Anti-virulence activities of some Tillandsia species (Bromeliaceae)

2020 ◽  
Vol 98 (1) ◽  
pp. 117-127
Author(s):  
Macrina Pérez-López ◽  
María Flores-Cruz ◽  
Mariano Martínez-Vázquez ◽  
Ramón Marcos Soto Hernández ◽  
Rodolfo García-Contreras ◽  
...  

Background: Using molecules that inhibit bacterial virulence is a potential strategy to fight infections, with the advantage that, in contrast to bactericidal compounds, they do not induce resistance. Several compounds with anti-virulence properties have been identified in plants, however, they represent a small portion of the total diversity, and in Mexico there are still few studies on this matter.  Hypothesis: Extracts of species of the Tillandsia genus inhibit the expression of diverse virulence factors without affecting the bacterial growth.  Studied species: Tillandsia recurvata (L.) L., T. schiedeana Steud. and T. fasciculata Sw.  Study site and date: These species were collected in December 2016 in the municipalities of Ixtlahuaca and Santo Tomás de los Plátanos, State of Mexico. Methods: The ability of dichloromethane (CH2Cl2) and methanol (CH3OH) extracts to inhibit production of violacein in Chromobacterium violaceum was evaluated, as well as the virulence factors regulated by quorum sensing, motility and biofilm in Pseudomonas aeruginosa. In addition, the bioactive fractions obtained were partially identified by 1H NMR. Results: CH2Cl2 and CH3OH extracts reduced violacein production from 43 to 85 %, but only those from CH2Cl2 reduced protease activity, biofilm formation and swarming. Interestingly, CH3OH extracts stimulated the formation of biofilms by up to 37 %. Presence of terpenes and phenolic compounds in these species was confirmed. In T. schiedeana glycosylated compounds and cycloartane-type triterpenes were identified. Conclusion: The species of Tillandsia show anti-virulence activity, mainly on factors related to adhesion and dispersion in Pseudomonas aeruginosa.

2021 ◽  
Vol 233 ◽  
pp. 02044
Author(s):  
Jing Huang ◽  
Haoming Li

Pseudomonas aeruginosa is an opportunistic pathogen, and it can produce cell-associated and extracellular virulence factors. Several of these virulence factors have been demonstrated to be regulated by quorum sensing (QS). Disabling QS system with anti-infective agent is considered as a potential strategy to prevent bacterial infection. Rabdosia rubescens has been used as antibacterial agents for many centuries in China. In this study, Oridonin, the major active components of Rabdosia rubescens, was tested for QS inhibition in Pseudomonas aeruginosa. QS inhibitory activity is demonstrated by reduction in pyocyanin (58.4%), rhamnolipids (64.3%), elastase (58.6%), and protease (49.1%) in Pseudomonas aeruginosa PAO1 at 125 µg/ml (MIC) concentration. Biofilm formation by Pseudomonas aeruginosa PAO1 was reduced considerably (40.3-57.7%) over control. These findings suggest that Oridonin might be a potent Quorum Sensing Inhibitor (QSI) and anti-biofilm agent in the treatment of Pseudomonas aeruginosa infections.


Author(s):  
Baydaa Hussein ◽  
Zainab A. Aldhaher ◽  
Shahrazad Najem Abdu-Allah ◽  
Adel Hamdan

Background: Biofilm is a bacterial way of life prevalent in the world of microbes; in addition to that it is a source of alarm in the field of health concern. Pseudomonas aeruginosa is a pathogenic bacterium responsible for all opportunistic infections such as chronic and severe. Aim of this study: This paper aims to provide an overview of the promotion of isolates to produce a biofilm in vitro under special circumstances, to expose certain antibiotics to produce phenotypic evaluation of biofilm bacteria. Methods and Materials: Three diverse ways were used to inhibited biofilm formation of P.aeruginosa by effect of phenolic compounds extracts from strawberries. Isolates produced biofilm on agar MacConkey under certain circumstances. Results: The results showed that all isolates were resistant to antibiotics except sensitive to azithromycin (AZM, 15μg), and in this study was conducted on three ways to detect the biofilm produced, has been detected by the biofilm like Tissue culture plate (TCP), Tube method (TM), Congo Red Agar (CRA). These methods gave a clear result of these isolates under study. Active compounds were analyzed in both extracts by Gas Chromatography-mass Spectrometry which indicate High molecular weight compound with a long hydrocarbon chain. Conclusion: Phenolic compounds could behave as bioactive material and can be useful to be used in pharmaceutical synthesis. Phenolic contents which found in leaves and fruits extracts of strawberries shows antibacterial activity against all strains tested by the ability to reduce the production of biofilm formation rate.


