Synergistic interactions in mixed-species biofilms of pathogenic bacteria from the respiratory tract

Varposhti, Maryam; Entezari, Fatemeh; Feizabadi, Mohammad Mehdi

doi:10.1590/0037-8682-0262-2013

Cited by 23 publications

(17 citation statements)

References 14 publications

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“…lac operon 47 . Further, the coexistence of Gram-positive and Gram-negative bacteria in multispecies or polymicrobial biofilms at oral or dental plaque 48 , 49 , respiratory tract 50 , catheters 51 , surface of marine algae 52 and many more further strengthen our findings. Although the instances for the occurrence of LuxR is very high as compared to LuxI that explain the extent for responding to QSSMs are very high as compared to synthesis in Gram-positive bacteria.…”

Section: Discussionsupporting

confidence: 76%

In silico analyses of conservational, functional and phylogenetic distribution of the LuxI and LuxR homologs in Gram-positive bacteria

Rajput

Kumar

2017

Sci Rep

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LuxI and LuxR are key factors that drive quorum sensing (QS) in bacteria through secretion and perception of the signaling molecules e.g. N-Acyl homoserine lactones (AHLs). The role of these proteins is well established in Gram-negative bacteria for intercellular communication but remain under-explored in Gram-positive bacteria where QS peptides are majorly responsible for cell-to-cell communication. Therefore, in the present study, we explored conservation, potential function, topological arrangements and evolutionarily aspects of these proteins in Gram-positive bacteria. Putative LuxI/LuxR containing proteins were retrieved using the domain-based strategy from InterPro v62.0 meta-database. Conservational analyses via multiple sequence alignment and domain showed that these are well conserved in Gram-positive bacteria and possess relatedness with Gram-negative bacteria. Further, Gene ontology and ligand-based functional annotation explain their active involvement in signal transduction mechanism via QS signaling molecules. Moreover, Phylogenetic analyses (LuxI, LuxR, LuxI + LuxR and 16s rRNA) revealed horizontal gene transfer events with significant statistical support among Gram-positive and Gram-negative bacteria. This in-silico study offers a detailed overview of potential LuxI/LuxR distribution in Gram-positive bacteria (mainly Firmicutes and Actinobacteria) and their functional role in QS. It would further help in understanding the extent of interspecies communications between Gram-positive and Gram-negative bacteria through QS signaling molecules.

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Section: Discussionsupporting

confidence: 76%

In silico analyses of conservational, functional and phylogenetic distribution of the LuxI and LuxR homologs in Gram-positive bacteria

Rajput

Kumar

2017

Sci Rep

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“…It was found that S. maltophilia increases the risk of resistance of P. aeruginosa to polymyxin; beta-lactamase leaking from S. maltophilia enhances the growth of P. aeruginosa in the presence of beta-lactam antibiotic agents; S. maltophilia might confer a selective fitness advantage to P. aeruginosa and increase the virulence of P. aeruginosa (18). The interaction of A. baumannii and S. maltophilia is not discussed in the literature, except for their ability to increase each other's biofilm production (19). It was reported that a Burkholderia cenocepacia subpopulation highly resistant to polymyxin B can protect a sensitive P. aeruginosa from polymyxin B in broth co-culture (20).…”

Section: Discussionmentioning

confidence: 99%

In Vitro Activity of Colistin and Trimethoprim/Sulfamethoxazole Against Consortia of Multidrug Resistant Non-Fermenting Gram-Negative Bacilli Isolated from Lower Respiratory Tract

