{"title":"Evaluation of gradient diffusion in vitro susceptibility testing of Aerococcus urinae","authors":"","doi":"10.1016/j.jgar.2024.07.014","DOIUrl":null,"url":null,"abstract":"<div><h3>Objective</h3><p><em>Aerococcus urinae</em> antimicrobial susceptibility testing can be performed via broth microdilution with Mueller-Hinton broth supplemented with lysed horse blood. We sought to compare this with the commonly used gradient diffusion method.</p></div><div><h3>Methods</h3><p>We compared broth microdilution with Mueller-Hinton broth supplemented with lysed horse blood and gradient diffusion via Mueller-Hinton agar supplemented with sheep blood for 190 <em>A. urinae</em> isolates against 16 antimicrobials.</p></div><div><h3>Results</h3><p>No antimicrobials demonstrated more than 90% essential and categorical agreement, and fewer than 3% demonstrated major and very major error rates. Trimethoprim-sulfamethoxazole demonstrated an 81% major error rate and ceftriaxone demonstrated a 76% very major error rate. Agar dilution with lysed horse blood was performed for trimethoprim-sulfamethoxazole against 94 isolates and showed 100% susceptibility, consistent with previous studies.</p></div><div><h3>Conclusions</h3><p>Given its limitations in detecting resistant strains, our findings cannot support the routine use of gradient diffusion with Mueller-Hinton agar supplemented with sheep blood for <em>A. urinae</em> in lieu of the Clinical and Laboratory Standards Institute method. Our results suggest that <em>A. urinae</em> is usually susceptible to penicillin, linezolid, tetracycline, and vancomycin. Future studies should evaluate alternative testing methods for clinical microbiology laboratories.</p></div>","PeriodicalId":15936,"journal":{"name":"Journal of global antimicrobial resistance","volume":null,"pages":null},"PeriodicalIF":3.7000,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2213716524001449/pdfft?md5=61136a45ff95860eee2efaed6fe52513&pid=1-s2.0-S2213716524001449-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of global antimicrobial resistance","FirstCategoryId":"3","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2213716524001449","RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"INFECTIOUS DISEASES","Score":null,"Total":0}
引用次数: 0
Abstract
Objective
Aerococcus urinae antimicrobial susceptibility testing can be performed via broth microdilution with Mueller-Hinton broth supplemented with lysed horse blood. We sought to compare this with the commonly used gradient diffusion method.
Methods
We compared broth microdilution with Mueller-Hinton broth supplemented with lysed horse blood and gradient diffusion via Mueller-Hinton agar supplemented with sheep blood for 190 A. urinae isolates against 16 antimicrobials.
Results
No antimicrobials demonstrated more than 90% essential and categorical agreement, and fewer than 3% demonstrated major and very major error rates. Trimethoprim-sulfamethoxazole demonstrated an 81% major error rate and ceftriaxone demonstrated a 76% very major error rate. Agar dilution with lysed horse blood was performed for trimethoprim-sulfamethoxazole against 94 isolates and showed 100% susceptibility, consistent with previous studies.
Conclusions
Given its limitations in detecting resistant strains, our findings cannot support the routine use of gradient diffusion with Mueller-Hinton agar supplemented with sheep blood for A. urinae in lieu of the Clinical and Laboratory Standards Institute method. Our results suggest that A. urinae is usually susceptible to penicillin, linezolid, tetracycline, and vancomycin. Future studies should evaluate alternative testing methods for clinical microbiology laboratories.
期刊介绍:
The Journal of Global Antimicrobial Resistance (JGAR) is a quarterly online journal run by an international Editorial Board that focuses on the global spread of antibiotic-resistant microbes.
JGAR is a dedicated journal for all professionals working in research, health care, the environment and animal infection control, aiming to track the resistance threat worldwide and provides a single voice devoted to antimicrobial resistance (AMR).
Featuring peer-reviewed and up to date research articles, reviews, short notes and hot topics JGAR covers the key topics related to antibacterial, antiviral, antifungal and antiparasitic resistance.