TABLE 1.

Expression of rpoS and RpoS-regulated genes is required by B. burgdorferi for persistence in mice.

Strain1	Mouse2	4 weeks3				8 weeks				12 weeks				16 weeks				20 weeks
		ear	skin	joint	heart	ear	skin	joint	heart	ear	skin	joint	heart	ear	skin	joint	heart	ear	skin	joint	heart
WT+empty vector1 (BbP1974)	1	+++	++	++	++	++	++	+++	+++	+++	+++	+++	–	+++	+++	+++	++	++	++	–	++
	2	+++	+++	+++	+++	+++	+++	+++	++	+++	+++	+++	+++	+++	++	+++	++	++	++	++	++
	3	+++	++	+++	++	+++	+++	+++	+++	+++	+++	+++	+++	++	+++	+++	++	++	++	++	++
rpoScomp (BbP1754)	1	++	++	++	–	++	–	–	–	+++	+++	+++	–	++	++	–	++	++	–	–	–
	2	+++	++	+++	–	++	++	++	+	+++	–	+++	+	+++	++	++	–	++	++	–	–
	3	+++	+++	++	–	++	++	++	–	–	+++	++	–	++	++	++	++	++	–	–	–

¹Wild-type B31 5A4 transformed with an empty cp9 shuttle vector; rpoScomp, B31 5A4 ΔrpoS mutant complemented in trans with a wild-type copy of rpoS on a cp9-based shuttle vector. ²3 mice per strain, per time point. ³Cultures were checked at least once weekly by darkfield microscopy for the appearance of spirochetes. Plus (+) signs are used to indicate the time required for cultured tissues to become positive for spirochetes by darkfield microscopy: (+++), 1–2 weeks; (++) 3–4 weeks; or (+) 4–5 weeks post-collection. Negative symbol (−) indicates tissues that were culture-negative > 5 weeks post-collection.