2015 ◽  
Vol 8 (10) ◽  
Author(s):  
Zahra Ghanbarzadeh Corehtash ◽  
Ahmad Khorshidi ◽  
Farzaneh Firoozeh ◽  
Hosein Akbari ◽  
Azam Mahmoudi Aznaveh

2019 ◽  
Vol 10 (9) ◽  
pp. 5759-5767
Author(s):  
Wan-Ting Lee ◽  
Boon-Khai Tan ◽  
Su-Anne Eng ◽  
Gan Chee Yuen ◽  
Kit Lam Chan ◽  
...  

A strategy to circumvent the problem of multidrug resistant pathogens is the discovery of anti-infectives targeting bacterial virulence or host immunity.


2011 ◽  
Vol 56 (1) ◽  
pp. 36-43 ◽  
Author(s):  
Akihiro Yamazaki ◽  
Jin Li ◽  
Quan Zeng ◽  
Devanshi Khokhani ◽  
William C. Hutchins ◽  
...  

ABSTRACTAntibiotic therapy is the most commonly used strategy to control pathogenic infections; however, it has contributed to the generation of antibiotic-resistant bacteria. To circumvent this emerging problem, we are searching for compounds that target bacterial virulence factors rather than their viability.Pseudomonas aeruginosa, an opportunistic human pathogen, possesses a type III secretion system (T3SS) as one of the major virulence factors by which it secretes and translocates T3 effector proteins into human host cells. The fact that this human pathogen also is able to infect several plant species led us to screen a library of phenolic compounds involved in plant defense signaling and their derivatives for novel T3 inhibitors. Promoter activity screening ofexoS, which encodes a T3-secreted toxin, identified two T3 inhibitors and two T3 inducers ofP. aeruginosaPAO1. These compounds alterexoStranscription by affecting the expression levels of the regulatory small RNAs RsmY and RsmZ. These two small RNAs are known to control the activity of carbon storage regulator RsmA, which is responsible for the regulation of the key T3SS regulator ExsA. As RsmY and RsmZ are the only targets directly regulated by GacA, our results suggest that these phenolic compounds affect the expression ofexoSthrough the GacSA-RsmYZ-RsmA-ExsA regulatory pathway.


2019 ◽  
Vol 78 ◽  
pp. 01004
Author(s):  
Shan Li ◽  
Jiangning Yao ◽  
Haoming Li

Pseudomonas aeruginosa is a Gram-negative organism that can survive under harsh conditions, and it is also an opportunistic pathogen that can produce cell-associated extracellular virulence factors. Several of these virulence factors have been demonstrated to be regulated by quorum sensing (QS). Plantain Herb has been used as antibacterial agents for many centuries in China. In this study, we analyzed Plantain Herb Extracts (PHE) at the concentration of 16 μg/mL (Group A, MIC), 8 μg/mL (Group B, 1/2 MIC) and 4 μg/mL (Group C, 1/4 MIC) for inhibition of the virulence factors production and biofilm formation in P. aeruginosa PAO1. The virulence factors included pyocyanin, rhamnolipids, protease and alginate. PHE showed significant inhibition of virulence factors as compared to the control group without interfering its growth. Thus, PHE might be a potent QS inhibitor and anti-biofilm agent in the treatment of Pseudomonas aeruginosa infections.


2007 ◽  
Vol 73 (10) ◽  
pp. 3183-3188 ◽  
Author(s):  
Takenori Ishida ◽  
Tsukasa Ikeda ◽  
Noboru Takiguchi ◽  
Akio Kuroda ◽  
Hisao Ohtake ◽  
...  

ABSTRACT N-Octanoyl cyclopentylamide (C8-CPA) was found to moderately inhibit quorum sensing in Pseudomonas aeruginosa PAO1. To obtain more powerful inhibitors, a series of structural analogs of C8-CPA were synthesized and examined for their ability to inhibit quorum sensing in P. aeruginosa PAO1. The lasB-lacZ and rhlA-lacZ reporter assays revealed that the chain length and the ring structure were critical for C8-CPA analogs to inhibit quorum sensing. N-Decanoyl cyclopentylamide (C10-CPA) was found to be the strongest inhibitor, and its concentrations required for half-maximal inhibition for lasB-lacZ and rhlA-lacZ expression were 80 and 90 μM, respectively. C10-CPA also inhibited production of virulence factors, including elastase, pyocyanin, and rhamnolipid, and biofilm formation without affecting growth of P. aeruginosa PAO1. C10-CPA inhibited induction of both lasI-lacZ by N-(3-oxododecanoyl)-l-homoserine lactone (PAI1) and rhlA-lacZ by N-butanoyl-l-homoserine lactone (PAI2) in the lasI rhlI mutant of P. aeruginosa PAO1, indicating that C10-CPA interferes with the las and rhl quorum-sensing systems via inhibiting interaction between their response regulators (LasR and RhlR) and autoinducers.


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