Crumbling the Castle: Targeting DNABII Proteins for Collapsing Bacterial Biofilms as a Therapeutic Approach to Treat Disease and Combat Antimicrobial Resistance

Beyond the double helix: the multifaceted landscape of extracellular DNA in Staphylococcus aureus biofilms

Staphylococcus aureus forms biofilms consisting of cells embedded in a matrix made of proteins, polysaccharides, lipids, and extracellular DNA (eDNA). Biofilm-associated infections are difficult to treat and can promote antibiotic resistance, resulting in negative healthcare outcomes. eDNA within the matrix contributes to the stability, growth, and immune-evasive properties of S. aureus biofilms. eDNA is released by autolysis, which is mediated by murein hydrolases that access the cell wall via membrane pores formed by holin-like proteins. The eDNA content of S. aureus biofilms varies among individual strains and is influenced by environmental conditions, including the presence of antibiotics. eDNA plays an important role in biofilm development and structure by acting as an electrostatic net that facilitates protein-cell and cell-cell interactions. Because of eDNA's structural importance in biofilms and its ubiquitous presence among S. aureus isolates, it is a potential target for therapeutics. Treatment of biofilms with DNase can eradicate or drastically reduce them in size. Additionally, antibodies that target DNABII proteins, which bind to and stabilize eDNA, can also disperse biofilms. This review discusses the recent literature on the release, structure, and function of eDNA in S. aureus biofilms, in addition to a discussion of potential avenues for targeting eDNA for biofilm eradication.

Antibacterial agents active against Gram Negative Bacilli in phase I, II, or III clinical trials

INTRODUCTION

Antimicrobial resistance is a major threat to modern healthcare, and it is often regarded that the antibiotic pipeline is 'dry.'

AREAS COVERED

Antimicrobial agents active against Gram negative bacilli in Phase I, II, or III clinical trials were reviewed.

EXPERT OPINION

Nearly 50 antimicrobial agents (28 small molecules and 21 non-traditional antimicrobial agents) active against Gram-negative bacilli are currently in clinical trials. These have the potential to provide substantial improvements to the antimicrobial armamentarium, although it is known that 'leakage' from the pipeline occurs due to findings of toxicity during clinical trials. Significantly, a lack of funding for large phase III clinical trials is likely to prevent trials occurring for the indications most relevant to loss of life attributed to antimicrobial resistance such as ventilator-associated pneumonia. Non-traditional antimicrobial agents face issues in clinical development such as a lack of readily available and reliable susceptibility tests, and the potential need for superiority trials rather than non-inferiority trials. Most importantly, concrete plans must be made during clinical development for access of new antimicrobial agents to areas of the world where resistance to Gram negative bacilli is most frequent.

Alloplastic temporomandibular joint replacement - past, present, and future: "Learn from the past, prepare for the future, live in the present." Thomas S. Monson

Based on evidence from the orthopaedic, biomedical engineering, and oral and maxillofacial surgical literature, this paper discusses reported successes and failures of past alloplastic temporomandibular joint (TMJ) devices that have led to the development of present total temporomandibular joint replacement (TMJR) devices. The paper concludes with discussion of the ongoing research that will lead to future embodiment (materials, designs, and manufacture) advances in TMJR management of severe and debilitating end-stage TMJ disease, further improving patients' mandibular function, form, and overall quality of life.

Marine-derived polysaccharides and their therapeutic potential in wound healing application - A review

Polysaccharides originating from marine sources have been studied as potential material for use in wound dressings because of their desirable characteristics of biocompatibility, biodegradability, and low toxicity. Marine-derived polysaccharides used as wound dressing, provide several benefits such as promoting wound healing by providing a moist environment that facilitates cell migration and proliferation. They can also act as a barrier against external contaminants and provide a protective layer to prevent further damage to the wound. Research studies have shown that marine-derived polysaccharides can be used to develop different types of wound dressings such as hydrogels, films, and fibres. These dressings can be personalised to meet specific requirements based on the type and severity of the wound. For instance, hydrogels can be used for deep wounds to provide a moist environment, while films can be used for superficial wounds to provide a protective barrier. Additionally, these polysaccharides can be modified to improve their properties, such as enhancing their mechanical strength or increasing their ability to release bioactive molecules that can promote wound healing. Overall, marine-derived polysaccharides show great promise for developing effective and safe wound dressings for various wound types.

