Occurrence of bla NDM-7 within IncX3-type plasmid of Escherichia coli from India
| Autor: | Birson Ingti, Nargis Alom Choudhury, Debadatta Dhar, Amitabha Bhattacharjee, Atanu Chakravarty, Anand Prakash Maurya, Deepjyoti Paul |
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| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Microbiology (medical) Carbapenem 030106 microbiology Context (language use) biochemical phenomena metabolism and nutrition Biology bacterial infections and mycoses medicine.disease_cause Microbiology 03 medical and health sciences chemistry.chemical_compound Transformation (genetics) Infectious Diseases Plasmid chemistry medicine Pharmacology (medical) Typing Ertapenem Escherichia coli Gene medicine.drug |
| Zdroj: | Journal of Infection and Chemotherapy. 23:206-210 |
| ISSN: | 1341-321X |
| DOI: | 10.1016/j.jiac.2016.12.009 |
| Popis: | Background New-Delhi metallo-β-lactamase-7 with higher hydrolytic activity than its ancestor NDM-1 is emerging across the globe including India. In this study, we have investigated the genetic context of bla NDM-7 and alteration in plasmid copy number under concentration gradient carbapenem stress. Materials and methods Six bla NDM-7 producing Escherichia coli isolates were obtained from Silchar Medical College and Hospital and the co-existence of other β-lactamases and transferability of this resistant determinant was determined by transformation and conjugation assay followed by typing of the plasmid by PBRT method. Genetic context and plasmid stability of bla NDM-7 was also determined. The change in copy number of transconjugable plasmid carrying bla NDM-7 under exposure of different carbapenem antibiotics was determined by quantitative Real Time PCR. Results All the six isolates carrying bla NDM-7 were conjugatively transferable through an IncX3-type plasmid and were also found to co-harbor bla CTX-M-15 . Genetic analysis of bla NDM-7 showed an association of IS Aba125 , IS 5 and a truncated portion of IS Aba12 5 in the upstream region and ble MBL gene in the downstream region of bla NDM-7 . Complete loss of the plasmids carrying bla NDM-7 was observed between 85th to 90th serial passages when antibiotic pressure was withdrawn. After analyzing the relative copy number it was observed that the copy number of the bla NDM-7 encoding plasmid was highly affected by the concentration of ertapenem. Conclusion The present study has first demonstrated presence of IncX3-type plasmid encoding bla NDM-7 within nosocomial isolates of E. coli . Measures must be taken to prevent or atleast slowdown the emergence of this resistance determinant in this country. |
| Databáze: | OpenAIRE |
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