Introduction:

Biofilms are complex microbial communities that form on biotic and abiotic surfaces within livestock farming environments. Within biofilms, bacteria can efficiently exchange genetic material, including antimicrobial resistance genes (ARGs), potentially serving as reservoirs and amplifiers of antimicrobial resistance (AMR). This scoping review aimed to summarize the current knowledge on AMR, ARGs, and antimicrobial residues (ARs) in biofilms from poultry, swine, and cattle farms.

Materials and methods:

This scoping review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines. Four databases (PubMed, Scopus, Web of Science, and Agricola) were searched using relevant keywords. Peer-reviewed studies assessing AMR, ARGs, and ARs in farm environment biofilms were eligible for inclusion. The identified studies were imported into Zotero for deduplication and subsequently screened in Rayyan in two phases (title/abstract and full text). Data from the included studies were extracted and charted using an ExcelⓇ 2016 spreadsheet.

Results:

A total of 1,242 studies were identified across the databases. After deduplication and title/abstract screening, 52 studies proceeded to the full-text screening, with only 4 meeting the eligibility criteria. The included studies were published between 2021 (n =1) and 2022 (n= 3) and originated from Germany, India, and Iran. Two of these studies focused on broiler farms, one on layer farms, and one on dairy cow farms. Among the four studies, three conducted antimicrobial susceptibility testing, one investigated ARGs, and none reported on ARs from biofilm isolates.

Conclusion:

This scoping review reveals a significant gap in the scientific evidence regarding AMR, ARGs, and ARs in biofilms from livestock farms and emphasizes the need for further research to clarify their role in the spread of AMR in the livestock sector.