Evidence on Vector-Associated Dissemination of Multidrug-Resistant Salmonella in the Philippines Food Supply Chain: A One Health Scoping Review

This scoping review evaluates the role of vector-associated dissemination in contaminating the Philippine food supply chain with antimicrobial-resistant (AMR) Salmonella, an emerging infectious disease threat, using a One Health perspective to map the mechanisms through which insects and rodents bridge environmental reservoirs to human food systems. This scoping review was conducted and reported in accordance with the PRISMA-ScR guidelines. From 1969 records identified through systematic database searches, 52 studies met the inclusion criteria. These comprised 21 primary Philippine studies, 28 non-Philippine studies (including ASEAN-based historical baseline reports), and 3 policy/gray literature studies, prioritized to reflect tropical ecological and agricultural settings. Results suggest that intensive swine and poultry farming may contribute to the emergence of multidrug resistance (MDR) linked to genes such as blaTEM and qnr. Evidence suggests that Salmonella persists in environmental matrices, such as manure and irrigation water, and that synanthropic vectors, including Rattus rattus and various fly species, potentially serve as biological and mechanical bridges in transmission. Clinical data reveal an alarming trend toward invasive non-typhoidal salmonellosis (iNTS) showing reduced susceptibility to cephalosporins and fluoroquinolones. Despite these findings, major evidence gaps remain, particularly regarding the prevalence of vector-borne Salmonella in pre-harvest produce. Consequently, mitigation requires a One Health framework that integrates non-antibiotic interventions, pest management to disrupt transmission pathways, and rapid diagnostic tools, such as loop-mediated isothermal amplification (LAMP), to enhance market surveillance.