Pseudomonas aeruginosa, a Gram-negative, rod-shaped bacterium causes widespread diseases in humans. This bacterium is frequently related to nosocomial infections such as pneumonia, urinary tract infections (UTIs) and bacteriaemia especially in immunocompromised patients. The current review focuses on the recent perspectives on biofilms formation by these bacteria. Biofilms are communities of microorganisms in which cells stick to each other and often adhere to a surface. These adherent cells are usually embedded within a self-produced matrix of extracellular polymeric substance (EPS). Pel, psl and alg operons present in P. aeruginosa are responsible for the biosynthesis of extracellular polysaccharide which plays an important role in cell surface interactions during biofilm formation. Recent studies suggested that cAMP signalling pathway, quorum-sensing pathway, Gac/Rsm pathway and c-di-GMP signalling pathway are the main mechanism that leads to the biofilm formation. Understanding the bacterial virulence depends on a number of cell-associated and extracellular factors and is very essential for the development of potential drug targets. Thus, the review focuses on the major genes involved in the biofilm formation, the state of art update on the biofilm treatment and the dispersal approaches such as targeting adhesion and maturation, targeting virulence factors and other strategies such as small molecule-based inhibitors, phytochemicals, bacteriophage therapy, photodynamic therapy, antimicrobial peptides and natural therapies and vaccines to curtail the biofilm formation by P. aeruginosa.

• Klíčová slova
• Alginate, Biofilm dispersal, Biofilms, EPS, Gac/Rsm pathway, Pel, Pseudomonas aeruginosa, Psl, Quorum-sensing pathway, Treatment advancement, c-di-GMP signalling pathway,
• MeSH
• antibakteriální látky farmakologie   MeSH
• bakteriální léková rezistence MeSH
• bakteriální polysacharidy chemie   MeSH
• biofilmy účinky léků   MeSH
• biologické modely MeSH
• lidé MeSH
• Pseudomonas aeruginosa účinky léků   genetika   růst a vývoj   fyziologie   MeSH
• quorum sensing MeSH
• regulace genové exprese u bakterií MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• antibakteriální látky MeSH
• bakteriální polysacharidy MeSH

Staphylococcus aureus is one of the most important pathogens causing chronic biofilm infections. These are becoming more difficult to treat owing to drug resistance, particularly because S. aureus biofilms limit the efficacy of antimicrobial agents, leading to high morbidity and mortality. In the present study, we screened for inhibitors of S. aureus biofilm formation using a natural product library from the Korea Chemical Bank (KCB). Screening by crystal violet-based biomass staining assay identified hit compounds. Further examination of antibiofilm properties of these compounds was conducted and led to the identification of celastrol and telithromycin. In vitro, both celastrol and telithromycin were toxic to planktonic S. aureus and also active against a clinical methicillin-resistant S. aureus (MRSA) isolate. The effect of the compounds on preformed biofilms of clinical MRSA isolates was evaluated by confocal laser scanning microscopy (CLSM), which revealed the absence of typical biofilm architecture. In addition, celastrol and telithromycin inhibited the production of extracellular protein at selected sub-MIC concentrations, which revealed the reduced extracellular polymeric substance (EPS) secretion. Celastrol exhibited greater cytotoxicity than telithromycin. These data suggest that the hit compounds, especially telithromycin, could be considered novel inhibitors of S. aureus biofilm. Although the mechanisms of the effects on S. aureus biofilms are not fully understood, our data suggest that telithromycin could be a useful adjuvant therapeutic agent for S. aureus biofilm-related infections.

• MeSH
• antibakteriální látky farmakologie   MeSH
• biofilmy účinky léků   růst a vývoj   MeSH
• biologické přípravky farmakologie   MeSH
• genciánová violeť MeSH
• ketolidy farmakologie   MeSH
• knihovny malých molekul farmakologie   MeSH
• methicilin rezistentní Staphylococcus aureus účinky léků   fyziologie   MeSH
• mikrobiální testy citlivosti MeSH
• pentacyklické triterpeny MeSH
• plankton účinky léků   růst a vývoj   MeSH
• rychlé screeningové testy MeSH
• Staphylococcus aureus účinky léků   fyziologie   MeSH
• triterpeny farmakologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antibakteriální látky MeSH
• biologické přípravky MeSH
• celastrol MeSH Prohlížeč
• genciánová violeť MeSH
• ketolidy MeSH
• knihovny malých molekul MeSH
• pentacyklické triterpeny MeSH
• telithromycin MeSH Prohlížeč
• triterpeny MeSH

