scholarly journals Alpha-Toxin Is Required for Biofilm Formation by Staphylococcus aureus

2003 ◽  
Vol 185 (10) ◽  
pp. 3214-3217 ◽  
Author(s):  
Nicky C. Caiazza ◽  
G. A. O'Toole
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Antimicrobial Agents ◽  
Clinical Settings ◽  
Alpha Toxin ◽  
Flow Conditions ◽  
Alpha Hemolysin ◽  
Integral Role ◽  
Hemolytic Toxin ◽  
Plastic Surfaces

ABSTRACT Staphylococcus aureus is a common pathogen associated with nosocomial infections. It can persist in clinical settings and gain increased resistance to antimicrobial agents through biofilm formation. We have found that alpha-toxin, a secreted, multimeric, hemolytic toxin encoded by the hla gene, plays an integral role in biofilm formation. The hla mutant was unable to fully colonize plastic surfaces under both static and flow conditions. Based on microscopy studies, we propose that alpha-hemolysin is required for cell-to-cell interactions during biofilm formation.

Biological Evaluation of Selected 1,2,3-triazole Derivatives as Antibacterial and Antibiofilm Agents

2020 ◽  
Vol 20 (24) ◽  
pp. 2186-2191
Author(s):  
Lialyz Soares Pereira André ◽  
Renata Freire Alves Pereira ◽  
Felipe Ramos Pinheiro ◽  
Aislan Cristina Rheder Fagundes Pascoal ◽  
Vitor Francisco Ferreira ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Antimicrobial Agents ◽  
Public Health Problem ◽  
Biological Evaluation ◽  
Major Public Health Problem ◽  
Community Environments ◽  
Scanning Electron

Background: Resistance to antimicrobial agents is a major public health problem, being Staphylococcus aureus prevalent in infections in hospital and community environments and, admittedly, related to biofilm formation in biotic and abiotic surfaces. Biofilms form a complex and structured community of microorganisms surrounded by an extracellular matrix adhering to each other and to a surface that gives them even more protection from and resistance against the action of antimicrobial agents, as well as against host defenses. Methods: Aiming to control and solve these problems, our study sought to evaluate the action of 1,2,3- triazoles against a Staphylococcus aureus isolate in planktonic and in the biofilm form, evaluating the activity of this triazole through Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) tests. We have also performed cytotoxic evaluation and Scanning Electron Microscopy (SEM) of the biofilms under the treatment of the compound. The 1,2,3-triazole DAN 49 showed bacteriostatic and bactericidal activity (MIC and MBC 128 μg/mL). In addition, its presence interfered with the biofilm formation stage (1/2 MIC, p <0.000001) and demonstrated an effect on young preformed biofilm (2 MICs, p <0.05). Results: Scanning Electron Microscopy images showed a reduction in the cell population and the appearance of deformations on the surface of some bacteria in the biofilm under treatment with the compound. Conclusion: Therefore, it was possible to conclude the promising anti-biofilm potential of 1,2,3-triazole, demonstrating the importance of the synthesis of new compounds with biological activity.

scholarly journals Bacteriophage-Derived PeptidaseCHAPKEliminates and Prevents Staphylococcal Biofilms

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Mark Fenton ◽  
Ruth Keary ◽  
Olivia McAuliffe ◽  
R. Paul Ross ◽  
Jim O'Mahony ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Antibacterial Agents ◽  
Antimicrobial Agents ◽  
Bovine Mastitis ◽  
Economic Losses ◽  
Food Sector ◽  
Staphylococcal Infections ◽  
Prevention And Treatment

New antibacterial agents are urgently needed for the elimination of biofilm-forming bacteria that are highly resistant to traditional antimicrobial agents. Proliferation of such bacteria can lead to significant economic losses in the agri-food sector. This study demonstrates the potential of the bacteriophage-derived peptidase,CHAPK, as a biocidal agent for the rapid disruption of biofilm-forming staphylococci, commonly associated with bovine mastitis. PurifiedCHAPKapplied to biofilms ofStaphylococcus aureusDPC5246 completely eliminated the staphylococcal biofilms within 4 h. In addition,CHAPKwas able to prevent biofilm formation by this strain. TheCHAPKlysin also reducedS. aureusin a skin decolonization model. Our data demonstrates the potential ofCHAPKas a biocidal agent for prevention and treatment of biofilm-associated staphylococcal infections or as a decontaminating agent in the food and healthcare sectors.

