Figure 1

Location of Salmonella in tissues of orally-challenged cattle. Three calves were challenged orally with an inoculum containing 10.67 log₁₀ CFU SD3246-GFP and viable bacteria were recovered from the ileum and LNs 48 h after infection. The mean total number of SD3246-GFP recovered from the distal ileum and LNs was 7.81 log₁₀ CFU g⁻¹ and 6.31 log₁₀ CFU g⁻¹, respectively. Homogenised tissues were also treated with gentamicin to determine the intracellular bacterial counts. The majority of the bacteria were sensitive to gentamicin treatment suggesting that they were extracellular. SD3246-GFP spiked into cell suspensions in vitro in comparable numbers to those found in cell suspensions from tissue was fully eliminated by gentamicin treatment (not shown).