7 December 2025
Centre d’Analyses et de Recherche (CAR), Unité de Recherche Technologies et Valorisation Agro-Alimentaire (UR-TVA), Laboratoire de Mycologie et Sécurité des Aliments (LMSA), Faculté des Sciences, Campus des Sciences et Technologies, Université Saint-Joseph de Beyrouth, Mar Roukos, Matn, Beirut P.O. Box 17-5208, Lebanon
Ecole Doctorale “Sciences et Santé”, Campus des Sciences Médicales et Infirmières, Université Saint-Joseph de Beyrouth, Riad El Solh, Beirut P.O. Box 17-5208, Lebanon
Department of Chemical Engineering, Faculty of Engineering, University of Balamand, Tripoli P.O. Box 100, Lebanon
Research Laboratory of Microbiology (RLM), Department of Life and Earth Sciences, Faculty of Sciences I, Lebanese University, Hadat Campus, Beirut P.O. Box 6573, Lebanon
Bacterial biofilms pose significant challenges in clinical, industrial, and environmental settings due to their inherent resistance to antimicrobial agents and host immune responses. Encased within a self-produced extracellular polymeric substance (EPS) matrix, these structured microbial communities demonstrate exceptional resilience, resisting conventional antimicrobial treatments and adapting to, as well as recovering from, environmental and therapeutic stresses, necessitating the development of novel anti-biofilm strategies. This review provides a comprehensive synthesis of biofilm formation, resistance mechanisms, and current and emerging approaches for controlling biofilms, with a primary focus on advancements made over the last decade. Chemical, physical, and biological strategies, including enzymatic degradation, natural compounds, chelating agents, nanoparticles, photodynamic therapy, and probiotics, have demonstrated promising antibiofilm activity. Additionally, combination therapies and targeted drug delivery systems have emerged as viable solutions to enhance the eradication of biofilms. Despite these advancements, challenges such as cytotoxicity, bacterial adaptation, and clinical applicability remain. Addressing these hurdles requires interdisciplinary research to refine existing strategies and develop innovative solutions for effective biofilm management.
Since the discovery of microorganisms, various research, experiments, and analyses have significantly advanced science and technology. In the seventeenth century, Antonie van Leeuwenhoek first identified microbes in the calculus on his teeth [1]. These deposits contained various “animalcules” now known as dental plaque bacteria. This formation of dental coatings is one of the earliest documented bacterial biofilms [2]. Biofilm formation is a strategy used by microorganisms to enhance their survival in hosts and harsh environments [3]. Although bacteria have a general tendency to live in a biofilm.
When faced with unfavorable conditions (such as desiccation, shear stress, toxic compounds, and protozoan grazing), bacteria can shift from a free-floating (planktonic) state to a sessile state, allowing them to adhere, grow, and form communities on surfaces [4].
Biofilms are an organized, three-dimensional community of microorganisms that adhere to biotic and abiotic surfaces and are encased in a self-produced extracellular substance (EPS) matrix [5]. These intricate structures, first described in detail by Ref. [6] in 1978, have since been recognized as a predominant form of microbial life in various environments. Within the biofilm matrix, organisms are arranged rather than scattered randomly and regulated by several genes [7]. Both homogeneous and heterogeneous biofilms are possible. A homogeneous biofilm consists of a single microbial species, whereas a heterogeneous biofilm includes different species living together. Common biofilm-forming bacteria include Pseudomonas aeruginosa, Staphylococcus epidermidis, Escherichia coli, and Staphylococcus aureus, with mixed-culture biofilms often demonstrating enhanced stability through interspecies interactions [8]. Indeed, these dynamic and complex structures offer remarkable protection to enclosed microbial communities against a wide array of environmental challenges. These include resistance to various biocides and antibiotics used in industrial and clinical settings, UV damage, metal toxicity, anaerobic conditions, acid exposure, salinity fluctuations, desiccation, and bacteriophages [9]. Furthermore, biofilms shield bacteria from mechanical stress, shear forces, and the host’s immune cells, while enabling them to endure external stressors like nutrient scarcity and osmolarity changes [10]. Thus, biofilms are ubiquitous due to this multifaceted protection mechanism, coupled with the biofilm’s ability to control various metabolic processes. They represent a fundamental microbial survival strategy in diverse environments, from soil and aquatic ecosystems to industrial piping systems, indwelling medical devices, and live tissues such as tooth enamel, heart valves, lungs, and middle ears. However, their impact extends beyond these everyday occurrences [11]. Biofilms can be neutral, harmful, or good. While biofilms that form on open wounds after infection are dangerous, biofilms that are a part of the natural ecosystem are neutral. Biofilms may help address oil spill-related ground contamination [12]. Consequently, the significance of biofilms extends across various fields, encompassing healthcare, industrial processes, and ecological studies, thereby making them a critical focus of interdisciplinary scientific research. [Figure 1](https://www.frankenthalerfoundation.org illustrates a concise overview of the principal ways in which biofilm-forming microorganisms negatively influence human health, industrial processes, and environmental systems in daily life.
