从孟加拉国一些选定奶牛场的牛临床乳腺炎中分离出的毒力决定因素和抗菌药物耐药性
Virulence determinants and antimicrobial resistance of isolated from bovine clinical mastitis in some selected dairy farms of Bangladesh.
作者信息
Bag Md Abdus Sattar, Khan Md Shahidur Rahman, Sami Md Deluar Hossain, Begum Ferdousi, Islam Md Shafiqul, Rahman Md Mizanur, Rahman Md Tanvir, Hassan Jayedul
机构信息
Department of Microbiology and Hygiene, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh.
Department of Livestock Services, Ministry of Fisheries & Livestock, Krishi Khamar Sarak, Farmgate, Dhaka 1215, Bangladesh.
出版信息
Saudi J Biol Sci. 2021 Nov;28(11):6317-6323. doi: 10.1016/j.sjbs.2021.06.099. Epub 2021 Jul 6.
is one of the major significant pathogens causing mastitis, the most complex and costly diseases in the dairy industry worldwide. Present study was undertaken to isolate, detect the virulence factors, phylogroup, antimicrobial susceptibility and antimicrobial resistance genes in from cows with clinical mastitis. A total of 68 milk samples comprising 53 from clinical mastitis and 15 from apparently healthy cattle were collected from four different established dairy farms in Bangladesh. was isolated from the milk samples and identified by PCR targeting gene and sequencing of 16S rRNA gene. isolates were screened by PCR for the detection of major virulence genes (, and ) of diarrheagenic followed by phylogenetic grouping. Antimicrobial susceptibility of the isolates was determined by disk diffusion test and showing resistance was further screened for the presence of antimicrobial resistance genes. was isolated from 35.8% of the mastitis milk samples but none from the apparently healthy cattle milk. All the isolates were negative for , and genes and belonged to the phylogenetic groups A and B1 which comprising of commensal . Antibiotic sensitivity testing revealed 84.2% (16/19) of the isolates as multidrug resistant. Highest resistance was observed against amoxicillin (94.5%) followed by ampicillin (89.5%) and tetracycline (89.5%). were found resistant against all the classes of antimicrobials used at the farm level. Tetracycline resistance gene () was detected in 100% of the tetracycline resistant and TEM-1 was present in 38.9% of the isolates. Findings of this study indicate a potential threat of developing antimicrobial resistance in commensal and their association with clinical mastitis. Occurrence of multidrug resistant might be responsible for the failure of antibiotic therapies in clinical mastitis as well as pose potential threat of transmitting and development of antibiotic resistance in human.
是引起乳腺炎的主要重要病原体之一，乳腺炎是全球乳制品行业中最复杂且成本最高的疾病。本研究旨在从患有临床乳腺炎的奶牛中分离、检测毒力因子、系统发育群、抗菌药物敏感性及抗菌耐药基因。从孟加拉国四个不同的既定奶牛场收集了总共68份牛奶样本，其中53份来自临床乳腺炎奶牛，15份来自明显健康的奶牛。从牛奶样本中分离出该菌，并通过靶向基因的PCR和16S rRNA基因测序进行鉴定。通过PCR对该菌分离株进行筛选，以检测致泻性主要毒力基因（、和），随后进行系统发育分组。通过纸片扩散试验测定该菌分离株的抗菌药物敏感性，并对显示耐药的菌株进一步筛选抗菌耐药基因。从35.8%的乳腺炎牛奶样本中分离出该菌，但在明显健康的奶牛牛奶样本中均未分离到。所有该菌分离株的、和基因均为阴性，属于系统发育群A和B1，其中包含共生菌。抗生素敏感性测试显示84.2%（16/19）的分离株为多重耐药。观察到对阿莫西林的耐药率最高（94.5%），其次是氨苄西林（89.5%）和四环素（89.5%）。发现该菌对农场使用的所有抗菌药物类别均有耐药。在100%对四环素耐药的该菌中检测到四环素耐药基因（），在38.9%的该菌分离株中存在TEM-1。本研究结果表明共生菌产生抗菌耐药性的潜在威胁及其与临床乳腺炎的关联。多重耐药该菌的出现可能是临床乳腺炎抗生素治疗失败的原因，也对人类抗生素耐药性的传播和发展构成潜在威胁。
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