Candidatus Bartonella merieuxii,a Potential New Zoonotic Bartonella Species in Canids from Iraq

Bartonellae are emerging vector-borne pathogens infecting erythrocytes and endothelial cells of various domestic and wild mammals. Blood samples were collected from domestic and wild canids in Iraq under the United States Army zoonotic disease surveillance program. Serology was performed using an indirect immunofluorescent antibody test for B. henselae, B. clarridgeiae, B. vinsonii subsp. berkhoffii and B. bovis. Overall seroprevalence was 47.4% in dogs (n = 97), 40.4% in jackals (n = 57) and 12.8% in red foxes (n = 39). Bartonella species DNA was amplified from whole blood and representative strains were sequenced. DNA of a new Bartonella species similar to but distinct from B. bovis, was amplified from 37.1% of the dogs and 12.3% of the jackals. B. vinsonii subsp. berkhoffii was also amplified from one jackal and no Bartonella DNA was amplified from foxes. Adjusting for age, the odds of dogs being Bartonella PCR positive were 11.94 times higher than for wild canids (95% CI: 4.55–31.35), suggesting their role as reservoir for this new Bartonella species. This study reports on the prevalence of Bartonella species in domestic and wild canids of Iraq and provides the first detection of Bartonella in jackals. We propose Candidatus Bartonella merieuxii for this new Bartonella species. Most of the Bartonella species identified in sick dogs are also pathogenic for humans. Therefore, seroprevalence in Iraqi dog owners and bacteremia in Iraqi people with unexplained fever or culture negative endocarditis requires further investigation as well as in United States military personnel who were stationed in Iraq. Finally, it will also be essential to test any dog brought back from Iraq to the USA for presence of Bartonella bacteremia to prevent any accidental introduction of a new Bartonella species to the New World.     

Identification of Different Bartonella Species in the Cattle Tail Louse (Haematopinus quadripertusus) and in Cattle Blood

Bartonella spp. are worldwide-distributed facultative intracellular bacteria that exhibit an immense genomic diversity across mammal and arthropod hosts. The occurrence of cattle-associated Bartonella species was investigated in the cattle tail louse Haematopinus quadripertusus and in dairy cattle blood from Israel. Lice were collected from cattle from two dairy farms during summer 2011, and both lice and cow blood samples were collected from additional seven farms during the successive winter. The lice were identified morphologically and molecularly using 18S rRNA sequencing. Thereafter, they were screened for Bartonella DNA by conventional and real-time PCR assays using four partial genetic loci (gltA, rpoB, ssrA, and internal transcribed spacer [ITS]). A potentially novel Bartonella variant, closely related to other ruminant bartonellae, was identified in 11 of 13 louse pools collected in summer. In the cattle blood, the prevalence of Bartonella infection was 38%, identified as B. bovis and B. henselae (24 and 12%, respectively). A third genotype, closely related to Bartonella melophagi and Bartonella chomelii (based on the ssrA gene) and to B. bovis (based on the ITS sequence) was identified in a single cow. The relatively high prevalence of these Bartonella species in cattle and the occurrence of phylogenetically diverse Bartonella variants in both cattle and their lice suggest the potential role of this animal system in the generation of Bartonella species diversity.     

Recombination Within and Between Species of the Alpha Proteobacterium Bartonella Infecting Rodents

