Bacterial biofilm-associated infections have emerged as a formidable challenge in global healthcare, posing significant hurdles to clinical treatment. Clinical data indicate that approximately 80% of bacterial infections are linked to biofilm formation, which is closely associated with the development of persistent or chronic infections. A biofilm is not a simple aggregation of bacteria but a structured community encapsulated by Extracellular Matrix (ECM) secreted by the bacteria themselves. Through multiple sophisticated mechanisms, biofilms exhibit remarkable tolerance and drug resistance, thereby severely compromising the therapeutic efficacy of conventional antibiotics. In-depth elucidation of these mechanisms and exploration of innovative therapeutic strategies are crucial for breaking the bottleneck in clinical treatment of biofilm-associated infections.

• Tolerance

• Bacterial Biofilms

• Global healthcare

• Chronic infections

Yao L, Yingjun L, Beiliang M, Shiwei L (2026) Mechanisms of Tolerance and Drug Resistance in Bacterial Biofilms and Nanotechnology-Based Therapeutic Strategies: A Perspective from Traditional Chinese Medicine. JSM Renal Med 7(1): 1020.

Bacterial biofilms establish a robust multi-dimensional defense system to counteract the effects of antibiotics through synergistic mechanisms, which can be specifically summarized into the following four aspects:

Firstly, the barrier effect of the physical structure. The ECM of biofilms is rich in polysaccharides, proteins, nucleic acids, and other components, forming a dense three-dimensional network structure. This structure can effectively restrict the penetration of antibiotics, reduce the intracellular drug concentration within the biofilm, and prevent antibiotics from reaching target bacteria, thereby abrogating their antibacterial activity [1-4]. Beyond simple spatial obstruction, the components of the ECM can also interact with certain antibiotics through non-covalent bonds or chemical reactions, further attenuating drug potency. Secondly, the promotion of gene mutation and Horizontal Gene Transfer (HGT). Bacteria within biofilms reside in a relatively stable microenvironment, where altered metabolic activities can enhance their intrinsic mutation rate. Meanwhile, biofilms provide a favorable microenvironment for HGT among bacteria, enabling the rapid transmission and dissemination of drug-resistant genes across different bacterial strains. This accelerates the formation of drug-resistant bacterial populations [5], significantly improving the overall drug resistance adaptability of the biofilm community. Thirdly, the active regulation of efflux pump systems. Bacteria in biofilms can upregulate the expression of efflux pump systems, which function as “molecular pumps” to actively expel intracellular antibiotics to the extracellular space. This maintains the intracellular drug concentration below the lethal dose [6]. Overexpression of efflux pumps is one of the key mechanisms underlying the development of multidrug resistance in bacteria, enabling them to tolerate a broad spectrum of antibiotics with distinct chemical structures. Fourthly, the dormant characteristics of persister cells. A small subset of metabolically dormant “persister cells” exists within biofilms. These cells are non-proliferative and insensitive to antibiotics that exert their effects by inhibiting bacterial growth and reproduction [7]. Following the termination of conventional antibiotic therapy, persister cells can reactivate their metabolic activity, leading to recurrent infections and the establishment of a chronic infection cycle.

Confronted with the multiple drug resistance mechanisms of bacterial biofilms, conventional antibiotic therapy has reached a bottleneck. Nanotechnology, endowed with unique physicochemical properties such as high surface area-to-volume ratio and tunable surface functionalities, provides innovative insights and efficient solutions to this challenge. Its core advantage lies in the capacity for multi-dimensional synergistic intervention.

Core Advantages of Nanotechnology

Firstly, multi-mechanistic synergistic intervention. Nanomaterials can surpass the single-action mode of conventional antibiotics, achieving comprehensive intervention against biofilms through multiple pathways, including disrupting the three-dimensional structure of mature biofilms, regulating bacterial heterogeneity within biofilms, inhibiting bacterial metabolic activity, activating the host immune response, and enhancing the permeability of drugs within biofilms [8,9]. This synergistic effect can effectively circumvent the single drug resistance mechanism of biofilms and improve therapeutic outcomes.

Secondly, precision-targeted delivery capability. Nanocarriers serve as efficient drug delivery platforms, which can significantly enhance the solubility and in vivo stability of hydrophobic antibiotics. Meanwhile, leveraging the specificity of the biofilm microenvironment (e.g., pH gradients, differential enzyme expression) or active targeting modifications (e.g., ligand conjugation), nanocarriers enable precise delivery of drugs to biofilm sites. This reduces drug distribution in normal tissues, thereby minimizing off-target effects and toxic side effects [10,11].

Thirdly, potential for multi-functional synergistic therapy. Some nanomaterials inherently possess antibacterial properties, such as metal nanoparticles and quantum dots. These nanomaterials can exert antibacterial effects by disrupting bacterial cell membranes, inducing reactive oxygen species (ROS) generation, and other mechanisms, which synergize with loaded antibiotics to further enhance anti-biofilm efficacy [12,13]. This “carrier + drug” dual-activity mode offers a new approach for constructing high-efficiency anti-biofilm systems.

