Polyhexamethylene Biguanide Nanoparticles Inhibit Biofilm Formation by Mastitis-Causing Staphylococcus aureus

Leite, RD; Garcia, BLN; Barbosa, KD; Mitsunaga, TM; Fidelis, CE; Dias, BJM; de Miranda, RR; Zucolotto, V; Good, L; dos Santos, MV

Abstract

Staphylococcus aureus is a mastitis pathogen that compromises cow health and causes significant economic losses in the dairy industry. High antimicrobial resistance and biofilm formation by S. aureus limit the efficacy of conventional treatments. This study evaluated the potential of polyhexamethylene biguanide nanoparticles (PHMB NPs) against mastitis-causing S. aureus. PHMB NPs showed low toxicity to bovine mammary epithelial cells (MAC-T cells) at concentrations up to four times higher than the minimum inhibitory concentration (1 mu g/mL) against S. aureus. In Experiment 1, PHMB NPs significantly reduced biofilm formation by S. aureus by 50% at concentrations >= 1 mu g/mL, though they showed limited efficacy against preformed biofilms. In Experiment 2, using an excised teat model, PHMB NPs reduced S. aureus concentrations by 37.57% compared to conventional disinfectants (chlorhexidine gluconate, povidone-iodine, and sodium dichloroisocyanurate), though limited by short contact time. These findings highlight the potential of PHMB NPs for the control of S. aureus growth and biofilm formation.

Citation

Leite, R., Garcia, B., Barbosa, K., Mitsunaga, T., Fidelis, C., Dias, B., de Miranda, R., Zucolotto, V., Good, L., & dos Santos, M. (2025). Polyhexamethylene Biguanide Nanoparticles Inhibit Biofilm Formation by Mastitis-Causing Staphylococcus aureus. Veterinary Sciences, 12(5), https://doi.org/10.3390/vetsci12050507

• Journal Article Type: Article
• Acceptance Date: May 16, 2025
• Online Publication Date: May 21, 2025
• Publication Date: 2025
• Deposit Date: Jun 19, 2025
• Publicly Available Date: Jun 19, 2025
• Print ISSN: 2306-7381
• Electronic ISSN: 2306-7381
• Publisher: MDPI
• Peer Reviewed: Peer Reviewed
• Volume: 12
• Issue: 5
• DOI: https://doi.org/10.3390/vetsci12050507
• Keywords: antimicrobial resistance; bovine mastitis; nanotechnology; intramammary treatment; teat disinfection; one health; BOVINE MASTITIS; TEAT DIP; ANTIMICROBIAL RESISTANCE; CHITOSAN NANOPARTICLES; CLINICAL MASTITIS; MILK; COW; ASSOCIATION; PREVALENCE; PATHOGEN