Non-traditional Antimicrobial Strategies and Multi-modal Therapies for Overcoming Antibiotic Resistance in Intra-abdominal Infections
Background
Intra-abdominal Infection (IAI) is a clinically significant and life-threatening condition with high mortality rates. Caused by appendicitis, peritonitis, and intra-abdominal abscesses, this disease often progresses to systemic sepsis if not promptly addressed. Historically, the medical field has relied on broad-spectrum antibiotics to manage such infections. However, the recent surge in antimicrobial resistance (AMR) among pathogens has exposed the limitations of conventional drug therapies.
AMR is a complex issue intricately linked to human healthcare, veterinary medicine, agriculture, and aquatic environments. The overuse of antibiotics in livestock and the release of resistant genes through wastewater into the ecosystem eventually lead to human exposure. The World Health Organization and the medical community advocate for a One Health approach, emphasizing the interconnectedness of human, animal, and environmental health, and calling for multinational collaborative responses. To control resistant pathogens within the confined abdominal cavity, a comprehensive treatment framework beyond individual drug administration is essential.
Key Findings
This study reviews the current status of next-generation antibiotics and novel combination agents under development globally for IAI treatment. Currently, numerous fluoroquinolone antibiotics, beta-lactamase inhibitors, and polymyxin analogues are undergoing clinical trials at various stages, demonstrating efficacy in neutralizing resistance mechanisms of pathogens through modified molecular structures.
Non-traditional antimicrobial alternatives are also being actively explored to minimize the risk of resistance development. Nanoparticles (NPs) and antimicrobial peptides (AMPs) employ multi-target mechanisms by physically disrupting bacterial cell membranes. Representative examples include bacteriophage-based targeted bacterial elimination and CRISPR/Cas gene editing systems for removing specific resistance genes. Probiotic administration to activate beneficial gut microbiota and suppress harmful bacterial growth in the peritoneum is also emerging as a key strategy.
Unlike traditional monotherapies, these combined strategies simultaneously block multiple pathways, making it extremely difficult for bacteria to evade treatment through specific mutations.
Implications and Outlook
Despite the promise of these new antimicrobial strategies, several challenges remain before they can be fully integrated into clinical practice. Secure delivery technologies are needed to ensure stable delivery of therapeutic agents to deep abdominal regions. Safety concerns and cellular toxicity issues have not yet been fully resolved. Meeting the complex regulatory requirements for new drug approvals remains a significant hurdle. Only with the supplementation of pharmacokinetic data reflecting the physiological environment of the abdomen can these treatments be practically prescribed to patients.
The future treatment paradigm for IAIs is likely to shift from a single-drug administration model to a patient-tailored, multi-modal therapeutic system. Scenarios involving rapid molecular diagnostics to identify resistance genes in pathogens and the subsequent formulation of optimal non-traditional treatment combinations are gaining prominence. To fundamentally overcome AMR, it is essential to combine the development of new drugs with institutional support for the strict adherence to appropriate antibiotic use guidelines.
Antimicrobial resistance (AMR) among pathogens involved in intra-abdominal infections (IAIs) represents a critical and escalating clinical challenge. The interconnected nature of antimicrobial resistance, spanning human medicine, veterinary practice, agricultural use and environmental reservoirs, has required coordinated international responses based on the 'One Health' principle. This study presents an update on efforts underway worldwide to develop new antibiotics, novel combined antimicrobial agents, and alternatives to classic therapies for IAIs. New antibiotics or compounds with antibacterial activity are currently in various stages of clinical trials, including several fluoroquinolones, beta-lactamase inhibitors, and polymyxin analogues. To reduce the risk of bacterial resistance, various additions to antimicrobial treatments are being explored, such as nanoparticles (NPs), antimicrobial peptides (AMPs), bacteriophages, the CRISPR/Cas system, and probiotics. Each modality offers distinct mechanisms that circumvent established resistance pathways, including multi-target membrane disruption, sequence-specific gene editing, and microbiome restoration. Current preclinical and clinical evidence is synthesized, and key translational barriers, including delivery challenges, safety concerns, regulatory complexity, and the need for IAI-specific pharmacokinetic data are critically examined. In conclusion, the convergence of novel antibiotic agents and non-traditional antimicrobial strategies reviewed herein provides the foundation for a new paradigm in the management of drug-resistant IAIs. The transition from a monotherapy-centric approach to an integrated, multi-modal treatment framework, guided by rapid diagnostics and informed by antimicrobial stewardship, will be essential to preserve therapeutic efficacy against AMR threats of the coming decades.
This analytical model is well-suited for application in real-world treatment scenarios for severe peritonitis patients infected with multidrug-resistant organisms. A representative example is the rapid identification of resistance genes in patients at risk of sepsis due to carbapenem-resistant Enterobacteriaceae. Combining existing antibiotics with new beta-lactamase inhibitors and co-administering NP-based cell membrane removal agents to enhance drug penetration is also being utilized. If treatment candidates are modularized and commercialized as customized combination formulations, they are expected to significantly improve clinical treatment success rates. Pharmaceutical companies are anticipated to prepare for the commercialization of combination packages tailored to specific genetic mutations, aiming to create new market opportunities.