INOCULATION OF SOLID MEDIA

• Solid media


  Solidifying agents - agar or gelatin, with firm surface on which cells can form discrete colonies
• Forms of solid media

  • Liquefiable (or reversible) solid media
  • Non-liquefiable (or non-reversible) solid media
• Incubation temperature


  • Most cultures are incubated @ 35ᵒ to 37ᵒ C
  • For fungi = 28ᵒC
• Incubation time


  • Routine = 48 to 72 hours
  • Cultures for anaerobes and broth culture = 5 to 7 days
• Unusual organisms may require special medium or conditions beyond routine
• Culture work-up


  • Reading and interpreting the culture
  • Identification and antimicrobial susceptibility testing
• Non-routine specimens


  • Vein grafts
  • Multiple lumen catheters
  • Heart valves
  • Implant soak solutions
  • Perfusates
  • Water samples
  • Equipment
• Communications of laboratory findings

  • The post analytical phase of the laboratory testing
  • Accurate and timely information/preliminary results
• Preparation for microscopic examination of infected materials


  • Wet preparation (direct or sedimented)
  • Cytocentrifuged (direct or presedimented)
  • Smear (drop, pellet, rolled, imprint)
• Specimen or organism type for microscopic examination

  • Parasites
  • Materials >1 mm in size
  • Fluids or semisolids
  • Clear or slightly turbid fluids
  • Pus or fluid
  • Tissue homogenate
  • Swab rinse
  • Blood culture
  • Dilute specimen
  • Swabbed materials
  • Tissue
• SMEARS preparation


  1. Thick but not opaque smear

  2. Thin (monolayer) smear
• HOW to prepare SMEARS


  1. Swab (two swabs) – rolled back and forth across the slide

  2. Thick liquids or semi-solids – use a swab to sample and smear the material

  3. Thick granular, or mucoid materials – rotate two glass surfaces against each other so that the shear forces break up the material

  4. Thin fluids (urine, CSF, transudates) – drop but do not spread on the slide (marked in the reverse side)
• Cytocentrifuged Preparation


  An excellent method for preparing non-viscous fluid (CSF and bronchoalveolar lavage fluids)
• Cytocentrifugation


  Is an excellent method for preparing non-viscous fluid (CSF and bronchoalveolar lavage fluids)