Bartonella quintana endocarditis in dogs

Advanced approaches for the diagnosis and chemoprevention of canine vector-borne pathogens and parasites-Implications for the Asia-Pacific region and beyond

Vector-borne pathogens (VBPs) of canines are a diverse range of infectious agents, including viruses, bacteria, protozoa and multicellular parasites, that are pernicious and potentially lethal to their hosts. Dogs across the globe are afflicted by canine VBPs, but the range of different ectoparasites and the VBPs that they transmit predominate in tropical regions. Countries within the Asia-Pacific have had limited prior research dedicated to exploring the epidemiology of canine VBPs, whilst the few studies that have been conducted show VBP prevalence to be high, with significant impacts on dog health. Moreover, such impacts are not restricted to dogs, as some canine VBPs are zoonotic. We reviewed the status of canine VBPs in the Asia-Pacific, with particular focus on nations in the tropics, whilst also investigating the history of VBP diagnosis and examining recent progress in the field, including advanced molecular methods, such as next-generation sequencing (NGS). These tools are rapidly changing the way parasites are detected and discovered, demonstrating a sensitivity equal to, or exceeding that of, conventional molecular diagnostics. We also provide a background to the armoury of chemopreventive products available for protecting dogs from VBP. Here, field-based research within high VBP pressure environments has underscored the importance of ectoparasiticide mode of action on their overall efficacy. The future of canine VBP diagnosis and prevention at a global level is also explored, highlighting how evolving portable sequencing technologies may permit diagnosis at point-of-care, whilst further research into chemopreventives will be essential if VBP transmission is to be effectively controlled.

Evaluation of ssrA-targeted real time PCR for the detection of Bartonella species in human clinical samples and reflex sequencing for species-level identification

The genus Bartonella includes species capable of causing disease in animals and humans. Due to its fastidious nature, direct detection of Bartonella causing human infection relies largely on molecular microbiological methods. Thus, it is imperative that diagnostic assays in use have the ability to detect a range of Bartonella species associated with human disease. In this study, we compared the performance of a real time polymerase chain reaction (PCR) assay targeting the ssrA gene to conventional rpoB-targeted PCR and sequencing for detection and differentiation of Bartonella species in human clinical samples. The real time ssrA PCR performed better for non-Bartonella henselae species, detecting B. clarridgeiae and B. quintana DNA in heart valve specimens that were not detected by rpoB PCR, and improved the sensitivity of B. henselae detection in blood specimens. Our findings suggest the real time ssrA PCR assay is suitable for detection and identification of Bartonella species in human clinical specimens.

Seroprevalence of Bartonella quintana infection: A systematic review

Introduction:

Bartonella quintana is an anaerobic bacillus whose main target is the erythrocyte. This bacterium transmitted by the body louse notably infected the soldiers of the First World War from where the name of this disease: fever of the trenches. The 90s marked the return of this bacterial infection. B. quintana infection in the homeless was reported in the literature with a high incidence in these populations worldwide. This upsurge of cases justified this study for a better understanding of B. quintana infections.

Methods:

We conducted a systematic review to evaluate the seroprevalence of B. quintana infection by using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to collect scientific papers from PubMed and Google Scholar based on combining keywords.

Results:

The review included 45 articles published from April 1996 to March 2020 with 84 subpopulations of 21 countries from 4 continents; among them, 61 subpopulations had a positive rate from 0.2% to 65%. These subpopulations were divided into four main groups: homeless people, healthy people, blood donors, and symptoms/diseases. Homeless people were the main target of this infection, and three factors related to susceptibility were homeless period, age, and alcoholism. 6/11, 12/20, and 32/41 subpopulations of healthy people, blood donors, symptoms/diseases, respectively, had a positive percentage. However, factors of exposure in these three groups were not mentioned. Other reservoirs, vectors, and transmitted routes were identified to partially explain the worldwide spread of the infection, and it is important to have more further investigations to identify potential risk factors. This will help to limit contamination and prevent effectively.

Conclusions:

This serological overview indicated the importance of B. quintana infection that has emerged in multiple regions, touched worldwide populations.