Biofilms represent mixed communities present in a diverse range of environments; however, their utility as inoculants is less investigated. Our investigation was aimed towards in vitro development of biofilms using fungal mycelia (Trichoderma viride) as matrices and nitrogen-fixing and P-solubilizing bacteria as partners, as a prelude to their use as biofertilizers (biofilmed biofertilizers, BBs) and biocontrol agents for different crops. The most suitable media in terms of population counts, fresh mass and dry biomass for Trichoderma and Bacillus subtilis/Pseudomonas fluorescens was found to be Pikovskaya broth ± 1 % CaCO(3), while for Trichoderma and Azotobacter chroococcum, Jensen's medium was most optimal. The respective media were then used for optimization of the inoculation rate of the partners in terms of sequence of addition of partners, fresh/dry mass of biofilms and population counts of partners for efficient film formation. Microscopic observations revealed significant differences in the progress of growth of biofilms and dual cultures. In the biofilms, the bacteria were observed growing intermingled within the fungal mycelia mat. Further, biofilm formation was compared under static and shaking conditions and the fresh mass of biofilms was higher in the former. Such biofilms are being further characterized under in vitro conditions, before using them as inoculants with crops.

• MeSH
• biofilmy * MeSH
• kultivační média chemie   metabolismus   MeSH
• mycelium růst a vývoj   fyziologie   MeSH
• očkovadla agrotechnická genetika   růst a vývoj   fyziologie   MeSH
• Trichoderma genetika   růst a vývoj   fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kultivační média MeSH

BACKGROUND: The genome of Pseudomonas aeruginosa contains at least three genes encoding eukaryotic-type Ser/Thr protein kinases, one of which, ppkA, has been implicated in P. aeruginosa virulence. Together with the adjacent pppA phosphatase gene, they belong to the type VI secretion system (H1-T6SS) locus, which is important for bacterial pathogenesis. To determine the biological function of this protein pair, we prepared a pppA-ppkA double mutant and characterised its phenotype and transcriptomic profiles. RESULTS: Phenotypic studies revealed that the mutant grew slower than the wild-type strain in minimal media and exhibited reduced secretion of pyoverdine. In addition, the mutant had altered sensitivity to oxidative and hyperosmotic stress conditions. Consequently, mutant cells had an impaired ability to survive in murine macrophages and an attenuated virulence in the plant model of infection. Whole-genome transcriptome analysis revealed that pppA-ppkA deletion affects the expression of oxidative stress-responsive genes, stationary phase σ-factor RpoS-regulated genes, and quorum-sensing regulons. The transcriptome of the pppA-ppkA mutant was also analysed under conditions of oxidative stress and showed an impaired response to the stress, manifested by a weaker induction of stress adaptation genes as well as the genes of the SOS regulon. In addition, expression of either RpoS-regulated genes or quorum-sensing-dependent genes was also affected. Complementation analysis confirmed that the transcription levels of the differentially expressed genes were specifically restored when the pppA and ppkA genes were expressed ectopically. CONCLUSIONS: Our results suggest that in addition to its crucial role in controlling the activity of P. aeruginosa H1-T6SS at the post-translational level, the PppA-PpkA pair also affects the transcription of stress-responsive genes. Based on these data, it is likely that the reduced virulence of the mutant strain results from an impaired ability to survive in the host due to the limited response to stress conditions.

• MeSH
• bakteriální proteiny genetika   MeSH
• bakteriální RNA genetika   MeSH
• buněčné linie MeSH
• delece genu * MeSH
• fenotyp MeSH
• makrofágy mikrobiologie   MeSH
• mikrobiální viabilita MeSH
• myši MeSH
• oligopeptidy biosyntéza   MeSH
• oxidační stres * MeSH
• protein-serin-threoninkinasy genetika   MeSH
• Pseudomonas aeruginosa genetika   růst a vývoj   patogenita   MeSH
• regulace genové exprese u bakterií MeSH
• salát (hlávkový) mikrobiologie   MeSH
• sekvenční analýza hybridizací s uspořádaným souborem oligonukleotidů MeSH
• testy genetické komplementace MeSH
• transkriptom MeSH
• virulence MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• bakteriální proteiny MeSH
• bakteriální RNA MeSH
• oligopeptidy MeSH
• ppkA protein, Pseudomonas aeruginosa MeSH Prohlížeč
• protein-serin-threoninkinasy MeSH
• pyoverdin MeSH Prohlížeč