Numbers of detached macrophages in the culture fluid of wells infected at an MOI of 1.0 with a serovar Dublin wild-type or spvB or spvR mutant straina

StrainNo. (± SE) of:
Detached cellsDetached bacteriaAttached bacteria
Wild type10,650 (1,417)39,000 (11,676)76,666 (10,349)
spvB 641 (182)2,033 (635)151,000 (9,712)
spvR 122 (27)776 (311)127,000 (3,511)
  • a Only intact cells were counted, and values represent the means of the results for three wells. Also shown are the results for the viable bacteria recovered from the detached and attached macrophage fractions. Aliquots of the concentrated detached cells were diluted and plated for determination of numbers of CFU. After removal of culture fluid, attached cells were lysed as described in the text and the numbers of viable bacteria were determined by plating. Values represent the means of the results for four wells. The entire experiment was repeated, with similar results.