Inhibitory Effect of Macrolide Antibiotics on Biofilm Formation by Pseudomonas Aeruginosa.

Introduction/Objective. Biofilm and pyocyanin production are essential components of Pseudomonas aeruginosa virulence and antibiotic resistance. Our objective was to examine inhibitory effect of synthetized propafenone derivatives 3-(2-Fluorophenyl)- 1-(2- (2-hydroxy-3-propylamino-propoxy)-phenyl)-propan-1-one hydrochloride (5OF) and3-(2- Trifluoromethyl-phenyl)-1-(2-(2-hydroxy-3-propylamino-propoxy)-phenyl)-propan-1-one hydrochloride (5CF3) on biofilm and pyocyanin in Pseudomonas aeruginosa clinical strains. Methods. Effects were tested on nine clinical isolates and one control laboratory strain of P. aeruginosa. In vitro analysis of biofilm growing was performed by incubating bacteria (0.5 McFarland) with 5OF and 5CF3 (500?31.2 ?g/ml) and measuring optical density (OD) at 570 nm. Bacteria in medium without compounds were positive control. Blank medium (an uninoculated medium without test compounds) was used as negative control. Pyocyanin production was estimated by OD at 520 nm, after bacteria incubated with 5CF3 and 5OF (250 and 500 ?g/ml), treated with chloroform, and chloroform layer mixed with HCl. Results. A total of 500 ?g/ml of 5OF and 5CF3 completely inhibited biofilm formation in 10/10 and 4/10 strains, respectively. A total of 250 ?g/ml of 5OF and 5CF3 strongly inhibited biofilm formation in 7/10 strains, while inhibition with 125 ?g/ml of 5OF and 5CF3 was moderate. Lower concentrations had almost no effect on biofilm production. Pyocyanin production was reduced to less than 40% of the control value in 6/9, and less than 50% of the control in 7/9 strains with 500 ?g/ml of 5OF and 5CF3, respectively. At 250 ?g/ml 5OF and 5CF3, most strains had pyocyanin production above 50% of the control value. Conclusion. Synthetized propafenone derivatives, 5OF and 5CF3, inhibited biofilms and pyocyanin production of Pseudomonas aeruginosa clinical strains. Presented results suggest that propafenone derivatives are potential lead-compounds for synthesis of novel antipseudomonal drugs.

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Inhibitory Effect of Mexican Oregano (Lippia berlandieri Schauer) Essential Oil on Pseudomonas aeruginosa and Salmonella Thyphimurium Biofilm Formation

Frontiers in Sustainable Food Systems ◽

10.3389/fsufs.2020.00036 ◽

2020 ◽

Vol 4 ◽

Author(s):

Fatima Reyes-Jurado ◽

Ricardo Munguía-Pérez ◽

Teresa Soledad Cid-Pérez ◽

Paola Hernández-Carranza ◽

Carlos Enrique Ochoa-Velasco ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Essential Oil ◽

Biofilm Formation ◽

Inhibitory Effect ◽

Salmonella Thyphimurium

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Tryptophan Inhibits Biofilm Formation by Pseudomonas aeruginosa

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00007-13 ◽

2013 ◽

Vol 57 (4) ◽

pp. 1921-1925 ◽

Cited By ~ 39

Author(s):

Kenneth S. Brandenburg ◽

Karien J. Rodriguez ◽

Jonathan F. McAnulty ◽

Christopher J. Murphy ◽

Nicholas L. Abbott ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Tissue Culture ◽

Biofilm Formation ◽

Chronic Wounds ◽

Inhibitory Effect ◽

Equimolar Ratio ◽

Biofilm Growth ◽

Content Type ◽

Swimming Motility

ABSTRACTBiofilm formation byPseudomonas aeruginosahas been implicated in the pathology of chronic wounds. Both thedandlisoforms of tryptophan inhibitedP. aeruginosabiofilm formation on tissue culture plates, with an equimolar ratio ofdandlisoforms producing the greatest inhibitory effect. Addition ofd-/l-tryptophan to existing biofilms inhibited further biofilm growth and caused partial biofilm disassembly. Tryptophan significantly increased swimming motility, which may be responsible in part for diminished biofilm formation byP. aeruginosa.

