Sampimon O C, Vernooij J C A, Mevius D J, Sol J
GD B.V., Postbus 9. AA Deventer.
Tijdschr Diergeneeskd. 2007 Mar 15;132(6):200-4.
During recent years the prevalence of coagulase-negative staphylococci in milk samples from Dutch dairy cows has increased. In 1999 16.2% of the bacteria isolated from milk collected from cows with subclinical mastitis were coagulase-negative staphylococci. In 2004 this proportion was 42.2%. The proportion of coagulase-negative staphylococci of the bacteria isolated from milk samples from cows with clinical mastitis was 7.3% in 1999 and 14.1% in 2004. In this study, the susceptibility of 108 coagulase-negative staphylococci to oxacillin, cefquinome, streptomycin, neomycin, penicillin, and the combination of nafcillin, penicillin, and streptomycin was tested. The isolates were cultured from milk collected from cows with mastitis and typed using the Api-Staph system. Eight species were identified. Staphylococcus chromogenes was the predominant species (41.7%), followed by Staphylococcus xylosus (15.7%) and Staphylococcus simulans (10.2%). With the agar dilution method all strains proved to be sensitive to cefquinome and 90% to oxacillin. Three isolates (2.8%) were mecA-positive. Despite the agar dilution results, these three isolates should be considered resistant to all beta-lactam antibiotics (penicillins, penicillins combined with a beta-lactamase inhibitor and all generations of cephalosporins). In the agar diffusion test, all isolates proved to be sensitive to the combination of nafcillin-penicillin-streptomycin, 99% were sensitive to neomycin and 1% intermediate sensitive, and 95% were sensitive to streptomycin, 4% resistant, and 1% intermediate sensitive. The coagulase-negative staphylococci were highly resistant to penicillin (37.4%), although the level of resistance varied between species, from 0% for Staphylococcus simulans to 100% for Staphylococcus saprophyticus. Because coagulase-negative staphylococci are resistant to several antibiotics, sensitivity testing is important for targeted treatment of mastitis.
近年来，荷兰奶牛乳汁样本中凝固酶阴性葡萄球菌的流行率有所上升。1999年，从患有亚临床乳腺炎奶牛采集的乳汁中分离出的细菌有16.2%是凝固酶阴性葡萄球菌。2004年，这一比例为42.2%。1999年，从患有临床乳腺炎奶牛的乳汁样本中分离出的细菌中，凝固酶阴性葡萄球菌的比例为7.3%，2004年为14.1%。在本研究中，检测了108株凝固酶阴性葡萄球菌对苯唑西林、头孢喹肟、链霉素、新霉素、青霉素以及萘夫西林、青霉素和链霉素组合的敏感性。这些分离株是从患有乳腺炎奶牛采集的乳汁中培养出来的，并使用Api-Staph系统进行分型。鉴定出了8个菌种。产色葡萄球菌是主要菌种（41.7%），其次是木糖葡萄球菌（15.7%）和模仿葡萄球菌（10.2%）。采用琼脂稀释法，所有菌株对头孢喹肟均敏感，对苯唑西林的敏感率为90%。有3株分离株（2.8%）mecA基因呈阳性。尽管琼脂稀释法检测结果如此，但这3株分离株应被视为对所有β-内酰胺类抗生素（青霉素、与β-内酰胺酶抑制剂联合使用的青霉素以及所有代头孢菌素）耐药。在琼脂扩散试验中，所有分离株对萘夫西林-青霉素-链霉素组合均敏感，对新霉素的敏感率为99%，1%为中度敏感，对链霉素的敏感率为95%，4%耐药，1%中度敏感。凝固酶阴性葡萄球菌对青霉素的耐药性较高（37.4%），不过不同菌种的耐药水平有所不同，从模仿葡萄球菌的0%到腐生葡萄球菌的100%。由于凝固酶阴性葡萄球菌对多种抗生素耐药，因此敏感性检测对于乳腺炎的针对性治疗很重要。
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