TABLE 3.

Quantitative assessment of the ability of atypical EPEC strain E128012 and its isogenic derivatives to adhere to cultured epithelial cells

StrainCharacteristic(s)Adherence to HEp-2 cells (%)aAdherence to T84 cells (%)b
E128012Wild type56.9 ± 8.9109.6 ± 21.7
CY88 pstCA mutant10.4 ± 1.4c8.8 ± 6.6c
CY88(pAC2)Trans-complemented pstCA mutant42.9 ± 4.090.8 ± 25.8
CY91 pstCA phoB double mutant54.4 ± 5.496.9 ± 16.2
  • a For HEp-2 cells, bacterial adherence is expressed as the number of cells with at least five attached bacteria as a percentage of the total number of cells counted. At least 100 cells were counted in each assay, which were performed in triplicate. Data are the means ± SD of the results.

  • b For T84 cells, bacterial adherence is expressed as the percentage of the initial inoculum recovered from T84 cells after incubation for 3 h at 37°C and removal of nonadherent bacteria. Data are the means ± SD of the results of five separate determinations.

  • c Significantly lower (P < 0.001) than the results for all other strains tested (two-tailed Student's t test).