1)(株)ティーセル研究所(〒989-3204 仙台市青葉区南吉成6-6-3) 2)NOSAI山形家畜診療研修所(〒990-2171 山形市大字七浦286-1) |
(1998年10月23日受付・2000年1月6日受理)
乳牛の臨床上健康な乳房68例および臨床型乳房炎罹患乳房101例の乳汁から,黄色ブドウ球菌(S. aureus)およびコアグラーゼ陰性ブドウ球菌(CNS)の分離を行った.さらに,分離した各ブドウ球菌の腸管毒素(SEs
: SEA,SEB,SEC,SEDおよびSEE)と毒素性ショック症候群毒素h1(TSST-1)の産生能を測定した.その結果,(1)健康牛乳汁からも慢性乳房炎牛乳汁と大差のない高頻度でS. aureusとCNSが分離されること,(2)分離したS.
aureusとCNSはいずれも高率にSEsとTSST-1を産生すること,(3)乳汁中に検出される毒素性物質である,ブドウ球菌の産生する腸管毒素の中で,SECが重度な乳房炎症状を示す乳房で高率かつ高濃度に産生されていることが判明した.以上の成績から,乳牛におけるブドウ球菌性乳房炎は,潜在性乳房炎から臨床型乳房炎へ移行する例が多いが,これには感染ブドウ球菌の産生するSECが深く関与している可能性が示唆された.
--------------------日獣会誌 53,435〜440(2000)
Isolation of Staphylococcus aureus and Coagulase-negative Staphylococci from Healthy and Mastitic Dairy-cow Mammary Glands and Production of StaphylococcalEnterotoxins and Toxic shock syndrome Toxin-1 by These BacteriaKen-ichi KOMINE*, Toshinobu KUROISHI, Ken-ichi ASAI,Yumiko KOMINE, Kenzo KAI,Masashi ITAGAKI, Sakae ABE, Hiromi SAITO and Katsuo KUMAGAI
SUMMARY To isolate Staphylococcus aureus (S. aureus) and coagulase-negative staphylococci
(CNS), examinations were made of mammary-gland secretions (MGS) from healthy and mastitic dairy cows
at different stages of lactation. In the MGS of healthy mammary glands, throughout both lactating and
nonlactating periods, S. aureus and CNS were detected at high levels near those observed in chronically
infected mammary glands. MGSs were examined also for incidence and concentration of such staphylococcal
enterotoxins (SEs) as SEA, SEB, SEC, SED, and SEE and for toxic shock syndrome toxin-1 (TSST-1). These
toxins were detected at levels of nearly 50% in cultures of both S. aureus and CNS. In the MGSs,
incidences and amounts of SEC, though of neither the other SEs nor TSST-1, correlated well with degree
of mammary-gland inflammation. These results strongly suggest that SEC may participate as a causal agent
in subclinical staphylococcal mammary-gland infection causing apparent mastitis.
--------------------J. Jpn. Vet. Med. Assoc., 53, 435〜440 (2000) |