VetPath is an ongoing pan-European antimicrobial susceptibility monitoring programme collecting pathogens from diseased cattle, pigs and poultry not recently treated with antibiotics. Non-duplicate isolates (n = 1244) were obtained from cows with acute clinical mastitis in eight countries during 2015–2016 for centrally antimicrobial susceptibility testing according CLSI standards.

Among Escherichia coli (n = 225), resistance was high to ampicillin and tetracycline, moderate to kanamycin and low to amoxicillin/clavulanic acid and cefazolin. The MIC_50/90 of danofloxacin, enrofloxacin and marbofloxacin were 0.03 and 0.06 μg/mL. For Klebsiella spp. (n = 70), similar results were noted, except for ampicillin and kanamycin. We detected 3.7 % (11/295) Enterobacteriaceae isolates carrying an ESBL/AmpC gene. Staphylococcus aureus (n = 247) and coagulase-negative staphylococci (CoNS; n = 189) isolates were susceptible to most antimicrobials tested except to penicillin (25.1 and 29.1 % resistance). Two S. aureus and thirteen CoNS isolates harboured mecA gene. Streptococcus uberis isolates (n = 208) were susceptible to β-lactam antibiotics (87.1–94.7 % susceptibility), 23.9 % were resistant to erythromycin and 37.5 % to tetracycline. Resistance to pirlimycin was moderate. For Streptococcus dysgalactiae (n = 132) the latter figures were 10.6 and 43.2 %; pirlimycin resistance was low. MIC values for Streptococcus agalactiae, Trueperella pyogenes and Corynebacterium spp. were generally low.

This current VetPath study shows that mastitis pathogens were susceptible to most antimicrobials with exceptions of staphylococci against penicillin and streptococci against erythromycin or tetracycline. For most antimicrobials, the percentage resistance and MIC_50/90 values among the major pathogens were comparable to that of the preceeding VetPath surveys. This work highlights the high need to set additional clinical breakpoints for antimicrobials frequently used to treat mastitis.

VetPath是一项持续进行的泛欧洲抗菌素敏感性监测计划，旨在收集近期未使用抗生素治疗过的病牛，猪和家禽的病原体。 在2015-2016年期间，从八个国家的患有急性临床乳腺炎的奶牛中获得了非重复分离株（n = 1244），用于按照CLSI标准进行集中抗菌药敏试验。

在大肠杆菌中（n  = 225），对氨苄青霉素和四环素的耐药性较高，对卡那霉素的耐药性中等，对阿莫西林/克拉维酸和头孢唑林的耐药性较低。达氟_沙星，恩诺沙星和马波沙星的MIC _50/90为0.03和0.06μg/ mL。对于克雷伯菌属。（n  = 70），除氨苄西林和卡那霉素外，结果相似。我们检测到了3.7％（11/295）带有ESBL / AmpC基因的肠杆菌科细菌。金黄色葡萄球菌（n  = 247）和凝固酶阴性葡萄球菌（CoNS; n  = 189）分离株除青霉素（耐药性分别为25.1和29.1％）外，对大多数抗菌药物均敏感。二金黄色葡萄球菌和13个CoNS分离株带有mecA基因。乳房链球菌分离株（n  = 208）对β-内酰胺类抗生素敏感（敏感性为87.1–94.7％），对红霉素耐药的占23.9％，对四环素耐药的占37.5％。对吡霉素的抗性为中等。对于停乳链球菌（Ñ  = 132），后者的数字分别为10.6和43.2％; 吡霉素的耐药性低。无乳链球菌，化脓性小球藻和棒状杆菌属的MIC值。普遍较低。

这项最新的VetPath研究表明，除了抗青霉素的葡萄球菌和抗红霉素或四环素的链球菌外，乳腺炎病原体对大多数抗菌药物均敏感。对于大多数抗菌剂，主要病原体之间的抗药性百分比和MIC _50/90值与之前的VetPath调查结果相当。这项工作突显了为经常用于治疗乳腺炎的抗菌素设定更多临床断点的强烈需求。