Table 1. Alphabetical listing of proven or likely virulence determinants of Bartonella, based on current literature, phenotypes (contact hemolysin, deformin and LPS) and GenBank listings (all others).

Virulence determinant	Bartonella bacilliformis	Bartonella quintana	Bartonella henselae
BatR/BatS	Present	Present	Present
Cohemolysin	?	Present	Present
Contact hemolysin	Present	Absent	Absent
C-terminal protease	Present	Present	Present
Deformin*	Present	?	?
Flagella-mediated motility	Present	Absent	Absent
Hbp family‡	Present§	Present§	Present§
Heme uptake system¶	Present#	Present	Present
IalA/IalB**	Present	Present	Present
LPS with low endotoxicity	Present	Present	Present
TAAs*‡	Present	Present	Present
Trw pilin system	Absent	Present	Present
VirB/VirD4 and Beps*§	Absent	Present	Present

^*Deformin (deformation factor) has been reported once for Bartonella henselae [13].

^‡Heme-binding proteins. Also referred to as phage-associated protein of 31 kDa (Pap31) of B. henselae.

^§Three Hbps in Bartonella bacilliformis, five in both B. henselae and Bartonella quintana.

^¶Heme receptor, periplasmic heme-binding protein, ABC transporter/permease and TonB.

^#A TonB ortholog is not encoded in this genome; possibly uses TolC.

^**Invasion-associated locus A and B for a nudix hydrolase and erythrocyte invasion protein, respectively.

^*‡Trimeric autotransporter adhesins [26]; an orthologous group of YadA-like outer membrane proteins/afimbrial adhesins. Designated as variably-expressed outer membrane proteins in B. quintana, Bartonella repetitive protein A in Bartonella vinsonii, and Bartonella adhesin A in B. henselae.

^*§Type IV secretion system and translocated Beps.

BatR: Bartonella regulator; BatS: Bartonella sensor; Bep: Bartonella effector protein; Hbp: Heme-binding protein; LPS: Lipopolysaccharide; TAA: Trimeric autotransporter adhesin.