Seroprevalence of Bartonella henselae and Bartonella quintana Infection and Impact of Related Risk Factors in People from Eastern Slovakia

The genus Bartonella is a rapidly expanding group of ubiquitous bacteria that occur mainly in different animal species, but some can also be transmitted to humans. Three species, B. henselae, B. bacilliformis, and B. quintana, are responsible for the majority of human cases. The severity of the clinical symptoms often depends on the immune status of the patient, but others factors such as the species of the pathogen, virulence factors, and bacterial load also can play an important role. As the information on the occurrence of bartonellosis in the human population in Slovakia is absent, the aim of our pilot study was to determine the seroprevalence against B. henselae and B. quintana in the population of people living in Eastern Slovakia, and to identify the impact of related risk factors. Of 536 people included in the study, 126 (23.5%) showed positivity for anti-B. henselae antibodies and 133 (24.8%) against B. quintana. A statistically higher prevalence was confirmed only in the case of B. quintana in women regardless of the risk group. In analyzing the risk factors, we found significant differences between B. henselae seropositive and seronegative groups only in uric acid levels and serum creatinine, both, however, clinically irrelevant. Significant, but clinically irrelevant differences were observed also in alanine aminotransferase (ALT) levels and creatinine in people seropositive to B. quintana.

Five millennia of Bartonella quintana bacteraemia

During the two World Wars, Bartonella quintana was responsible for trench fever and is now recognised as an agent of re-emerging infection. Many reports have indicated widespread B. quintana exposure since the 1990s. In order to evaluate its prevalence in ancient populations, we used real-time PCR to detect B. quintana DNA in 400 teeth collected from 145 individuals dating from the 1^st to 19^th centuries in nine archaeological sites, with the presence of negative controls. Fisher’s exact test was used to compare the prevalence of B. quintana in civil and military populations. B. quintana DNA was confirmed in a total of 28/145 (19.3%) individuals, comprising 78 citizens and 67 soldiers, 20.1% and 17.9% of which were positive for B. quintana bacteraemia, respectively. This study analysed previous studies on these ancient samples and showed that the presence of B. quintana infection followed the course of time in human history; a total of 14/15 sites from five European countries had a positive prevalence. The positive rate in soldiers was higher than those of civilians, with 20% and 18.8%, respectively, in the 18^th and 19^th centuries, but the difference in frequency was not significant. These results confirmed the role of dental pulp in diagnosing B. quintana bacteraemia in ancient populations and showed the incidence of B. quintana in both civilians and soldiers.

Molecular detection and phylogenetic analysis of 'Candidatus Bartonella merieuxii' in dogs and its effect on hematologic parameters

Emerging Bartonella spp. infection can result in clinical symptoms such as endocarditis in humans and animals. This study analyzed the genetic phylogeny of the Bartonella spp. circulating in Iranian dogs. Also, this is first study on the relationship of Bartonella spp. and haematological factors from dogs in Fars. Ninety-eight blood samples were collected from the dogs of Fars province, Iran. Two different PCRs targeting rpoB gene and ITS sequence of Bartonella spp., followed by sequencing were performed. In addition, CBC and the differential count of WBC were determined. The "prevalence" of Bartonella spp. was 12.2 % (95 % CI: 5.72-18.68 %) in this population and the sequences matched with a newly proposed species; 'Candidatus Bartonella merieuxii'. A significant increase in WBC due to neutrophilia and decreased RBC, Hct, and Hb concentrations were detected in Bartonella spp. infected dogs. The close contact between humans and dogs, and the zoonosis potential of Candidatus Bartonella merieuxii, emphasize on the need for more studies on 'Candidatus Bartonella merieuxii'.

Aortic valve endocarditis due to Bartonella clarridgeiae in a dog in Brazil

We report the first documented case of endocarditis associated with Bartonella clarridgeiae in a dog in Latin America. Infective vegetative valvular aortic endocarditis was diagnosed in a 10-year-old male mixed breed dog. The dog presented grade V/VI systolic and diastolic murmur, hyperthermia, and progressive weight loss. Cardiomegaly and presence of diffuse alveolar pattern in the lung fields were observed in the thorax radiography evaluation. Irregular and hyperechogenic structures adhered to the aortic leaflets, causing obstruction of the left ventricular outflow tract and severe aortic insufficiency, were observed in the echocardiography evaluation. A vegetative, whitish, hardened structure measuring 1.0 cm in diameter was observed in aortic semilunar valve at necropsy. Based on a combination of pre-enrichment insect-based medium liquid culture, quantitative real-time and conventional PCR assays based on nuoG and gltA genes, respectively, followed by sequencing and phylogenetic inferences, B. clarridgeiae DNA was detected in the patient's aortic valve lesions. Clinical, echocardiographic, anatomopathologic and molecular features supported the diagnosis of severe aortic vegetative endocarditis possibly caused by B. clarridgeiae in a dog in Brazil.

