Trung Duc Dao1, Ikuro Kasuga2, Aki Hirabayashi3, Dong Tu Nguyen4, Hien Thi Tran1, Hieu Vu1, Linh Tuyet Ngoc Pham1, Thi My Hanh Vu1, Futoshi Hasebe1, Ha Thanh Nguyen4, Trang Le Thi4, Hoang Huy Tran4, Keigo Shibayama5, Taichiro Takemura6, Masato Suzuki7. 1. Vietnam Research Station, Center for Infectious Disease Research in Asia and Africa, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan. 2. Vietnam-Japan University, Vietnam National University, Hanoi, Vietnam; Department of Urban Engineering, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan. 3. Antimicrobial Resistance Research Center, National Institute of Infectious Diseases, Tokyo, Japan. 4. National Institute of Hygiene and Epidemiology, Hanoi, Vietnam. 5. Nagoya University Graduate School of Medicine, Nagoya, Japan. 6. Vietnam Research Station, Center for Infectious Disease Research in Asia and Africa, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan. Electronic address: taichiro@nagasaki-u.ac.jp. 7. Antimicrobial Resistance Research Center, National Institute of Infectious Diseases, Tokyo, Japan. Electronic address: suzuki-m@nih.go.jp.
Abstract
OBJECTIVES: Tigecycline resistance mediated by the mobile tigecycline-inactivating enzyme gene tet(X) in Gram-negative bacteria is an emerging concern for global public health. However, limited information is available on the distribution of tet(X) in the natural environment. In this study, we investigated the presence of tet(X) in environmental Gram-negative bacteria. METHODS: A carbapenem- and tigecycline-resistant Shewanella xiamenensis isolate (NUITM-VS1) was obtained from an urban drainage in Hanoi, Vietnam, in March 2021. Whole-genome sequencing analysis was performed by long- and short-read sequencing, resulting in a complete genome sequence. Antimicrobial resistance genes (ARGs) in the genome were detected based on the custom ARG database, including all known tigecycline resistance genes. RESULTS: Shewanella xiamenensis isolate NUITM-VS1 harboured the tet(X4) gene and the blaOXA-48 carbapenemase gene on the chromosome. tet(X4) was flanked by IS91 family transposase genes, suggesting that the acquisition of tet(X4) was mediated by this mobile gene element (MGE), whereas no MGE was found surrounding blaOXA-48, consistent with previous findings that blaOXA-48-like β-lactamase genes are species-specific intrinsic ARGs in Shewanella spp. CONCLUSION: To the best of our knowledge, this is the first report of a tet(X4)-harbouring Shewanella sp. isolate. Our results provide genetic evidence of the complexity of the dynamics of clinically important ARGs among bacteria in the water environment.
OBJECTIVES: Tigecycline resistance mediated by the mobile tigecycline-inactivating enzyme gene tet(X) in Gram-negative bacteria is an emerging concern for global public health. However, limited information is available on the distribution of tet(X) in the natural environment. In this study, we investigated the presence of tet(X) in environmental Gram-negative bacteria. METHODS: A carbapenem- and tigecycline-resistant Shewanella xiamenensis isolate (NUITM-VS1) was obtained from an urban drainage in Hanoi, Vietnam, in March 2021. Whole-genome sequencing analysis was performed by long- and short-read sequencing, resulting in a complete genome sequence. Antimicrobial resistance genes (ARGs) in the genome were detected based on the custom ARG database, including all known tigecycline resistance genes. RESULTS: Shewanella xiamenensis isolate NUITM-VS1 harboured the tet(X4) gene and the blaOXA-48 carbapenemase gene on the chromosome. tet(X4) was flanked by IS91 family transposase genes, suggesting that the acquisition of tet(X4) was mediated by this mobile gene element (MGE), whereas no MGE was found surrounding blaOXA-48, consistent with previous findings that blaOXA-48-like β-lactamase genes are species-specific intrinsic ARGs in Shewanella spp. CONCLUSION: To the best of our knowledge, this is the first report of a tet(X4)-harbouring Shewanella sp. isolate. Our results provide genetic evidence of the complexity of the dynamics of clinically important ARGs among bacteria in the water environment.