Main Strategies and Challenges of Nanotechnology in Anti-Biofilm Therapy

Currently, nanotechnology-based anti-biofilm strategies have formed a diversified development pattern, mainly including: designing specific interventional nanotherapeutics targeting different stages of the biofilm lifecycle (i.e., adhesion, formation, maturation, and dispersion) regulating the biofilm microenvironment (e.g., pH, redox potential, nutrient distribution) through nanomaterials to disrupt bacterial survival conditions [9]; developing surface charge-adaptive nanoplatforms to enhance the penetration and retention capacity of nanotherapeutics within biofilms [13]; and constructing lipid-based nanosystems to improve drug delivery efficiency and biocompatibility [7], among others. Despite the broad prospects of nanotechnology in the field of anti-biofilm therapy, its clinical translation still faces numerous challenges: the limited drug-loading capacity of nanocarriers fails to meet the requirements for long-term therapeutic efficacy; insufficient targeting accuracy leads to the clearance of some nanotherapeutics by the host immune system, hindering their effective accumulation at infection sites; and biosafety concerns, such as in vivo accumulation, cytotoxicity, and immunogenicity of certain nanomaterials [14]. Future efforts should focus on optimizing nanomaterial design, strengthening research on targeting mechanisms, and improving biosafety evaluation systems to promote the translation of nanotechnology from basic research to clinical application [15].

Traditional Chinese Medicine (TCM), a treasure of Chinese traditional medicine, is characterized by multi component, multi-target, and multi-pathway therapeutic effects, which are inherently compatible with the complex drug resistance mechanisms of bacterial biofilms. In recent years, research on TCM against biofilms has gradually become a research hotspot, providing a new perspective and strategy for addressing the global antibiotic resistance crisis.

Anti-Biofilm Effects of Heat-Clearing and Detoxifying TCMs

Heat-clearing and detoxifying TCMs are commonly used in the treatment of infectious diseases in TCM practice and have demonstrated significant potential in the treatment of biofilm-associated infections. For example, in the treatment of erosive gastritis, a digestive system infection associated with biofilms, TCM formulas such as Qing weisan and Xiexintang exert therapeutic effects through multi-level and multi-target mechanisms, including regulating immune function, alleviating local inflammatory responses, and disrupting the pathological basis of biofilm formation. The multi-target action mode of these TCMs can effectively circumvent the single drug resistance mechanism of bacteria, providing a new option for the clinical treatment of biofilm-associated infections [16].

Antibacterial and Anti-Biofilm Mechanisms of TCM Compounds

TCM compounds are formulated based on the “monarch-minister-adjuvant-guide” compatibility theory, with complex compositions that can exert anti biofilm effects through multiple pathways. For instance, the Kidney-Tonifying and Collateral-Dredging Formula (KCF) not only improves the symptoms of benign prostatic hyperplasia but also inhibits the formation and development of bacterial biofilms in the prostate gland, which may be associated with the regulation of the AMPK signaling pathway [17,18]. Additionally, formulas with the effect of warming meridians and dredging collaterals, such as Danggui Sini Decoction, can exert neuroprotective effects by regulating intestinal flora balance and improving the local microenvironment, thereby indirectly interfering with the formation and homeostasis of intestinal biofilms [19]. The holistic regulatory advantage of TCM compounds endows them with unique value in the treatment of chronic biofilm-associated infections.

Anti-Biofilm Activity and Mechanisms of TCM Extracts

Some TCM extracts exhibit significant antibacterial and anti-biofilm activities with clear and efficient mechanisms of action. Studies have shown that extracts from Dendrocalamus grandis can significantly inhibit bacterial motility, reduce biofilm formation by 56.4%, and attenuate biofilm compactness [20]. Further mechanistic studies have revealed that these extracts exert synergistic antibacterial effects and disrupt biofilm structural stability by damaging bacterial cell membrane integrity, inducing excessive ROS production in bacteria, and interfering with bacterial metabolic pathways [21]. TCM extracts with definite active components and clear mechanisms provide high-quality raw materials for the development of novel anti-biofilm agents.

The multiple tolerance and drug resistance mechanisms of bacterial biofilms are the core causes of intractable chronic infections, and conventional antibiotic therapy is no longer sufficient to meet clinical needs. Nanotechnology offers an efficient modern therapeutic approach to break the bottleneck of biofilm drug resistance, with advantages such as synergistic intervention, precision delivery, and multi-functional integration. However, key issues including drug-loading capacity, targeting accuracy, and biosafety need to be addressed for its successful clinical translation. TCM exhibits unique advantages in anti biofilm therapy, such as multi-component, multi-target, and holistic regulation. Heat-clearing and detoxifying TCMs, TCM compounds, and TCM extracts all demonstrate promising anti-biofilm activities.

In the future, the integration of nanotechnology and TCM to construct a novel therapeutic system of “nanocarriers + TCM active components” is expected to achieve synergistic advantages: nanotechnology can improve the solubility, stability, and targeting of TCM components, enhancing their anti-biofilm efficacy; the multi-target effects of TCM can further optimize the synergistic therapeutic capacity of nanotherapeutics and reduce the risk of bacterial drug resistance. Meanwhile, it is necessary to strengthen research on the integration of TCM theory and modern molecular mechanisms, thoroughly elucidate the molecular mechanisms of TCM against biofilms, optimize nanocarrier design, and promote the translation of this field from basic research to clinical practice. This will provide more effective therapeutic strategies for addressing bacterial biofilm-associated infections and the global antibiotic resistance crisis.

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