Aerococcus urinae and Aerococcus sanguinicola: Susceptibility Testing of 120 Isolates to Six Antimicrobial Agents Using Disk Diffusion (EUCAST), Etest, and Broth Microdilution Techniques

Derya Carkaci; Xiaohui C Nielsen; Kurt Fuursted; Robert Skov; Ole Skovgaard; Emilio P Trallero; Reto Lienhard; Jenny Åhman; Erika Matuschek; Gunnar Kahlmeter; Jens J Christensen

doi:10.2174/1874285801711010160

Aerococcus urinae and Aerococcus sanguinicola: Susceptibility Testing of 120 Isolates to Six Antimicrobial Agents Using Disk Diffusion (EUCAST), Etest, and Broth Microdilution Techniques

Open Microbiol J. 2017 Sep 21:11:160-166. doi: 10.2174/1874285801711010160. eCollection 2017.

Authors

Derya Carkaci^{1

2

3}, Xiaohui C Nielsen¹, Kurt Fuursted², Robert Skov², Ole Skovgaard³, Emilio P Trallero⁴, Reto Lienhard⁵, Jenny Åhman⁶, Erika Matuschek⁶, Gunnar Kahlmeter⁶, Jens J Christensen^{1

7}

Affiliations

¹ Department of Clinical Microbiology, Slagelse Hospital, Slagelse, Denmark.
² Department of Microbiology and Infection Control, Reference Laboratory Statens Serum Institut, Copenhagen, Denmark.
³ Department of Science and Environment, Roskilde University, Roskilde, Denmark.
⁴ Department of Microbiology, Hospital Universitario Donostia, San Sebastián, Spain.
⁵ ADMED Microbiologie, La Chaux-de-Fonds, Switzerland.
⁶ EUCAST Development Laboratory, Clinical Microbiology, Central Hospital, Växjö, Sweden.
⁷ Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark.

Abstract

Background: Aerococcus urinae and Aerococcus sanguinicola are relatively newcomers and emerging organisms in clinical and microbiological practice. Both species have worldwide been associated with urinary tract infections. More rarely cases of bacteremia/septicemia and infective endocarditis have been reported. Treatment options are therefore important. Just recently, European recommendations on susceptibility testing and interpretive criteria have been released.

Objective: In this investigation 120 A. urinae and A. sanguinicola isolates were tested for susceptibility to six antimicrobial agents: Penicillin, cefotaxime, meropenem, vancomycin, linezolid, and rifampicin.

Methods: Three susceptibility testing methods were used; disk diffusion according to The European Committee on Antimicrobial Susceptibility Testing (EUCAST) standardized disk diffusion methodology and MIC determination with Etest and broth microdilution (BMD). All testing was performed with EUCAST media for fastidious organisms.

Results: Data obtained in this study were part of the background data for establishing EUCAST breakpoints. MIC values obtained by Etest and BMD were well correlated with disk diffusion results.

Conclusion: All isolates were found susceptible to all six antimicrobial agents: penicillin, cefotaxime, meropenem, vancomycin, linezolid, and rifampicin.

Keywords: Aerococcus sanguinicola; Aerococcus urinae; Antimicrobial susceptibility testing; Broth microdilution; Disk diffusion; Etest; Urinary tract infections.