Bartonella infections in cats and dogs including zoonotic aspects

Bartonellosis is a vector-borne zoonotic disease with worldwide distribution that can infect humans and a large number of mammals including small companion animals (cats and dogs). In recent years, an increasing number of studies from around the world have reported Bartonella infections, although publications have predominantly focused on the North American perspective. Currently, clinico-pathological data from Europe are more limited, suggesting that bartonellosis may be an infrequent or underdiagnosed infectious disease in cats and dogs. Research is needed to confirm or exclude Bartonella infection as a cause of a spectrum of feline and canine diseases. Bartonella spp. can cause acute or chronic infections in cats, dogs and humans. On a comparative medical basis, different clinical manifestations, such as periods of intermittent fever, granulomatous inflammation involving the heart, liver, lymph nodes and other tissues, endocarditis, bacillary angiomatosis, peliosis hepatis, uveitis and vasoproliferative tumors have been reported in cats, dogs and humans. The purpose of this review is to provide an update and European perspective on Bartonella infections in cats and dogs, including clinical, diagnostic, epidemiological, pathological, treatment and zoonotic aspects.

Evaluation of cell culture-grown Bartonella antigens in immunofluorescent antibody assays for the serological diagnosis of bartonellosis in dogs

BACKGROUND

Because of poor sensitivity and questionable specificity of immunofluorescent antibody assays (IFAs), serological diagnosis of Bartonella species infections in dogs remains challenging. Despite limitations, IFA testing is the historical "gold standard" for Bartonella serodiagnosis in animals and humans. Because most diagnostic laboratories test against only 1 or 2 Bartonella spp., testing against a broader panel of Bartonella antigens may enhance diagnostic sensitivity and specificity.

OBJECTIVE

To evaluate the sensitivity and specificity of Bartonella IFA using 8 cell culture-grown Bartonella spp. isolates.

ANIMALS

Archived serum samples from 34 Bartonella spp. naturally exposed, polymerase chain reaction (PCR)-positive dogs and from 26 PCR-negative and IFA-negative dogs.

METHODS

Bartonella IFA sensitivity and specificity were assessed using cell culture-grown whole cell antigens derived from 3 Bartonella henselae (Bh) strains (Bh Houston 1, Bh San Antonio Type 2, Bh California 1), 3 Bartonella vinsonii subsp. berkhoffii genotypes (Bvb I, II, and III), Bartonella koehlerae (Bk), and Bartonella quintana (Bq).

RESULTS

Only 62% of 34 Bartonella spp. PCR-positive dogs were seroreactive to any of the 8 Bartonella IFA antigens, indicating low IFA sensitivity. PCR-positive dogs were most often IFA seroreactive to Bq (n = 15), to Bvb II (n = 13), or to both (n = 9) antigens. Of the 26 previously IFA-negative/PCR-negative dogs, 4 (15%) were seroreactive using the expanded antigen panel.

CONCLUSION AND CLINICAL IMPORTANCE

Despite IFA testing of dogs against 8 different Bartonella isolates, IFA sensitivity remained poor, and specificity was only 85%. Development of a reliable serological assay is needed to facilitate the diagnosis of Bartonella infection in dogs.

Polymerase chain reaction detection of Bartonella spp. in dogs from Spain with blood culture-negative infectious endocarditis

OBJECTIVES

The presence of Bartonella spp. was detected by polymerase chain reaction (PCR) in dogs from Spain with blood culture-negative endocarditis. The aim of this study is to add information about canine infectious endocarditis in Europe.

ANIMALS

Thirty dogs with naturally occurring blood culture-negative endocarditis were examined from 2010 to 2017 at three veterinary referral hospitals, located in northwest, northeast, and southeast of Spain.

METHODS

It is a retrospective study. Medical records were reviewed to extract relevant data. Frozen or paraffin-embedded cardiac valve tissue and/or ethylenediamine tetraacetic acid blood samples were evaluated by PCR for the presence of Bartonella DNA. Positive results were sequenced to confirm the species.

RESULTS

Polymerase chain reaction was positive for eight out of 30 dogs included (26.6%). Bartonella rochalimae, Bartonella vinsonii subsp. berkhoffii, and Bartonella koehlerae were detected in valve tissue or blood.