Antimicrobial Resistance Development Pathways in Surface Waters and Public Health Implications

Human health is threatened by antibiotic-resistant bacteria and their related infections, which cause thousands of human deaths every year worldwide. Surface waters are vulnerable to human activities and natural processes that facilitate the emergence and spread of antibiotic-resistant bacteria in the environment. This study evaluated the pathways and drivers of antimicrobial resistance (AR) in surface waters. We analyzed antibiotic resistance healthcare-associated infection (HAI) data reported to the CDC's National Healthcare Safety Network to determine the number of antimicrobial-resistant pathogens and their isolates detected in healthcare facilities. Ten pathogens and their isolates associated with HAIs tested resistant to the selected antibiotics, indicating the role of healthcare facilities in antimicrobial resistance in the environment. The analyzed data and literature research revealed that healthcare facilities, wastewater, agricultural settings, food, and wildlife populations serve as the major vehicles for AR in surface waters. Antibiotic residues, heavy metals, natural processes, and climate change were identified as the drivers of antimicrobial resistance in the aquatic environment. Food and animal handlers have a higher risk of exposure to resistant pathogens through ingestion and direct contact compared with the general population. The AR threat to public health may grow as pathogens in aquatic systems adjust to antibiotic residues, contaminants, and climate change effects. The unnecessary use of antibiotics increases the risk of AR, and the public should be encouraged to practice antibiotic stewardship to decrease the risk.

Novel antimicrobial agents for combating antibiotic-resistant bacteria

Antibiotic therapy has become increasingly ineffective against bacterial infections due to the rise of resistance. In particular, ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) have caused life-threatening infections in humans and represent a major global health threat due to a high degree of antibiotic resistance. To respond to this urgent call, novel strategies are urgently needed, such as bacteriophages (or phages), phage-encoded enzymes, immunomodulators and monoclonal antibodies. This review critically analyses these promising antimicrobial therapies for the treatment of multidrug-resistant bacterial infections. Recent advances in these novel therapeutic strategies are discussed, focusing on preclinical and clinical investigations, as well as combinatorial approaches. In this 'Bad Bugs, No Drugs' era, novel therapeutic strategies can play a key role in treating deadly infections and help extend the lifetime of antibiotics.

Biofilm Formation of Helicobacter pylori in Both Static and Microfluidic Conditions Is Associated With Resistance to Clarithromycin

It is widely accepted that production of biofilm is a protective mechanism against various type of stressors, including exposure to antibiotics. However, the impact of this structure on the spread of antibiotic resistance in Helicobacter pylori is still poorly understood. Therefore, the aim of the current research was to determine the relationship between biofilm formation and antibiotic resistance of H. pylori. The study was carried out on 24 clinical strains with different resistance profiles (antibiotic-sensitive, mono-resistant, double-resistant and multidrug-resistant) against clarithromycin (CLR), metronidazole (MTZ) and levofloxacin (LEV). Using static conditions and a crystal violet staining method, a strong correlation was observed between biofilm formation and resistance to CLR but not MTZ or LEV. Based on the obtained results, three the strongest and three the weakest biofilm producers were selected and directed for a set of microfluidic experiments performed in the Bioflux system combined with fluorescence microscopy. Under continuous flow conditions, it was observed that strong biofilm producers formed twice as much of biofilm and created significantly more eDNA and in particular proteins within the biofilm matrix when compared to weak biofilm producers. Additionally, it was noticed that strong biofilm producers had higher tendency for autoaggregation and presented morphostructural differences (a greater cellular packing, shorter cells and a higher amount of both OMVs and flagella) in relation to weak biofilm counterparts. In conclusion, resistance to CLR in clinical H. pylori strains was associated with a broad array of phenotypical features translating to the ability of strong biofilm formation.