Bartonella infections from wild mice and voles (Apodemus flavicollis, Mi. oeconomus, Microtus arvalis and Myodes glareolus) were sampled from a forest and old-field habitats of eastern Poland; a complex network of Bartonella isolates, referrable to B. taylorii, B. grahamii, B. birtlesii and B. doshiae, was identified by the sequencing of a gltA fragment, comparable to previous studies of Bartonella diversity in rodents. Nested clade analysis showed that isolates could be assigned to zero- and one-step clades which correlated with host identity and were probably the result of clonal expansion; however, sequencing of other housekeeping genes (rpoB, ribC, ftsZ, groEl) and the 16S RNA gene revealed a more complex situation with clear evidence of numerous recombinant events in which one or both Bartonella parents could be identified. Recombination within gltA was found to have generated two distinct variant clades, one a hybrid between B. taylorii and B. doshiae, the other between B. taylorii and B. grahamii. These recombinant events characterised the differences between the two-step and higher clades within the total nested cladogram, involved all four species of Bartonella identified in this work and appear to have played a dominant role in the evolution of Bartonella diversity. It is clear, therefore, that housekeeping gene phylogenies are not robust indicators of Bartonella diversity, especially when only a single gene (gltA or 16S RNA) is used. Bartonella clades infecting Microtus were most frequently involved in recombination and were most frequently tip clades within the cladogram. The role of Microtus in influencing the frequency of Bartonella recombination remains unknown.     

Relationship between the Presence of Bartonella Species and Bacterial Loads in Cats and Cat Fleas (Ctenocephalides felis) under Natural Conditions

Cats are considered the main reservoir of three zoonotic Bartonella species: Bartonella henselae, Bartonella clarridgeiae, and Bartonella koehlerae. Cat fleas (Ctenocephalides felis) have been experimentally demonstrated to be a competent vector of B. henselae and have been proposed as the potential vector of the two other Bartonella species. Previous studies have reported a lack of association between the Bartonella species infection status (infected or uninfected) and/or bacteremia levels of cats and the infection status of the fleas they host. Nevertheless, to date, no study has compared the quantitative distributions of these bacteria in both cats and their fleas under natural conditions. Thus, the present study explored these relationships by identifying and quantifying the different Bartonella species in both cats and their fleas. Therefore, EDTA-blood samples and fleas collected from stray cats were screened for Bartonella bacteria. Bacterial loads were quantified by high-resolution melt real-time quantitative PCR assays. The results indicated a moderate correlation between the Bartonella bacterial loads in the cats and their fleas when both were infected with the same Bartonella species. Moreover, a positive effect of the host infection status on the Bartonella bacterial loads of the fleas was observed. Conversely, the cat bacterial loads were not affected by the infection status of their fleas. Our results suggest that the Bartonella bacterial loads of fleas are positively affected by the presence of the bacteria in their feline host, probably by multiple acquisitions/accumulation and/or multiplication events.     

Deciphering Bartonella Diversity,Recombination, and Host Specificity in a Rodent Community

Host-specificity is an intrinsic feature of many bacterial pathogens, resulting from a long history of co-adaptation between bacteria and their hosts. Alpha-proteobacteria belonging to the genus Bartonella infect the erythrocytes of a wide range of mammal orders, including rodents. In this study, we performed genetic analysis of Bartonella colonizing a rodent community dominated by bank voles (Myodes glareolus) and wood mice (Apodemus sylvaticus) in a French suburban forest to evaluate their diversity, their capacity to recombine and their level of host specificity. Following the analysis of 550 rodents, we detected 63 distinct genotypes related to B. taylorii, B. grahamii, B. doshiae and a new B. rochalimae-like species. Investigating the most highly represented species, we showed that B. taylorii strain diversity was markedly higher than that of B. grahamii, suggesting a possible severe bottleneck for the latter species. The majority of recovered genotypes presented a strong association with either bank voles or wood mice, with the exception of three B. taylorii genotypes which had a broader host range. Despite the physical barriers created by host specificity, we observed lateral gene transfer between Bartonella genotypes associated with wood mice and Bartonella adapted to bank voles, suggesting that those genotypes might co-habit during their life cycle.     

