scholarly journals Anti-biofilm and anti-virulence effects of zerumbone against Acinetobacter baumannii

Microbiology ◽  
2020 ◽  
Vol 166 (8) ◽  
pp. 717-726
Author(s):  
Hye-Rim Kim ◽  
Da-Seul Shin ◽  
Hye-In Jang ◽  
Yong-Bin Eom
Keyword(s):  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Type Species ◽  
Laser Scanning ◽  
Multidrug Resistant ◽  
Laser Scanning Microscopy ◽  
Transcriptional Analysis ◽  
Confocal Laser ◽  
Content Type ◽  
Link Type

Acinetobacter baumannii is a multidrug-resistant opportunistic pathogen that affects patients with a compromised immune system and is becoming increasingly important as a hospital-derived infection. This pathogen is difficult to treat owing to its intrinsic multidrug resistance and ability to form antimicrobial-tolerant biofilms. In the present study, we aimed to assess the potential use of zerumbone as a novel anti-biofilm and/or anti-virulence agent against A. baumannii . The results showed that zerumbone at sub-inhibitory doses decreased biofilm formation and disrupted established A. baumannii biofilms. The zerumbone-induced decrease in biofilm formation was dose-dependent based on the results of microtitre plate biofilm assays and confocal laser scanning microscopy. In addition, our data validated the anti-virulence efficacy of zerumbone, wherein it significantly interfered with the motility of A. baumannii . To support these phenotypic results, transcriptional analysis revealed that zerumbone downregulated the expression of biofilm- and virulence-associated genes (adeA, adeB, adeC and bap) in A. baumannii . Overall, our findings suggested that zerumbone might be a promising bioactive agent for the treatment of biofilm- and virulence-related infections caused by multidrug-resistant A. baumannii .

scholarly journals Subinhibitory Concentrations of Mupirocin Stimulate Staphylococcus aureus Biofilm Formation by Upregulating cidA

2020 ◽  
Vol 64 (3) ◽  
Author(s):  
Ye Jin ◽  
Yinjuan Guo ◽  
Qing Zhan ◽  
Yongpeng Shang ◽  
Di Qu ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Multidrug Resistant ◽  
Laser Scanning Microscopy ◽  
Extracellular Dna ◽  
Confocal Laser ◽  
Content Type ◽  
Subinhibitory Concentrations ◽  
Biofilm Development

ABSTRACT Previous studies have shown that the administration of antibiotics at subinhibitory concentrations stimulates biofilm formation by the majority of multidrug-resistant Staphylococcus aureus (MRSA) strains. Here, we investigated the effect of subinhibitory concentrations of mupirocin on biofilm formation by the community-associated (CA) mupirocin-sensitive MRSA strain USA300 and the highly mupirocin-resistant clinical S. aureus SA01 to SA05 isolates. We found that mupirocin increased the ability of MRSA cells to attach to surfaces and form biofilms. Confocal laser scanning microscopy (CLSM) demonstrated that mupirocin treatment promoted thicker biofilm formation, which also correlated with the production of extracellular DNA (eDNA). Furthermore, quantitative real-time PCR (RT-qPCR) results revealed that this effect was largely due to the involvement of holin-like and antiholin-like proteins (encoded by the cidA gene), which are responsible for modulating cell death and lysis during biofilm development. We found that cidA expression levels significantly increased by 6.05- to 35.52-fold (P < 0.01) after mupirocin administration. We generated a cidA-deficient mutant of the USA300 S. aureus strain. Exposure of the ΔcidA mutant to mupirocin did not result in thicker biofilm formation than that in the parent strain. We therefore hypothesize that the mupirocin-induced stimulation of S. aureus biofilm formation may involve the upregulation of cidA.

scholarly journals Individual or Combined Effects of Meropenem, Imipenem, Sulbactam, Colistin, and Tigecycline on Biofilm-Embedded Acinetobacter baumannii and Biofilm Architecture

2016 ◽  
Vol 60 (8) ◽  
pp. 4670-4676 ◽  
Author(s):  
Yung-Chih Wang ◽  
Shu-Chen Kuo ◽  
Ya-Sung Yang ◽  
Yi-Tzu Lee ◽  
Chun-Hsiang Chiu ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Laser Scanning ◽  
Bactericidal Effect ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Roughness Coefficient ◽  
Content Type ◽  
Biofilm Thickness ◽  
Carbapenem Resistant ◽  
Biofilm Architecture

