Letter to the Editor
Ann Lab Med 2022; 42(2): 290-292
Published online March 1, 2022 https://doi.org/10.3343/alm.2022.42.2.290
Copyright © Korean Society for Laboratory Medicine.
First Case of Bacteremia and Epididymo-orchitis Caused by Oceanobacillus oncorhynchi subspecies incaldanensis in an Immunocompetent Patient
1Department of Laboratory Medicine, Gyeongsang National University Hospital, Gyeongsang National University College of Medicine, Jinju, Korea; 2Department of Urology, Gyeongsang National University Hospital, Gyeongsang National University College of Medicine, Jinju, Korea; 3Department of Microbiology, Gyeongsang National University College of Medicine, Jinju, Korea
Correspondence to: Jung-Hyun Byun, M.D.
Department of Laboratory Medicine, Gyeongsang National University Hospital, Gyeongsang National University College of Medicine, 79 Gangnam-ro, Jinju 52727, Korea
Tel: +82-55-750-8423, Fax: +82-55-762-2696
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
This study was approved by the Institutional Review Board of Gyeongsang National University Hospital, Jinju, Korea, with a waiver of informed consent (202012007). A 69-year-old male patient was admitted to Gyeongsang National University Hospital in August 2020 because of scrotal pain that had started five days prior to admission. He had no remarkable medical history. He was suspected of having epididymo-orchitis. Laboratory tests showed increased leukocyte counts (11.41×109/L; reference range, 4–10×109/L) and C-reactive protein level (120.8 mg/L; <5 mg/L). Other laboratory blood test results were within the reference ranges. Two sets of aerobic and anaerobic blood culture (BACT/ALERT Culture Media, bioMérieux, Marcy l’Etoile, France) were performed before initiating empiric antimicrobial treatment with ceftriaxone, and gram-positive bacilli were isolated from an aerobic blood culture. The colony morphology on sheep blood agar plate was non-hemolytic, grayish, circular, and smooth, and the cell morphology was thin, straight, and with endospores. We considered this catalase- and oxidase-positive bacillus to be a contaminant. Matrix-associated laser desorption ionization-time of flight mass spectrometry (bioMérieux) and biochemical tests using the VITEK 2 system (bioMérieux) did not provide reliable identification of the bacterium. Therefore, we concluded that the “unidentified gram-positive bacilliform bacterium” was a contaminant. The next day, a closed pus specimen obtained during incision and drainage was submitted for bacterial culture. On Gram staining of a smear, 5–10 leukocytes per high-power field and gram-positive bacilli were observed. The colony morphology was identical to that of the microbes found in the blood cultures. As we recognized that this bacterium could be of clinical significance, we conducted 16S rRNA gene sequencing for species identification. The highest similarity was observed with
Figure 1. Neighbor-joining phylogenetic tree based on 16S rRNA gene sequences of 24 similar species, including the
Oceanobacillus oncorhynchisubsp. incaldanensisstrain (GNUH2008-0948) isolated from a 69-year-old male patient in South Korea, generated using MEGA7 (Molecular Evolutionary Genetics Analysis version 7.0, Kumar, Stecher, and Tamura 2015). Numbers at each node are percentages at which the associated taxa clustered together in the bootstrap test (1,000 replicates).
Antimicrobial susceptibility testing using disk diffusion was performed, and the results were interpreted according to the European Committee on Antimicrobial Susceptibility Testing clinical breakpoint table v. 11.0 for
Intravenous ceftriaxone (2 g daily) was administered for two days, and the regimen was stepped up to intravenous piperacillin/tazobactam (4.5 g at eight-hour intervals) and tobramycin (80 mg at eight-hour intervals). The wound was kept open with betadine-soaked gauze packing for a week, after which the necrotic tissue was removed. Three days later, the wound improved and was closed.
Human diseases caused by
The pathogen resource for this study was provided by Gyeongsang National University Hospital, a branch of National Culture Collection for Pathogens (GNUH-NCCP, Jinju, Korea). We thank Chang Kun Ha, Young Bin Lee, and Ji Gwang Lee for technical support.
Conceptualization: Byun JH. Data curation: Kim M, Choi JH, Shin H, Lee WK. Writing-review and editing: Byun JH, Kim M. Final approval of the manuscript: all authors.
CONFLICTS OF INTEREST
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (Ministry of Science and ICT) (NRF-2020R1F1A1066895).
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