Anne M. Whitney
4-14-2009
http://scholarworks.gsu.edu/cgi/viewcon ... ology_diss
ABSTRACT
B. henselae, B. bacilliformis and B. quintana are capable of causing vasoproliferative diseases in humans by modulating apoptosis and proliferation of endothelial cells.
Bartonella clarridgeiae, a close relative of the pathogenic Bartonellae, has been implicated in human disease but has not yet been isolated from a human patient.
Both B. bacilliformis and B. clarridgeiae have flagella and a flagellar type 3 secretion system, while B. henselae and B. quintana do not. We created 2 non-motile mutants of B. clarridgeiae by interrupting the flagellin gene, flaA, or the flagellar motor genes, motBC.
We investigated whether B. clarridgeiae could invade human endothelial cells (HMECs) and if functional flagella were important for invasion.
The non-motile mutants and the wild-type strain were capable of entering HMECs in vitro.
The flaA mutant was deficient in attachment, but the HMECs in culture with the flaA mutant demonstrated increased proliferation.
The motBC mutant showed enhanced invasion.
Differential secretion of proteins was revealed by 2-D electrophoresis and MALDI-TOF analysis of secretomes from the co-cultures
compared to uninfected HMECs. HMECS infected with wild-type B. clarridgeiae secreted proteins indicative of proliferation.
The flaA mutant induced the secretion of proteins involved in cytoskeletal rearrangement, cell migration, and proliferation.
The motBC-infected HMECs showed signs of hypoxia.
The co-chaperonin GroES was found in higher concentration in the supernatant of the hyper-invasive motBC strain/HMEC co-culture than the wild-type co-culture and was found at a very low concentration in the flaA culture supernatant.
Cross-talk between secretion systems is suggested.
The Genus Bartonella
Bartonella clarridgeiae is one of more than 19 bacterial species belonging to the genus Bartonella.
From 1909 until 1993, this genus contained only one species, B. bacilliformis.
Brenner et al. determined from the results of 16S rRNA sequence analysis, DNA-DNA hybridization, guanosine plus cytosine content and phenotypic characteristics that several species in the genus Rochalimaea were very closely related to B. bacilliformis (Brenner et al.,1993). In 1993 the two genera were combined, and B. quintana, B. vinsonii, B. henselae and B. elizabethae were included with B. bacilliformis in the genus.
A similar event took place in 1995 when the genus Grahamella was combined with Bartonella, and B. talpae, B. peromysci,
B. grahamii, B. taylorii and B. doshiae joined the genus.
This brought the number of Bartonella species to 10, although the original strains of B. talpae and B. peromysci were found to be no longer viable (Birtles et al.,1995).
Further studies culturing blood from wild and domestic animals brought about the discoveries of B. schoenbuchensis and B. capreoli from deer, B. alsatica from wild rabbits, B. tribocorum from wild rats, B. vinsonii subspecies berkhoffii from domestic dogs, B. koehlerae from cats, B. chomelii and B. bovis Bermond et al from cattle, B. birtlesii and B. vinsonii subspecies arupensis from mice.
B. weissi and B. washoensis are unofficial names of two additional species.
B. weissi was recovered from cats and later was found to be identical by 16S rRNA gene sequence to B. bovis (Bermond et al.,2002),
and B. washoensis was reported in ground squirrels and a dog (Chomel et al.,2003; Kosoy et al.,2003).
Other species with no official taxonomic acceptance are B. australis, B. phoceenis, B. rattimassiliensis, and B. tamiae............
B. clarridgeaie was first described in 1995 when the organism was isolated from a kitten belonging to a B. henselae-positive patient (Clarridge et al.,1995; Collins,1996).
Several studies in all four quarters of the world have demonstrated that cats serve as a reservoir for B. clarridgeiae and B. henselae and are even coinfected with both species in a small percentage of cases (Gurfield et al.,1997; Marston et al.,1999).
Therefore, infection by one species does not confer protection against the other
B. clarridgeiae has been isolated from dogs with infective vegetative valvular endocarditis and in liver specimens from dogs with hepatic disease (Chomel et al.,2001; Gillespie et al.,2003). The number of human infections by B. clarridgeiae is unknown
It has been estimated that there are 24,000 cases of CSD yearly in the US (Jackson et al.,1996) and that up to 60% of CSD cases are negative for B. henselae by serology (Yoshida et al.,1996). Because serologic tests for B. clarridgeiae are not usually performed, and because Bartonella are difficult to culture, the percentage of CSD cases caused by B. clarridgeiae has not been determined......