Trends in Antimicrobial Resistance of Major Mastitis-Causing Pathogens: A Nine-Year Study.

IF 1.7 3区农林科学 Q2 VETERINARY SCIENCES

Veterinary Medicine and Science Pub Date : 2025-07-01 DOI:10.1002/vms3.70417

Amir Moradi, Behnam Bidarian, Fatemeh Mohammadian, Farideh Akbarian, Hamideh Kalateh Rahmani, Niloufar Tashakkori, Babak Khoramian

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引用次数: 0

Abstract

Background: Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Streptococcus agalactiae (S. agalactiae) are among the primary pathogens responsible for mastitis on dairy farms. The emergence of antimicrobial resistance (AMR) exacerbates this issue, posing a significant global threat, particularly in veterinary medicine, where mastitis leads to substantial economic losses for the dairy industry.

Objectives: This retrospective study aimed to evaluate the resistance patterns of these mastitis-causing pathogens in Iran over a nine-year period (2016-2024).

Methods: A total of 5275 milk samples were collected from farms of varying size (small, medium and large). Of these, 960 samples (18.19%) underwent antimicrobial susceptibility testing.

Results: Tylosin resistance was the most prevalent among all pathogen isolates, with resistance rates of 46.09% in S. aureus, 61.24% in S. agalactiae, and 91.63% in E. coli. Among the tested pathogens, E. coli exhibited the highest multidrug resistance (MDR) rate at 45.86%, followed by S. aureus (30.4%) and S. agalactiae (22.05%). For S. aureus, resistance to gentamicin increased significantly over time, whereas resistance to cloxacillin showed a marked decline. In E. coli, resistance to penicillin and amoxicillin demonstrated significant upward trends. For S. agalactiae, enrofloxacin resistance declined significantly, while resistance to trimethoprim/sulfamethoxazole increased notably. Farm size was a significant predictor of MDR status, with larger farms associated with lower odds of MDR. Additionally, clinical status was linked to higher MDR odds. Seasonal variations also influenced MDR, with certain seasons showing reduced odds.

Conclusions: This study highlighted key factors contributing to MDR in mastitis pathogens. The findings emphasised the complex nature of antimicrobial resistance and the necessity for tailored strategies-such as improved farm management, seasonal interventions, and targeted antimicrobial use-to effectively mitigate resistance.

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主要乳腺炎致病菌的抗微生物药物耐药性趋势：一项为期9年的研究。

背景：大肠杆菌（E. coli）、金黄色葡萄球菌（S. aureus）和无乳链球菌（S. agalactiae）是导致奶牛场乳腺炎的主要病原体。抗菌素耐药性（AMR）的出现加剧了这一问题，构成了重大的全球威胁，特别是在兽医学领域，乳腺炎给乳制品行业带来了巨大的经济损失。目的：本回顾性研究旨在评估伊朗9年（2016-2024年）期间这些乳腺炎病原体的耐药模式。方法：从不同规模的农场（小、中、大）采集5275份牛奶样本。其中960份（18.19%）进行了药敏试验。结果：所有病原菌对泰洛素的耐药率最高，金黄色葡萄球菌耐药率为46.09%，无乳葡萄球菌耐药率为61.24%，大肠杆菌耐药率为91.63%。其中，大肠杆菌耐多药率最高，为45.86%，其次是金黄色葡萄球菌（30.4%）和无乳葡萄球菌（22.05%）。对于金黄色葡萄球菌，随着时间的推移，对庆大霉素的耐药性显著增加，而对氯西林的耐药性则明显下降。在大肠杆菌中，对青霉素和阿莫西林的耐药性显示出显著的上升趋势。无乳链球菌对恩诺沙星的耐药性明显下降，对甲氧苄啶/磺胺甲恶唑的耐药性明显上升。农场规模是MDR状态的重要预测因子，较大的农场与较低的MDR发生率相关。此外，临床状态与耐多药发生率较高有关。季节变化也影响MDR，某些季节的发病率降低。结论：本研究突出了导致乳腺炎病原体耐多药耐药的关键因素。研究结果强调了抗菌素耐药性的复杂性以及为有效减轻耐药性而采取量身定制策略的必要性，例如改进农场管理、季节性干预和有针对性地使用抗菌素。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Veterinary Medicine and Science Veterinary-General Veterinary

CiteScore

3.00

自引率

0.00%

发文量

296

期刊介绍： Veterinary Medicine and Science is the peer-reviewed journal for rapid dissemination of research in all areas of veterinary medicine and science. The journal aims to serve the research community by providing a vehicle for authors wishing to publish interesting and high quality work in both fundamental and clinical veterinary medicine and science. Veterinary Medicine and Science publishes original research articles, systematic reviews, meta-analyses, and research methods papers, along with invited editorials and commentaries. Original research papers must report well-conducted research with conclusions supported by the data presented in the paper. We aim to be a truly global forum for high-quality research in veterinary medicine and science, and believe that the best research should be published and made widely accessible as quickly as possible. Veterinary Medicine and Science publishes papers submitted directly to the journal and those referred from a select group of prestigious journals published by Wiley-Blackwell. Veterinary Medicine and Science is a Wiley Open Access journal, one of a new series of peer-reviewed titles publishing quality research with speed and efficiency. For further information visit the Wiley Open Access website.