Bartonella Genotypes in Fleas (Insecta: Siphonaptera) Collected from Rodents in the Negev Desert,Israel

Fleas collected from rodents in the Negev Desert in southern Israel were molecularly screened for Bartonella species. A total of 1,148 fleas, collected from 122 rodents belonging to six species, were pooled in 245 pools based on flea species, sex, and rodent host species. Two Bartonella gene fragments, corresponding to RNA polymerase B (rpoB) and citrate synthase (gltA), were targeted, and 94 and 74 flea pools were found positive by PCR, respectively. The Bartonella 16S-23S internal transcribed spacer (ITS) region was also targeted, and 66 flea pools were found to be positive by PCR. Sixteen different Bartonella gltA genotypes were detected in 94 positive flea pools collected from 5 different rodent species, indicating that fleas collected from each rodent species can harbor several Bartonella genotypes. Based on gltA analysis, identified Bartonella genotypes were highly similar or identical to strains previously detected in rodent species from different parts of the world. A gltA fragment 100% similar to Bartonella henselae was detected in one flea pool. Another 2 flea pools contained gltA fragments that were closely related to B. henselae (98% similarity). The high sequence similarities to the zoonotic pathogen B. henselae warrant further investigation.Bartonellae are small Gram-negative bacilli belonging to the alpha-2 subdivision of the Proteobacteria. Different Bartonella species were detected in a wide range of vertebrate animals. There are currently 30 known species or subspecies, among which 14 have been associated with human diseases (7). Bartonella organisms are parasites of mammalian erythrocytes and endothelial cells and are transmitted by fleas and lice and potentially by other blood-feeding arthropods such as ticks and flies (2). Infection in the natural host commonly causes a chronic bacteremia, which is asymptomatic in most cases.Rodents are being extensively studied and were found to have a high prevalence of Bartonella infection, with a high diversity of Bartonella spp. and strains (3). The close contacts between human and rodent populations around the world create excellent conditions for transmission of Bartonella spp. from animals to humans (28). The transmission routes of Bartonella bacteria by arthropod vectors among rodents and between rodents and other mammalian hosts have public health implications. In order to understand the extent to which rodents serve as source of human infections, investigations of rodent-borne Bartonella are essential (28). A few cases of human infections with Bartonella bacteria of rodent origin have been reported: B. elizabethae was associated with endocarditis, B. washoensis was associated with cases of myocarditis and meningitis, B. vinsonii subsp. arupensis was reported to cause fever and neurologic symptoms, and B. grahamii was isolated from the intraocular fluids of a patient with neuroretinitis (5, 11, 12, 25, 29).An earlier survey carried out in the Tel Aviv region, Israel, demonstrated the occurrence of Bartonella strains closely related to B. elizabethae and B. tribocorum in commensal rats (Rattus rattus) (8). Another study has surveyed wild rodents and their fleas for Bartonella spp. in 19 geographical locations in Israel from the Upper Galilee in the north to Beer Sheba in the south. Bartonella DNA was detected in spleen samples of 19 out of 79 (24%) black rats (R. rattus), in 1 of 4 (25%) Cairo spiny mice (Acomys cahirinus), and in 15 of 34 (44%) flea pools collected from black rats (R. rattus) (21). The objectives of the current study were to screen fleas collected from rodents inhabiting the Negev Desert south to Beer Sheba for Bartonella infection and to compare Bartonella prevalences between male and female fleas.     

Bartonella spp. Bacteremia in Blood Donors from Campinas,Brazil

Bartonella species are blood-borne, re-emerging organisms, capable of causing prolonged infection with diverse disease manifestations, from asymptomatic bacteremia to chronic debilitating disease and death. This pathogen can survive for over a month in stored blood. However, its prevalence among blood donors is unknown, and screening of blood supplies for this pathogen is not routinely performed. We investigated Bartonella spp. prevalence in 500 blood donors from Campinas, Brazil, based on a cross-sectional design. Blood samples were inoculated into an enrichment liquid growth medium and sub-inoculated onto blood agar. Liquid culture samples and Gram-negative isolates were tested using a genus specific ITS PCR with amplicons sequenced for species identification. Bartonella henselae and Bartonella quintana antibodies were assayed by indirect immunofluorescence. B. henselae was isolated from six donors (1.2%). Sixteen donors (3.2%) were Bartonella-PCR positive after culture in liquid or on solid media, with 15 donors infected with B. henselae and one donor infected with Bartonella clarridgeiae. Antibodies against B. henselae or B. quintana were found in 16% and 32% of 500 blood donors, respectively. Serology was not associated with infection, with only three of 16 Bartonella-infected subjects seropositive for B. henselae or B. quintana. Bartonella DNA was present in the bloodstream of approximately one out of 30 donors from a major blood bank in South America. Negative serology does not rule out Bartonella spp. infection in healthy subjects. Using a combination of liquid and solid cultures, PCR, and DNA sequencing, this study documents for the first time that Bartonella spp. bacteremia occurs in asymptomatic blood donors. Our findings support further evaluation of Bartonella spp. transmission which can occur through blood transfusions.     