ABSTRACTAcinetobacter baumanniibiofilms are difficult to eradicate. We investigated the effects of meropenem (2 mg/liter), imipenem (2 mg/liter), sulbactam (4 mg/liter), colistin (2 mg/liter), and tigecycline (2 mg/liter), alone or in combination, on biofilm-embedded carbapenem-resistant and carbapenem-susceptibleA. baumannii(CRAb and CSAb, respectively) cells, as well as on the architecture of the biofilms.A. baumanniiATCC 15151 (Ab15151) and its OXA-82-overproducing transformant, along with two clinical CSAb and two clinical CRAb isolates of differing clonalities, were used. The minimal bactericidal concentrations for biofilm-embedded cells of the six tested isolates were >50-fold those of their planktonic cells. When used individually, meropenem exhibited a higher killing effect than the other four antimicrobials on biofilm-embedded CSAb cells in the colony biofilm assay. For two clinical CRAb isolates, meropenem plus sulbactam or sulbactam plus tigecycline showed >100-fold the bactericidal effect exhibited by these agents used alone after 48 h of treatment. The effect of antimicrobials on the architecture of Ab15151 biofilm emitting green fluorescence was determined by confocal laser scanning microscopy using COMSTAT software. Significant decreases in the maximum biofilm thickness were observed after exposure to meropenem and imipenem. Meropenem plus sulbactam significantly decreased the biomass and mean thickness and increased the roughness coefficient of biofilms, but sulbactam plus tigecycline only decreased the maximum and mean biofilm thickness compared to any of these agents used alone. Meropenem was active against biofilm-embedded CSAb, whereas meropenem plus sulbactam exhibited synergism against biofilm-embedded CRAb and caused significantly more damage to the biofilm architecture than did any of the agents used alone.

scholarly journals Biofilm Formation by the Fish Pathogen Flavobacterium columnare: Development and Parameters Affecting Surface Attachment

2013 ◽  
Vol 79 (18) ◽  
pp. 5633-5642 ◽  
Author(s):  
Wenlong Cai ◽  
Leonardo De La Fuente ◽  
Covadonga R. Arias
Keyword(s):  
Biofilm Formation ◽  
Laser Scanning ◽  
Time Course ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Freshwater Species ◽  
Flavobacterium Columnare ◽  
Fish Pathogen ◽  
Flow Conditions ◽  
Content Type

ABSTRACTFlavobacterium columnareis a bacterial fish pathogen that affects many freshwater species worldwide. The natural reservoir of this pathogen is unknown, but its resilience in closed aquaculture systems posits biofilm as the source of contagion for farmed fish. The objectives of this study were (i) to characterize the dynamics of biofilm formation and morphology under static and flow conditions and (ii) to evaluate the effects of temperature, pH, salinity, hardness, and carbohydrates on biofilm formation. NineteenF. columnarestrains, including representatives of all of the defined genetic groups (genomovars), were compared in this study. The structure of biofilm was characterized by light microscopy, confocal laser scanning microscopy, and scanning electron microscopy.F. columnarewas able to attach to and colonize inert surfaces by producing biofilm. Surface colonization started within 6 h postinoculation, and microcolonies were observed within 24 h. Extracellular polysaccharide substances and water channels were observed in mature biofilms (24 to 48 h). A similar time course was observed whenF. columnareformed biofilm in microfluidic chambers under flow conditions. The virulence potential of biofilm was confirmed by cutaneous inoculation of channel catfish fingerlings with mature biofilm. Several physicochemical parameters modulate attachment to surfaces, with the largest influence being exerted by hardness, salinity, and the presence of mannose. Maintenance of hardness and salinity values within certain ranges could prevent biofilm formation byF. columnarein aquaculture systems.

scholarly journals Role of Exopolysaccharides in Pseudomonas aeruginosa Biofilm Formation and Architecture

2011 ◽  
Vol 77 (15) ◽  
pp. 5238-5246 ◽  
Author(s):  
Aamir Ghafoor ◽  
Iain D. Hay ◽  
Bernd H. A. Rehm
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Bacterial Biofilm ◽  
Laser Scanning Microscopy ◽  
Extracellular Dna ◽  
Confocal Laser ◽  
Content Type ◽  
Biofilm Architecture

