a biological triplicate.

Project description:Background The Gram-negative bacteria Fusobacterium nucleatum and Porphyromonas gingivalis are associated with periodontitis and members of a complex microbial biofilm. The self-produced extracellular polymeric matrix (EPM) of biofilms generally consists of lipids, exopolysaccharides, nucleic acids and proteins. The proteinaceous components of the biofilm matrix play many roles in biofilm development and function. In this study the protein composition of the matrices in mono- and dual-species biofilms of F. nucleatum and P. gingivalis were analyzed. Methods The bacteria were grown in a static biofilm model. Extraction of EPM was performed by careful mechanical shearing and filtration. Initial tryptic digestion of EPMs was followed by liquid chromatography-tandem mass spectrometry to analyze the resulting peptide mixtures. Quantitative proteomic software MaxQuant was then employed for protein identifications and label-free quantitative (LFQ) analysis. Functional analyses of identified proteins were applied in classification and prediction of their possible roles in EPM. Results We identified 542 proteins in the matrix of F. nucleatum, 93 proteins in the matrix of P. gingivalis and 280 proteins in the dual-species biofilm matrix. Similarly, relative quantification based on LFQ intensity scores identified generally higher protein amounts in F. nucleatum and dual species EMPs, when compared to P. gingivalis EPM. Acetyl-CoA acetyltransferase, alkyl hydroperoxide reductase C22 protein, neutrophil-activating protein A, tryptophanase and glutamate dehydrogenase were the top five proteins in the matrix of F. nucleatum biofilm. The oxidoreductase NAD-specific glutamate dehydrogenase and the proteolytic and adhesive protein Lys-gingipain were most abundant in P. gingivalis EPM. In the dual species EPM, F. nucleatum contributed to four out of the five with glutamate dehydrogenase on top. NAD-specific dehydrogenase from P. gingivalis was among the top five. Functional analyses with respect to virulence for example, revealed the stress-induced protein yicC in F. nucleatum EPM, while hemagglutinin HagA and fimbriae minor component FimD were among the top 5 in P. gingivalis EPM. Conclusions We showed that the biofilm matrix of two important periodontal pathogens is abundant in proteins and nearly 70% of all EPM proteins originate from F. nucleatum when grown together with P. gingivalis. Outer membrane proteins, virulence related and oxidative stress proteins were among the most abundant proteins identified.

Dataset Information

MacAB-TolC, a determinant of solid-liquid biofilms in Acinetobacter baumannii

Publications

MacAB-TolC Contributes to the Development of <i>Acinetobacter baumannii</i> Biofilm at the Solid-Liquid Interface.

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