Department of Biomedical and Diagnostic Sciences, University of Tennessee, College of Veterinary Medicine, 2407 River Drive, Knoxville, TN 37996, USA.
Institute for Genomics and Evolutionary Medicine, Temple University, 1925 N. 12 Street, Philadelphia, PA 19122, USA.
Comp Immunol Microbiol Infect Dis. 2023 Sep;100:102028. doi: 10.1016/j.cimid.2023.102028. Epub 2023 Jul 24.
The aim of this study was to perform a phenotypic and molecular epidemiological survey to determine temporal changes in the antimicrobial resistance and population structure of methicillin-resistant Staphylococcus pseudintermedius (MRSP) in the United States. Samples from 200 S. pseudintermedius isolates were obtained from veterinary diagnostic facilities located in geographic regions sampled approximately ten years ago and compared to samples obtained in 2021. Kirby-Bauer disk diffusion was used to determine antimicrobial susceptibility. geoBURST analysis and MrBayes were used to infer relationships of isolates using MLST data. Almost all MRSP isolates (98%) in 2021 were multidrug-resistant with 21% of these isolates resistant to more than 16 antimicrobials. In 2010, 190 S. pseudintermedius isolates were collected and 141 of them were MRSP. From 2010-2021 there was a significant increase in resistance observed to all antibiotics tested except cephalothin and sulfonamides. Whereas ten years previously multilocus sequence types (ST) ST68 (35.7%), ST71 (10%), and ST84 (17.4%) predominated, these strains have been supplanted by other STs, notably ST45 (n = 14), ST155 (n = 9), ST181 (n = 13), ST496 (n = 9) and ST551 (n = 9). The newly prevalent STs are distantly related to ST68, ST71 and ST84 and most likely do not share any recent common ancestors. The population structure of MRSP is far more elastic than expected with new, highly resistant strains replacing the ones that predominated in the United States a decade ago. Antibiotic use may play a role in selection; however, the strains that were replaced were also multidrug-resistant and other factors are likely involved.
本研究旨在进行表型和分子流行病学调查，以确定美国耐甲氧西林金黄色葡萄球菌（MRSP）的耐药性和种群结构随时间的变化。从位于大约十年前采样的地理区域的兽医诊断设施中获得了 200 株金黄色葡萄球菌分离株的样本，并将其与 2021 年获得的样本进行了比较。采用 Kirby-Bauer 圆盘扩散法测定抗菌药物敏感性。使用 geoBURST 分析和 MrBayes 基于 MLST 数据推断分离株的关系。2021 年几乎所有（98%）MRSP 分离株均为多药耐药，其中 21%的分离株对超过 16 种抗菌药物耐药。2010 年共收集了 190 株金黄色葡萄球菌分离株，其中 141 株为 MRSP。与 2010 年至 2021 年相比，所有测试的抗生素耐药性均显著增加，除头孢噻肟和磺胺类药物外。尽管十年前优势菌株为 ST68（35.7%）、ST71（10%）和 ST84（17.4%），但这些菌株已被其他 ST 取代，特别是 ST45（n=14）、ST155（n=9）、ST181（n=13）、ST496（n=9）和 ST551（n=9）。新流行的 ST 与 ST68、ST71 和 ST84 关系较远，很可能没有任何近期的共同祖先。MRSP 的种群结构比预期的更具弹性，新的高度耐药菌株取代了十年前在美国占主导地位的菌株。抗生素的使用可能在选择中起作用；然而，被取代的菌株也是多药耐药的，可能还有其他因素参与其中。
