TABLE 3.

Comparison of virulence gene expression by S. aureus strains RN4256 (agrA::Tn551) and RN4282 (agr⁺) recovered from subcutaneous infection chambers at 2 and 8 h after inoculation

Gene	Description or product	Fold expression changea at:
		2 h	8 h
RNAIIb	agrBDCA	−2.9 ± 0.5	−1.6 ± 0.4
RNAIII	Effector molecule of agr locus	−15.1 ± 3.4	−7.1 ± 1.0
spa	Protein A	1.6 ± 0.2	1.4 ± 0.2
hla	Alpha-hemolysin	1.3 ± 0.3	1.3 ± 0.1
tstH	TSS toxin 1	−1.5 ± 0.5	1.5 ± 0.2
hlgA	Gamma-hemolysin, a-component	−1.4 ± 0.2	−1.5 ± 0.1

^aValues represent the fold change in gene expression ± standard error of the mean in strain RN4256 compared to strain RN4282 as determined using triplicate DNA microarrays. Results are averages of data obtained using four rabbits, two infected with RN4256 and two infected with RN4282.

^bInsertion of Tn551 did not interfere with the ability to detect RNAII, as the microarray probe for RNAII was specific for a region upstream of agrA.