2021年江苏省部分牧场奶牛临床型乳腺炎源病原菌的分离鉴定及地区、月份分布情况分析

Isolation and identification of clinical mastitis-derived pathogens in dairy cows from some farms in Jiangsu Province in 2021,and analysis of regional and monthly distribution

为了解江苏省部分地区奶牛临床型乳腺炎源病原菌感染情况及其与地区及月份分布的关系,试验选择苏北(新沂市、泗洪县、淮安市)、苏中(盐城市、泰州市)、苏南(张家港市)地区的六个规模化牧场,于2021年5—12月份采集患临床型乳腺炎奶牛奶样316份,进行病原菌分离培养及16S rDNA基因的PCR扩增及测序鉴定,根据病原菌鉴定结果分析江苏省不同地区及不同月份的病原菌检出情况。结果表明:在316份临床型乳腺炎奶样中,287份奶样检测出病原菌,检出率为90.82%。不同地区间的样品检出情况表现出较大差异,苏北地区共检测出14种病原菌,检出率为92.52%;苏中地区共检测出10种病原菌,检出率最高,达到了97.01%;苏南地区仅检测出9种病原菌,检出率最低,为68.57%。不同月份间样品检出情况也存在差异,12月病原菌检出率最高,达到了100%,但病原菌种类却最少,仅为8种;5,6,7月份病原菌检出率均低于其他月份,但病原菌检出种类较多。不同地区间奶牛临床型乳腺炎病原菌感染模式存在差异,7种病原菌感染模式仅出现在苏北地区,苏南地区未检测出6种及以上的病原菌感染模式;除12月份以4种和5种病原菌感染模式为主外,其余各月份均以2种和3种病原菌感染模式最多。临床型乳腺炎的病原菌优势菌种在各地区和各月份间存在差异,苏北地区以肺炎克雷伯菌、葡萄球菌属、大肠杆菌和酵母菌为主,苏南地区以葡萄球菌属为主;10月份以牛支原体和金黄色葡萄球菌检出率最高,分别为72.41%、51.72%;12月份以葡萄球菌属检出率最高,达到了86.67%;其他各月份样品均以肺炎克雷伯菌检出率最高。说明江苏省六个牧场奶牛临床型乳腺炎源病原菌的总体检出率较高,同时病原菌检出率、病原菌检出种类和优势病原菌在不同地区及不同月份间的分布存在差异。

In order to understand the infection of clinical mastitis-derived pathogens in dairy cows from some areas of Jiangsu Province,and its relationship with the regional and monthly distribution,in this experiment,six large-scale farms in Northern Jiangsu Province(Xinyi City,Sihong County,Huaian City),Central Jiangsu Province(Yancheng City,Taizhou City)and Southern Jiangsu Province(Zhangjiagang City)were selected.From May to December 2021,316 milk samples of clinical mastitis were collected for the isolation and culture of the pathogens,and PCR amplification and sequencing identification of 16S rDNA gene;the results of pathogen identification were based for the analysis on the detection of the pathogens in different areas and months in Jiangsu Province.The results showed that among 316 milk samples of clinical mastitis,287 samples were detected with the pathogens,with a detection rate of 90.82%.There was significant difference in the detection of the samples between different areas;a total of 14 pathogens were detected in Northern Jiangsu Province,with a detection rate of 92.52%;a total of 10 pathogens were detected in Central Jiangsu Province,with the highest detection rate,reaching 97.01%;and only 9 pathogens were detected in Southern Jiangsu Province,with the lowest detection rate of 68.57%.The detection of the samples also varied between different months;in December,the detection rate of pathogens was the highest,reaching 100%,but the lowest number of pathogen types was only 8.The detection rates of pathogens in May,June and July was lower than those in other months,but there were many types of pathogens.There was the difference in the infection patterns of clinical mastitis pathogens in dairy cows between different areas;7 pathogen infection patterns only appeared in Northern Jiangsu Province,and 6 or more pathogen infection patterns were not detected in Southern Jiangsu Province.Except for December,which was dominated by 4 and 5 pathogen infection patterns,2 and 3 pathogen infection patterns were the most common in the remaining months.The dominant bacteria causing clinical mastitis varied by areas and months.The pathogens in Northern Jiangsu Province were mainly Klebsiella pneumoniae,the genus Staphylococcus,Escherichia coli and yeast;the genus Staphylococcus was the dominant pathogen in Southern Jiangsu Province.In October,the detection rates of Mycoplasma bovine and Staphylococcus aureus were the highest,reaching 72.41%and 51.72%,respectively;in December,the detection rate of the genus Staphylococcus was the highest,reaching 86.67%;in other months,the samples had the highest detection rates of Klebsiella pneumoniae.The results suggested that the overall detection rate of clinical mastitis-derived pathogens in dairy cows in six farms in Jiangsu Province was high,and there was difference in the detection rates of pathogens,the detection types of pathogens and the distribution of dominant pathogens in different areas and different months.