Table 2.

Relationship between MOI, internalization, and persistence of B. bronchiseptica CBF2 in P388D1 cellsa

MOIMean (SD) CFU/ml at h postinfection indicated
424487296
1:14,000 (600)  450 (200) 190 (470)21 (11)<10
10:15.1 × 104 (900)3,900 (3300)460 (210) 9 (10)<10
100:12.2 × 105 (2.1 × 104)7,600 (2000)860 (130)16 (9) <10
500:12.1 × 106 (2.0 × 105)1.6 × 106 (4.9 × 105)2.0 × 106 (2.8 × 105)2.3 × 106 (2.0 × 105)1.9 × 106 (2.0 × 105)
1,000:15.4 × 106 (4.7 × 105)5.9 × 106 (4.0 × 106)5.5 × 106 (1.8 × 106)4.8 × 106 (3.4 × 105)4.9 × 106 (4.4 × 105)
  • a Macrophages at 5 × 105/ml in 96-well trays were infected at MOI (bacteria to macrophages) of 1:1, 10:1, 100:1, 500:1, and 1,000:1, which represent 5 × 105, 5 × 106, 5 × 107, 2.5 × 108, and 5 × 108 CFU of bacteria/ml, respectively. Assays were done in triplicate.