Das Arnab, Guha Chanchal, Biswas Ujjwal, Jana Partha Sarathi, Chatterjee Amaresh, Samanta Indranil
Animal Resources Development Department, Institute of Animal Health and Veterinary Biologicals, Government of West Bengal, Kolkata, West Bengal, India.
Department of Veterinary Epidemiology and Preventive Medicine, Faculty of Veterinary and Animal Sciences, West Bengal University of Animal and Fishery Sciences, Kolkata, West Bengal, India.
Vet World. 2017 May;10(5):517-520. doi: 10.14202/vetworld.2017.517-520. Epub 2017 May 12.
The aim of this work was to detect antibiotic resistance in Gram-negative bacteria isolated from subclinical mastitis in cattle in West Bengal.
The milk samples were collected from the cattle suffering with subclinical mastitis in West Bengal. The milk samples were inoculated into the nutrient broth and incubated at 37°C. On the next day, the growth was transferred into nutrient agar and MacConkey agar. All the pure cultures obtained from nutrient agar slant were subjected to Gram-staining and standard biochemical tests. All the bacterial isolates were tested in vitro for their sensitivity to different antibiotics commonly used in veterinary practices. All Gram-negative isolates including positive control were subjected to polymerase chain reaction (PCR) for detection of bla, bla, bla, bla, tetA, tetB, tetC, and tetM genes considered for extended-spectrum β-lactamase (ESBL), metallo-β-lactamase, and tetracycline resistance.
In total, 50 Gram-negative organisms (Escherichia coli, Proteus, Pseudomonas, Klebsiella, and Enterobacter) were isolated from milk samples of subclinical mastitis infected cattle. Among these Gram-negative isolates, 48% (24/50) were found either ESBL producing or tetracycline resistant. Out of total 50 Gram-negative isolates, bla was detected in 18 (36%) isolates, and 6 (12%) harbored bla genes in PCR. None of the isolates carried bla genes. Further, in this study, 5 (10%) isolates harbored tet(A) gene, and 8 (16%) isolates carried tet(B) gene. No tet(C) gene was detected from the isolates.
This study showed emerging trend of antibiotic-resistant Gram-negative bacteria associated with subclinical mastitis in cattle in West Bengal, India.
本研究旨在检测从西孟加拉邦奶牛亚临床型乳腺炎中分离出的革兰氏阴性菌的抗生素耐药性。
从西孟加拉邦患有亚临床型乳腺炎的奶牛身上采集牛奶样本。将牛奶样本接种到营养肉汤中，于37°C孵育。次日，将生长物转接至营养琼脂和麦康凯琼脂上。从营养琼脂斜面获得的所有纯培养物均进行革兰氏染色和标准生化试验。所有细菌分离株均在体外测试其对兽医实践中常用的不同抗生素的敏感性。所有革兰氏阴性分离株（包括阳性对照）均进行聚合酶链反应（PCR），以检测与超广谱β-内酰胺酶（ESBL）、金属β-内酰胺酶和四环素耐药性相关的bla、bla、bla、bla、tetA、tetB、tetC和tetM基因。
总共从亚临床型乳腺炎感染奶牛的牛奶样本中分离出50株革兰氏阴性菌（大肠杆菌、变形杆菌、假单胞菌、克雷伯菌和肠杆菌）。在这些革兰氏阴性分离株中，48%（24/50）被发现产生ESBL或对四环素耐药。在总共50株革兰氏阴性分离株中，18株（36%）在PCR检测中检测到bla基因，6株（12%）携带bla基因。没有分离株携带bla基因。此外，在本研究中，5株（10%）分离株携带tet(A)基因，8株（16%）分离株携带tet(B)基因。分离株中未检测到tet(C)基因。
本研究表明，在印度西孟加拉邦，与奶牛亚临床型乳腺炎相关的革兰氏阴性菌出现了抗生素耐药性的新趋势。
