Sriram Kk1, Elina Ekedahl1, Ngoc Thi Bich Hoang2, Tsegaye Sewunet3, Björn Berglund4, Ludwig Lundberg5, Shoeib Nematzadeh3, Maud Nilsson4, Lennart E Nilsson4, Ngai Kien Le6, Dien Minh Tran7, Håkan Hanberger4, Linus Olson8, Mattias Larsson9, Christian G Giske10, Fredrik Westerlund11. 1. Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden. 2. Department of Microbiology, Vietnam National Children's Hospital, Hanoi, Vietnam. 3. Division of Clinical Microbiology, Department of Laboratory medicine, Karolinska Institutet, Stockholm, Sweden. 4. Department of Biomedical and Clinical Sciences, Faculty of medicine, Linköping University, Linköping, Sweden. 5. Department of Biomedical and Clinical Sciences, Faculty of medicine, Linköping University, Linköping, Sweden; Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden. 6. Department of Infection Control, Vietnam National Children's Hospital, Hanoi, Vietnam. 7. Department of Surgery, Vietnam National Children's Hospital, Hanoi, Vietnam. 8. Department of Global Public Health, Karolinska Institutet, Stockholm, Sweden; Department of Women and Children's Health, Karolinska Institutet, Stockholm, Sweden. 9. Department of Global Public Health, Karolinska Institutet, Stockholm, Sweden. 10. Division of Clinical Microbiology, Department of Laboratory medicine, Karolinska Institutet, Stockholm, Sweden; Clinical microbiology, Karolinska University Hospital, Stockholm, Sweden. 11. Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden.. Electronic address: fredrikw@chalmers.se.
Abstract
OBJECTIVES: The carbapenemase-encoding gene blaNDM-1 has been reported in Vietnam during the last 10 years, and blaNDM-producing Enterobacteriaceae are now silently and rapidly spreading. A key factor behind dissemination of blaNDM-1 is plasmids, mobile genetic elements that commonly carry antibiotic resistance genes and spread via conjugation. The diversity of blaNDM-1-encoding plasmids from neonates at a large Vietnamese hospital was characterized in this study. METHODS: 18 fecal Klebsiella pneumoniae and Klebsiella quasipneumoniae isolates collected from 16 neonates at a large pediatric hospital in Vietnam were studied using optical DNA mapping (ODM) and next-generation sequencing (NGS). Plasmids carrying the blaNDM-1 gene were identified by combining ODM with Cas9 restriction. The plasmids in the isolates were compared to investigate whether the same plasmid was present in different patients. RESULTS: Although the same plasmid was found in some isolates, ODM confirmed that there were at least 10 different plasmids encoding blaNDM-1 among the 18 isolates, thus indicating wide plasmid diversity. The ODM results concur with the NGS data. Interestingly, some isolates had two distinct plasmids encoding blaNDM-1 that could be readily identified with ODM. The coexistence of different plasmids carrying the same blaNDM-1 gene in a single isolate has rarely been reported, probably because of limitations in plasmid characterization techniques. CONCLUSIONS: The plasmids encoding the blaNDM-1 gene in this study cohort were diverse and may represent a similar picture in Vietnamese society. The study highlights important aspects of the usefulness of ODM for plasmid analysis.
OBJECTIVES: The carbapenemase-encoding gene blaNDM-1 has been reported in Vietnam during the last 10 years, and blaNDM-producing Enterobacteriaceae are now silently and rapidly spreading. A key factor behind dissemination of blaNDM-1 is plasmids, mobile genetic elements that commonly carry antibiotic resistance genes and spread via conjugation. The diversity of blaNDM-1-encoding plasmids from neonates at a large Vietnamese hospital was characterized in this study. METHODS: 18 fecal Klebsiella pneumoniae and Klebsiella quasipneumoniae isolates collected from 16 neonates at a large pediatric hospital in Vietnam were studied using optical DNA mapping (ODM) and next-generation sequencing (NGS). Plasmids carrying the blaNDM-1 gene were identified by combining ODM with Cas9 restriction. The plasmids in the isolates were compared to investigate whether the same plasmid was present in different patients. RESULTS: Although the same plasmid was found in some isolates, ODM confirmed that there were at least 10 different plasmids encoding blaNDM-1 among the 18 isolates, thus indicating wide plasmid diversity. The ODM results concur with the NGS data. Interestingly, some isolates had two distinct plasmids encoding blaNDM-1 that could be readily identified with ODM. The coexistence of different plasmids carrying the same blaNDM-1 gene in a single isolate has rarely been reported, probably because of limitations in plasmid characterization techniques. CONCLUSIONS: The plasmids encoding the blaNDM-1 gene in this study cohort were diverse and may represent a similar picture in Vietnamese society. The study highlights important aspects of the usefulness of ODM for plasmid analysis.