Attachment to and biofilm formation on abiotic surfaces by Acinetobacter baumannii: involvement of a novel chaperone-usher pili assembly system

Microbiology ◽  
2003 ◽  
Vol 149 (12) ◽  
pp. 3473-3484 ◽  
Author(s):  
Andrew P. Tomaras ◽  
Caleb W. Dorsey ◽  
Richard E. Edelmann ◽  
Luis A. Actis
Keyword(s):  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Prototype Strain ◽  
Culture Conditions ◽  
Sequencing Analysis ◽  
Cell Aggregates ◽  
Surface Attachment ◽  
Abiotic Surfaces ◽  
Air Interface ◽  
Dna Sequencing Analysis

Acinetobacter baumannii causes severe infections in compromised patients, survives on abiotic surfaces in hospital environments and colonizes different medical devices. In this study the analysis of the processes involved in surface attachment and biofilm formation by the prototype strain 19606 was initiated. This strain attaches to and forms biofilm structures on plastic and glass surfaces, particularly at the liquid–air interface of cultures incubated stagnantly. The cell aggregates, which contain cell stacks separated by water channels, formed under different culture conditions and were significantly enhanced under iron limitation. Electron and fluorescence microscopy showed that pili and exopolysaccharides are part of the cell aggregates formed by this strain. Electron microscopy of two insertion derivatives deficient in attachment and biofilm formation revealed the disappearance of pili-like structures and DNA sequencing analysis showed that the transposon insertions interrupted genes with the highest similarity to hypothetical genes found in Pseudomonas aeruginosa, Pseudomonas putida and Vibrio parahaemolyticus. Although the products of these genes, which have been named csuC and csuE, have no known functions, they are located within a polycistronic operon that includes four other genes, two of which encode proteins related to chaperones and ushers involved in pili assembly in other bacteria. Introduction of a copy of the csuE parental gene restored the adherence phenotype and the presence of pili on the cell surface of the csuE mutant, but not that of the csuC derivative. These results demonstrate that the expression of a chaperone-usher secretion system, some of whose components appear to be acquired from unrelated sources, is required for pili formation and the concomitant attachment to plastic surfaces and the ensuing formation of biofilms by A. baumannii cells.

scholarly journals Cryptococcal Traits Mediating Adherence to Biotic and Abiotic Surfaces

2018 ◽  
Vol 4 (3) ◽  
pp. 88 ◽  
Author(s):  
Emma Camacho ◽  
Arturo Casadevall
Keyword(s):  
Biofilm Formation ◽  
Microbial Pathogenesis ◽  
Structural Components ◽  
Surface Attachment ◽  
Mortality And Morbidity ◽  
Fungal Adhesion ◽  
Adaptation Mechanisms ◽  
Abiotic Surfaces ◽  
Animal Hosts ◽  
Cryptococcus Spp

Several species in the genus Cryptococcus are facultative intracellular pathogens capable of causing disease associated with high mortality and morbidity in humans. These fungi interact with other organisms in the soil, and these interactions may contribute to the development of adaptation mechanisms that function in virulence by promoting fungal survival in animal hosts. Fungal adhesion molecules, also known as adhesins, have been classically considered as cell-surface or secreted proteins that play critical roles in microbial pathogenesis or in biofilm formation as structural components. Pathogenic Cryptococcus spp. differ from other pathogenic yeasts in having a polysaccharide capsule that covers the cell wall surface and precludes interactions of those structures with host cell receptors. Hence, pathogenic Cryptococcus spp. use unconventional tools for surface attachment. In this essay, we review the unique traits and mechanisms favoring adhesion of Cryptococcus spp. to biotic and abiotic surfaces. Knowledge of the traits that mediate adherence could be exploited in the development of therapeutic, biomedical, and/or industrial products.

scholarly journals Advanced understanding of prokaryotic biofilm formation using a cost-effective and versatile multi-panel adhesion (mPAD) mount

2022 ◽  
Author(s):  
Stefan Schulze ◽  
Heather Schiller ◽  
Jordan Solomonic ◽  
Orkan Telhan ◽  
Kyle Costa ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Cost Effective ◽  
Flow Chamber ◽  
Culture Conditions ◽  
Multiple Time ◽  
Wild Type ◽  
Surface Attachment ◽  
Flowing Liquid ◽  
Multiple Time Points ◽  
Static Conditions