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Characterization of Putative Virulence Factors of Pseudomonas aeruginosa Strain RBS Isolated from a Saltern, Tunisia: Effect of Metal Ion Cofactors on the Structure and the Activity of LasB

BioMed Research International ◽

10.1155/2020/6047528 ◽

2020 ◽

Vol 2020 ◽

pp. 1-13

Author(s):

E. Rigane ◽

R. Dutoit ◽

S. Matthijs ◽

N. Brandt ◽

S. Flahaut ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Metal Ions ◽

Virulence Factors ◽

Binding Sites ◽

Biofilm Formation ◽

Metal Ion ◽

Enzyme Stability ◽

Inhibitory Effect ◽

Ion Binding ◽

Metal Ion Binding

Pseudomonas aeruginosa is a ubiquitous Gram-negative bacterium able to survive in diverse environments such as soil, plants, freshwater, and seawater. P. aeruginosa can be an opportunistic pathogen to humans when their immune system is deficient. Its pathogenicity may be linked to the production of virulence factors. We isolated P. aeruginosa strain RBS from the saltern of Sfax in Tunisia. In this study, we characterized the halotolerance, antibiotic susceptibility, and some virulence factors of strain RBS. High NaCl concentrations inhibited growth and motility. However, biofilm formation was enhanced to protect bacteria against salt stress. Among the 18 antibiotics tested, quinolones and tetracycline showed a significant inhibitory effect on growth, motility, and biofilm formation of strain RBS. β-Lactams, however, did not have any inhibitory effect on neither bacterial growth nor motility. In some cases, resistance was due, in part, to biofilm formation. We also showed that RBS produces two proteases, LasB and AprA, which have been shown to be implicated in host infection. LasB was further characterized to study the role of metal ions in enzyme stability. It possesses two distinct metal ion-binding sites coordinating a calcium and a zinc ion. The effect of metal ion chelation was evaluated as well as substitutions of residues involved in metal ion binding. Impairing metal ion binding of LasB led to a loss of activity and a sharp decrease of stability. Our findings suggest that the binding of both metal ions is interdependent as the two metal ions’ binding sites are linked via a hydrogen bond network.

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Effect of chitosan nanoparticles on quorum sensing-controlled virulence factors and expression of LasI and RhlI genes among Pseudomonas aeruginosa clinical isolates

AIMS Microbiology ◽

10.3934/microbiol.2021025 ◽

2021 ◽

Vol 7 (4) ◽

pp. 415-430

Author(s):

Rana Abdel Fattah Abdel Fattah ◽

◽

Fatma El zaharaa Youssef Fathy ◽

Tahany Abdel Hamed Mohamed ◽

Marwa Shabban Elsayed

Keyword(s):

