학술논문
Knema retusa is antibacterial and antibiofilm against antibiotic resistant Staphylococcus aureus and S. haemolyticus isolated in bovine mastitis
Document Type
Original Paper
Author
Chuprom, Julalak; Kidsin, Kamchai; Sangkanu, Suthinee; Nissapatorn, Veeranoot; Wiart, Christophe; de Lourdes Pereira, Maria; Wongtawan, Tuempong; Daus, Mareena; Sotthibandhu, Dennapa Saeloh; Tipmanee, Varomyalin; Paul, Alok K.; Scholfield, Charles Norman; Zulkipli, Masyitah Binti; Abdullah, Nor Hayati; Mitsuwan, Watcharapong
Source
Veterinary Research Communications: An International Journal Publishing Topical Reviews and Research Articles on all Aspects of the Veterinary Sciences. 47(2):523-538
Subject
Language
English
ISSN
0165-7380
1573-7446
1573-7446
Abstract
This study aimed to assess antibacterial activity of Knema retusa wood extract (KRe) against antibiotic resistant staphylococci which are causative agents of bovine mastitis. From 75 cases of intramammary infections in dairy cows, 66 staphylococcal isolates were collected, including 11 Staphylococcus aureus isolates (17%) and 55 coagulase-negative staphylococci (83%). Sixty isolates (91%) formed strong biofilms. KRe had minimal inhibitory concentrations (MIC) and minimal bactericidal concentrations (MBC) against the isolates ranging 32–256 ug/mL and 64–512 ug/mL, respectively. Two-hour KRe exposures at 4×MIC, viabilities of S. aureus and S. haemolyticus decreased by 3 log10 compared to the control. Scanning EM (SEM) showed that KRe disrupted the bacterial cells of both species. KRe at 1/16×MIC significantly inhibited biofilm formation (P < 0.05) in both S. aureus and S. haemolyticus. At 1/2×MIC, S. aureus and S. haemolyticus biofilm inhibition ranged from 75 to 99%. Cells within established biofilms were disrupted 66–83% by KRe at 32×MIC. Moreover, 1/2×MIC KRe reduced bacterial adhesion to glass surfaces observed by SEM. According to GC-MS analysis, the major compound in KRe was endo-2-hydroxy-9,9-(ethylenedioxy)-1-carbethoxy bicyclo [3.3.1] nonane (E2N). Molecular docking analysis of E2N has a high affinity for staphylococcal accessory regulator A (SarA), binding free-energy − 6.40kcal/mol. The results suggested that KRe may have medicinal benefits by inhibiting the growth, biofilm, and adhesion of antibiotic resistant staphylococci isolated from bovine mastitis.