Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Avenida Carlos Chagas Filho, 373, Cidade Universitária, 21941-590, Rio de Janeiro, Brazil.
Vet Microbiol. 2012 Mar 23;155(2-4):362-8. doi: 10.1016/j.vetmic.2011.09.004. Epub 2011 Sep 12.
Bovine mastitis remains worldwide a major challenge for the dairy industry despite the widespread implementation of control strategies. The increasing number of coagulase-negative staphylococci (CNS) causing mastitis and of bacteria resistant to conventional antibiotics has become a serious problem in recent years. Marine sponges are a rich source of bioactive compounds, and many species can be useful for the development of new antimicrobial drugs. In the present study, 49 CNS strains were isolated from bovine mastitis cases from 21 different dairy herds kept at farms in Southeast Brazil. Strains were analyzed for antimicrobial susceptibility and mecA gene detection. Fifty-nine percent of the CNS strains were resistant to at least one of the drugs tested and 12.2% were classified as multiresistant. Three strains carried the mecA gene, confering resistance to the beta-lactamic antibiotics. In addition, the CNS strains were submitted to in vitro screening for antimicrobial activities of extracts from marine sponges. Extracts from the sponge species Cinachyrella sp., Haliclona sp. and Petromica citrina showed antibacterial activity against 61% of the CNS strains, including strains resistant to conventional antibiotics. Extracts from P. citrina showed the largest spectrum of inhibitory activity. The aqueous extract inhibited 51% of the CNS strains and presented a bactericidal effect over susceptible and multiresistant-bacteria at a minimal inhibitory concentration of 1.024μg/ml. This study shows the potential of marine sponges as new sources of antibiotics and disinfectants for the control of CNS involved in bovine mastitis.
牛乳腺炎仍然是全球奶牛养殖业的主要挑战，尽管已经广泛实施了控制策略。近年来，凝固酶阴性葡萄球菌（CNS）引起乳腺炎的数量不断增加，而且对常规抗生素有耐药性的细菌也成为了一个严重的问题。海洋海绵是生物活性化合物的丰富来源，许多物种可用于开发新的抗菌药物。在本研究中，从巴西东南部农场的 21 个不同奶牛场的乳腺炎病例中分离出 49 株 CNS 菌株。对菌株进行了抗药性和 mecA 基因检测分析。59%的 CNS 菌株对至少一种测试药物有耐药性，12.2%被归类为多耐药性。有 3 株携带 mecA 基因，对β-内酰胺类抗生素具有耐药性。此外，还对 CNS 菌株进行了海洋海绵提取物的体外抗菌活性筛选。海绵属 Cinachyrella sp.、Haliclona sp.和 Petromica citrina 的提取物对 61%的 CNS 菌株具有抗菌活性，包括对常规抗生素耐药的菌株。P. citrina 的提取物显示出最大的抑制活性谱。水提取物抑制了 51%的 CNS 菌株，在最小抑菌浓度为 1.024μg/ml 时对敏感和多耐药细菌具有杀菌作用。本研究表明海洋海绵具有作为控制牛乳腺炎中 CNS 的新型抗生素和消毒剂的潜力。