Increase in the in vitro susceptibility of Staphylococcus aureus to antimicrobial agents in the presence of Candida albicans

1979 ◽  
Vol 25 (4) ◽  
pp. 429-435 ◽  
Author(s):  
J. deRepentigny ◽  
R. Lévesque ◽  
L. G. Mathieu
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Candida Albicans ◽  
Inhibitory Activity ◽  
Antimicrobial Agents ◽  
Mixed Cultures ◽  
Alpha Toxin ◽  
In Vitro Susceptibility ◽  
Pure Cultures

In experiments with mixed cultures of Staphylococcus aureus and Candida albicans both in the absence and in the presence of 5-fluorocytosine (5-FC), we have observed that (1) there is an inhibition of S. aureus growth in mixed cultures with C. albicans in media supplemented with 1 μg/mL of 5-FC and that 5-FC has no effect on staphylococci in pure cultures; (2) this inhibition occurred with clinically isolated and laboratory strains and could be reversed by specific metabolites; (3) Staphylococcus aureus was inhibited by filtrates of C. albicans cultures treated with 5-FC and this seemed to be favored by some C. albicans filterable product which can affect the cell wall and the permeability of the staphylococcal cells since they become sensitive to 5-FC; (4) nine other commonly used antimicrobials showed an increased inhibitory activity against S. aureus in mixed cultures with C. albicans; and (5) there is a decrease in the number of precipitating antigens of S. aureus and of the activity of alpha toxin when this species was grown with both C. albicans and 5-FC. Our results indicate that the susceptibility of some species to antimicrobials could be significantly modified in the presence of other species. One cannot exclude that a similar phenomenon could happen in hosts under treatment with antibiotics against infection.

scholarly journals Antimicrobial, Antibiofilm, and Anti-persister Activities of Penfluridol Against Staphylococcus aureus

2021 ◽  
Vol 12 ◽  
Author(s):  
Yaqian Liu ◽  
Pengfei She ◽  
Lanlan Xu ◽  
Lihua Chen ◽  
Yimin Li ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Agents ◽  
Atp Release ◽  
Drug Repurposing ◽  
Skin Wound ◽  
Clinical Settings ◽  
Dependent Manner ◽  
Acute Peritonitis ◽  
Opportunistic Human Pathogen ◽  
Long Acting

Staphylococcus aureus has increasingly attracted global attention as a major opportunistic human pathogen owing to the emergence of biofilms (BFs) and persisters that are known to increase its antibiotic resistance. However, there are still no effective antimicrobial agents in clinical settings. This study investigated the antimicrobial activity of penfluridol (PF), a long-acting antipsychotic drug, against S. aureus and its clinical isolates via drug repurposing. PF exhibited strong bactericidal activity against S. aureus, with a minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 4–8 and 16–32 μg/ml, respectively. PF could significantly inhibit biofilm formation and eradicate 24 h preformed biofilms of S. aureus in a dose-dependent manner. Furthermore, PF could effectively kill methicillin-resistant S. aureus (MRSA) persister cells and demonstrated considerable efficacy in a mouse model of subcutaneous abscess, skin wound infection, and acute peritonitis caused by MRSA. Notably, PF exerted almost no hemolysis activity on human erythrocytes, with limited cytotoxicity and low tendency to cause resistance. Additionally, PF induced bacterial membrane permeability and ATP release and further caused membrane disruption, which may be the underlying antibacterial mechanism of PF. In summary, our findings suggest that PF has the potential to serve as a novel antimicrobial agent against S. aureus biofilm- or persister-related infections.

