Banerjee S, Batabyal K, Joardar S N, Isore D P, Dey S, Samanta I, Samanta T K, Murmu S
Department of Veterinary Microbiology, Faculty of Veterinary and Animal Sciences, West Bengal University of Animal and Fishery Sciences, Kolkata, West Bengal, India.
Avian Influenza Laboratory, Institute of Animal Health & Veterinary Biologicals (R&T), Government of West Bengal, Kolkata, West Bengal, India.
Vet World. 2017 Jul;10(7):738-742. doi: 10.14202/vetworld.2017.738-742. Epub 2017 Jul 4.
Subclinical mastitis in bovines is mainly responsible for the huge economic loss of the dairy farmers, of which is one of the causative agents. The study was aimed at a screening of suspected milk samples from different cattle farms of West Bengal for detection and confirmation of strains followed by their characterization.
Around 422 milk samples were screened from different dairy farms primarily by on-spot bromothymol blue (BTB) test and then in the lab by somatic cell counts (SCC) to finally consider 352 samples for detection of . Selective isolation and confirmation of the isolates were done using selective media, ., cetrimide and Pseudomonas agar followed by confirmation by fluorescent technique. Molecular characterization of the strains was done by polymerase chain reaction for the presence of A (enterotoxin A, 352 bp) and S (exoenzyme S, 504 bp) genes.
Approximately, 371 (87.9%) samples were positive in on-spot BTB test among which 352 (94.8%) samples revealed high SCC values (more than 3 lakh cells/ml) showing infection when screened. Among these, 23 (6.5%) samples yielded typical sp. isolates out of which only 19 (5.4%) isolates were confirmed to be which showed characteristic blue-green fluorescence due to the presence of pigment pyoverdin under ultraviolet light. Out of these 19 isolates, 11 isolates were positive for A, 6 isolates for S, and 2 for both these pathogenic genes.
Approximately, 5.4% cases of bovine subclinical mastitis infections in South Bengal were associated with which possess pathogenic genes such as A (63.2%) and S (36.8%).
奶牛亚临床型乳腺炎是奶农巨大经济损失的主要原因，其中 是致病因子之一。本研究旨在对西孟加拉邦不同奶牛场的疑似牛奶样本进行筛查，以检测和确认 菌株，随后对其进行特性鉴定。
从不同奶牛场筛选了约422份牛奶样本，首先通过现场溴麝香草酚蓝（BTB）试验进行初步筛选，然后在实验室通过体细胞计数（SCC）进行检测，最终选取352份样本用于 的检测。使用选择性培养基（如溴化十六烷基三甲铵和假单胞菌琼脂）对分离株进行选择性分离和确认，随后通过荧光技术进行确认。通过聚合酶链反应对菌株进行分子特性鉴定，检测A（肠毒素A，352 bp）和S（外毒素S，504 bp）基因的存在情况。
约371份（87.9%）样本现场BTB试验呈阳性，其中352份（94.8%）样本在筛查时显示体细胞计数高（超过30万个细胞/毫升），表明存在感染。在这些样本中，23份（6.5%）样本产生了典型的 菌属分离株，其中只有19份（5.4%）分离株被确认为 ，在紫外线下因存在绿脓菌素而呈现特征性的蓝绿色荧光。在这19份分离株中，11份对A呈阳性，6份对S呈阳性，2份对这两个致病基因均呈阳性。
在南孟加拉邦，约5.4%的奶牛亚临床型乳腺炎感染与 有关，该菌具有A（63.2%）和S（36.8%）等致病基因。
