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The Journal of the Japanese Society for Clinical Microbiology |
Biblioraphy Information
| ArticleTitle |
Accuracy of Nocardia species identification by the VITEK MS Mass Spectrometer and Antimicrobial Susceptibilities of the Nocardia Isolates obtained at Kyushu University Hospital |
| Language |
J |
| AuthorList |
Mai Ohno1), Makiko Kiyosuke1), Masamune Aihara1,2), Yuka Yamashita1), Taeko Hotta1), Yuya Kunisaki1) |
| Affiliation |
1) Department of Clinical Laboratory, Kyushu University Hospital
2) Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University |
| Publication |
J.J.C.M.: 35 (3), 223-229, 2025 |
| Received |
January 14, 2025 |
| Accepted |
May 7, 2025 |
| Abstract |
Rapid identification of Nocardia spp. is helpful for the diagnosis of nocardiosis and the empirical treatment. In the clinical laboratories, the VITEK MS mass spectrometer is widely used for rapid identification of pathogens. However, the accuracy of Nocardia spp. identification by VITEK MS and the appropriate pretreatments of Nocardia isolates before VITEK MS analysis has not been evaluated.
Sulfamethoxazole-trimethoprim (ST) has long been the monotherapy treatment of choice, but resistance to this treatment has recently emerged. In this study, we confirmed the evaluation of identification performance and drug susceptibility of 46 isolates from Kyushu University Hospital. By 16S rRNA gene sequencing, 40 out of the 46 isolates were determined as the species listed in the VITEK MS Version 3.2 database. VITEK MS accurately identified thirty-six isolates (90%) by direct deposit. The four isolates unidentified by direct deposit were pretreated with 70% formic acid on the target slides and with the VITEK MS Mycobacterium/Nocardia Kit, respectively, for further VITEK MS identification. While one of the four isolates was successfully identified by the former pretreatment, the latter pretreatment resulted in the accurate identification of all four isolates. All the 46 isolates were susceptible to linezolid and ST. One of the nine isolates identified as Nocardia cyriacigeorgica, which expected to be susceptible to ceftriaxone, showed resistance to the drug. These findings reveal that VITEK MS can accurately identify the Nocardia isolates at the species levels and the appropriate pretreatment method increases its identification performance. The presence of acquired resistance, although in small numbers, it was shown that antimicrobial susceptibility testing is necessary in addition to identification testing for treatment. |
| Keywords |
VITEK MS |
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