scholarly journals Antibiotic susceptibility of Staphylococcus aureus with different degrees of biofilm formation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hyo-Jung Shin ◽  
Sungtae Yang ◽  
Yong Lim
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Antimicrobial Agents ◽  
Resistance Mechanisms ◽  
Minimal Bactericidal Concentration ◽  
Chronic Infections ◽  
Planktonic Bacteria ◽  
Growth Modes ◽  
Biofilm Bacteria ◽  
Biofilm Development

AbstractStaphylococcus aureus is one of the most common pathogens in biofilm-associated chronic infections. S. aureus living within biofilms evades the host immune response and is more resistant to antibiotics than planktonic bacteria. In this study, we generated S. aureus with low and high levels of biofilm formation using the rbf (regulator of biofilm formation) gene and performed a BioTimer assay to determine the minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of various types of antibiotics. We showed that biofilm formation by S. aureus had a greater effect on MBC than MIC, probably due to the different growth modes between planktonic and biofilm bacteria. Importantly, we found that the MBC for biofilm S. aureus was much higher than that for planktonic cells, but there was little difference in MBC between low and high levels of biofilm formation. These results suggest that once the biofilm is formed, the bactericidal activity of antibiotics is significantly reduced, regardless of the degree of S. aureus biofilm formation. We propose that S. aureus strains with varying degrees of biofilm formation may be useful for evaluating the anti-biofilm activity of antimicrobial agents and understanding antibiotic resistance mechanisms by biofilm development.

scholarly journals Organoselenium Coating on Cellulose Inhibits the Formation of Biofilms by Pseudomonas aeruginosa and Staphylococcus aureus

2009 ◽  
Vol 75 (11) ◽  
pp. 3586-3592 ◽  
Author(s):  
Phat L. Tran ◽  
Adrienne A. Hammond ◽  
Thomas Mosley ◽  
Janette Cortez ◽  
Tracy Gray ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Bacterial Infections ◽  
Antimicrobial Agents ◽  
Bacterial Attachment ◽  
Wound Dressings ◽  
Aqueous Environment ◽  
Burn Victims ◽  
Surgical Wounds

ABSTRACT Among the most difficult bacterial infections encountered in treating patients are wound infections, which may occur in burn victims, patients with traumatic wounds, necrotic lesions in people with diabetes, and patients with surgical wounds. Within a wound, infecting bacteria frequently develop biofilms. Many current wound dressings are impregnated with antimicrobial agents, such as silver or antibiotics. Diffusion of the agent(s) from the dressing may damage or destroy nearby healthy tissue as well as compromise the effectiveness of the dressing. In contrast, the antimicrobial agent selenium can be covalently attached to the surfaces of a dressing, prolonging its effectiveness. We examined the effectiveness of an organoselenium coating on cellulose discs in inhibiting Pseudomonas aeruginosa and Staphylococcus aureus biofilm formation. Colony biofilm assays revealed that cellulose discs coated with organoselenium completely inhibited P. aeruginosa and S. aureus biofilm formation. Scanning electron microscopy of the cellulose discs confirmed these results. Additionally, the coating on the cellulose discs was stable and effective after a week of incubation in phosphate-buffered saline. These results demonstrate that 0.2% selenium in a coating on cellulose discs effectively inhibits bacterial attachment and biofilm formation and that, unlike other antimicrobial agents, longer periods of exposure to an aqueous environment do not compromise the effectiveness of the coating.

scholarly journals Alpha-Toxin Promotes Staphylococcus aureus Mucosal Biofilm Formation