Pseudomonas Aeruginosa ◽

Quorum Sensing ◽

Virulence Factors ◽

Biofilm Formation ◽

Chitosan Nanoparticles ◽

Inhibitory Effect ◽

Biofilm Inhibition ◽

Expression Levels ◽

The Mean ◽

Biofilm Development

<abstract> <p>Antibiotic-resistant strains of <italic>Pseudomonas aeruginosa (P. aeruginosa</italic>) pose a major threat for healthcare-associated and community-acquired infections. <italic>P. aeruginosa</italic> is recognized as an opportunistic pathogen using quorum sensing (QS) system to regulate the expression of virulence factors and biofilm development. Thus, meddling with the QS system would give alternate methods of controlling the pathogenicity. This study aimed to assess the inhibitory impact of chitosan nanoparticles (CS-NPs) on <italic>P. aeruginosa</italic> virulence factors regulated by QS (e.g., motility and biofilm formation) and <italic>LasI</italic> and <italic>RhlI</italic> gene expression. Minimum inhibitory concentration (MIC) of CS-NPs against 30 isolates of <italic>P. aeruginosa</italic> was determined. The CS-NPs at sub-MIC were utilized to assess their inhibitory effect on motility, biofilm formation, and the expression levels of <italic>LasI</italic> and <italic>RhlI</italic> genes. CS-NPs remarkably inhibited the tested virulence factors as compared to the controls grown without the nanoparticles. The mean (±SD) diameter of swimming motility was decreased from 3.93 (±1.5) to 1.63 (±1.02) cm, and the mean of the swarming motility was reduced from 3.5 (±1.6) to 1.9 (±1.07) cm. All isolates became non-biofilm producers, and the mean percentage rate of biofilm inhibition was 84.95% (±6.18). Quantitative real-time PCR affirmed the opposition of QS activity by lowering the expression levels of <italic>LasI</italic> and <italic>RhlI</italic> genes; the expression level was decreased by 90- and 100-folds, respectively. In conclusion, the application of CS-NPs reduces the virulence factors significantly at both genotypic and phenotypic levels. These promising results can breathe hope in the fight against resistant <italic>P. aeruginosa</italic> by repressing its QS-regulated virulence factors.</p> </abstract>

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Different effects of sub-minimum inhibitory concentrations of gentamicin on the expression of genes involved in alginate production and biofilm formation of Pseudomonas aeruginosa

Iranian Journal of Microbiology ◽

10.18502/ijm.v13i6.8085 ◽

2021 ◽

Author(s):

Fateme Davarzani ◽

Zahra Yousefpour ◽

Navid Saidi ◽

Parviz Owlia

Keyword(s):

Pseudomonas Aeruginosa ◽

Biofilm Formation ◽

Virulence Genes ◽

Microtiter Plate ◽

Inhibitory Effect ◽

Clinical Isolates ◽

Minimum Inhibitory Concentrations ◽

Alginate Production ◽

Broth Microdilution Method ◽

Encoding Genes

Background and Objectives: Antibiotics at sub-minimum inhibitory concentrations (sub-MIC) may alter bacterial viru- lence factors. The objective of this study was to investigate the effect of gentamicin at sub-MIC concentrations on the expres- sion of genes involved in alginate production and biofilm formation of Pseudomonas aeruginosa. Materials and Methods: The broth microdilution method was used to determine the MIC of gentamicin for three P. aeru- ginosa clinical isolates (P1-P3) and standard strains (PAO1 and 8821M). Alginate production and biofilm formation of the bacteria in the presence and absence of sub-MIC concentrations of gentamicin were measured using microtiter plate and carbazole assay, respectively. The real-time PCR method was used to determine the effect of gentamicin at sub-MIC con- centrations on the expression level of genes involved in biofilm formation (pelA and pslA) and alginate production (algD and algU). Results: Gentamicin at sub-MIC concentrations significantly reduced alginate production, biofilm formation, and the expres- sion of alginate and biofilm-encoding genes in clinical isolate P1. This inhibitory effect was also observed on the alginate production of 8821M strain and biofilm formation of PAO1strain. In clinical isolates, P2 and P3, alginate production, biofilm formation, and the expression of alginate and biofilm-encoding genes were significantly increased in exposure to sub-MIC concentrations of gentamicin. Conclusion: This study showed that different phenotypic changes in clinical isolates and standard strains of P. aeruginosa in exposure to sub-MIC concentrations of gentamicin are associated with changes in the expression of virulence genes. Further researches are required to understand the mechanisms involved in regulating the expression of virulence genes after exposure to sub-MIC concentrations of antibiotics.

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Benefits of Usage of Immobilized Silver Nanoparticles as Pseudomonas aeruginosa Antibiofilm Factors

International Journal of Molecular Sciences ◽

10.3390/ijms23010284 ◽

2021 ◽

Vol 23 (1) ◽

pp. 284

Author(s):

Kamila Korzekwa ◽

Anna Kędziora ◽

Bartłomiej Stańczykiewicz ◽

Gabriela Bugla-Płoskońska ◽

Dorota Wojnicz

Keyword(s):