High prevalence and diversity of Bartonella in small mammals from the biodiverse Western Ghats

Bartonella species are recognized globally as emerging zoonotic pathogens. Small mammals such as rodents and shrews are implicated as major natural reservoirs for these microbial agents. Nevertheless, in several tropical countries, like India, the diversity of Bartonella in small mammals remain unexplored and limited information exists on the natural transmission cycles (reservoirs and vectors) of these bacteria. Using a multi-locus sequencing approach, we investigated the prevalence, haplotype diversity, and phylogenetic affinities of Bartonella in small mammals and their associated mites in a mixed-use landscape in the biodiverse Western Ghats in southern India. We sampled 141 individual small mammals belonging to eight species. Bartonella was detected in five of the eight species, including three previously unknown hosts. We observed high interspecies variability of Bartonella prevalence in the host community. However, the overall prevalence (52.5%) and haplotype diversity (0.9) was high for the individuals tested. Of the seven lineages of Bartonella identified in our samples, five lineages were phylogenetically related to putative zoonotic species–B. tribocorum, B. queenslandensis, and B. elizabethae. Haplotypes identified from mites were identical to those identified from their host species. This indicates that these Bartonella species may be zoonotic, but further work is necessary to confirm whether these are pathogenic and pose a threat to humans. Taken together, these results emphasize the presence of hitherto unexplored diversity of Bartonella in wild and synanthropic small mammals in mixed-use landscapes. The study also highlights the necessity to assess the risk of spillover to humans and other incidental hosts.     

Prevalence and diversity of small rodent-associated Bartonella species in Shangdang Basin,China

The aim of this study was to investigate the occurrence and molecular characteristics of Bartonella infections in small rodents in the Shangdang Basin, China. Small rodents were captured using snap traps, and their liver, spleen, and kidney tissues were harvested for Bartonella detection and identification using a combination of real-time PCR of the ssrA gene (296 bp) and conventional PCR and sequencing of the gltA gene (379 bp). Results showed that 55 of 147 small rodents to be positive for Bartonella, with a positivity rate of 37.41%, and 95% confidence interval of 29.50%- 45.33%. While the positivity rate across genders (42.62% in males and 33.72% in females, χ² = 1.208, P = 0.272) and tissues (28.57% in liver, 33.59% in spleen, and 36.76% in kidney, χ² = 2.197, P = 0.333) of small rodents was not statistically different, that in different habitats (5.13% in villages, 84.44% in forests, and 54.17% in farmlands, χ² = 80.105, P<0.001) was statistically different. There were 42 Bartonella sequences identified in six species, including 30 B. grahamii, three B. phoceensis, two B. japonica, two B. queenslandensis, one B. fuyuanensis and four unknown Bartonella species from Niviventer confucianus, Apodemus agrarius and Tscherskia triton. In addition to habitat, Bartonella species infection could be affected by the rodent species as well. Among the Bartonella species detected in this area, B. grahamii was the dominant epidemic species (accounting for 71.43%). B. grahamii exhibited four distinct clusters, and showed a certain host specificity. In addition, 11 haplotypes of B. grahamii were observed using DNASP 6.12.03, among which nine haplotypes were novel. Overall, high occurrence and genetic diversity of Bartonella were observed among small rodents in the Shangdang Basin; this information could potentially help the prevention and control of rodent-Bartonella species in this area.     