Most microorganisms exist in biofilms, which comprise aggregates of cells surrounded by an extracellular matrix that provides protection from external stresses. Based on the conditions under which they form, biofilm structures vary in significant ways. For instance, biofilms that develop when microbes are incubated under static conditions differ from those formed when microbes encounter the shear forces of a flowing liquid. Moreover, biofilms develop dynamically over time. Here, we describe a cost-effective, 3D-printed coverslip holder that facilitates surface adhesion assays under a broad range of standing and shaking culture conditions. This multi-panel adhesion (mPAD) mount further allows cultures to be sampled at multiple time points, ensuring consistency and comparability between samples and enabling analyses of the dynamics of biofilm formation. As a proof of principle, using the mPAD mount for shaking, oxic cultures, we confirm previous flow chamber experiments showing that Pseudomonas aeruginosa wild type and a phenazine deletion mutant (Δ phz ) form biofilms with similar structure but reduced density in the mutant strain. Extending this analysis to anoxic conditions, we reveal that microcolony and biofilm formation can only be observed under shaking conditions and are decreased in the Δ phz mutant compared to wild-type cultures, indicating that phenazines are crucial for the formation of biofilms if oxygen as an electron acceptor is unavailable. Furthermore, while the model archaeon Haloferax volcanii does not require archaella for surface attachment under static conditions, we demonstrate that H. volcanii mutants that lack archaella are impaired in early stages of biofilm formation under shaking conditions. Importance: Due to the versatility of the mPAD mount, we anticipate that it will aid the analysis of biofilm formation in a broad range of bacteria and archaea. Thereby, it contributes to answering critical biological questions about the regulatory and structural components of biofilm formation and understanding this process in a wide array of environmental, biotechnological, and medical contexts.

scholarly journals RecA levels modulate biofilm development in Acinetobacter baumannii

2019 ◽  
Author(s):  
Carly Ching ◽  
Paul Muller ◽  
Merlin Brychcy ◽  
Alicyn Reverdy ◽  
Brian Nguyen ◽  
...  
Keyword(s):  
Dna Damage ◽  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Bacterial Infections ◽  
Opportunistic Pathogen ◽  
Cell Types ◽  
Surface Attachment ◽  
Damage Response ◽  
Fundamental Biology ◽  
Biofilm Development

AbstractInfections caused by Acinetobacter baumannii, a Gram-negative opportunistic pathogen, are difficult to eradicate due to the bacterium’s propensity to quickly gain antibiotic resistances and form protective bacterial multicellular communities known as biofilms. The A. baumannii DNA damage response (DDR) mediates antibiotic resistance acquisition and regulates RecA in an atypical fashion; both RecALow and RecAHigh cell types are formed in response to DNA damage. In this study, we show that RecA levels modulate biofilm development, formation and dispersal, through bfmR, the global biofilm regulator. RecA loss results in surface attachment and prominent biofilms while elevated RecA leads to diminished attachment and dispersal. Recalcitrance to treatment may be explained by DDR induction, common during infection, and the balance between biofilm maintenance in low RecA cells, and increased mutagenesis and dispersal to reach new niches in high RecA cells. These data highlight the importance of understanding fundamental biology to better treat bacterial infections.ImpactThe mechanism of biofilm formation and dispersal in A. baumannii, shown here to depend on RecA levels, contributes to the understanding of recalcitrant infections caused by this important pathogen.

Inhibition of Virulence Factors and Biofilm Formation of Acinetobacter Baumannii by Naturally-derived and Synthetic Drugs

2020 ◽  
Vol 21 ◽  
Author(s):  
Nilushi Indika Bamunuar Achchi ◽  
Fazlurrahman Khan ◽  
Young-Mog Kim
Keyword(s):  
Acinetobacter Baumannii ◽  
Virulence Factors ◽  
Biofilm Formation ◽  
Resistance Mechanisms ◽  
Initial Surface ◽  
Surface Attachment ◽  
Synthetic Compounds ◽  
Mortality And Morbidity ◽  
Synthetic Drugs ◽  
Host Cell Surface

: Acinetobacter baumannii is a Gram-negative, aerobic, non-motile, and pleomorphic bacillus. A. baumanii is also a highly-infectious pathogen causing high mortality and morbidity rates in intensive care units. The discovery of novel agents against A. baumanii infections is urgently needed due to the emergence of drug-resistant A. baumannii strains and the limited number of efficacious antibiotics available for treatment. In addition to the production of several virulence factors, A. baumannii forms biofilms on the host cell surface as well. Formation of biofilms occurs through initial surface attachment, microcolony formation, biofilm maturation, and detachment stages, and is one of the major drug resistance mechanisms employed by A. baumanii. Several studies have previously reported the efficacy of naturally-derived and synthetic compounds as anti-biofilm and anti-virulence agents against A. baumannii. Here, inhibition of biofilm formation and virulence factors of A. baumannii using naturally-derived and synthetic compounds are reviewed.

