Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
Vet Microbiol. 2010 Sep 28;145(1-2):84-9. doi: 10.1016/j.vetmic.2010.03.001. Epub 2010 Mar 7.
Arcanobacterium pyogenes is considered the most significant bacterium involved in the pathogenesis of metritis in cattle. Infections caused by antimicrobial-resistant bacteria are a great challenge in both human and veterinary medicine. The purpose of this study was to present an overview of antimicrobial resistance in A. pyogenes isolated from the uteruses of postpartum Holstein dairy cows and to identify virulence factors. Seventy-two A. pyogenes isolates were phenotypically characterized for antimicrobial resistance to amoxicillin, ampicillin, ceftiofur, chloramphenicol, florfenicol, oxytetracycline, penicillin, spectinomycin, streptomycin and tetracycline by the broth microdilution method. Presence of virulence factor genes of A. pyogenes was investigated. Isolates exhibited resistance to all antimicrobial agents tested; high levels of resistance were found to amoxicillin (56.9%); ampicillin (86.1%), chloramphenicol (100%), florfenicol (59.7%), oxytetracycline (54.2%), penicillin (86.1%) and tetracycline (50%). Of all isolates, 69 (95.8%) were resistant to at least 2 of the antimicrobial agents tested and multidrug resistance (resistant to at least 3 antimicrobials) was observed in 64 (88.9%) of the A. pyogenes isolates. The major multidrug resistance profile was found for chloramphenicol-ampicillin-penicillin-florfenicol-amoxicillin-tetracycline, which was observed in 21 (29.2%) multidrug resistant isolates. No isolate was resistant to all nine antimicrobial agents tested but four isolates (5.6%) were resistant to eight antimicrobials. The information highlights the need for prudent use of specific antimicrobial agents. All four virulence factor genes occurred in isolates from normal puerperium and clinical metritis; however, the fimA gene was present in significantly higher frequency in isolates from metritis cows.
化脓隐秘杆菌被认为是导致奶牛子宫内膜炎的最重要细菌。抗菌药物耐药菌引起的感染是人类和兽医医学的重大挑战。本研究的目的是概述从产后荷斯坦奶牛子宫中分离的化脓隐秘杆菌对抗菌药物的耐药性，并确定其毒力因子。通过肉汤微量稀释法对 72 株化脓隐秘杆菌分离株进行了阿莫西林、氨苄西林、头孢噻呋、氯霉素、氟苯尼考、土霉素、青霉素、壮观霉素、链霉素和四环素的表型抗菌药物耐药性特征分析。研究了化脓隐秘杆菌毒力因子基因的存在情况。分离株对所有测试的抗菌药物均表现出耐药性；对阿莫西林（56.9%）、氨苄西林（86.1%）、氯霉素（100%）、氟苯尼考（59.7%）、土霉素（54.2%）、青霉素（86.1%）和四环素（50%）的耐药性较高。所有分离株中，有 69 株（95.8%）至少对 2 种测试的抗菌药物耐药，有 64 株（88.9%）化脓隐秘杆菌分离株表现出多药耐药（至少对 3 种抗菌药物耐药）。观察到的主要多药耐药谱是氯霉素-氨苄西林-青霉素-氟苯尼考-阿莫西林-四环素，在 21 株（29.2%）多药耐药分离株中观察到该谱。没有分离株对所有 9 种测试的抗菌药物均耐药，但有 4 株（5.6%）分离株对 8 种抗菌药物耐药。这些信息突出表明需要谨慎使用特定的抗菌药物。所有 4 种毒力因子基因均存在于正常产褥期和临床子宫内膜炎的分离株中；然而，fimA 基因在来自子宫内膜炎奶牛的分离株中存在的频率显著更高。
