BacterBlood™ Anaerobic Blood Culture Bottle

• Inspect the bottle for contamination or damage. Label appropriately and remove the protective plastic cap. Disinfect the rubber stopper with 70% alcohol and let it dry.
• Collect 5–10 mL of blood aseptically. Inject the blood into the liquid phase through the rubber stopper. Swirl gently to mix.
• Incubate at 35 – 37°C under 5% CO₂ for 18 – 24 hours.
• Observe daily for signs of microbial growth:
  • If growth is observed, withdraw 1 mL for Gram staining, subculture, and susceptibility testing.
  • If no growth, continue incubation up to 7 days.
• Report negative if no growth is observed by day 7.

RESULTS

Microorganisms growing in broth bottles:

• Staphylococcus aureus: Typically grows as small, uniform particles with a pellicle (film) on the surface.
• Streptococci: Usually settle at the bottom or stick to the sides of the bottle in clusters resembling cotton wool or crumbs.
• Gram-negative bacilli: Generally cause uniform turbidity in the broth (except for Salmonella, which may leave the broth clear while forming a white layer above the bottom of the bottle).
• Pseudomonas spp.: Grow with a surface pellicle resembling fermented pickles, causing turbid broth, sometimes with bubbles.

Subculturing positive blood culture bottles and incubation:

• Shake the broth bottle gently.
• Use a syringe to withdraw approximately 0,5 mL of broth.
• Place one drop of the broth onto a clean glass slide, allow it to air dry, fix it, and perform a Gram stain. Make a preliminary assessment of the bacterial morphology, arrangement, and staining characteristics.
• Subculture the broth onto Blood Agar, Chocolate Agar, and MacConkey Agar. Use a sterile inoculating loop to streak evenly across the agar surface to form distinct colonies.