For maintenance after screening, to what should you subculture?

For maintenance after screening, to what should you subculture?

• A. Subculture to a medium without antibiotics for maintenance
• B. Keep pathogenic isolates sealed
• C. Incubate at 37 C
• D. Use antibiotics and incubate at 25 C

Answer: (A)

Subculture onto a medium without antibiotics. During screening, antibiotics help suppress contaminants, but continuing them for maintenance applies selective pressure that can change the organism’s characteristics or promote resistance. An antibiotic-free medium lets the isolate grow under normal conditions, preserving its phenotype and making it easier to recover later. The other options either impose unnecessary stress or selection, or describe unsafe or inappropriate handling for maintenance.

Subculture onto a medium without antibiotics. During screening, antibiotics help suppress contaminants, but continuing them for maintenance applies selective pressure that can change the organism’s characteristics or promote resistance. An antibiotic-free medium lets the isolate grow under normal conditions, preserving its phenotype and making it easier to recover later. The other options either impose unnecessary stress or selection, or describe unsafe or inappropriate handling for maintenance.