Biofilm-forming, drug-resistant non-typhoidal Salmonella poses a significant global food safety challenge. Recognizing the public health threat of both this foodborne zoonotic pathogen and the rise of antimicrobial resistance (AMR), researchers from the University of Wroclaw have reviewed the unique challenges presented by Salmonella biofilms and emerging alternative (non-antibiotic) control strategies in the journal Pharmaceuticals. The paper's authors include Michał Małaszczuk, Ph.D. candidate, Aleksandra Pawlak, Ph.D., and Paweł Krzyżek, Ph.D.

Salmonella in the One Health–One Biofilm Framework

The review looked at Salmonella through the One Health–One Biofilm framework, which emphasizes the interconnectedness of human, animal, and environmental health, and places biofilm at the core of this relationship, positioning it as a biological link. Relevant to food safety, this concept highlights microbiological risks rising from contaminated foods, food animals, and water systems, and points to antimicrobial use in animal agriculture as a key driver of AMR.

The Threat of Drug-Resistant Salmonella Biofilms

The World Health Organization (WHO) includes fluoroquinolone-resistant Salmonella strains on its Bacterial Priority Pathogens List, underscoring their high-risk status.

A critical virulence factor for Salmonella is its ability to produce biofilms, which help facilitate colonization of the host. These microbial communities also enhance survival, promote multidrug resistance (MDR), and contribute to treatment failures. Biofilms persist on food contact surfaces and within animal reservoirs, especially poultry, presenting an important food safety challenge as they enable Salmonella to survive harsh environmental conditions and resist sanitizers.

Promising Alternatives to Conventional Antibiotics for Salmonella Biofilms

Considering the growing threat of antibiotic-resistant Salmonella, researchers are exploring alternative, integrated strategies to prevent and disrupt Salmonella biofilms, such as:

• Vaccination: Although vaccination is considered the most effective method for preventing infectious diseases, at present, no vaccine for invasive non-typhoidal Salmonella (iNTS) is commercially available. There are some promising candidates in clinical phases, such as the Trivalent Salmonella Conjugate Vaccine (TSCV), which successfully completed a successful Phase 1 trial in October 2025. Additionally, the iNTS-GMMA vaccine, based on Generalized Module of Membrane Antigen (GMMA) technology, has qualified for Phase 1 human clinical trials.
• Bacteriophages: Research has demonstrated the strong anti-biofilm activity of bacteriophages and their potential usefulness for pathogen control along the food production chain. For example, recent studies have shown the efficacy of phage cocktails for S. enterica on chicken meat, against mature Salmonella biofilms on stainless steel surfaces, and controlling S. Enteritidis on poultry drinkers. Widely abundant and highly adaptable, phages are viruses capable of infecting bacterial cells, leading to genetic alterations within bacterial cells and, oftentimes, cell lysis. Their antimicrobial efficacy is primarily attributed to their ability to encode enzymatically active proteins, targeting components that facilitate virulence and biofilm formation. Importantly, phage efficacy is dependent on many variables; therefore, validating treatments for relevant application conditions is key.
• Plant-based compounds: Essential oils, phenolic acids, and nano-emulsions derived from plant sources have shown inhibitory effects on biofilm formation and gene expression. For example, studies have proven clove and star anise essential oils to be effective against S. Thompson biofilm formation, and nano-garlic emulsion to enhance antimicrobial effects of traditional treatments.
• Antimicrobial peptides (AMPs): Recent research has shown that naturally occurring and synthetic peptides, along with short-chain fatty acids, can disrupt biofilm integrity and bacterial membranes. AMPs are present across all forms of life, where they help limit pathogen spread; when applied for pathogen control, they can attach to and disrupt microbial membranes, including those within established biofilms. For example, a new study has shown the ability of Lactobacillus rhamnosus-derived peptides to inhibit S. Typhimurium and S. Enteritidis under processing conditions.
• Fatty acids: A class of antimicrobial lipids, fatty acids can disrupt bacterial membranes through destabilization and pore formation, interfere with essential cellular processes, and, due to their structural resemblance to certain molecules, may modify microbial communication pathways that are dependent on these molecules and thereby impede biofilm formation ability. Studies have shown several short-chain fatty acids to exhibit inhibitory activity against both planktonic cells and biofilms of S. Typhimurium and S. Enteritidis.
• Synthetic/semi-synthetic compounds: Novel synthetic and semi-synthetic therapeutics can be valuable for addressing salmonellosis while mitigating AMR when these compounds feature new mechanisms of action and/or bind at sites distinct from those targeted by clinically used antibiotics. Other innovative approaches, such as plasma-treated materials, are also emerging; plasma-treated water has been shown to significantly reduce S. Typhimurium biofilm formation.

The Path Forward

Despite promising research, bringing alternative strategies for Salmonella biofilm control into the real world is complicated by biofilm heterogeneity, host-specific conditions, and the potential for microorganisms to develop resistance to alternative therapies. Further studies are required to understand the mechanisms of biofilm formation under relevant environmental and host-associated conditions and to assess the effectiveness of alternative interventions for Salmonella as part of an integrated One Health approach.

Overall, the authors believe that a shift toward a multi-pronged approach to Salmonella control—combining vaccines, phages, and other non-traditional or novel anti-biofilm agents—offers a pathway to reducing reliance on antibiotics while safeguarding public health from foodborne pathogens.