Prevalence and Phylogenetic Analysis of <Emphasis Type="Italic">Bartonella</Emphasis> Species of Wild Carnivores and Their Fleas in Northwestern Mexico

The host–parasite–vector relationship of Bartonella spp. system in wild carnivores and their fleas from northwestern Mexico was investigated. Sixty-six carnivores belonging to eight species were sampled, and 285 fleas belonging to three species were collected during spring (April–May) and fall (October–November) seasons. We detected Bartonella species in 7 carnivores (10.6%) and 27 fleas (9.5%) through either blood culture or PCR. Of the 27 Bartonella-positive fleas, twenty-two were Pulex simulans, three were Pulex irritans and one was Echidnophaga gallinacea. The gltA gene and ITS region sequences alignment revealed six and eight genetic variants of Bartonella spp., respectively. These variants were clustered into Bartonella rochalimae, Bartonella vinsonii subsp. berkhoffii and another genotype, which likely represents a novel species of Bartonella spp. Although experimental infection studies are required to prove the vector role of P. simulans, our results suggest that this flea may play an important role in the Bartonella transmission. The results indicated possible host-specific relationships between Bartonella genotypes and the families of the carnivores, but further studies are needed to verify this finding. The presence of zoonotic species of Bartonella spp. in wild carnivores raises the issue of their potential risk for humans in fragmented ecosystems.     

Comparison of sand fly trapping approaches for vector surveillance of Leishmania and Bartonella species in ecologically distinct,endemic regions of Peru

BackgroundIn Peru, the information regarding sand fly vectors of leishmaniasis and bartonellosis in the Amazon region is limited. In this study, we carried out sand fly collections in Peruvian lowland and highland jungle areas using different trap type configurations and screened them for Leishmania and Bartonella DNA.Methodology/Principal findingsPhlebotomine sand flies were collected in Peruvian Amazon jungle and inter Andean regions using CDC light trap, UV and color LED traps, Mosquito Magnet trap, BG Sentinel trap, and a Shannon trap placed outside the houses. Leishmania spp. screening was performed by kDNA PCR and confirmed by a nested cytochrome B gene (cytB) PCR. Bartonella spp. screening was performed by ITS PCR and confirmed by citrate synthase gene (gltA). The PCR amplicons were sequenced to identify Leishmania and Bartonella species.UV and Blue LED traps collected the highest average number of sand flies per hour in low jungle; UV, Mosquito Magnet and Shannon traps in high jungle; and Mosquito Magnet in inter Andean region. Leishmania guyanensis in Lutzomyia carrerai carrerai and L. naiffi in Lu. hirsuta hirsuta were identified based on cytB sequencing. Bartonella spp. related to Bartonella bacilliformis in Lu. whitmani, Lu. nevesi, Lu. hirsuta hirsuta and Lu. sherlocki, and a Bartonella sp. related to Candidatus B. rondoniensis in Lu. nevesi and Lu. maranonensis were identified based on gltA gene sequencing.Conclusions/SignificanceUV, Blue LED, Mosquito Magnet and Shannon traps were more efficient than the BG-Sentinel, Green, and Red LED traps. This is the first report of L. naiffi and of two genotypes of Bartonella spp. related to B. bacilliformis and Candidatus B. rondoniensis infecting sand fly species from the Amazon region in Peru.     

Bartonella spp. in Fruit Bats and Blood-Feeding Ectoparasites in Madagascar

We captured, ectoparasite-combed, and blood-sampled cave-roosting Madagascan fruit bats (Eidolon dupreanum) and tree-roosting Madagascan flying foxes (Pteropus rufus) in four single-species roosts within a sympatric geographic foraging range for these species in central Madagascar. We describe infection with novel Bartonella spp. in sampled Eidolon dupreanum and associated bat flies (Cyclopodia dubia), which nest close to or within major known Bartonella lineages; simultaneously, we report the absence of Bartonella spp. in Thaumapsylla sp. fleas collected from these same bats. This represents the first documented finding of Bartonella infection in these species of bat and bat fly, as well as a new geographic record for Thaumapsylla sp. We further relate the absence of both Bartonella spp. and ectoparasites in sympatrically sampled Pteropus rufus, thus suggestive of a potential role for bat flies in Bartonella spp. transmission. These findings shed light on transmission ecology of bat-borne Bartonella spp., recently demonstrated as a potentially zoonotic pathogen.     

