Evaluating the level of nitroreductase activity in clinical Klebsiella pneumoniae isolates to support strategies for nitro drug and prodrug development
| Autor: | Shirin Jamshidi, Hollie V. Taylor, Charlotte K. Hind, Khondaker M. Rahman, Jennifer L. Auer, Lucy J. Bock, Matthew E. Wand, J. Mark Sutton |
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| Rok vydání: | 2019 |
| Předmět: |
0301 basic medicine
Microbiology (medical) Klebsiella pneumoniae 030106 microbiology Gene mutation Microbiology 03 medical and health sciences Nitroreductase 0302 clinical medicine Humans Prodrugs Pharmacology (medical) 030212 general & internal medicine Gene chemistry.chemical_classification biology Activator (genetics) Genetic Variation Gene Expression Regulation Bacterial General Medicine Nitroreductases biology.organism_classification Enzyme assay Anti-Bacterial Agents Molecular Docking Simulation SOXS Infectious Diseases Enzyme chemistry biology.protein Protein Binding |
| Zdroj: | International Journal of Antimicrobial Agents. 54:538-546 |
| ISSN: | 0924-8579 |
| Popis: | To understand the potential utility of novel nitroreductase (NR)-activated prodrugs, NR enzyme activity was assessed in clinical Klebsiella pneumoniae isolates using a NR-activated fluorescent probe. NR activity was constant throughout the bacterial growth cycle, but individual K. pneumoniae isolates exhibited a wide range of NR activity levels. The genes of major NR enzymes (nfsA and nfnB) showed a number of sequence variants. Aside from a C-terminal extension of NfnB, which may be responsible for lower NR activity in specific isolates, the genetic differences did not explain the variation in activity. Analysis of important clinical strains (ST11, ST258, ST14 and ST101) showed significant variation in NR activity between isolates within the same sequence type despite conservation of nfsA/nfnB sequences. Addition of methyl viologen (MV), a known activator of soxRS, caused a significant increase in NR activity for all strains, with proportionally larger increases in activity seen for strains with low uninduced NR levels. Real-time PCR on selected strains following exposure to MV showed upregulation of soxS (15-32-fold) and nfsA (5-22-fold) in all strains tested. Expression of nfnB was upregulated 2-5-fold in 4/6 strains tested. High levels of NR activity in the absence of MV activation correlated with nitrofurantoin susceptibility. These data provide evidence that NR gene mutations and regulatory pathways influence NR activity in K. pneumoniae isolates and this is likely to impact treatment efficacy with novel nitro-containing drugs or prodrugs. |
| Databáze: | OpenAIRE |
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