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

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.

scholarly journals The effect of Zinc Oxide Nanoparticles on Pseudomonas Aeruginosa Biofilm Formation and Virulence Genes Expression

2020 ◽  
Author(s):  
wedad abdelraheem ◽  
Ebtisam S. Mohamed
Keyword(s):  
Biofilm Formation ◽  
Virulence Genes ◽  
Antimicrobial Agents ◽  
Public Health Problem ◽  
Microtiter Plate ◽  
Clinical Isolates ◽  
Expression Level ◽  
Microdilution Method ◽  
Genes Expression ◽  
Broth Microdilution Method

Abstract Background: Due to increased resistance to antimicrobial agents, infectious disease remains a public health problem worldwide. Aim: The current study was designed to examine the effect of ZnO nanoparticles (ZnO –np) against the biofilm formation ability of P.aeruginosa clinical isolates and to study its effect on the expression level of the genes involved in biofilm formation and virulence factors production. Methodology: The MIC of ZnO –np against P. aeruginosa was determined by the broth microdilution method. The Effect of ZnO –np on the biofilm-forming isolates of P. aeruginosa was monitored by the microtiter plate method. P.aeruginosa isolates were tested for the expression of different biofilm and virulence genes using real-time rt-PCR. Results: ZnO –np significantly downregulated the expression level of all biofilm and virulence genes of P.aeruginosa clinical isolates except the toxA gene. Conclusions: This study demonstrates the promising use of ZnO –np as an anti-biofilm and anti-virulence compound.

scholarly journals Enhancement of pyocyanin production by subinhibitory concentration of royal jelly in Pseudomonas aeruginosa

F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 14
Author(s):  
Dina Auliya Amly ◽  
Puspita Hajardhini ◽  
Alma Linggar Jonarta ◽  
Heribertus Dedy Kusuma Yulianto ◽  
Heni Susilowati
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Growth ◽  
Biofilm Formation ◽  
Royal Jelly ◽  
Microtiter Plate ◽  
Multidrug Resistant ◽  
Clinical Isolates ◽  
Antibiotic Tolerance ◽  
Subinhibitory Concentration ◽  
Pyocyanin Production

Background: Pseudomonas aeruginosa, a multidrug-resistant Gram-negative bacterium, produces pyocyanin, a virulence factor associated with antibiotic tolerance. High concentrations of royal jelly have an antibacterial effect, which may potentially overcome antibacterial resistance. However, in some cases, antibiotic tolerance can occur due to prolonged stress of low-dose antibacterial agents. This study aimed to investigate the effect of subinhibitory concentrations of royal jelly on bacterial growth, pyocyanin production, and biofilm formation of P. aeruginosa. Methods: Pseudomonas aeruginosa ATCC 10145 and clinical isolates were cultured in a royal jelly-containing medium to test the antibacterial activity. Pyocyanin production was observed by measuring the absorbance at 690 nm after 36 h culture and determined using extinction coefficient 4310 M-1 cm-1. Static microtiter plate biofilm assay performed to detect the biofilm formation, followed by scanning electron microscopy. Results: Royal jelly effectively inhibited the viability of both strains from a concentration of 25%. The highest production of pyocyanin was observed in the subinhibitory concentration group 6.25%, which gradually decreased along with the decrease of royal jelly concentration. Results of one-way ANOVA tests differed significantly in pyocyanin production of the two strains between the royal jelly groups. Tukey HSD test showed concentrations of 12.5%, 6.25%, and 3.125% significantly increased pyocyanin production of ATCC 10145, and the concentrations of 12.5% and 6.25% significantly increased production of the clinical isolates. Concentrations of 12.5% and 6.125% significantly induced biofilm formation of P. aeruginosa ATCC 10145, in line with the results of the SEM analysis. Conclusions: The royal jelly concentration of 25% or higher inhibits bacterial growth; however, the subinhibitory concentration increases pyocyanin production and biofilm formation in P. aeruginosa. It is advisable to determine the appropriate concentration of royal jelly to obtain beneficial virulence inhibiting activity.

