Hitoshi Ano

Clindamycin in the Treatment of Babesia gibsoni Infections in Dogs

This report examines the effectiveness of clindamycin for the treatment of babesiosis in dogs (n=10) experimentally infected with Babesia gibsoni (B. gibsoni). Clindamycin (25 mg/kg body weight, per os, q 12 hours for 14 days) gradually reduced parasitemia levels and induced morphological changes that indicated degeneration of parasites (e.g., segmentation; size reduction; localization in the cell limbic and/or torn state of the nucleus; and swelling, decrease, or disappearance of the cytoplasm) in the majority of dogs. Clindamycin treatment reduced the clinical symptoms characteristic of Babesia infection, including anemia, anorexia, and listlessness. Clindamycin might be useful as a medicine for treatment of B. gibsoni infection.

In vitro synergistic activities of cefazolin and nisin A against mastitis pathogens

First-generation cephalosporins such as cefazolin (CEZ) have been widely used for mastitis treatment in dairy cattle. However, the use of antibiotics results in the presence of antibiotic residues in milk, which is used for human consumption. Nisin A, a bacteriocin produced by Lactococcus lactis, has been used as a broad-spectrum food preservative for over 50 years. Therefore, a combination of CEZ and nisin A might provide an extended activity spectrum against mastitis pathogens and reduce the antibiotic dose for mastitis treatment. This study aimed to evaluate the combined effect of CEZ and nisin A against mastitis pathogens using the checkerboard and time-kill assays. In the checkerboard assay, the CEZ-nisin A combination exhibited a synergistic effect against Staphylococcus aureus (n=20/20) and Enterococcus faecalis (n=13/18), and meanwhile exhibited a mostly additive effect against Staphylococcus intermedius (n=12/20), Streptococcus agalactiae (n=10/10), Streptococcus dysgalactiae (n=18/18), and Escherichia coli (n=14/18). There were no indifferent or antagonistic effects between CEZ and nisin A. In the time-kill assay, the CEZ-nisin A combination at 0.5 × or 1 × minimum inhibitory concentration exhibited synergistic reduction of bacterial growth by over 3 log10 colony forming units per ml relative to that observed with either antimicrobial substance alone. These results suggest that the CEZ-nisin A combination can be used for developing an intramammary infusion for mastitis treatment, with lower antibiotic concentrations than normal.

Seasonal changes in serum oxidative stress biomarkers in dairy and beef cows in a daytime grazing system

This study aims to evaluate the oxidative stress during hot summer season using serum oxidative stress biomarkers and elucidate the effects of serum antioxidant vitamin levels in dairy and beef cows in a daytime grazing system. Blood samples were collected once a month from eight Holstein Friesian (HF) and 10 Japanese Black (JB) cows from November 2013 to October 2014. Serum values of derivatives of reactive oxygen metabolites (d-ROMs) tended to be higher in March in both breeds and those in HF cows were kept at higher (P<0.001) levels than those in JB cows during the study period. Serum levels of biological antioxidant potential (BAP) in both breeds were maintained at almost the same values during study period. The OSI [(d-ROMs/BAP) × 100] values in both breeds showed similar seasonal changes, i. e. increase from December to March and decrease from March to August or September. In addition, the OSI values in HF cows were kept at higher (P<0.01) levels than those in JB cows during the study period. Serum concentrations of α-tocopherol, β-carotene, blood urea nitrogen and total cholesterol showed similar seasonal changes in both breeds, low in the winter and high from spring to summer, which may be attributed to the pasture grass intake. Opposite changes in OSI values and serum concentrations of α-tocopherol and β-carotene indicated that antioxidant vitamin levels could affect oxidative stress status.

Histopathological changes in the pancreas of cattle with abdominal fat necrosis

The association between pancreatic disorder and abdominal fat necrosis in cattle remains unclear. The pancreases of 29 slaughtered cattle with or without fat necrosis were collected to investigate pathological changes. Japanese Black (JB) cattle were classified into the FN group (with abdominal fat necrosis; n=9) and N group (without fat necrosis; n=5). The pancreases were also collected from 15 Holstein Friesian (HF) cows. All JB cattle showed high body condition scores. Regarding the pathological findings, fatty pancreas which involves adipocyte infiltration into the pancreas and fat necrosis (saponification) were observed in 25 and 27 cases, respectively. Immunohistochemical staining with anti-Iba-1 antibody showed large numbers of macrophages surrounding the saponified fat in the pancreas. CD3-positive T cells were significantly more common in the pancreas of both the FN and N groups compared with the HF group (P<0.05). Furthermore, fibrosis in the pancreas exhibited a correlative tendency with the formation of necrotic fat mass in the peritoneal cavity (P<0.1). These results indicate that obesity leads to increased severity of pancreatic disorder, including fatty pancreas and pancreatitis. The pathological lesions in the pancreas may play a key role in abdominal fat necrosis through the inflammatory process.

Recurrent Sebaceous Adenitis Treated with Low-dose Prednisolone in an Akita Dog

* 連絡先:片本 宏(宮崎大学農学部獣医内科学研究室) 〒 889-2192 宮崎県宮崎市学園木花台西 1-1 TEL 0985-58-7277 FAX 0985-58-7277 E-mail: katamoto@cc.miyazaki-u.ac.jp 脂腺炎は角化亢進を主とする皮膚疾患で,病理 組織学的には炎症細胞の浸潤による皮脂腺の破壊 を特徴とする,比較的まれな疾患である。犬にお いてはスタンダードプードル,ヴィズラ,サモエド, 秋田犬などいくつかの好発犬種の存在が知られて いる 。 治療には主にシクロポリンなどの免疫抑制剤や ビタミン A誘導体が用いられ,補助的療法として 角質溶解性シャンプーの使用などが実施されてい るが,症例および病変の程度により治療への反応 性は様々である。 今回,我々は Vogt-Koyanagi-Harada-like syndrome によるブドウ膜炎が疑われ,加療中に脂腺炎を再 発した秋田犬に対し,低用量のプレドニゾロンを 投与したところ,皮膚症状が改善し,脂腺の再生 が認められた 1例に遭遇したのでこれを報告する。 症例は 4歳,未去勢雄の秋田犬で,約 2年前よ り両眼のブドウ膜炎で近医および本学動物病院に て加療中であった。以前より特に夏季に脱毛,落 屑増加を主とした皮膚病を繰り返していたとのこ とであったが,これまで確定診断はされておらず, 抗生剤による対症療法のみを受けていた。今回, 皮膚病変の診察依頼を受け,診察を行ったところ, 稟告では 3ヵ月前より後肢大腿部外側より皮膚病 図 1 治療前および治療開始 4週間後の症例の外貌所見