CONCLUSIONS

Bartonella could be an important cause of blood culture-negative infectious endocarditis in dogs from Spain. The outcome for those dogs affected with Bartonella spp. was grave. Prompt empirical treatment with amoxicillin-clavulanate plus fluoroquinolones could be of value in cases of blood culture-negative endocarditis.

Prevalence of Bartonella spp. by culture, PCR and serology, in veterinary personnel from Spain

Background

The genus Bartonella includes fastidious, facultative intracellular bacteria mainly transmitted by arthropods and distributed among mammalian reservoirs. Bartonella spp. implicated as etiological agents of zoonoses are increasing. Apart from the classical Bartonella henselae, B. bacilliformis or B. quintana, other species (B. elizabethae, B. rochalimae, B. vinsonii arupensis and B. v. berkhoffii, B. tamiae or B. koehlerae, among others) have also been associated with human and/or animal diseases. Laboratory techniques for diagnosis (culture, PCR assays and serology) usually show lack of sensitivity. Since 2005, a method based on a liquid enrichment Bartonella alphaproteobacteria growth medium (BAPGM) followed by PCRs for the amplification of Bartonella spp. has been developed. We aimed to assess culture, molecular and serological prevalence of Bartonella infections in companion animal veterinary personnel from Spain.

Methods

Each of 89 participants completed a questionnaire. Immunofluorescence assays (IFA) using B. vinsonii berkhoffii (genotypes I, II and III), B. henselae, B. quintana and B. koehlerae as antigens were performed. A cut-off of 1:64 was selected as a seroreactivity titer. Blood samples were inoculated into BAPGM and subcultured onto blood agar plates. Bartonella spp. was detected using conventional and quantitative real-time PCR assays and DNA sequencing.

Results

Among antigens corresponding to six Bartonella spp. or genotypes, the lowest seroreactivity was found against B. quintana (11.2%) and the highest, against B. v. berkhoffii genotype III (56%). A total of 27% of 89 individuals were not seroreactive to any test antigen. Bartonella spp. IFA seroreactivity was not associated with any clinical sign or symptom. DNA from Bartonella spp., including B. henselae (n = 2), B. v. berkhoffii genotypes I (n = 1) and III (n = 2), and B. quintana (n = 2) was detected in 7/89 veterinary personnel. PCR and DNA sequencing findings were not associated with clinical signs or symptoms. No co-infections were observed. One of the two B. henselae PCR-positive individuals was IFA seronegative to all tested antigens whereas the other one was not B. henselae seroreactive. The remaining PCR-positive individuals were seroreactive to multiple Bartonella spp. antigens.

Conclusions

High serological and molecular prevalences of exposure to, or infection with, Bartonella spp. were found in companion animal veterinary personnel from Spain. More studies using BAPGM enrichment blood culture and PCR are needed to clarify the finding of Bartonella PCR-positive individuals lacking clinical symptoms.

Electronic supplementary material

The online version of this article (10.1186/s13071-017-2483-z) contains supplementary material, which is available to authorized users.

First molecular detection and characterization of zoonotic Bartonella species in fleas infesting domestic animals in Tunisia

Background

Bartonellosis is an emerging vector-borne disease caused by different intracellular bacteria of the genus Bartonella (Rhizobiales: Bartonellaceae) that is transmitted primarily by blood-sucking arthropods such as sandflies, ticks and fleas. In Tunisia, there are no data available identifying the vectors of Bartonella spp. In our research, we used molecular methods to detect and characterize Bartonella species circulating in fleas collected from domestic animals in several of the country’s bioclimatic areas.

Results

A total of 2178 fleas were collected from 5 cats, 27 dogs, 34 sheep, and 41 goats at 22 sites located in Tunisia’s five bioclimatic zones. The fleas were identified as: 1803 Ctenocephalides felis (83%) (Siphonaptera: Pulicidae), 266 C. canis (12%) and 109 Pulex irritans (5%) (Siphonaptera: Pulicidae). Using conventional PCR, we screened the fleas for the presence of Bartonella spp., targeting the citrate synthase gene (gltA). Bartonella DNA was detected in 14% (121/866) of the tested flea pools [estimated infection rate (EIR) per 2 specimens: 0.072, 95% confidence interval (CI): 0.060–0.086]. The Bartonella infection rate per pool was broken down as follows: 55% (65/118; EIR per 2 specimens: 0.329, 95% CI: 0.262–0.402) in C. canis; 23.5% (8/34; EIR per 2 specimens: 0.125, 95% CI: 0.055–0.233) in P. irritans and 6.7% (48/714; EIR per 2 specimens: 0.032, 95% CI: 0.025–0.045) in C. felis. Infection rates, which varied significantly by bioclimatic zone (P < 0.0001), were highest in the humid areas. By sequencing, targeting the gltA gene and the 16S–23S rRNA Intergenic Spacer Regions (ITS), we identified three Bartonella zoonotic species: B. elizabethae, B. henselae, B. clarridgeiae, as well as uncharacterized Bartonella genotypes.