Run-Off Replication of Host-Adaptability Genes Is Associated with Gene Transfer Agents in the Genome of Mouse-Infecting Bartonella grahamii

The genus Bartonella comprises facultative intracellular bacteria adapted to mammals, including previously recognized and emerging human pathogens. We report the 2,341,328 bp genome sequence of Bartonella grahamii, one of the most prevalent Bartonella species in wild rodents. Comparative genomics revealed that rodent-associated Bartonella species have higher copy numbers of genes for putative host-adaptability factors than the related human-specific pathogens. Many of these gene clusters are located in a highly dynamic region of 461 kb. Using hybridization to a microarray designed for the B. grahamii genome, we observed a massive, putatively phage-derived run-off replication of this region. We also identified a novel gene transfer agent, which packages the bacterial genome, with an over-representation of the amplified DNA, in 14 kb pieces. This is the first observation associating the products of run-off replication with a gene transfer agent. Because of the high concentration of gene clusters for host-adaptation proteins in the amplified region, and since the genes encoding the gene transfer agent and the phage origin are well conserved in Bartonella, we hypothesize that these systems are driven by selection. We propose that the coupling of run-off replication with gene transfer agents promotes diversification and rapid spread of host-adaptability factors, facilitating host shifts in Bartonella.     

The Distribution and Diversity of Bartonella Species in Rodents and Their Ectoparasites across Thailand

Our study highlights the surveillance of Bartonella species among rodents and their associated ectoparasites (ticks, fleas, lice, and mites) in several regions across Thailand. A total of 619 rodents and 554 pooled ectoparasites (287 mite pools, 62 flea pools, 35 louse pools, and 170 tick pools) were collected from 8 provinces within 4 regions of Thailand. Bandicota indica (279), Rattus rattus (163), and R. exulans (96) were the most prevalent species of rats collected in this study. Real-time PCR assay targeting Bartonella-specific ssrA gene was used for screening and each positive sample was confirmed by PCR using nuoG gene. The prevalence of Bartonella DNA in rodent (around 17%) was recorded in all regions. The highest prevalence of Bartonella species was found in B. savilei and R. rattus with the rate of 35.7% (5/14) and 32.5% (53/163), respectively. High prevalence of Bartonella-positive rodent was also found in B. indica (15.1%, 42/279), and R. norvegicus (12.5%, 5/40). In contrast, the prevalence of Bartonella species in ectoparasites collected from the rats varied significantly according to types of ectoparasites. A high prevalence of Bartonella DNA was found in louse pools (Polyplax spp. and Hoplopleura spp., 57.1%) and flea pools (Xenopsylla cheopis, 25.8%), while a low prevalence was found in pools of mites (Leptotrombidium spp. and Ascoschoengastia spp., 1.7%) and ticks (Haemaphysalis spp., 3.5%). Prevalence of Bartonella DNA in ectoparasites collected from Bartonella-positive rodents (19.4%) was significantly higher comparing to ectoparasites from Bartonella-negative rodents (8.7%). The phylogenetic analysis of 41 gltA sequences of 16 Bartonella isolates from rodent blood and 25 Bartonella-positive ectoparasites revealed a wide range of diversity among Bartonella species with a majority of sequences (61.0%) belonging to Bartonella elizabethae complex (11 rodents, 1 mite pool, and 5 louse pools), while the remaining sequences were identical to B. phoceensis (17.1%, 1 mite pool, 5 louse pools, and 1 tick pool), B. coopersplainensis (19.5%, 5 rodents, 1 louse pool, and 2 tick pools), and one previously unidentified Bartonella species (2.4%, 1 louse pool).     

