Effects of <i>Piper betle</i> Extracts against Biofilm Formation by Methicillin-Resistant <i>Staphylococcus pseudintermedius</i> Isolated from Dogs

• Published in: Pharmaceuticals
• Main Authors: Arpron Leesombun, Sivapong Sungpradit, Norasuthi Bangphoomi, Orathai Thongjuy, Jantraporn Wechusdorn, Sunee Riengvirodkij, Jakaphan Wannawong, Sookruetai Boonmasawai
• Format: Article
• Language: English
• Published: MDPI AG 2023-05-01
• Subjects: ethanolic extracts; <i>Piper betle</i>; <i>Piper sarmentosum</i>; <i>Piper nigrum</i>; pyoderma; biofilm
• Online Access: https://www.mdpi.com/1424-8247/16/5/741

Emergence of methicillin-resistant <i>Staphylococcus pseudintermedius</i> (MRSP) isolated from dogs with cutaneous and wound infections has significantly impacted veterinary medicine. This study aimed to isolate <i>S. pseudintermedius</i> from canine pyoderma and investigate the effects of ethanolic extracts of <i>Piper betle</i> (PB), <i>P. sarmentosum</i> (PS), and <i>P. nigrum</i> (PN) on the bacterial growth and biofilm formation of <i>S. pseudintermedius</i> and MRSP. Of the isolated 152 isolates, 53 were identified as <i>S. pseudintermedius</i> using polymerase chain reaction, and 10 isolates (6.58%) were identified as MRSP based on the presence of <i>mecA</i>. Based on phenotype, 90% of MRSPs were multidrug-resistant. All MRSP had moderate (10%, 1/10) and strong (90%, 9/10) biofilm production ability. PB extracts were the most effective in inhibiting planktonic cells, and the minimum inhibitory concentration at which ≥50% of the isolates were inhibited (MIC₅₀) was 256 µg/mL (256–1024 µg/mL) for <i>S. pseudintermedius</i> isolates and 512 µg/mL (256–1024 µg/mL) for MRSP isolates. The MIC₉₀ for <i>S. pseudintermedius</i> and MRSP was 512 µg/mL. In XTT assay, PB at 4× MIC showed an inhibition rate of 39.66–68.90% and 45.58–59.13% for <i>S. pseudintermedius</i> and MRSP, respectively, in inhibiting biofilm formation. For PB at 8× MIC, the inhibition rates for <i>S. pseudintermedius</i> and MRSP were 50.74–81.66% and 59.57–78.33%, respectively. Further, 18 compounds were identified in PB using gas chromatography–mass spectrometry, and hydroxychavicol (36.02%) was the major constituent. These results indicated that PB could inhibit bacteria growth of and biofilm formation by <i>S. pseudintermedius</i> and MRSP isolated from canine pyoderma in a concentration-dependent manner. Therefore, PB is a potential candidate for the treatment of MRSP infection and biofilm formation in veterinary medicine.