Selection of Streptomycin‑Resistant Transformants: Isolates colonies carrying plasmids with streptomycin resistance markers (e.g., aadA) in Escherichia coli and other hosts.

Plasmid Maintenance: Maintains selective pressure for streptomycin‑resistant plasmids during routine culture and passaging of E. coli.

Colony Isolation and Streaking: Obtains single colonies of streptomycin‑resistant strains for downstream cloning or analysis.

CFU Enumeration: Quantifies viable counts of streptomycin‑resistant bacteria from liquid cultures or environmental samples.

Counter‑Selection of Contaminants: Suppresses streptomycin‑sensitive background flora while enriching desired resistant strains (e.g., E. coli, Bacillus subtilis).

Conjugation and Mating Selections: Selects transconjugants that acquire streptomycin resistance markers after bacterial mating experiments.

Transposon/Insertion Mutagenesis Screens: Recovers mutants carrying streptomycin‑marked insertions in Gram‑negative hosts.

Phage Work with Selective Hosts: Supports lawns of streptomycin‑resistant host bacteria for plaque assays on LB agar.

Strain Verification and Stability Testing: Confirms retention of streptomycin resistance in engineered strains over passages.

Short‑Term Archiving: Stores and transports streptomycin‑resistant clones on sealed LB agar plates.