Figure 1. Summary of the global impact of biofilm-forming microorganisms.
In medical settings, both device-related and non-device-related biofilm infections are common worldwide and cause many fatalities every year [13]. Biofilms cause over $4 trillion in global economic losses annually, impacting healthcare, infrastructure, agriculture, and energy sectors [14]. These biofilms pose significant challenges in treating chronic infections, particularly those associated with implanted medical devices such as heart valves, catheters, joint prostheses, intrauterine devices, orthopedic implants, cardiac pacemakers, and contact lenses [12,15,16]. The clinical impact of biofilm formation on medical devices is substantial, with approximately 65% of device-related infections attributed to biofilms. Therefore, these infections can lead to severe complications, often necessitating device removal and prolonged antimicrobial therapy [17]. For example, catheter-associated urinary tract infections (CAUTIs) are frequently caused by biofilm-forming pathogens like E. coli, S. aureus, and P. aeruginosa, leading to complications in hospitalized patients [18]. Other common biofilm-associated pathogens include Enterobacteriaceae, coagulase-negative staphylococci, Acinetobacter spp., and Enterococcus spp. [19]. Additionally, scanning electron microscopy has revealed that most indwelling central venous catheters are colonized by these aggregates of microorganisms embedded in a biofilm matrix. Among these, staphylococci are the leading cause of biofilm-associated infections, with highly virulent S. aureus strains frequently causing severe localized infections or sepsis [20]. These infections can result in bloodstream infections and device failure in hospitalized patients [21]. Beyond catheters, biofilms are also implicated in prosthetic heart valve infections [22,23] and contribute to periodontal diseases and tooth decay through dental plaque formation [24]. Additionally, P. aeruginosa and S. aureus biofilms have been extensively reported in the context of persistent wound infections and respiratory tract infections in cystic fibrosis patients [25,26]. In healthcare, biofilm-related chronic wounds, lung infections, prosthetic joint failures, catheter infections, and antimicrobial resistance contribute billions in costs annually [27]. According to the National Institutes of Health (NIH), biofilms are responsible for approximately 80% of chronic infections and numerous pathogen outbreaks in healthcare settings [21]. The challenge is further intensified by the emergence and global spread of multidrug-resistant (MDR) bacteria, defined as organisms resistant to at least one agent in three or more antimicrobial categories [28]. These MDR pathogens, including P. aeruginosa, S. aureus, K. pneumoniae, and A. baumannii, are frequently implicated in biofilm-related device infections and chronic wounds, and their resistance severely limits therapeutic options [29]. Their resistance to antimicrobial agents, disinfectants, and immune responses makes them particularly difficult to eradicate, with biofilm-embedded bacteria being up to 1000 times more resistant to antibiotics than planktonic cells [30]. This resistance exacerbates the global antimicrobial resistance crisis, which has contributed to an estimated 4.71 million deaths worldwide, with biofilms representing a significant and persistent factor in this burden [31]. Industrial sectors face substantial economic losses due to biofilm-related issues. Microbial corrosion alone accounts for around $2.76 trillion annually, significantly impacting infrastructure [32]. Different studies have described how biofilms cause biofouling in industrial equipment [33], leading to decreased efficiency, increased energy consumption, and accelerated material degradation [34]. A prime example is the formation of biofilms in water distribution systems, where they can harbor pathogens like P. aeruginosa, posing public health risks [35]. Biofilm contamination further escalates food safety expenses and disrupts water and energy systems, creating widespread economic and environmental challenges. Although in the food industry, biofilms can have both positive and negative effects. On the positive side, biofilms can be used in wastewater treatment to degrade