Table 6.

Viable counts of test (Nalr) and challenge (Spc) mutants of S. Typhimurium F98 in the ceca of newly hatched chickens in a competition assaya

MutationViable count ofb:
Test strainChallenge strain postmortem
At time of challengePostmortem
metF8.32, 8.42, 8.597.17 (6.60–7.82)<2 (<2–<2)
csgA8.40, 7.64, 8.047.79 (7.18–8.18)<2 (<2–<2)
ttrS7.73, 6.30, 7.086.95 (6.00–7.79)<2 (<2–2.85)
ttrB7.93, 8.43, 9.117.74 (7.00–8.00)<2 (<2–<2)
pdu8.08, 8.04, 8.006.60 (6.00–7.65)<2 (<2–5.2)
eut8.2, 8.88, 9.007.59 (7.18–7.68)<2 (<2–<2)
argA7.11, 7.88, 7.286.00 (6.00–6.90)<2 (<2–2.78)
potG7.90, 7.836.95 (6.70–7.28)<2 (<2–<2)
Parent8.80, 8.18, 8.287.00 (6.60–8.57)<2 (<2–<2)
None<2, <2, <2<2 (<2–<2)4.3 (4.00–7.82)
  • a Ten chickens were inoculated with the test strain. Three chickens were killed to enumerate this strain 24 h later at the time of challenge. All chickens were killed 3 days later to enumerate both strains in the ceca.

  • b Viable counts at time of challenge are presented for all three chickens. Viable counts postmortem of all other chickens are the means and ranges.