Table 1.

Effect of iron on Brucella abortus survival and growth in C57Bl/10 macrophages

Exp. No.	Treatment	CFU (log10)*	CFU recovered relative to medium (log10)†
1	Medium	5·37
	FeTf	4·76	−0·61
	FeNTA	3·86	−1·51
2	Medium	4·74
	FeTf	3·88	−0·86
	FeNTA	3·26	−1·48

^*Mean colony-forming units (CFU) 48 h after infection. The variation (s.e.m.) incurred from determining CFU from replicate plates and multiple sample dilutions was < 5% in all experiments (not shown). Peptone-elicited peritoneal macrophages were cultured in medium alone or with either iron-bound transferrin (FeTf) for 24 h before infection or with iron salt (FeNTA) after infection only.

^†Relative log₁₀ CFU represents the change in CFU in experimental groups with iron relative to the medium controls. Iron significantly decreased the number of intracellular brucellae recovered compared with the medium controls in both experiments (P < 0·05).