Wataradee Sirirat, Boonserm Thanasak, Samngamnim Sukuma, Ajariyakhajorn Kittisak
Department of Veterinary Medicine, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand.
Animals (Basel). 2024 Jan 30;14(3):447. doi: 10.3390/ani14030447.
is a contagious pathogen that causes bovine mastitis. The ability of to cause widespread mastitis relies on bacterial virulence factors. In this study, we detected 10 virulence determinants associated with mastitis pathogenicity using conventional PCR. The antimicrobial susceptibility of 100 isolates from 13 Thai dairy herds was assessed using the Kirby-Bauer disk diffusion susceptibility test. All strains had at least three virulence factors responsible for invasion, adhesion, and infection (, , and , respectively). The predominant virulent profile of strains revealed the presence of , , , , and ( = 96). Most strains were sensitive to penicillin, ampicillin, amoxicillin-clavulanic acid, cefotaxime, ceftiofur, erythromycin, sulfamethoxazole-trimethoprim, and vancomycin. However, all strains were resistant to aminoglycosides, including kanamycin and gentamicin attributed to the unnecessary antimicrobial use. Furthermore, we identified seven multidrug resistant (MDR) strains among four dairy herds, of which, two were vancomycin resistant. Our study provides profiles for virulence factors and antimicrobial susceptibility, which are beneficial for the clinical monitoring, prevention, and control of bovine mastitis in dairy cattle in Thailand. Moreover, we emphasize the need for awareness regarding the judicious use of antimicrobials on dairy farms.
是一种引起牛乳腺炎的传染性病原体。引起广泛乳腺炎的能力依赖于细菌毒力因子。在本研究中，我们使用常规PCR检测了10种与乳腺炎致病性相关的毒力决定因素。使用 Kirby - Bauer纸片扩散药敏试验评估了来自13个泰国奶牛场的100株该病原体分离株的抗菌药敏性。所有菌株至少有三种分别负责侵袭、黏附和感染的毒力因子（分别为、和）。该病原体菌株的主要毒力谱显示存在、、、和（= 96）。大多数菌株对青霉素、氨苄西林、阿莫西林 - 克拉维酸、头孢噻肟、头孢噻呋、红霉素、磺胺甲恶唑 - 甲氧苄啶和万古霉素敏感。然而，由于不必要的抗菌药物使用，所有菌株对包括卡那霉素和庆大霉素在内的氨基糖苷类耐药。此外，我们在四个奶牛场中鉴定出七株多重耐药（MDR）该病原体菌株，其中两株对万古霉素耐药。我们的研究提供了毒力因子和抗菌药敏性概况，这有助于泰国奶牛乳腺炎的临床监测、预防和控制。此外，我们强调了奶牛场合理使用抗菌药物意识的必要性。