scholarly journals Evaluation of Antibiotic Resistance Pattern, Alginate and Biofilm Production in Clinical Isolates of Pseudomonas aeruginosa

2021 ◽  
Author(s):  
Fateme DAVARZANI ◽  
Navid SAIDI ◽  
Saeed BESHARATI ◽  
Horieh SADERI ◽  
Iraj RASOOLI ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Bacterial Resistance ◽  
Antimicrobial Agents ◽  
Clinical Isolates ◽  
Diffusion Method ◽  
Clinical Samples ◽  
Resistance Pattern ◽  
Alginate Production ◽  
Opportunistic Bacteria

Background: Pseudomonas aeruginosa is one of the most common opportunistic bacteria causing nosocomial infections, which has significant resistance to antimicrobial agents. This bacterium is a biofilm and alginate producer. Biofilm increases the bacterial resistance to antibiotics and the immune system. Therefore, the present study was conducted to investigate the biofilm formation, alginate production and antimicrobial resistance patterns in the clinical isolates of P. aeruginosa. Methods: One hundred isolates of P. aeruginosa were collected during the study period (from Dec 2017 to Jul 2018) from different clinical samples of the patients admitted to Milad and Pars Hospitals at Tehran, Iran. Isolates were identified and confirmed by phenotypic and genotypic methods. Antimicrobial susceptibility was specified by the disk diffusion method. Biofilm formation and alginate production were measured by microtiter plate and carbazole assay, respectively. Results: Sixteen isolates were resistant to all the 12 studied antibiotics. Moreover, 31 isolates were MultidrugResistant (MDR). The highest resistance rate was related to ofloxacin (36 isolates) and the least resistance was related to piperacillin-tazobactam (21 isolates). All the isolates could produce the biofilm and alginate. The number of isolates producing strong, medium and weak biofilms was equal to 34, 52, and 14, respectively. Alginate production was more than 400 μg/ml in 39 isolates, 250-400 μg/ml in 51 isolates and less than 250 μg/ml in 10 isolates. Conclusion: High prevalence of MDR, biofilm formation, and alginate production were observed among the clinical isolates of P. aeruginosa. The results also showed a significant relationship between the amount of alginate production and the level of biofilm formation.

scholarly journals Enhancement of pyocyanin production by subinhibitory concentration of royal jelly in Pseudomonas aeruginosa

F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 14
Author(s):  
Dina Auliya Amly ◽  
Puspita Hajardhini ◽  
Alma Linggar Jonarta ◽  
Heribertus Dedy Kusuma Yulianto ◽  
Heni Susilowati
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Growth ◽  
Biofilm Formation ◽  
Royal Jelly ◽  
Microtiter Plate ◽  
Multidrug Resistant ◽  
Clinical Isolates ◽  
Antibiotic Tolerance ◽  
Subinhibitory Concentration ◽  
Pyocyanin Production

Background: Pseudomonas aeruginosa, a multidrug-resistant Gram-negative bacterium, produces pyocyanin, a virulence factor associated with antibiotic tolerance. High concentrations of royal jelly have an antibacterial effect, which may potentially overcome antibacterial resistance. However, in some cases, antibiotic tolerance can occur due to prolonged stress of low-dose antibacterial agents. This study aimed to investigate the effect of subinhibitory concentrations of royal jelly on bacterial growth, pyocyanin production, and biofilm formation of P. aeruginosa. Methods: Pseudomonas aeruginosa ATCC 10145 and clinical isolates were cultured in a royal jelly-containing medium to test the antibacterial activity. Pyocyanin production was observed by measuring the absorbance at 690 nm after 36 h culture and determined using extinction coefficient 4310 M-1 cm-1. Static microtiter plate biofilm assay performed to detect the biofilm formation, followed by scanning electron microscopy. Results: Royal jelly effectively inhibited the viability of both strains from a concentration of 25%. The highest production of pyocyanin was observed in the subinhibitory concentration group 6.25%, which gradually decreased along with the decrease of royal jelly concentration. Results of one-way ANOVA tests differed significantly in pyocyanin production of the two strains between the royal jelly groups. Tukey HSD test showed concentrations of 12.5%, 6.25%, and 3.125% significantly increased pyocyanin production of ATCC 10145, and the concentrations of 12.5% and 6.25% significantly increased production of the clinical isolates. Concentrations of 12.5% and 6.125% significantly induced biofilm formation of P. aeruginosa ATCC 10145, in line with the results of the SEM analysis. Conclusions: The royal jelly concentration of 25% or higher inhibits bacterial growth; however, the subinhibitory concentration increases pyocyanin production and biofilm formation in P. aeruginosa. It is advisable to determine the appropriate concentration of royal jelly to obtain beneficial virulence inhibiting activity.

