Comparison of MALDI-TOF mass spectrometry and rpoB gene sequencing for the identification of clinical isolates of Aeromonas spp.
Daisuke Kitagawa,
Yuki Suzuki,
Noriyuki Abe,
Koji Ui,
Keitaro Suzuki,
Takaya Yamashita,
Atsuko Sakaguchi,
Soma Suzuki,
Kazue Masuo,
Akiyo Nakano,
Ryuichi Nakano,
Masatoshi Sato,
Koichi Maeda,
Fumihiko Nakamura,
Hisakazu Yano
Affiliations
Daisuke Kitagawa
Department of Microbiology and Infectious Diseases, Nara Medical University, Japan; Department of Laboratory Medicine, Nara Prefecture General Medical Center, Japan; Corresponding author.
Yuki Suzuki
Department of Microbiology and Infectious Diseases, Nara Medical University, Japan
Noriyuki Abe
Department of Laboratory Medicine, Tenri Hospital, Japan
Koji Ui
Department of Central Laboratory Medicine, Nara Medical University Hospital, Japan
Keitaro Suzuki
Department of Laboratory, The Yamatotakada Municipal Hospital, Japan
Takaya Yamashita
Department of Laboratory Medicine, Nara City Hospital, Japan
Atsuko Sakaguchi
Department of Clinical Laboratory, Nara City General Medical Inspection Center, Japan
Soma Suzuki
Department of Laboratory Medicine, Nara Prefecture General Medical Center, Japan
Kazue Masuo
Department of Laboratory Medicine, Nara Prefecture General Medical Center, Japan
Akiyo Nakano
Department of Microbiology and Infectious Diseases, Nara Medical University, Japan
Ryuichi Nakano
Department of Microbiology and Infectious Diseases, Nara Medical University, Japan
Masatoshi Sato
Department of Infectious Diseases, Nara Prefecture General Medical Center, Japan
Koichi Maeda
Department of Infectious Diseases, Nara Prefecture General Medical Center, Japan
Fumihiko Nakamura
Department of Laboratory Medicine, Nara Prefecture General Medical Center, Japan
Hisakazu Yano
Department of Microbiology and Infectious Diseases, Nara Medical University, Japan
Aeromonas spp., widely present in rivers and soil, cause mild gastroenteritis, severe septicemia, and soft tissue infections in humans. Treatment of these infections require accurate identification of pathogenic Aeromonas spp. However, identification at the species level using conventional methods is highly challenging. In this study, we aimed to compare the accuracy of two different approaches developed for bacterial identification: (i) housekeeping gene sequencing (rpoB) in conjunction with phylogenetic analysis and (ii) matrix-assisted laser desorption ionization mass spectrometry-time of flight (MALDI-TOF MS) (MALDI Biotyper and VITEK MS), for differentiating Aeromonas spp. We analyzed 58 Aeromonas isolates recovered from patients at different medical institutions in Japan using both identification methods. The rpoB sequencing method was the most accurate, identifying all Aeromonas isolates at the species level. Meanwhile, the MALDI Biotyper system correctly identified 53 (91.4%) isolates at the genus level and an additional 30 (51.7%) at the species level. The VITEK MS system correctly identified 58 (100%) isolates at the genus level and an additional 34 (58.6%) at the species level. Thus, MALDI Biotyper and VITEK MS accurately identified isolates at the genus level, but differences were found in the accuracy of identification of species. However, the low cost and ease of analysis make MALDI-TOF MS-based methods strong candidates for use in clinical laboratories that require easy-to-use identification methods.