ABSTRACTPseudomonas aeruginosais an opportunistic human pathogen and has been established as a model organism to study bacterial biofilm formation. At least three exopolysaccharides (alginate, Psl, and Pel) contribute to the formation of biofilms in this organism. Here mutants deficient in the production of one or more of these polysaccharides were generated to investigate how these polymers interactively contribute to biofilm formation. Confocal laser scanning microscopy of biofilms formed in flow chambers showed that mutants deficient in alginate biosynthesis developed biofilms with a decreased proportion of viable cells than alginate-producing strains, indicating a role of alginate in viability of cells in biofilms. Alginate-deficient mutants showed enhanced extracellular DNA (eDNA)-containing surface structures impacting the biofilm architecture. PAO1 ΔpslAΔalg8overproduced Pel, and eDNA showing meshwork-like structures presumably based on an interaction between both polymers were observed. The formation of characteristic mushroom-like structures required both Psl and alginate, whereas Pel appeared to play a role in biofilm cell density and/or the compactness of the biofilm. Mutants producing only alginate, i.e., mutants deficient in both Psl and Pel production, lost their ability to form biofilms. A lack of Psl enhanced the production of Pel, and the absence of Pel enhanced the production of alginate. The function of Psl in attachment was independent of alginate and Pel. A 30% decrease in Psl promoter activity in the alginate-overproducing MucA-negative mutant PDO300 suggested inverse regulation of both biosynthesis operons. Overall, this study demonstrated that the various exopolysaccharides and eDNA interactively contribute to the biofilm architecture ofP. aeruginosa.

scholarly journals R-Thanatin Inhibits Growth and Biofilm Formation of Methicillin-Resistant Staphylococcus epidermidisIn VivoandIn Vitro

2013 ◽  
Vol 57 (10) ◽  
pp. 5045-5052 ◽  
Author(s):  
Zheng Hou ◽  
Fei Da ◽  
Baohui Liu ◽  
Xiaoyan Xue ◽  
Xiuli Xu ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Drug Candidate ◽  
Coagulase Negative Staphylococci ◽  
Methicillin Resistant ◽  
Content Type

ABSTRACTStaphylococcus epidermidisis one of the most frequent causes of device-associated infections, because it is known to cause biofilms that grow on catheters or other surgical implants. The persistent increasing resistance ofS. epidermidisand other coagulase-negative staphylococci (CoNS) has driven the need for newer antibacterial agents with innovative therapeutic strategies. Thanatin is reported to display potent antibiotic activities, especially against extended-spectrum-beta-lactamase-producingEscherichia coli. The present study aimed to investigate whether a shorter derivative peptide (R-thanatin) could be used as a novel antibacterial agent. We found that R-thanatin was highly potentin vitroagainst coagulase-negative staphylococci, such asS. epidermidis,S. haemolyticus, andS. hominis, and inhibited biofilm formation at subinhibitory concentrations. Properties of little toxicity to human red blood cells (hRBCs) and human umbilical vein endothelial cells, a low incidence of resistance, and relatively high stability in plasma were confirmed. Excellentin vivoprotective effects were also observed using a methicillin-resistantS. epidermidis(MRSE)-induced urinary tract infection rat model. Electron microscopy and confocal laser-scanning microscopy analyses suggested that R-thanatin disturbed cell division of MRSE severely, which might be the reason for inhibition of MRSE growth. These findings indicate that R-thanatin is active against the growth and biofilm formation of MRSEin vitroandin vivo. R-thanatin might be considered as a specific drug candidate for treating CoNS infections.

Increased biofilm formation by Staphylococcus aureus clinical isolates on surfaces covered with plasma proteins

2021 ◽  
Vol 70 (8) ◽  
Author(s):  
Lorrayne Cardoso Guimarães ◽  
Bruna Marques de Souza ◽  
Carolina de Oliveira Whitaker ◽  
Fernanda Abreu ◽  
Rosana Barreto Rocha Ferreira ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Virulence Factor ◽  
Biofilm Formation ◽  
Plasma Proteins ◽  
Type Species ◽  
Laser Scanning Microscopy ◽  
Clinical Isolates ◽  
Content Type ◽  
Link Type ◽  
Biofilm Production

