Media composition to revive leptospires stored at -80 °C

Area of Science:

• Microbiology
• Bacteriology
• Infectious Diseases

Background:

• Leptospira preservation is challenging due to low recovery rates with freezing or liquid nitrogen.
• Frequent sub-culturing in semisolid media is often used but can be laborious.

Purpose of the Study:

• To evaluate three liquid EMJH medium compositions for reviving Leptospira after -80°C storage.
• To determine optimal conditions for long-term Leptospira preservation.

Main Methods:

• Eighteen Leptospira serovars were stored at -80°C in liquid EMJH medium (Medium A).
• Stored cultures were sub-cultured into three EMJH variations (Medium A, B, C) over 30 months.
• Medium B lacked 5-fluorouracil, and Medium C included sodium pyruvate.

Main Results:

• Sub-culturing in Medium B (no 5-fluorouracil) and Medium C (with sodium pyruvate) showed significantly better and faster Leptospira recovery (89-100%) compared to Medium A (67-100%).
• The p-value was less than 0.05, indicating statistical significance.

Conclusions:

• Leptospires can be stored longer at -80°C.
• Optimal recovery is achieved when sub-cultured onto EMJH medium formulations lacking 5-fluorouracil.