New Page 2

FACTORS WICH AFFECT THE VIABILITY OF LEPTOSPIRES

Factor which affect the viability of leptospires are:

Imperfectly cleaned glassware.

Inappropriate media

- Milk samples are best inoculated on solid medium (EMJH) with 1% agar. Immediately after sampling inoculate at 1:10-1:10,000 dilutions. Comparisons were made of semi-solid and solid media. Only solid medium was capable of isolating from cow's milk. Cultures from milk were only obtained during the first 10 days of "mastitis". In culture isolations from cow's urine, semi-solid medium with 5FU proved to be the most efficient. Filtration through 0,22 um filters should be considered as useful.

Inhibitory substances

- When rabbit serum is to be added to the medium this serum should first be checked for antibodies against leptospires. Even fetal calf serum should alwaysbe checked for the presecne of antibodies against leptospires.

Antibiotic therapy

- Antibiotic treatment reduces the chance of isolation

Contamination

- Contamination with other micro-organiss, i.e. overgrowth with bacteria

Incubation temperature

- The optimum temperature is from 28 C till 30 C

pH of the medium

- It is important that the medium has a pH from 7.2 to 7.4.