Preservation of tissue specimens during transport to mycobacteriology laboratories.

Chloramine-T and sodium borate solutions were evaluated for their effectiveness in preserving Mycobacterium bovis and controlling the growth of non-mycobacterial contaminants on tissue specimens during transport to laboratories. The number of culturable M. bovis cells in suspension was reduced by 5.1 log10 upon exposure to chloramine-T solution and by less than 1 log10 upon exposure to sodium borate solution for 7 days. Reinoculation of laboratory media (because of overgrowth by non-mycobacterial contaminants) was required for 52.6% of 190 routine bovine tissue specimens shipped refrigerated in chloramine-T solution and for 6.1% of 520 specimens shipped unrefrigerated in sodium borate solution. M. bovis was isolated from bovine tissue stored in sodium borate solution at 23 degrees C for 17 weeks and at 4 degrees C for 25 weeks. Unrefrigerated sodium borate solution has been used successfully to ship tissue specimens to our laboratory for the past 11 years.