Inhibitory effect of α-mangostin on Acinetobacter baumannii biofilms – an in vitro study

Sivaranjani, Murugesan; Ramanathan, S.; Aravindraja, Chairmandurai; Pandian, Shunmugiah Karutha; Ravi, Arumugam Veera

doi:10.1080/08927014.2018.1473387

Cited by 35 publications

(25 citation statements)

References 53 publications

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“…First, AB has such a strong adhesion capacity that it can easily adhere to living or non-living surfaces and form biofilms both in vitro and in vivo. 27,28 The formation of biofilms makes it difficult for antibacterial drugs to act directly on bacteria. Furthermore, biofilm bacteria have slower growth rates than planktonic bacteria, resulting in slower responses to antibiotics and increased drug resistance, as there is a lack of oxygen and nutrients in biofilms.…”

Section: Discussionmentioning

confidence: 99%

Synergistic antibacterial effect of ultrasound microbubbles combined with chitosan-modified polymyxin B-loaded liposomes on biofilm-producing Acinetobacter baumannii

Fu¹,

Zhang²,

Yang³

et al. 2019

IJN

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Purpose: Resistant strains of Acinetobacter baumannii (AB) that can form biofilms are resistant to polymyxin. Therefore, effective and safe polymyxin preparations against biofilm-producing AB are urgently needed. This study aims to prepare chitosan-modified polymyxin B-loaded liposomes (CLPs) and ultrasound microbubbles (USMBs) and then explore the synergistic antibacterial effects of USMBs combined with CLPs in vitro. Methods: CLPs were prepared using a modified injection method, and microbubbles were prepared using a simple mechanical vibration method. Minimal biofilm inhibitory concentration (MBIC) of CLPs against resistant biofilm-producing AB was determined. Antibacterial activities of CLPs with or without USMBs were analyzed by crystal violet staining and resazurin assays to evaluate biofilm mass and viable counts, respectively. Then, the anti-biofilm effects of CLPs with or without USMBs on biofilm-producing AB were confirmed via scanning electron microscopy (SEM) analysis. Results: We prepared CLPs that were 225.17±17.85 nm in size and carried positive charges of 12.64±1.44 mV. These CLPs, with higher encapsulation efficiency and drug loading, could exhibit a sustained release effect. We prepared microbubbles that were 2.391±0.052 µm in size and carried negative charges of −4.32±0.43 mV. The MBICs of the CLPs on the biofilmproducing AB was 8±2 µg/mL, while that of polymyxin B was 32±2 µg/mL. USMBs in combination with 2 µg/mL of polymyxin B could completely eliminate the biofilm-producing AB and achieve the maximum antimicrobial effects (P.0.05 vs sterile blank control). SEM imaging revealed some scattered bacteria without a biofilm structure in the USMB combined with the CLP group, confirming that this combination has the greatest anti-biofilm effects. Conclusion: In this research, we successfully prepared USMBs and CLPs that have a more significant antibacterial effect on biofilm-forming AB than polymyxin B alone. Experiments in vitro indicate that the synergistic antibacterial effect of combining USMBs with CLPs containing as little as 2 µg/mL of polymyxin B is sufficient to almost eliminate drug-resistant biofilm-producing AB.

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Section: Discussionmentioning

confidence: 99%

Synergistic antibacterial effect of ultrasound microbubbles combined with chitosan-modified polymyxin B-loaded liposomes on biofilm-producing Acinetobacter baumannii

Fu¹,

Zhang²,

Yang³

et al. 2019

IJN

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“…The pgaABCD locus in A. baumannii encodes poly-β-1-6- N -acetylglucosamine, a molecule that plays a role in biofilm formation (Choi et al, 2009). In other pathogens, this molecule plays a major role in cell-to-surface and cell-to-cell adherence and protects cells against host defense mechanisms (Vuong et al, 2004; Sivaranjani et al, 2018). A mutation in the abaI gene that encodes the acyl-homoserine lactone autoinducer significantly affects biofilm formation and is favored following the addition of purified acyl-homoserine lactone or overexpression of the abaI gene (Bhargava et al, 2010).…”

