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Streptomycin resistance in a streptomycin-producing microorganism
Antimicrobial Agents and Chemotherapy
|August 1, 1979
Summary
Streptomyces bikiniensis develops streptomycin resistance through a specific enzyme, streptomycin-6-kinase, which inactivates the antibiotic by phosphorylation. This kinase activity increases as cells mature, correlating with heightened resistance to streptomycin.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Streptomyces bikiniensis is a bacterium known for producing antibiotics.
- Understanding antibiotic resistance mechanisms is crucial for developing effective treatments.
Purpose of the Study:
- To investigate the mechanism of streptomycin resistance in Streptomyces bikiniensis.
- To identify the enzyme responsible for streptomycin inactivation.
Main Methods:
- Analysis of cell-free extracts from different growth phases.
- Enzymatic assays to detect streptomycin inactivation.
- Identification of phosphorylation products.
- Characterization of dye-induced resistant and susceptible isolates.
- Ribosome binding assays for dihydrostreptomycin.
Main Results:
- A streptomycin-inactivating, adenosine 5'-triphosphate-dependent kinase (streptomycin-6-kinase) was identified in cell-free extracts.
- This kinase phosphorylates streptomycin (Sm) and dihydrostreptomycin to streptomycin 6-phosphate and dihydrostreptomycin 6-phosphate.
- Kinase activity was absent in susceptible logarithmic-phase cells but present in resistant stationary-phase cells.
- Isolates treated with acriflavine or ethidium bromide lost kinase activity and became susceptible to streptomycin.
- No correlation was found between dihydrostreptomycin uptake or ribosome binding and resistance.
Conclusions:
- Phosphorylation by streptomycin-6-kinase is a primary mechanism conferring streptomycin resistance in Streptomyces bikiniensis.
- The development of resistance is linked to the expression of streptomycin-6-kinase during cell growth.