Gene duplication and deletion,not horizontal transfer,drove intra-species mosaicism of Bartonella henselae

Bartonella henselae is a facultative intracellular pathogen that occurs worldwide and is responsible primarily for cat-scratch disease in young people and bacillary angiomatosis in immunocompromised patients. The principal source of genome-level diversity that contributes to B. henselae's host-adaptive features is thought to be horizontal gene transfer events. However, our analyses did not reveal the acquisition of horizontally-transferred islands in B. henselae after its divergence from other Bartonella. Rather, diversity in gene content and genome size was apparently acquired through two alternative mechanisms, including deletion and, more predominantly, duplication of genes. Interestingly, a majority of these events occurred in regions that were horizontally transferred long before B. henselae's divergence from other Bartonella species. Our study indicates the possibility that gene duplication, in response to positive selection pressures in specific clones of B. henselae, might be linked to the pathogen's adaptation to arthropod vectors, the cat reservoir, or humans as incidental host-species.     

Adaptive immune defense prevents Bartonella persistence upon trans-placental transmission

Vertical transmission of Bartonella infection has been reported for several mammalian species including mice and humans. Accordingly, it is commonly held that acquired immunological tolerance contributes critically to the high prevalence of Bartonellae in wild-ranging rodent populations. Here we studied an experimental model of Bartonella infection in mice to assess the impact of maternal and newborn immune defense on vertical transmission and bacterial persistence in the offspring, respectively. Congenital infection was frequently observed in B cell-deficient mothers but not in immunocompetent dams, which correlated with a rapid onset of an antibacterial antibody response in infected WT animals. Intriguingly, B cell-deficient offspring with congenital infection exhibited long-term bacteremia whereas B cell-sufficient offspring cleared bacteremia within a few weeks after birth. Clearance of congenital Bartonella infection resulted in immunity against bacterial rechallenge, with the animals mounting Bartonella-neutralizing antibody responses of normal magnitude. These observations reveal a key role for humoral immune defense by the mother and offspring in preventing and eliminating vertical transmission. Moreover, congenital Bartonella infection does not induce humoral immune tolerance but results in anti-bacterial immunity, questioning the contribution of neonatal tolerance to Bartonella prevalence in wild-ranging rodents.     

Coexistence of Bartonella henselae and B. clarridgeiae in populations of cats and their fleas in Guatemala

Cats and their fleas collected in Guatemala were investigated for the presence of Bartonella infections. Bartonella bacteria were cultured from 8.2% (13/159) of cats, and all cultures were identified as B. henselae. Molecular analysis allowed detection of Bartonella DNA in 33.8% (48/142) of cats and in 22.4% (34/152) of cat fleas using gltA, nuoG, and 16S–23S internal transcribed spacer targets. Two Bartonella species, B. henselae and B. clarridgeiae, were identified in cats and cat fleas by molecular analysis, with B. henselae being more common than B. clarridgeiae in the cats (68.1%; 32/47 vs 31.9%; 15/47). The nuoG was found to be less sensitive for detecting B. clarridgeiae compared with other molecular targets and could detect only two of the 15 B. clarridgeiae‐infected cats. No significant differences were observed for prevalence between male and female cats and between different age groups. No evident association was observed between the presence of Bartonella species in cats and in their fleas.     