2012 ◽  
Vol 2 ◽  
Author(s):  
Michele J. Anderson ◽  
Ying-Chi Lin ◽  
Aaron N. Gillman ◽  
Patrick J. Parks ◽  
Patrick M. Schlievert ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Alpha Toxin

scholarly journals Antibacterial and Anti-biofilm Efficacy of Chinese Dragon’s Blood Against Staphylococcus aureus Isolated From Infected Wounds

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiangkuo Zheng ◽  
Lijiang Chen ◽  
Weiliang Zeng ◽  
Wenli Liao ◽  
Zhongyong Wang ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Membrane ◽  
Biofilm Formation ◽  
Empiric Therapy ◽  
Sem Analysis ◽  
Clinical Settings ◽  
Expression Levels ◽  
Dragon’S Blood ◽  
Infected Wounds ◽  
Time Kill

Chinese dragon’s blood (CDB), a characteristic red resin, is an important traditional Chinese medicine (TCM), and empiric therapy of infected wounds with CDB is performed in clinical settings. For the first time, we herein report the antibacterial and anti-biofilm efficacy of CDB against Staphylococcus aureus (S. aureus). Antimicrobial susceptibility testing, growth curve assay, time-kill curve assay, crystal violet biofilm assay, scanning electron microscope (SEM) analysis, cell membrane tests, and quantitative real-time polymerase chain reaction (qRT-PCR) were used for this purpose. The results suggested that the minimum inhibitory concentration (MIC) values of CDB against S. aureus ranged from 32 to 128 μg/mL. Growth curves and time-kill curves confirmed that CDB could inhibit the growth of S. aureus. The biofilm formation ability and the expression levels of saeR, saeS, and hla of S. aureus in the presence and absence of CDB were statistically significant (P &lt; 0.01). The results of SEM analysis and cell membrane tests revealed that exposure to CDB had some destructive effects on S. aureus cells. In conclusion, CDB exhibits positive antibacterial activity against S. aureus. Moreover, CDB could reduce the biofilm formation and the virulence factors of S. aureus by downregulating the expression levels of saeR, saeS, and hla genes. These findings indicated that CDB has immense potential to serve as a viable alternative for the treatment of infected wounds caused by S. aureus in clinical settings.

scholarly journals Variation in Biofilm-Forming Potential of Staphylococcus aureus from Clinical and Non-Clinical Sources

2021 ◽  
pp. 1-7
Author(s):  
K. Otokunefor ◽  
J. J. Jesutobi ◽  
O. E. Agbagwa
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Agents ◽  
Clinical Isolates ◽  
Clinical Settings ◽  
High Association ◽  
Term Survival ◽  
Medical Microbiology ◽  
Potential Marker ◽  
Port Harcourt

Introduction: Biofilm forming ability has been described as a potential marker of pathogenicity, particularly in Staphylococcus aureus. These biofilms are notable as an important contributor to virulence abilities, further aiding the producing strain in long term survival and resistance to antimicrobial agents. Regional data exploring biofilm forming ability of S. aureus from various sources is limited. This study therefore set out to explore variations in biofilm-forming potential of S. aureus from clinical and non-clinical sources. Place and Duration of Study: Medical Microbiology Laboratory, Department of Microbiology, University of Port Harcourt, Nigeria from August to October 2019. Methodology: Eighty five S. aureus clinical and non-clinical isolates were studied. Biofilm-forming potential was assessed using the Congo Red agar (CRA) method which describes both the presence and degree biofilm-forming potential. Results: Majority of isolates (65.9%) did not exhibit any biofilm-forming potential using the CRA method. Biofilm-forming potential however appeared source based with 100% of non-clinical S. aureus isolates lacking biofilm-forming potential, while 58% of clinical isolates showed biofilm-forming potential. A higher proportion (65.5%) of the clinical isolates exhibiting biofilm-forming potential where associated with strong biofilm-forming potential. Conclusion: This study reports a high association of biofilm-forming potential with S. aureus isolated from clinical rather than non-clinical settings. If this characteristic can indeed be used as a general marker of pathogenicity would however require more extensive studies.

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