Pseudomonas Aeruginosa ◽

Silver Nanoparticles ◽

Biofilm Formation ◽

Inhibitory Concentration ◽

Colorimetric Assay ◽

Inorganic Compounds ◽

Sol Gel ◽

Lavage Fluid ◽

Inhibitory Effect ◽

Broth Microdilution Method

The aim of this study was to assess the beneficial inhibitory effect of silver nanoparticles immobilized on SiO2 or TiO2 on biofilm formation by Pseudomonas aeruginosa—one of the most dangerous pathogens isolated from urine and bronchoalveolar lavage fluid of patients hospitalized in intensive care units. Pure and silver doped nanoparticles of SiO2 and TiO2 were prepared using a novel modified sol-gel method. Ten clinical strains of P. aeruginosa and the reference PAO1 strain were used. The minimal inhibitory concentration (MIC) was determined by the broth microdilution method. The minimal biofilm inhibitory concentration (MBIC) and biofilm formation were assessed by colorimetric assay. Bacterial enumeration was used to assess the viability of bacteria in the biofilm. Silver nanoparticles immobilized on the SiO2 and TiO2 indicated high antibacterial efficacy against P. aeruginosa planktonic and biofilm cultures. TiO2/Ag0 showed a better bactericidal effect than SiO2/Ag0. Our results indicate that the inorganic compounds (SiO2, TiO2) after nanotechnological modification may be successfully used as antibacterial agents against multidrug-resistant P. aeruginosa strains.

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Correlation of quorum sensing and virulence factors in Pseudomonas aeruginosa isolates in Egypt

The Journal of Infection in Developing Countries ◽

10.3855/jidc.6492 ◽

2015 ◽

Vol 9 (10) ◽

pp. 1091-1099 ◽

Cited By ~ 7

Author(s):

Hamida M. Aboushleib ◽

Hoda M. Omar ◽

Rania Abozahra ◽

Amel Elsheredy ◽

Kholoud Baraka

Keyword(s):

Pseudomonas Aeruginosa ◽

Quorum Sensing ◽

Virulence Factors ◽

Biofilm Formation ◽

Point Mutations ◽

Inhibitory Effect ◽

Clinical Isolates ◽

Clove Oil ◽

Twitching Motility ◽

Pyocyanin Production

Introduction: Pseudomonas aeruginosa is one of the most virulent nosocomial pathogens worldwide. Quorum sensing (QS) regulates the production of pathogenic virulence factors and biofilm formation in P. aeruginosa. The four genes lasR, lasI, rhlR,and rhlI were found to regulate this QS system. In this study, we aimed to assess the correlation between these four genes and QS-dependent virulence factors and to detect the inhibitory effect of clove oil on QS. Methodology: Fifty P. aeruginosa clinical isolates were collected. Susceptibility to different antibiotics was tested. Virulence factors including biofilm formation, pyocyanin production, and twitching motility were phenotypically detected. QS genes were amplified by polymerase chain reaction (PCR), and one strain subsequently underwent sequencing. The inhibitory effect of clove oil on virulence factors was also tested. Results: A positive correlation was found between biofilm formation and the presence of lasR and rhlI genes. Twitching motility was positively correlated with the presence of lasR, lasI, and rhlI genes. On the other hand, no correlation was found between pyocyanin production and any of the studied genes. Only one isolate amplified all the tested QS gene primers, but it did not express any of the tested virulence factors phenotypically. Sequence analyses of this isolate showed that the four genes had point mutations. Conclusions: Results emphasize the importance of QS in P. aeruginosa virulence; however, QS-deficient clinical isolates occur and are still capable of causing clinical infections in humans. Also, clove oil has an obvious inhibitory effect on QS, which should be clinically exploited.