scholarly journals Imipenem Treatment Induces Expression of Important Genes and Phenotypes in a Resistant Acinetobacter baumannii Isolate

2015 ◽  
Vol 60 (3) ◽  
pp. 1370-1376 ◽  
Author(s):  
Ghulam Nasser Dhabaan ◽  
Sazaly AbuBakar ◽  
Gustavo Maia Cerqueira ◽  
Mohammed Al-Haroni ◽  
Sui Ping Pang ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Clinical Success ◽  
Multidrug Resistant ◽  
Type Iv Pili ◽  
Control Measures ◽  
Content Type ◽  
Type Iv ◽  
Abiotic Surfaces ◽  
Colonization Factors

Acinetobacter baumanniihas emerged as a notorious multidrug-resistant pathogen, and development of novel control measures is of the utmost importance. Understanding the factors that play a role in drug resistance may contribute to the identification of novel therapeutic targets. Pili are essential forA. baumanniiadherence to and biofilm formation on abiotic surfaces as well as virulence. In the present study, we found that biofilm formation was significantly induced in an imipenem-resistant (Impr) strain treated with a subinhibitory concentration of antibiotic compared to that in an untreated control and an imipenem-susceptible (Imps) isolate. Using microarray and quantitative PCR analyses, we observed that several genes responsible for the synthesis of type IV pili were significantly upregulated in the Imprbut not in the Impsisolate. Notably, this finding is corroborated by an increase in the motility of the Imprstrain. Our results suggest that the ability to overproduce colonization factors in response to imipenem treatment confers biological advantage toA. baumanniiand may contribute to clinical success.

scholarly journals Flagellar Motility Is Critical for Listeria monocytogenes Biofilm Formation

2007 ◽  
Vol 189 (12) ◽  
pp. 4418-4424 ◽  
Author(s):  
Katherine P. Lemon ◽  
Darren E. Higgins ◽  
Roberto Kolter
Keyword(s):  
Listeria Monocytogenes ◽  
Biofilm Formation ◽  
Molecular Mechanisms ◽  
Early Stage ◽  
Food Contamination ◽  
Initial Surface ◽  
Flagellar Motility ◽  
Surface Attachment ◽  
Abiotic Surfaces ◽  
Biofilm Development

ABSTRACT The food-borne pathogen Listeria monocytogenes attaches to environmental surfaces and forms biofilms that can be a source of food contamination, yet little is known about the molecular mechanisms of its biofilm development. We observed that nonmotile mutants were defective in biofilm formation. To investigate how flagella might function during biofilm formation, we compared the wild type with flagellum-minus and paralyzed-flagellum mutants. Both nonmotile mutants were defective in biofilm development, presumably at an early stage, as they were also defective in attachment to glass during the first few hours of surface exposure. This attachment defect could be significantly overcome by providing exogenous movement toward the surface via centrifugation. However, this centrifugation did not restore mature biofilm formation. Our results indicate that it is flagellum-mediated motility that is critical for both initial surface attachment and subsequent biofilm formation. Also, any role for L. monocytogenes flagella as adhesins on abiotic surfaces appears to be either minimal or motility dependent under the conditions we examined.

scholarly journals The Acinetobacter baumannii Biofilm-Associated Protein Plays a Role in Adherence to Human Epithelial Cells

2011 ◽  
Vol 80 (1) ◽  
pp. 228-233 ◽  
Author(s):  
Kari A. Brossard ◽  
Anthony A. Campagnari
Keyword(s):  
Epithelial Cells ◽  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Bacterial Colonization ◽  
Water Channel ◽  
Cell Surface Hydrophobicity ◽  
Health Care Facilities ◽  
Content Type ◽  
Abiotic Surfaces ◽  
Normal Human

ABSTRACTAcinetobacter baumanniiis a significant source of nosocomial infections worldwide. This bacterium has the ability to survive and persist on multiple abiotic surfaces in health care facilities, and once a focus has been established, this opportunistic pathogen is difficult to eradicate. This paper demonstrates that theA. baumanniibiofilm-associated protein (Bap) is necessary for mature biofilm formation on medically relevant surfaces, including polypropylene, polystyrene, and titanium. Scanning electron microscopy analyses of biofilms show that Bap is required for three-dimensional tower structure and water channel formation. In conjunction with persistence on abiotic surfaces, adherence to eukaryotic cells is an important step in bacterial colonization resulting in infection of the host. We have described Bap as the surface structure involved in adherence ofA. baumanniito both normal human bronchial epithelial cells and normal human neonatal keratinocytes. However, Bap is not involved in internalization of the bacterium in these two cell lines. Furthermore, this study shows that the presence of Bap increases the bacterial cell surface hydrophobicity. The results of this study are pertinent, as the data lead to a better understanding of the role of Bap in biofilm formation on medical surfaces and in colonization of the host.