Detection and identification of Bartonella sp. in fleas from carnivorous mammals in Andalusia,Spain

A total of 559 fleas representing four species (Pulex irritans, Ctenocephalides felis, Ctenocephalides canis and Spilopsyllus cuniculi) collected on carnivores (five Iberian lynx Lynx pardinus, six European wildcat Felis silvestris, 10 common genet Genetta genetta, three Eurasian badger Meles meles, 22 red fox Vulpes vulpes, 87 dogs and 23 cats) in Andalusia, southern Spain, were distributed in 156 pools of monospecific flea from each carnivore, and tested for Bartonella infection in an assay based on polymerase chain reaction (PCR) amplification of the 16 S–23 S rRNA intergenic spacer region. Twenty‐one samples (13.5%) were positive and the sequence data showed the presence of four different Bartonella species. Bartonella henselae was detected in nine pools of Ctenocephalides felis from cats and dogs and in three pools of Ctenocephalides canis from cats; Bartonella clarridgeiae in Ctenocephalides felis from a cat, and Bartonella alsatica in Spilopsyllus cuniculi from a wildcat. DNA of Bartonella sp., closely related to Bartonella rochalimae, was found in seven pools of Pulex irritans from foxes. This is the first detection of B. alsatica and Bartonella sp. in the Iberian Peninsula. All of these Bartonella species have been implicated as agents of human diseases. The present survey confirms that carnivores are major reservoirs for Bartonella spp.     

Evidence of Transfer by Conjugation of Type IV Secretion System Genes between Bartonella Species and Rhizobium radiobacter in Amoeba

Background

Bartonella species cospeciate with mammals and live within erythrocytes. Even in these specific niches, it has been recently suggested by bioinformatic analysis of full genome sequences that Lateral Gene Transfer (LGT) may occur but this has never been demonstrated biologically. Here we describe the sequence of the B. rattaustraliani (AUST/NH4^T) circular plasmid (pNH4) that encodes the tra cluster of the Type IV secretion system (T4SS) and we eventually provide evidence that Bartonella species may conjugate and exchange this plasmid inside amoeba.

Principal Findings

The T4SS of pNH4 is critical for intracellular viability of bacterial pathogens, exhibits bioinformatic evidence of LGT among bacteria living in phagocytic protists. For instance, 3 out of 4 T4SS encoding genes from pNH4 appear to be closely related to Rhizobiales, suggesting that gene exchange occurs between intracellular bacteria from mammals (bartonellae) and plants (Rhizobiales). We show that B. rattaustraliani and Rhizobium radiobacter both survived within the amoeba Acanthamoeba polyphaga and can conjugate together. Our findings further support the hypothesis that tra genes might also move into and out of bacterial communities by conjugation, which might be the primary means of genomic evolution for intracellular adaptation by cross-talk of interchangeable genes between Bartonella species and plant pathogens.

Conclusions

Based on this, we speculate that amoeba favor the transfer of genes as phagocytic protists, which allows for intraphagocytic survival and, as a consequence, promotes the creation of potential pathogenic organisms.     

Bartonella Infection among Cats Adopted from a San Francisco Shelter,Revisited

Bartonella infection among cats from shelters can pose a health risk to adopters. Bartonella henselae is the most common species, with B. clarridgeiae and B. koehlerae being less common. The lower rates of infection by the latter species may reflect their rarity or an inefficiency of culture techniques. To assess the incidence of infection, blood cultures, serology, and PCR testing were performed on 193 kittens (6 to 17 weeks old) and 158 young adult cats (5 to 12 months old) from a modern regional shelter. Classical B. henselae culture medium was compared to a medium supplemented with insect cell growth factors. Bartonella colonies were isolated from 115 (32.8%) animals, including 50 (25.9%) kittens and 65 (41.1%) young adults. Therefore, young adults were twice as likely to be culture positive as kittens. Enhanced culture methods did not improve either the isolation rate or species profile. B. henselae was isolated from 40 kittens and 55 young adults, while B. clarridgeiae was cultured from 10 animals in each group. B. koehlerae was detected in one young adult by PCR only. B. henselae genotype II was more commonly isolated from young adults, and genotype I was more frequently isolated from kittens. Kittens were 4.7 times more likely to have a very high bacterial load than young adults. A significantly higher incidence of bacteremia in the fall and winter than in the spring and summer was observed. Bartonella antibodies were detected in 10% (19/193) of kittens and 46.2% (73/158) of young adults, with culture-positive kittens being 9.4 times more likely to be seronegative than young adults.