Section: Discussionmentioning

confidence: 99%

Whole-Genome Sequences of Five Acinetobacter baumannii Strains From a Child With Leukemia M2

et al. 2019

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Acinetobacter baumannii is an opportunistic pathogen and is one of the primary etiological agents of healthcare-associated infections (HAIs). A. baumannii infections are difficult to treat due to the intrinsic and acquired antibiotic resistance of strains of this bacterium, which frequently limits therapeutic options. In this study, five A. baumannii strains (810CP, 433H, 434H, 483H, and A-2), all of which were isolated from a child with leukemia M2, were characterized through antibiotic susceptibility profiling, the detection of genes encoding carbapenem hydrolyzing oxacillinases, pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), adherence and invasion assays toward the A549 cell line, and the whole-genome sequence (WGS). The five strains showed Multidrug resistant (MDR) profiles and amplification of the blaOXA-23 gene, belonging to ST758 and grouped into two PFGE clusters. WGS of 810CP revealed the presence of a circular chromosome and two small plasmids, pAba810CPa and pAba810CPb. Both plasmids carried genes encoding the Sp1TA system, although resistance genes were not identified. A gene-by-gene comparison analysis was performed among the A. baumannii strains isolated in this study and others A. baumannii ST758 strains (HIMFG and INCan), showing that 86% of genes were present in all analyzed strains. Interestingly, the 433H, 434H, and 483H strains varied by 8–10 single-nucleotide variants (SNVs), while the A2 and 810CP strains varied by 46 SNVs. Subsequently, an analysis using BacWGSTdb showed that all of our strains had the same resistance genes and were ST758. However, some variations were observed in relation to virulence genes, mainly in the 810CP strain. The genes involved in the synthesis of hepta-acylated lipooligosaccharides, the pgaABCD locus encoding poly-β-1-6-N-acetylglucosamine, the ompA gene, Csu pili, bap, the two-component system bfms/bfmR, a member of the phospholipase D family, and two iron-uptake systems were identified in our A. baumannii strains genome. The five A. baumannii strains isolated from the child were genetically different and showed important characteristics that promote survival in a hospital environment. The elucidation of their genomic sequences provides important information for understanding their epidemiology, antibiotic resistance, and putative virulence factors.

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“…To determine the effect of morin on C. albicans catalase production, a H 2 O 2 sensitivity assay was performed (Sivaranjani et al, 2018). For this, 1% of C. albicans culture was swabbed over the SDA plates supplemented with and without morin (at MBIC).…”

Section: H 2 O 2 Sensitivity Assaymentioning

confidence: 99%

Inhibitory Effect of Morin Against Candida albicans Pathogenicity and Virulence Factor Production: An in vitro and in vivo Approaches

et al. 2020

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Candida albicans is considered an exclusive etiologic agent of candidiasis, a very common fungal infection in human. The expression of virulence factors contributes highly to the pathogenicity of C. albicans. These factors include biofilm formation, yeast-to-hyphal transition, adhesins, aspartyl proteases, and phospholipases secretion. Moreover, resistance development is a critical issue for the therapeutic failure of antifungal agents against systemic candidiasis. To circumvent resistance development, the present study investigated the virulence targeted therapeutic activity of the phytobioactive compound morin against C. albicans. Morin is a natural compound commonly found in medicinal plants and widely used in the pharmaceutical and cosmetic products/industries. The present study explicated the significant inhibitory potential of morin against biofilm formation and other virulence factors' production, such as yeast-hyphal formation, phospholipase, and exopolymeric substances, in C. albicans. Further, qPCR analysis confirmed the downregulation of biofilm and virlence-related genes in C. albicans upon morin treatment, which is in correspondence with the in vitro bioassays. Further, the docking analysis revealed that morin shows strong affinity with Hwp-1 protein, which regulates the expression of biofilm and hyphal formation in C. albicans and, thereby, abolishes fungal pathogenicity. Moreover, the anti-infective potential of morin against C. albicans-associated systemic candidiasis is confirmed through an in vivo approach using biomedical model organism zebrafish (Danio rerio). The outcomes of the in vivo study demonstrate that the morin treatment effectively rescues animals from C. albicans infections and extends their survival rate by inhibiting the internal colonization of C. albicans. Histopathology analysis revealed extensive candidiasis-related pathognomonic changes in the gills, intestine, and kidney of animals infected with C. albicans, while no extensive abnormalities were observed in morintreated animals. The results evidenced that morin has the ability to protect against the pathognomonic effect and histopathological lesions caused by C. albicans infection in zebrafish. Thus, the present study suggests that the utilization of morin could act as a potent therapeutic medication for C. albicans instigated candidiasis.

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Inhibitory effect of α-mangostin on Acinetobacter baumannii biofilms – an in vitro study

Cited by 35 publications

References 53 publications

<p>Synergistic antibacterial effect of ultrasound microbubbles combined with chitosan-modified polymyxin B-loaded liposomes on biofilm-producing <em>Acinetobacter baumannii</em></p>

<p>Synergistic antibacterial effect of ultrasound microbubbles combined with chitosan-modified polymyxin B-loaded liposomes on biofilm-producing <em>Acinetobacter baumannii</em></p>

Whole-Genome Sequences of Five Acinetobacter baumannii Strains From a Child With Leukemia M2

Inhibitory Effect of Morin Against Candida albicans Pathogenicity and Virulence Factor Production: An in vitro and in vivo Approaches

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