PDF(Pubmed)
Abstract：
Bacillus licheniformis is a gram-positive, endospore-forming, saprophytic and facultative anaerobe that is resistant to heat and environmental conditions. This study was the first to isolate and confirm B. licheniformis as a cause of bovine mastitis in Iran. In the summer of 2020, 105 samples of mastitic milk were collected from dairy farms around Tehran and sent to the microbiology laboratory of the Faculty of Veterinary Medicine at the University of Tehran. The bacterial pathogens were identified using selective and differential culture media and confirmed by PCR to contain the toxin synthetase genes licA, licB and licC in mastitic isolates of B. licheniformis. Resistance patterns to 19 antibiotics were determined for two isolates of B. licheniformis. Staphylococcus aureus and Escherichia coli were identified as the most important organisms in the samples. B. licheniformis was isolated from the two samples containing all three genes. Both isolates were resistant to streptomycin, trimethoprim-sulfamethoxazole, cefixime, ampicillin, bacitracin, clindamycin, and gentamicin. B. licheniformis was reported for the first time in Iran as a cause of bovine mastitis with clinical symptoms. The first isolation of toxin-producing strains of B. licheniformis from mastitic cows in Iran raises concerns about the safety of dairy products. In principle, selected strains with toxigenic potential should not be used as feed additives and animal feed. However, whole genome sequencing is proposed to search for genes coding for toxins.
摘要：
地衣芽孢杆菌是革兰氏阳性,内生孢子形成，抗高温和环境条件的腐生和兼性厌氧菌。这项研究是第一个在伊朗分离并确认地衣芽孢杆菌是牛乳腺炎的原因。2020年夏天，从德黑兰附近的奶牛场收集了105份乳汁样本，并送往德黑兰大学兽医学院的微生物实验室。使用选择性和差异培养基鉴定细菌病原体，并通过PCR确认含有毒素合成酶基因licA，地衣芽孢杆菌乳房分离株中的licB和licC。确定了两种地衣芽孢杆菌分离株对19种抗生素的耐药模式。金黄色葡萄球菌和大肠杆菌被鉴定为样品中最重要的生物。从含有所有三个基因的两个样品中分离地衣芽孢杆菌。两种分离株都对链霉素有抗性，甲氧苄啶-磺胺甲恶唑,头孢克肟,氨苄青霉素,杆菌肽,克林霉素,还有庆大霉素.在伊朗首次报道地衣芽孢杆菌是具有临床症状的牛乳腺炎的原因。首次从伊朗的奶牛中分离产毒素的地衣芽孢杆菌菌株引起了人们对乳制品安全性的担忧。原则上,具有产毒潜力的选定菌株不应用作饲料添加剂和动物饲料。然而,全基因组测序是为了寻找编码毒素的基因。