Juhász

Kovács

Pongrácz

et al. 2017

Jundishapur J Microbiol

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Background: Multidrug resistant (MDR) Pseudomonas aeruginosa, Acinetobacter baumannii and Stenotrophomonas maltophilia have a leading role in nosocomial infections, including lower respiratory tract (LRT) infections. When polymicrobial infection by these three bacteria occurs, colistin against MDR P. aeruginosa and A. baumannii and trimethoprim/sulfamethoxazole (SXT) against S. maltophilia can be an optional antimicrobial strategy. Objectives: The aim of this study was to investigate the potential synergic effect of colistin-plus-SXT against those MDR P. aeruginosa, A. baumannii and S. maltophilia isolates that were isolated at the same time, from the same LRT sample of patients. Methods: Sixty connected isolates from 20 different patients were collected in a two-year study period. The checkerboard method and time-kill assays were used for synergy testing. Results: All P. aeruginosa and A. baumannii strains were susceptible to colistin, whereas all S. maltophilia isolates were resistant to it. Fifteen percent of MDR A. baumannii strains and all S. maltophilia isolates were susceptible to SXT. By the checkerboard method, colistin-plus-SXT showed synergy in 50%, 35% and 45% of S. maltophilia, MDR P. aeruginosa and MDR A. baumannii strains, respectively. Antagonistic effect was not found. A time-kill assay was performed on strains which showed synergy by the checkerboard method: 70%, 57% and 56% of S. maltophilia, P. aeruginosa and A. baumannii strains showed the same results. Synergic activity of the combination was already detected after 6 h incubation in 86% of S. maltophilia isolates and 50% of P. aeruginosa strains. Regrowth of A. baumannii after 24 hour in the presence of colistin was prevented by the combination. The results gained by CB and TKA methods

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“…Firstly, it evaluates the nature of interactions occurring between P. aeruginosa and S. maltophilia under both planktonic and biofilm growth, and specifically whether these interactions offer enhanced fitness compared to single cultures. Secondly, it considers S. maltophilia and P. aeruginosa strains isolated at the same time from the same CF patient during a PE episode, whereas previous works were conducted using strains isolated from different, and non-CF, patients (Kataoka et al, 2003 ; Ryan et al, 2008 ; Varposhti et al, 2014 ).…”

Section: Discussionmentioning

confidence: 99%

Cooperative pathogenicity in cystic fibrosis: Stenotrophomonas maltophilia modulates Pseudomonas aeruginosa virulence in mixed biofilm

et al. 2015

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The present study was undertaken in order to understand more about the interaction occurring between S. maltophilia and P. aeruginosa, which are frequently co-isolated from CF airways. For this purpose, S. maltophilia RR7 and P. aeruginosa RR8 strains, co-isolated from the lung of a chronically infected CF patient during a pulmonary exacerbation episode, were evaluated for reciprocal effect during planktonic growth, adhesion and biofilm formation onto both polystyrene and CF bronchial cell monolayer, motility, as well as for gene expression in mixed biofilms. P. aeruginosa significantly affected S. maltophilia growth in both planktonic and biofilm cultures, due to an inhibitory activity probably requiring direct contact. Conversely, no effect was observed on P. aeruginosa by S. maltophilia. Compared with monocultures, the adhesiveness of P. aeruginosa on CFBE41o- cells was significantly reduced by S. maltophilia, which probably acts by reducing P. aeruginosa's swimming motility. An opposite trend was observed for biofilm formation, confirming the findings obtained using polystyrene. When grown in mixed biofilm with S. maltophilia, P. aeruginosa significantly over-expressed aprA, and algD—codifying for protease and alginate, respectively—while the quorum sensing related rhlR and lasI genes were down-regulated. The induced alginate expression by P. aeruginosa might be responsible for the protection of S. maltophilia against tobramycin activity we observed in mixed biofilms. Taken together, our results suggest that the existence of reciprocal interference of S. maltophilia and P. aeruginosa in CF lung is plausible. In particular, S. maltophilia might confer some selective “fitness advantage” to P. aeruginosa under the specific conditions of chronic infection or, alternatively, increase the virulence of P. aeruginosa thus leading to pulmonary exacerbation.

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Synergistic interactions in mixed-species biofilms of pathogenic bacteria from the respiratory tract

Cited by 23 publications

References 14 publications

In silico analyses of conservational, functional and phylogenetic distribution of the LuxI and LuxR homologs in Gram-positive bacteria

In silico analyses of conservational, functional and phylogenetic distribution of the LuxI and LuxR homologs in Gram-positive bacteria

In Vitro Activity of Colistin and Trimethoprim/Sulfamethoxazole Against Consortia of Multidrug Resistant Non-Fermenting Gram-Negative Bacilli Isolated from Lower Respiratory Tract

Cooperative pathogenicity in cystic fibrosis: Stenotrophomonas maltophilia modulates Pseudomonas aeruginosa virulence in mixed biofilm

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