lmo Laboratory Medicine Online Lab Med Online ∗∗ 2093-6338 The Korean Society for Laboratory Medicine 10.3343/lmo.2019.9.3.181 lmo-9-181 Original Article The First Case of Otitis in Korea Caused by Brevibacterium otitidis MunSeon-HoM.D. LeeA-JinM.D. KimSang-GyungM.D. JeonChang-HoM.D. ParkCheon-GangM.D. SuhHun SukM.D. Department of Laboratory Medicine, Daegu Catholic University School of Medicine, Daegu, Korea Corresponding author: Hun Suk Suh, M.D., Ph.D. https://orcid.org/0000-0001-6364-5525 Department of Laboratory Medicine, Daegu Catholic University School of Medicine, 33 Duryugongwon-ro 17-gil, Nam-gu, Daegu 42472, Korea Tel: +82-53-650-4143, Fax: +82-53-653-8672, E-mail: hssuh@cu.ac.kr 07 2019 20 07 2019 9 3 181 184 11092018 08122018 10122018 Copyright © 2019 The Korean Society for Laboratory Medicine 2019 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract

Brevibacterium spp. are gram-positive rods that are considered to be strictly nonpathogenic, and a very few cases of their infection in humans have been reported. In this study, we report a case of otitis caused by Brevibacterium otitidis. A 53-year-old woman, who visited the hospital, complained of symptoms, such as otorrhea from both ears, ear fullness, tinnitus, and hearing impairment, for several months. Ear discharge was cultured on blood agar for pathogen identification. Bacteria from the isolated colony were initially identified as Actinomyces odontolyticus by VITEK 2 (bioMerieux, France), whereas VITEK® MS (bioMerieux, France) identified them as Brevibacterium luteolum. Subsequently, bacteria from the isolated colony were confirmed as B. otitidis by 16S rRNA sequencing. Antimicrobial susceptibility testing confirmed their sensitivity to vancomycin and linezolid and resistance to clindamycin and penicillin. To our knowledge, this is the first reported case of otitis caused by B. otitidis in Korea.

 Brevibacterium otitidis 16S Ribosomal RNA Otitis References Pascual C Collins MD Funke G Pitcher DG Phenotypic and genotypic characterisation of two Brevibacterium strains from the human ear: description of Brevibacterium otitidis sp. nov Med Microbiol Lett 19965 11323 Jorgensen JH, Pfaller MA, eds Maual of clinical microbiology 11th ed. Washington DC ASM Press 2015 475 Jung YJ Huh HJ Ki CS Lee NY Misidentifcation of Brevibacterium casei as Propionibacterium acnes isolated from the blood of a patient with malignant lymphoma Ann Clin Microbiol 201417 958 Antoniou S Dimitriadis A Polydorou F Malaka E Brevibacterium io-dinum peritonitis associated with acute urticaria in a CAPD patient Perit Dial Int 199717 6145 Alida FT Henry M Meaghan C Anne B Denise M Edmond S Brevibacterium otitidis: an elusive cause of neurosurgical infection J Med Microbiol 201362 4868 Krishna ND Margo AS Vee JG Steven AG Daniel RL Brevibacterium endocarditis: a frst report Clin Infect Dis 200235 e201 Lina B Carlotti A Lesaint V Devaux Y Freney J Fleurette J Persistent bacteremia due to Brevibacterium species in an immunocompromised patient Clin Infect Dis 199418 4878 Georges W Bernard VB Veronique A Rene C Jacqueline C Michele J Peritonitis due to Brevibacterium otitidis in a patient undergoing continuous ambulatory peritoneal dialysis J Clin Microbiol 200038 42923 Gruner E Steigerwalt AG Hollis DG Weyant RS Weaver RE Moss CW Human infections caused by Brevibacterium casei, formerly CDC groups B-1 and B-3 J Clin Microbiol 199432 15118 Valour F SénéchalA Dupieux C Karsenty J Lustig S Breton P Actinomycosis: etiology, clinical features, diagnosis, treatment, and management Infect Drug Resist 20147 18397 Jorgensen JH, Pfaller MA, eds Manual of clinical microbiology 11th ed. Washington DC ASM Press 2015 926 Funmilola AA and Maureen O Comparison of ViTEK 2, MALDI-TOF and partial sequencing of 16S rRNA gene in identifcation of Brevibacterium species with its antibiotic susceptibility pattern Nig J Pharm Res 201612 6973 European Committee on Antimicrobial Susceptibility Testing Breakpoint tables for interpretation of MICs and zone diameters Version 6.0. http://www.eucast.org/fleadmin/src/media/PDFs/EUCAST_fles/Break-point_tables/v_6.0_Breakpoint_table.pdf (Updated on Jan 2016). Roland PS and Stroman DW Microbiology of acute otitis externa Laryngoscope 2002112 116677 Figures and Tables

Images of microscopic findings and colony morphology of Brevibacterium otitidis. (A) Gram staining of ear discharge observed under 1,000× shows many neutrophils and gram-positive v-shaped or rod shaped diplobacilli. (B) Growth of yellowish, smooth, circular colonies on blood agar plate.

Disc diffusion test of Brevibacterium otitidis

Antibiotic Inhibition zone diameter (mm) Breakpoint∗ (mm) Result
CC 10 20 Resistant
VA 44 17 Susceptible
E 28 NA† NA†
IPM 40 NA† NA†
LZD 26 25 Susceptible
P 16 29 Resistant

From Corynebacterium spp. disc diffusion breakpoint of the EUCAST. Breakpoint tables for interpretation of MICs and zone diameters. Version 6.0, 2016

No breakpoint exists for erythromycin and imipenem.

Abbreviations: CC, clindamycin; VA, vancomycin; E, erythromycin; IPM, imipenem; LZD, linezolid; P, penicillin; EUAST, European Committee on Antimicrobial Susceptibility Testing.