Table 1.

Replication of L. pneumophila in lungs after intratracheal inoculation

Mouse strain and experimental groupaNo. of bacteria in lungs (CFU/g)c after:
2 h1 day2 days4 days
A/J
 BCYE-grown bacteria(2.0 ± 0.3) × 105 (6.2 ± 0.3) × 106 (9.4 ± 0.3) × 106 (2.1 ± 0.4) × 107
 BCYE-grown bacteria + amoebal lysate(9.6 ± 0.5) × 104 (5.8 ± 0.4) × 106 (8.4 ± 0.3) × 106 (1.1 ± 0.2) × 107
 Amoebae infected with bacteria(9.1 ± 0.4) × 104 (6.9 ± 0.3) × 108 b (1.9 ± 0.3) × 108 b (4.3 ± 0.3) × 109 b
 Amoeba-grown bacteria(1.6 ± 0.1) × 105 (8.6 ± 0.4) × 108 b (2.7 ± 0.6) × 109 b (4.1 ± 0.5) × 109 b
C57BL/6 Beige
 BCYE-grown bacteria(3.6 ± 0.4) × 105 (2.9 ± 0.3) × 106 (6.1 ± 0.1) × 106 (5.3 ± 0.4) × 106
 BCYE-grown bacteria + amoebal lysate(1.4 ± 0.3) × 105 (3.3 ± 0.4) × 106 (7.4 ± 0.2) × 106 (5.9 ± 0.2) × 106
 Amoebae infected with bacteria(2.4 ± 0.3) × 105 (5.8 ± 0.3) × 108 b (9.1 ± 0.3) × 108 b (9.9 ± 0.3) × 108 b
 Amoeba-grown bacteria(1.8 ± 0.5) × 105 (6.7 ± 0.4) × 108 b (9.7 ± 0.5) × 108 b (9.3 ± 0.4) × 108 b
C57BL/6
 BCYE-grown bacteria(2.0 ± 0.3) × 105 (2.1 ± 0.4) × 106 (4.5 ± 0.4) × 106 (4.0 ± 0.3) × 106
 BCYE-grown bacteria + amoebal lysate(9.8 ± 0.2) × 104 (3.0 ± 0.1) × 106 (5.7 ± 0.3) × 106 (6.3 ± 0.4) × 106
 Amoebae infected with bacteria(2.1 ± 0.2) × 105 (5.0 ± 0.3) × 108 b (8.3 ± 0.4) × 108 b (5.1 ± 0.2) × 108 b
 Amoeba-grown bacteria(1.5 ± 0.5) × 105 (6.1 ± 0.4) × 108 b (9.4 ± 0.5) × 108 b (6.5 ± 0.3) × 106
  • a An inoculum of 106 bacteria was used for all experimental groups.

  • b Significantly different (P < 0.05) from BCYE-grown L. pneumophila alone.

  • c Data represent the means ± standard deviations of duplicate platings from seven mice.