湖南省原料乳中 分离株的耐药性与分子分型
Antimicrobial resistance and molecular typing of isolates from raw milk in Hunan Province.
机构信息
College of Veterinary Medicine, Hunan Agricultural University, Hunan, China.
Hunan Provincial Institute of Veterinary Drugs and Feed Control, Hunan, China.
出版信息
PeerJ. 2023 Aug 28;11:e15847. doi: 10.7717/peerj.15847. eCollection 2023.
BACKGROUND
is one of the most important foodborne pathogens in the world and the main cause of dairy cow mastitis. Few studies have investigated the epidemic pedigree of of bovine origin in Hunan, China. Therefore, we aimed to analyze the capsular polysaccharides (CP), molecular typing, and antibiotic resistance characteristics of isolated from raw milk of dairy farms in Hunan Province.
METHODS
Between 2018 and 2022, 681 raw milk samples were collected from dairy cows from farms in Changsha, Changde, Shaoyang, Yongzhou, and Chenzhou in Hunan Province. was isolated from these samples, and the isolates were subjected to molecular typing, CP typing, and determination of antibiotic resistance through broth dilution and polymerase chain reaction (PCR).
RESULTS
From 681 raw milk samples, 76 strains of were isolated. The pathogenicity of 76 isolates was determined preliminarily by detecting and CP genes. Eighteen types of antimicrobial resistance phenotypes of 76 strains were detected by the broth dilution method, and 11 kinds of related resistance genes were amplified by PCR. The isolates had CP5 (42.10%) and CP8 (57.89%). had a multiple antimicrobial resistance rate of 26.75%. The isolated strains had the highest resistance rate to penicillin (82.89%) and showed varying degrees of resistance to other drugs, but no isolate showed resistance to doxycycline. The 76 isolates all carried two or more antibiotic resistance genes, with a maximum of eight antibiotics resistance genes. was detected in all isolates, but none of isolates carried , , or . The 76 isolates were divided into 22 sequence types (ST) and 20 types by MLST and typing, and the number of t796-ST7 ( = 15) isolates was the highest, which may be the major epidemic strain of multidrug-resistant .
CONCLUSION
The present findings indicate the need to increase production of the CP8 vaccine in Hunan Province and strengthen resistance monitoring of t796-ST7 isolates with the prevalent molecular type of multi-drug resistant strains. The use of -lactam, macrolides, and lincosamides should be reduced; doxycycline, sulfonamides, and glycopeptides could be appropriately added to veterinary antibiotics to treat infectious diseases in dairy cows.
背景
是世界上最重要的食源性致病菌之一，也是奶牛乳腺炎的主要原因。在中国湖南，很少有研究调查牛源的流行谱系。因此，我们旨在分析湖南省奶牛场原奶中分离的 的荚膜多糖（CP）、分子分型和抗生素耐药特性。
方法
2018 年至 2022 年，从湖南省长沙市、常德市、邵阳市、永州市和郴州市奶牛场采集了 681 份原奶样本。从这些样本中分离出 ，并通过肉汤稀释和聚合酶链反应（PCR）进行分子分型、CP 分型和抗生素耐药性测定。
结果
从 681 份原奶样本中分离出 76 株 。通过检测 和 CP 基因，初步确定了 76 株分离株的致病性。用肉汤稀释法检测了 76 株 18 种抗菌药物耐药表型，用 PCR 扩增了 11 种相关耐药基因。 分离株的 CP5（42.10%）和 CP8（57.89%）。 具有 26.75%的多重抗菌耐药率。分离株对青霉素的耐药率最高（82.89%），对其他药物有不同程度的耐药，但无分离株对多西环素耐药。76 株分离株均携带两种或两种以上抗生素耐药基因，最多携带八种抗生素耐药基因。 所有分离株均检测到，但均未检测到 、 或 。76 株分离株通过 MLST 和 分型分为 22 个序列型（ST）和 20 个型，其中 t796-ST7（=15）分离株数量最多，可能是多药耐药 t796-ST7 优势流行株。
结论
本研究结果表明，有必要增加湖南省 CP8 疫苗的生产，并加强对流行分子型多药耐药 t796-ST7 分离株的耐药监测。应减少 -内酰胺类、大环内酯类和林可酰胺类的使用；可适当添加兽医抗生素中的多西环素、磺胺类和糖肽类药物，以治疗奶牛的传染病。
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