Selection of Streptomycin-Resistant Bacteria: Isolation and recovery of strains carrying streptomycin resistance (50 µg/mL) on rich 3.7% Brain Heart Infusion with 1.5% agar.

Maintenance of Resistant Strains: Routine propagation of streptomycin-resistant lab and clinical isolates (e.g., Escherichia coli, Staphylococcus aureus, Streptococcus spp., Enterococcus spp., Listeria monocytogenes) under selective pressure.

Counterselection in Conjugation/Mating: rpsL-based counterselection to eliminate streptomycin-sensitive donors and enrich for desired recombinants.

Resistance Verification: Phenotypic confirmation of streptomycin resistance by direct streaking or replica plating at 50 µg/mL.

Differential Enumeration in Mixed Cultures: Quantification of a streptomycin-resistant population within complex microbiota or co-cultures.

Contamination Control: Purity checks where streptomycin-sensitive contaminants are suppressed while resistant production strains grow.

Surveillance and Screening: Environmental or clinical screening for prevalence of streptomycin-resistant organisms.

Fastidious Organism Workflows: Cultivation of resistant fastidious bacteria supported by BHI (e.g., Streptococcus pneumoniae, Neisseria meningitidis) under selective conditions.

Competition and Fitness Assays: Tracking a marked (streptomycin-resistant) strain in competitive growth experiments.

Plasmid/Marker Retention: Ensuring retention of streptomycin resistance cassettes during cloning or strain construction.