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

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.

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

2015 ◽  
Vol 9 (10) ◽  
pp. 1091-1099 ◽  
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.

The prevalence of some Pseudomonas virulence genes related to biofilm formation and alginate production among clinical isolates

2015 ◽  
Vol 13 (1) ◽  
pp. 61-68 ◽  
Author(s):  
Abdolamir Ghadaksaz ◽  
Abbas Ali Imani Fooladi ◽  
Hamideh Mahmoodzadeh Hosseini ◽  
Mohsen Amin
Keyword(s):  
Biofilm Formation ◽  
Virulence Genes ◽  
Clinical Isolates ◽  
Alginate Production

scholarly journals Enhancement of pyocyanin production by subinhibitory concentration of royal jelly in Pseudomonas aeruginosa

F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 14
Author(s):  
Dina Auliya Amly ◽  
Puspita Hajardhini ◽  
Alma Linggar Jonarta ◽  
Heribertus Dedy Kusuma Yulianto ◽  
Heni Susilowati
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Growth ◽  
Biofilm Formation ◽  
Royal Jelly ◽  
Microtiter Plate ◽  
Clinical Isolates ◽  
Antibiotic Tolerance ◽  
Subinhibitory Concentration ◽  
Subinhibitory Concentrations ◽  
Pyocyanin Production

Background: Pseudomonas aeruginosa, a multidrug-resistant Gram-negative bacterium, produces pyocyanin, a virulence factor associated with antibiotic tolerance. High concentrations of royal jelly have an antibacterial effect, which may potentially overcome antibacterial resistance. However, in some cases, antibiotic tolerance can occur due to prolonged stress of low-dose antibacterial agents. This study aimed to investigate the effect of subinhibitory concentrations of royal jelly on bacterial growth, pyocyanin production, and biofilm formation of P. aeruginosa. Methods: Pseudomonas aeruginosa ATCC 10145 and clinical isolates were cultured in a royal jelly-containing medium to test the antibacterial activity. Pyocyanin production was observed by measuring the absorbance at 690 nm after 36 h culture and determined using extinction coefficient 4310 M-1 cm-1. Static microtiter plate biofilm assay performed to detect the biofilm formation, followed by scanning electron microscopy. Results: Royal jelly effectively inhibited the viability of both strains from a concentration of 25%. The highest production of pyocyanin was observed in the subinhibitory concentration group 6.25%, which gradually decreased along with the decrease of royal jelly concentration. Results of one-way ANOVA tests differed significantly in pyocyanin production of the two strains between the royal jelly groups. Tukey HSD test showed concentrations of 12.5%, 6.25%, and 3.125% significantly increased pyocyanin production of ATCC 10145, and the concentrations of 12.5% and 6.25% significantly increased production of the clinical isolates. Concentrations of 12.5% and 6.125% significantly induced biofilm formation of P. aeruginosa ATCC 10145, in line with the results of the SEM analysis. Conclusions: Royal jelly concentrations of 25% or higher can inhibit bacterial growth; however, subinhibitory concentrations could increase pyocyanin production and biofilm formation in P. aeruginosa. It is advisable to determine the appropriate concentration of royal jelly to obtain beneficial virulence inhibiting activity.

scholarly journals Natural products and polysorbates: Potential Inhibitors of biofilm formation in Pseudomonas aeruginosa

