VIABILITY OF BORDETELLA-PERTUSSIS IN 4 SUSPENDING SOLUTIONS AT 3 TEMPERATURES

We studied the survival of Bordetella pertussis in four suspending sol utions (Casamino Acids broth, deionized water, phosphate-buffered sali ne, and serum inositol), subjected to three storage temperatures (4, - 20, and -70 degrees C) and two freezing methods (direct freezing and f ast-freezing in an ethanol-dry-ice bath). Recovery rates were higher f or longer periods for suspensions stored at -70 degrees C than those s tored at -20 or 4 degrees C. Serum inositol showed the highest recover y rates for all experimental conditions, followed by Casamino Acids, d eionized water, and phosphate-buffered saline. Cell viability was sign ificantly reduced in phosphate-buffered saline suspensions fast-frozen before storage. These results identify optimal conditions for storing B. pertussis cells and are applicable to the collection, transport, a nd storage of aspirated nasopharyngeal samples for use in the laborato ry diagnosis of pertussis.