Introduction. Biofilm formation is a major virulence factor associated with Staphylococcus aureus infections. However, the influence of plasma proteins on biofilm formation of clinical isolates in vitro remains unclear. Hypotheses. We hypothesized that coating surfaces with plasma proteins might induce biofilm formation by S. aureus of different clonal lineages. Aim. To evaluate biofilm production by clinical S. aureus isolates of different clonal lineages isolated in Rio de Janeiro hospitals and investigated the presence of biofilm-associated genes. Methodology. This study assessed biofilm production of 60 S. aureus isolates in polystyrene microtitre plates with and without fibrinogen or fibronectin. The biochemical composition of the biofilm matrices was determined and the biofilm formation on fibrinogen-coated surfaces was also evaluated by confocal laser scanning microscopy. The presence of biofilm-related genes was detected by PCR, and the typing and functionality of agr operon was also evaluated. Results. Most of the isolates (45 %) were weak biofilm producers or non-producers. However, most of them presented a significant increase in biofilm production on plates covered with plasma proteins. There was no significant difference in biofilm formation between methicillin-resistant and -susceptible S. aureus isolates, or between different clonal lineages, except for ST30-IV (weak producers) and ST239-III (strong producers). The fnbB gene was associated with higher biofilm production. Conclusion. An increase in biofilm production in the presence of plasma proteins highlights the importance of investigating biofilm formation by S. aureus clinical isolates under different conditions since this virulence factor contributes to persistent infections and increased resistance to antimicrobials.

scholarly journals Microevolution in the major outer membrane protein OmpA of Acinetobacter baumannii

2020 ◽  
Vol 6 (6) ◽  
Author(s):  
Alejandro M. Viale ◽  
Benjamin A. Evans
Keyword(s):  
Acinetobacter Baumannii ◽  
Outer Membrane ◽  
Biofilm Formation ◽  
Type Species ◽  
Acinetobacter Calcoaceticus ◽  
Content Type ◽  
Link Type ◽  
Periplasmic Domain ◽  
Host Cell Recognition ◽  
Combined Data

Acinetobacter baumannii is nowadays a relevant nosocomial pathogen characterized by multidrug resistance (MDR) and concomitant difficulties to treat infections. OmpA is the most abundant A. baumannii outer membrane (OM) protein, and is involved in virulence, host-cell recognition, biofilm formation, regulation of OM stability, permeability and antibiotic resistance. OmpA members are two‐domain proteins with an N‐terminal eight‐stranded β‐barrel domain with four external loops (ELs) interacting with the environment, and a C‐terminal periplasmic domain binding non‐covalently to the peptidoglycan. Here, we combined data from genome sequencing, phylogenetic and multilocus sequence analyses from 975 strains/isolates of the Acinetobacter calcoaceticus / Acinetobacter baumannii complex (ACB), 946 from A. baumannii , to explore ompA microevolutionary divergence. Five major ompA variant groups were identified (V1 to V5) in A. baumannii , encompassing 52 different alleles coding for 23 different proteins. Polymorphisms were concentrated in five regions corresponding to the four ELs and the C‐terminal end, and provided evidence for intra‐genic recombination. ompA variants were not randomly distributed across the A . baumannii phylogeny, with the most frequent V1(lct)a1 allele found in most clonal complex 2 (CC2) strains and the second most frequent V2(lct)a1 allele in the majority of CC1 strains. Evidence was found for assortative exchanges of ompA alleles not only between separate A . baumannii lineages, but also different ACB species. The overall results have implications for A. baumannii evolution, epidemiology, virulence and vaccine design.

Adaptations of carbapenem resistant Acinetobacter baumannii (CRAB) in the hospital environment causing sustained outbreak

2021 ◽  
Vol 70 (3) ◽  
Author(s):  
Swati Sharma ◽  
Arghya Das ◽  
Tuhina Banerjee ◽  
Hiranmay Barman ◽  
Ghanshyam Yadav ◽  
...  
Keyword(s):  
Risk Factors ◽  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Type Species ◽  
Hospital Environment ◽  
Genetic Profile ◽  
Content Type ◽  
Slow Growth Rate ◽  
Link Type ◽  
Carbapenem Resistant