pollutants, in biofuel production, and for the filtration of drinking water [36]. Nonetheless, biofilms can play a crucial role in fermentation processes, contributing to improved flavor and texture in products such as yogurt and cheese [37]. These biofilms often involve beneficial microorganisms, such as lactic acid bacteria (LAB) and yeast, which are essential for traditional fermented foods like cheese, vinegar, kombucha, kefir, wine, lambic beer, miso, and kimchi [38]. However, biofilms in the food industry can contaminate food products, leading to foodborne illnesses. Those formed by major foodborne pathogens such as E. coli, Listeria monocytogenes, Salmonella spp., and Campylobacter jejuni pose a particular risk, contributing to persistent contamination and food safety concerns [39]. In agriculture, biofilms contribute 10% of global crop losses and cause $2 billion in dairy industry damages annually [27]. Furthermore, in urban contexts, biofilms play dual roles. They can actively participate in wastewater treatments, organic matter decomposition, nutrient dynamics, and biogeochemical cycling, being a key component of ecosystem functioning [40,41]. However, they can also be detrimental, where biofilms in water distribution systems can harbor pathogenic organisms and contribute to the deterioration of water quality [42]. Additionally, biofilm formation on microplastics can enhance the sorption of hydrophobic organic compounds (HOCs), potentially increasing their transfer through food chains and contributing to ecological pollution [43]. Biofilms also serve as reservoirs for antibiotic resistance genes (ARGs), facilitating the spread of antimicrobial resistance among microbial communities in aquatic ecosystems exposed to anthropogenic pollutants like wastewater treatment plant effluents [44].
While numerous reviews have summarized biofilm biology and conventional control measures, this article uniquely focuses on emerging multimodal strategies for biofilm eradication developed over the last decade. We highlight innovative chemical, physical, and biological interventions, such as enzymatic degradation, natural compounds, nanoparticles, aPDT, CAP, and phage–antibiotic combinations, emphasizing their mechanisms, advantages, and limitations. Furthermore, this review integrates recent findings on combination therapies and targeted delivery systems, providing insights into overcoming persistent biofilm resistance. By synthesizing these advances and identifying ongoing challenges, this review seeks future research directions in strategic biofilm control.
This narrative review was based on peer-reviewed literature retrieved from major scientific databases and online research platforms. Articles were selected according to their relevance to the topic and scientific quality without date restrictions. The GenAI tool Napkin AI was used exclusively to generate illustrative charts for the visual representation of concepts. No text, interpretation, or scientific content was created by the tool. All figures were manually checked, edited, and finalized by the authors in accordance with MDPI’s GenAI transparency policy.
Biofilms are highly organized microbial communities composed primarily of water (up to 90%) and microbial mass [45]. Their structure consists of microcolonies of bacterial cells embedded within an EPS matrix, interconnected by water channels that facilitate the diffusion of nutrients, enzymes, metabolites, oxygen, and waste products [46,47]. The basal layer of the biofilm consists of a hydrated mixture of polysaccharides, proteins, extracellular DNA (eDNA), lipids, and enzymes, which contribute to biofilm stability and functionality [48,49]. The EPS matrix, also known as the glycocalyx, constitutes 75–95% of the biofilm’s dry mass, with polysaccharides such as poly-N-acetylglucosamine (PNAG), alginate, amylose-like glucan, cellulose, and galactosaminogalactan comprising 50–90% of its organic components [8,50]. These polysaccharides form a dense, mesh-like matrix stabilized by intermolecular interactions among their hydroxyl groups [51]. The EPS matrix varies in thickness from nanometers to hundreds of micrometers, acting as a structural scaffold that supports cell adhesion, cohesion, and protection against environmental stressors [52]. Its ionic composition
