Adaptive laboratory evolution triggers pathogen-dependent broad-spectrum antimicrobial potency in Streptomyces

Area of Science:

• Microbiology
• Evolutionary Biology
• Biotechnology

Background:

• Streptomyces strain JB140 exhibited limited antimicrobial activity.
• Adaptive laboratory evolution was employed to enhance antibiotic production.
• Competition experiments involved serial passages challenging the strain with bacterial pathogens.

Purpose of the Study:

• To stimulate antibiotic production in Streptomyces strain JB140.
• To investigate the adaptive potential of Streptomyces phenotypes and genotypes.
• To develop a laboratory model for inducing antibiotic production.

Main Methods:

• Adaptive laboratory evolution using competition experiments.
• Serial passages over three cycles (15 days each).
• Challenging Streptomyces with one, two, or three target pathogens (bi-, tri-, or quadri-culture).

Main Results:

• Seven unique mutant phenotypes evolved with increased constitutive antimicrobial activity.
• Mutants inhibited Salmonella Typhi, Staphylococcus aureus, and Proteus vulgaris.
• Improved activity against a multidrug-resistant (MDR) uropathogenic Escherichia coli (UPEC) isolate was observed.
• RAPD profiling revealed significant polymorphism between wild-type and evolved mutants.

Conclusions:

• Competition-based adaptive laboratory evolution is effective for enhancing antibacterial profiles.
• This method can serve as a platform for evolutionary engineering.
• Improved Streptomyces phenotypes with increased antibacterial activity were selected.