Introduction. Carbapenem resistance in Acinetobacter baumannii ( A. baumannii ) is an emerging global threat. Gap statement. The adaptation strategies of A. baumannii for this emergence as a nosocomial pathogen has been less studied. Aim. This prospective study analysed a sustained outbreak of carbapenem resistant Acinetobacter baumannii (CRAB) in the intensive care unit (ICU) with reference to antimicrobial resistance and virulence in the colonizing and pathogenic isolates under carbapenem stress. Results. The CRAB isolates from initial and sustained outbreak were found harbouring multiple carbapenemase genes. These genes included bla OXA-23 ,bla IMP, bla VIM and bla NDM. From NICU environment three phenotypically carbapenem susceptible isolates were found carrying bla OXA-23, bla IMP, bla VIM genes. Prior imipenem therapy was one of the risk factors (P=0.0016). The outbreak was polyclonal. Under imipenem stress, outbreak isolates showed no loss of carbapenemase genes against stress free conditions (23.7±1.33 days). Biofilm formation increased with imipenem concentration, with outbreak isolates producing highest biomass. While the pathogens showed a slow growth rate on imipenem exposure, the colonisers grew rapidly (P <0.0001). Methods. Sustained outbreak of CRAB was identified in the ICU (July 2015 to December 2017). Risk factors for acquisition of CRAB was studied. A. baumannii isolates were also collected from the environments of ICU and neonatal ICU (NICU) and blood cultures of septic neonates. Isolates were characterized based on antimicrobial susceptibility, genetic profile, integrons carriage and clonality. Biofilm formation and growth kinetics were studied under varying carbapenem stress. Conclusion. Intense carbapenem exposure in the ICU facilitates persistence of CRAB by several adaptations causing sustained outbreaks.

scholarly journals Overcoming Drug Resistance with Alginate Oligosaccharides Able To Potentiate the Action of Selected Antibiotics

2012 ◽  
Vol 56 (10) ◽  
pp. 5134-5141 ◽  
Author(s):  
Saira Khan ◽  
Anne Tøndervik ◽  
Håvard Sletta ◽  
Geir Klinkenberg ◽  
Charlotte Emanuel ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Health Care Systems ◽  
Multidrug Resistant ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Bacterial Cells ◽  
Biofilm Growth ◽  
Content Type ◽  
Inappropriate Use ◽  
Alginate Oligosaccharides

ABSTRACTThe uncontrolled, often inappropriate use of antibiotics has resulted in the increasing prevalence of antibiotic-resistant pathogens, with major cost implications for both United States and European health care systems. We describe the utilization of a low-molecular-weight oligosaccharide nanomedicine (OligoG), based on the biopolymer alginate, which is able to perturb multidrug-resistant (MDR) bacteria by modulating biofilm formation and persistence and reducing resistance to antibiotic treatment, as evident using conventional and robotic MIC screening and microscopic analyses of biofilm structure. OligoG increased (up to 512-fold) the efficacy of conventional antibiotics against important MDR pathogens, includingPseudomonas,Acinetobacter, andBurkholderiaspp., appearing to be effective with several classes of antibiotic (i.e., macrolides, β-lactams, and tetracyclines). Using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM), increasing concentrations (2%, 6%, and 10%) of alginate oligomer were shown to have a direct effect on the quality of the biofilms produced and on the health of the cells within that biofilm. Biofilm growth was visibly weakened in the presence of 10% OligoG, as seen by decreased biomass and increased intercellular spaces, with the bacterial cells themselves becoming distorted and uneven due to apparently damaged cell membranes. This report demonstrates the feasibility of reducing the tolerance of wound biofilms to antibiotics with the use of specific alginate preparations.

scholarly journals Hydrogen Peroxide-Generating Electrochemical Scaffold Activity against Trispecies Biofilms

2020 ◽  
Vol 64 (4) ◽  
Author(s):  
Yash S. Raval ◽  
Abdelrhman Mohamed ◽  
James Song ◽  
Kerryl E. Greenwood-Quaintance ◽  
Haluk Beyenal ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Laser Scanning ◽  
Matrix Protein ◽  
Multidrug Resistant ◽  
Laser Scanning Microscopy ◽  
Time Dependent ◽  
Confocal Laser ◽  
Antibiofilm Activity ◽  
Content Type ◽  
Wound Biofilms

ABSTRACT The antibiofilm activity of a hydrogen peroxide-generating electrochemical scaffold (e-scaffold) was determined against mono- and trispecies biofilms of methicillin-resistant Staphylococcus aureus, multidrug-resistant Pseudomonas aeruginosa, and Candida albicans. Significant time-dependent decreases were found in the overall CFU of biofilms of all three monospecies and the trispecies forms. Confocal laser scanning microscopy showed dramatic reductions in fluorescence intensities of biofilm matrix protein and polysaccharide components of e-scaffold-treated biofilms. The described e-scaffold has potential as a novel antibiotic-free strategy for treating wound biofilms.

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