Table 1.

Internalization of M+ streptococci in the presence of cytochalasin D and colchicinea

InhibitorConcn (μg/ml)Internalizationb (CFU)% Inhibition of internalizationP (internalized CFU)
Cytochalasin D0.04,000 ± 1,025
0.1252,300 ± 1,00042NS
0.25283 ± 13493<0.01
0.5416 ± 32490<0.01
Colchicine0.03,800 ± 2,000
102,000 ± 65447NS
203,000 ± 1,40021NS
402,600 ± 1,20032NS
  • a The inhibitor was added 30 min prior to the infection of 24-well plates with confluently cultured pharyngeal cells. The bacterial inoculum was prepared as described for the adherence and internalization assays, and each well was infected with approximately 5 × 105 CFU of the streptococcal strain M+ (S. pyogenes D471). NS, not significant.

  • b Data represent the means ± SD of three independent experiments with two infected wells per inhibitor concentration per experiment.