2020 ◽  
Vol 14 (06) ◽  
pp. 580-588
Author(s):  
Mariam Miari ◽  
Sari S Rasheed ◽  
Nathaline Haidar Ahmad ◽  
Dana Itani ◽  
Antoine Abou Fayad ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Zingiber Officinale ◽  
Inhibitory Effect ◽  
Bacterial Cells ◽  
Growth Inhibition Assay ◽  
Potential Inhibitors ◽  
Encoding Genes ◽  
Wild Blueberry

Introduction: With all the challenges super bugs are imposing, biofilm formation opens the door against various more complicated challenges. Such issue may be highlighted with the ability of the latter to render the antibiotics hardly accessible to bacterial cells and sheds the light on the importance of finding antibiofilm formers. Therefore, we assessed the inhibitory effect of natural product extracts (ginger, wild blueberry) and polysorbates (PS20, PS80) on biofilm formation at the molecular level. Methodology: Growth inhibition assay was performed to test the effect of ginger (Zingiber Officinale), wild blueberry (Vaccinium Angustifolium), and polysorbates on Pseudomonas aeruginosa (PAN14) growth. Transcription levels of biofilm exopolysaccharides encoding genes (ndvB, pelC, algC) and quorum sensing genes (lasI, lasR, rhlI, rhlR) for LasI/LasR and RhlI/ RhlR systems were evaluated by RT qPCR. Results: The polysorbates and the extracts of both ginger and wild blueberry had no effect on the growth of P. aeruginosa. Biofilms’ examination has unraveled the effectiveness of treatments used in reducing its formation. Moreover, a significant reduction in the expression of all genes tested for biofilm exopolysaccharides and its quorum sensing system was observed. Conclusion: The decrease in the relative gene expression of the exopolysaccharides and quorum sensing encoding genes sheds the light on the mechanism of action of ginger and wild blueberry’s constituents as well as polysorbates 20 and 80 on P. aeruginosa biofilm formation. Future studies need to assess the antibiofilm effect of each fraction of herbal extracts separately.

scholarly journals Cephalosporin nitric oxide-donor prodrug DEA-C3D disperses biofilms formed by clinical cystic fibrosis isolates of Pseudomonas aeruginosa

2019 ◽  
Vol 75 (1) ◽  
pp. 117-125 ◽  
Author(s):  
Odel Soren ◽  
Ardeshir Rineh ◽  
Diogo G Silva ◽  
Yuming Cai ◽  
Robert P Howlin ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Clinical Isolates ◽  
Nitric Oxide Donor ◽  
Confocal Laser ◽  
Broth Microdilution Method

Abstract Objectives The cephalosporin nitric oxide (NO)-donor prodrug DEA-C3D (‘DiEthylAmin-Cephalosporin-3′-Diazeniumdiolate’) has been shown to initiate the dispersal of biofilms formed by the Pseudomonas aeruginosa laboratory strain PAO1. In this study, we investigated whether DEA-C3D disperses biofilms formed by clinical cystic fibrosis (CF) isolates of P. aeruginosa and its effect in combination with two antipseudomonal antibiotics, tobramycin and colistin, in vitro. Methods β-Lactamase-triggered release of NO from DEA-C3D was confirmed using a gas-phase chemiluminescence detector. MICs for P. aeruginosa clinical isolates were determined using the broth microdilution method. A crystal violet staining technique and confocal laser scanning microscopy were used to evaluate the effects of DEA-C3D on P. aeruginosa biofilms alone and in combination with tobramycin and colistin. Results DEA-C3D was confirmed to selectively release NO in response to contact with bacterial β-lactamase. Despite lacking direct, cephalosporin/β-lactam-based antibacterial activity, DEA-C3D was able to disperse biofilms formed by three P. aeruginosa clinical isolates. Confocal microscopy revealed that DEA-C3D in combination with tobramycin produces similar reductions in biofilm to DEA-C3D alone, whereas the combination with colistin causes near complete eradication of P. aeruginosa biofilms in vitro. Conclusions DEA-C3D is effective in dispersing biofilms formed by multiple clinical isolates of P. aeruginosa and could hold promise as a new adjunctive therapy to patients with CF.

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