Influence of oxytetracycline susceptibility as a first-line antibiotic on the clinical outcome in dairy cattle with acute Escherichia coli mastitis

The Journal of Veterinary Medical Science

Kazuhiro KAWAI¹  Akira TAKEDA²  Yasunori SHINOZUKA³ 

[1] NOSAI Doto, 11-6-1 Nishi-6jou-minami, Nakashibetsu, Shibetsu, Hokkaido 086-1106, Japan;NOSAI Miyagi, 1-8-10 Uesugi, Aoba, Sendai, Miyagi 980-0011, Japan;School of Veterinary Medicine, Azabu University, 1-17-71 Fuchinobe, Sagamihara, Kanagawa 252-5201, Japan

关键词: acute E.coli mastitis;    minimum inhibitory concentration (MIC);    outcome;    oxytetracycline;   

DOI  :  10.1292/jvms.19-0035

学科分类：兽医学

来源: Japanese Society of Veterinary Science

【 摘 要 】

The purpose of this study was to clarify the therapeutic effects of oxytetracycline (OTC) as a first-line antibiotic in cattle with acute Escherichia coli mastitis and systemic signs. Drug susceptibility was determined by the minimum inhibitory concentration (MIC) of E. coli isolated from cows with acute E. coli mastitis (n=38). Cattle were divided into OTC-susceptible (S, n=30) and OTC-resistant (R, n=8) groups. They were further subdivided according to susceptibility to the antibiotic used as a second treatment, into susceptible-susceptible (SS, n=30), resistant-susceptible (RS, n=5), and resistant-resistant (RR, n=3) groups. Clinical signs on the day after initial treatment were compared between S and R groups as short-term indicators of treatment effects. The 28-day survival rate of cattle was then compared among SS, RS, and RR groups as a long-term indicator of treatment effects. There were no differences in clinical signs between S and R groups on the day after the first dose, but the 28-day survival rate was significantly greater in the SS group than in the RR group (P=0.04). The results demonstrated that an effective drug is essential for first-line treatment of acute coliform mastitis. However, anticipating the effectiveness of a first-line antibiotic based on clinical symptoms at the second day of treatment is impossible. It is important to build a picture of drug resistance trends in cattle herds for empirical selection of antibiotics to be administered.

【 授权许可】

Unknown