Brown M B, Scasserra A E
Department of Infectious Diseases, College of Veterinary Medicine, University of Florida, Gainesville 32610.
Am J Vet Res. 1990 Dec;51(12):2015-8.
Streptococcal species isolated from dairy cows with clinical mastitis were obtained from mastitis research workers in Florida, Louisiana, New York, Vermont, Washington, and West Virginia. Seventy-one streptococcal isolates were tested, including 39 strains of Streptococcus agalactiae, 21 strains of S dysgalactiae, and 11 strains of S uberis. The minimal inhibitory concentration of erythromycin, lincomycin, oxytetracycline, penicillin, spectinomycin, streptomycin, and tetracycline was determined for each isolate. Differences were not detected among strains with respect to geographic origin. None of the strains was resistant to penicillin. Lincomycin was the next most effective antimicrobial, with only 2 resistant strains of each streptococcal species. There were no differences among the streptococcal species with respect to resistance to either penicillin or lincomycin. Streptococcus uberis was more likely to be resistant to erythromycin than were S agalactiae and S dysgalactiae (P less than 0.02). Streptococcus agalactiae and S uberis had similar distributions for resistance to oxytetracycline, tetracycline, spectinomycin, and streptomycin. Strains of S dysgalactiae were more likely to have intermediate resistance to oxytetracycline and streptomycin than were strains of S agalactiae and S uberis, which were highly resistant to oxytetracycline and streptomycin (P less than 0.001). Differences were not detected among the streptococcal species with respect to resistance to spectinomycin. Resistance to multiple antimicrobials was observed in all streptococcal species tested. Although S dysgalactiae appeared to have a greater percentage of strains (73%) that were resistant to multiple antimicrobials than did S agalactiae (31%) or S uberis (45%), differences were not statistically significant.
从患有临床乳腺炎的奶牛身上分离出的链球菌菌株，取自佛罗里达州、路易斯安那州、纽约州、佛蒙特州、华盛顿州和西弗吉尼亚州的乳腺炎研究人员。对71株链球菌分离株进行了测试，其中包括39株无乳链球菌、21株停乳链球菌和11株乳房链球菌。测定了每种分离株对红霉素、林可霉素、土霉素、青霉素、壮观霉素、链霉素和四环素的最低抑菌浓度。未检测到不同地理来源的菌株之间存在差异。所有菌株对青霉素均无耐药性。林可霉素是其次最有效的抗菌药物，每种链球菌属仅有2株耐药菌株。各链球菌属对青霉素或林可霉素的耐药性没有差异。乳房链球菌比无乳链球菌和停乳链球菌更易对红霉素耐药（P小于0.02）。无乳链球菌和乳房链球菌对土霉素、四环素、壮观霉素和链霉素的耐药分布相似。停乳链球菌菌株比无乳链球菌和乳房链球菌菌株更易对土霉素和链霉素呈现中度耐药，而后两者对土霉素和链霉素高度耐药（P小于0.001）。各链球菌属对壮观霉素的耐药性未检测到差异。在所有测试的链球菌属中均观察到对多种抗菌药物的耐药性。尽管停乳链球菌似乎比无乳链球菌（31%）或乳房链球菌（45%）有更高比例（73%）的菌株对多种抗菌药物耐药，但差异无统计学意义。