scholarly journals Microbicides Alter the Expression and Function of RND-Type Efflux Pump AdeABC in Biofilm-Associated Cells of Acinetobacter baumannii Clinical Isolates

2015 ◽  
Vol 60 (1) ◽  
pp. 57-63 ◽  
Author(s):  
Suvarna Krishnamoorthy ◽  
Bhavikkumar P. Shah ◽  
Hiu Ham Lee ◽  
Luis R. Martinez
Keyword(s):  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Efflux Pump ◽  
Acquired Resistance ◽  
Multidrug Resistant ◽  
Clinical Isolates ◽  
Content Type ◽  
Abiotic Surfaces ◽  
Hospital Environments ◽  
And Function

ABSTRACTAcinetobacter baumanniiis a Gram-negative bacterium that causes nosocomial infections worldwide. This microbe's propensity to form biofilms allows it to persist and to survive on clinical abiotic surfaces for long periods. In fact,A. baumanniibiofilm formation and its multidrug-resistant nature severely compromise our capacity to care for patients in hospital environments. In contrast, microbicides such as cetrimide (CT) and chlorhexidine (CHX) play important roles in the prevention and treatment of infections. We assessed the efficacy of CT and CHX, either alone or in combination, in eradicatingA. baumanniibiofilms formed by clinical isolates, by using stainless steel washers to mimic hard abiotic surfaces found in hospital settings. We demonstrated that increasing amounts of each microbicide, alone or in combination, were able to damage and to reduce the viability ofA. baumanniibiofilms efficaciously. Interestingly, theadeBgene of the resistance-nodulation-cell division (RND) family is predominantly associated with acquired resistance to antimicrobials inA. baumannii. We showed that CT and CHX adversely modified the expression and function of the RND-type efflux pump AdeABC in biofilm-associatedA. baumanniicells. Furthermore, we established that these microbicides decreased the negative charges onA. baumanniicell membranes, causing dysregulation of the efflux pump and leading to cell death. Our findings suggest that CT and CHX, alone or in combination, can be used efficaciously for eradication ofA. baumanniifrom hospital surfaces, in order to reduce infections caused by this nosocomial agent.

scholarly journals The Acinetobacter baumannii 19606 OmpA Protein Plays a Role in Biofilm Formation on Abiotic Surfaces and in the Interaction of This Pathogen with Eukaryotic Cells

2009 ◽  
Vol 77 (8) ◽  
pp. 3150-3160 ◽  
Author(s):  
Jennifer A. Gaddy ◽  
Andrew P. Tomaras ◽  
Luis A. Actis
Keyword(s):  
Epithelial Cells ◽  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Protein A ◽  
Bacterial Attachment ◽  
Alveolar Epithelial Cells ◽  
Eukaryotic Cells ◽  
Temperature Sensitive ◽  
Alveolar Epithelial ◽  
Abiotic Surfaces

ABSTRACT The ability of Acinetobacter baumannii to adhere to and persist on surfaces as biofilms could be central to its pathogenicity. The production of pili and a biofilm-associated protein and the expression of antibiotic resistance are needed for robust biofilm formation on abiotic and biotic surfaces. This multistep process also depends on the expression of transcriptional regulatory functions, some of which could sense nutrients available to cells. This report extends previous observations by showing that although outer membrane protein A (OmpA) of A. baumannii 19606 plays a partial role in the development of robust biofilms on plastic, it is essential for bacterial attachment to Candida albicans filaments and A549 human alveolar epithelial cells. In contrast to abiotic surfaces, the interaction with biotic surfaces is independent of the CsuA/BABCDE-mediated pili. The interaction of A. baumannii 19606 with fungal and epithelial cells also results in their apoptotic death, a response that depends on the direct contact of bacteria with these two types of eukaryotic cells. Furthermore, the bacterial adhesion phenotype correlates with the ability of bacteria to invade A549 epithelial cells. Interestingly, the killing activity of cell-free culture supernatants proved to be protease and temperature sensitive, suggesting that its cytotoxic activity is due to secreted proteins, some of which are different from OmpA.

scholarly journals Use of a stainless steel washer platform to study Acinetobacter baumannii adhesion and biofilm formation on abiotic surfaces

Microbiology ◽  
2013 ◽  
Vol 159 (Pt_12) ◽  
pp. 2594-2604 ◽  
Author(s):  
Samantha J. Orsinger-Jacobsen ◽  
Shenan S. Patel ◽  
Ernestine M. Vellozzi ◽  
Phillip Gialanella ◽  
Leonardo Nimrichter ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Abiotic Surfaces
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