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Inhibitory effect of biofilm-forming Lactobacillus kunkeei strains against virulent Pseudomonas aeruginosa in vitro and in honeycomb moth (Galleria mellonella) infection model

Beneficial Microbes ◽

10.3920/bm2017.0048 ◽

2018 ◽

Vol 9 (2) ◽

pp. 257-268 ◽

Cited By ~ 13

Author(s):

P. Berríos ◽

J.A. Fuentes ◽

D. Salas ◽

A. Carreño ◽

P. Aldea ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Biofilm Formation ◽

Pathogenic Bacteria ◽

Galleria Mellonella ◽

Wide Spectrum ◽

Inhibitory Effect ◽

Lactobacillus Species ◽

Infection Model ◽

Lactobacillus Kunkeei

Biofilms correspond to complex communities of microorganisms embedded in an extracellular polymeric matrix. Biofilm lifestyle predominates in Pseudomonas aeruginosa, an opportunistic Gram negative pathogen responsible for a wide spectrum of infections in humans, plants and animals. In this context, anti-biofilm can be considered a key strategy to control P. aeruginosa infections, thereby more research in the field is required. On the other hand, Lactobacillus species have been described as beneficial due to their anti-biofilm properties and their consequent effect against a wide spectrum of pathogens. In fact, biofilm-forming Lactobacilli seem to be more efficient than their planktonic counterpart to antagonise pathogenic bacteria. In this work, we demonstrated that Lactobacillus kunkeei, a novel Lactobacillus species isolated from honeybee guts, can form biofilms in vitro. In addition, the L. kunkeei biofilm can, in turn, inhibit the formation of P. aeruginosa biofilms. Finally, we found that L. kunkeei strains attenuate infection of P. aeruginosa in the Galleria mellonella model, presumably by affecting P. aeruginosa biofilm formation and/or their stability. Since L. kunkeei presents characteristics of a probiotic, this work provides evidence arguing that the use of this Lactobacillus species in both animals (including insects) and humans could contribute to impair P. aeruginosa biofilm formation.

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Evaluating ginger extract, wild blueberry extract, and polysorbates (PS20, PS80) on Pseudomonas aeruginosa biofilm formation

The Journal of Infection in Developing Countries ◽

10.3855/jidc.10098 ◽

2018 ◽

Vol 12 (02.1) ◽

pp. 12S

Author(s):

Mariam Miari ◽

Sari S Rasheed ◽

Nathaline Haidar-Ahmad ◽

Antoine Abou Fayad ◽

Ghassan M Matar

Keyword(s):

Pseudomonas Aeruginosa ◽

Quorum Sensing ◽

Mechanism Of Action ◽

Biofilm Formation ◽

Zingiber Officinale ◽

Inhibitory Effect ◽

Ginger Extract ◽

Biofilm Inhibition ◽

Wild Blueberry

Introduction: Pseudomonas aeruginosa is a biofilm forming pathogen that challenges clinical and industrial settings. Many natural products and surfactants have been screened and valued for their anti-biofilm capacity. In this study we assessed the inhibitory effect and molecular mechanism of action of ginger extract (Zingiber officinale Rosc.), wild blueberry extract (Vaccinium angustifolium), and polysorbates (PS20/PS80) on biofilm formation. Methodology: Ginger and wild blueberry extractions were done using ethanol and distilled water, respectively. Hexane and methanol were used for extracts’ liquid-liquid portioning. LC-HRMS was performed to obtain extract fractions. Efficacy of the crude extracts, fractions, and polysorbates was assessed on P. aeruginosa PAN14 growth and biofilm. Transcription levels of biofilm encoding genes ndvB, pelC, algC and quorum sensing genes lasI, lasR, rhlI, rhlR were evaluated by RT-qPCR. Results: Extracts and polysorbates concentrations did not affect P. aeruginosa growth. Biofilm assay showed a reduction in biofilm when 5% ginger, 25% wild blueberry extracts, 0.2% PS20, and 0.25% PS80 were added. LC-HRMS analysis of ginger extract showed abundant gingerol in the hexane layer. Wild blueberry chromatograms showed various constituents differing between their peel and pulp, and pulp extracts. RT-qPCR showed decreased transcription levels of exopolysaccharide and quorum sensing genes with a 363.6 folds reduction in ndvB upon treatment with 25% wild blueberry peel and pulp extract. Conclusion: These results shed light on the mechanism of action of ginger and wild blueberry constituents as well as PS20/80 on P. aeruginosa biofilm formation. Future mouse model experiments are useful to test biofilm inhibition in-vivo.

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