Conclusions

To the best of our knowledge, this is the first time that fleas in Tunisia have been shown to carry zoonotic species of Bartonella. The dog flea, Ctenocephalides canis, should be considered the main potential vector of Bartonella. Our study not only provides new information about this vector, but also offers a public health update: medical practitioners and farmers in Tunisia should be apprised of the presence of Bartonella in fleas and implement preventive measures.

Electronic supplementary material

The online version of this article (10.1186/s13071-017-2372-5) contains supplementary material, which is available to authorized users.

Experimental infection of dogs with various Bartonella species or subspecies isolated from their natural reservoir

Dogs can be infected by a wide variety of Bartonella species. However, limited data is available on experimental infection of dogs with Bartonella strains isolated from domestic animals or wildlife. We report the inoculation of six dogs with Bartonella henselae (feline strain 94022, 16S rRNA type II) in three sets of two dogs, each receiving a different inoculum dose), four dogs inoculated with B. vinsonii subsp. berkhoffii type I (ATCC strain, one mongrel dog) or type II (coyote strain, two beagles and one mongrel) and B. rochalimae (coyote strain, two beagles). None of the dogs inoculated with B. henselae became bacteremic, as detected by classical blood culture. However, several dogs developed severe necrotic lesions at the inoculation site and all six dogs seroconverted within one to two weeks. All dogs inoculated with the B. v. berkhoffii and B. rochalimae strains became bacteremic at levels comparable to previous experimental infections with either a dog isolate or a human isolate. Our data support that dogs are likely accidental hosts for B. henselae, just like humans, and are efficient reservoirs for both B. v. berkhoffii and B. rochalimae.

Genetic diversity of Bartonella quintana in macaques suggests zoonotic origin of trench fever

Bartonella quintana is a bacterium that causes a broad spectrum of diseases in humans including trench fever. Humans were previously considered to be the primary, if not the only, reservoir hosts for B. quintana. To identify the animal reservoir and extend our understanding of the ecological and evolutionary history of B. quintana, we examined blood samples from macaques and performed multilocus sequence typing (MLST) analysis. We demonstrated the prevalence of B. quintana infection was common in macaques from main primate centres in mainland China. Overall, 18.0% (59/328) of rhesus macaques and 12.7% (39/308) of cynomolgus macaques were found to be infected with B. quintana by blood culture and/or polymerase chain reaction. The infection was more frequently identified in juvenile and young monkeys compared with adult animals. In contrast with the relatively low level of sequence divergence of B. quintana reported in humans, our investigation revealed much higher genetic diversity in nonhuman primates. We identified 44 new nucleotide variable sites and 14 novel sequence types (STs) among the B. quintana isolates by MLST analysis. Some STs were found only in cynomolgus macaques, while some others were detected only in rhesus macaques, suggesting evidence of host-cospeciation, which were further confirmed by phylogenetic analysis and Splits decomposition analysis. Our findings suggest that trench fever may primarily be a zoonotic disease with macaques as the natural hosts.

Molecular detection of Bartonella species in ticks from Peru

A total of 103 ticks, collected from canines, horses, donkeys, and snakes from Peru, were screened for the presence of Bartonella DNA by polymerase chain reaction analysis. Bartonella DNA was detected in two ticks using Bartonella 16S-23S intergenic spacer region primers and in an additional two ticks using Bartonella NADH dehydrogenase gamma subunit gene (nuoG) primers. Bartonella rochalimae Eremeeva et al., B. quintana Schmincke, and B. elizabethae Daly et al. DNA was detected in a Rhipicephalus sanguineus Latreille (Acari: Ixodidae) female tick removed from a dog and B. quintana DNA was present in a Dermacentor nitens Neumann (Acari: Ixodidae) pool of five larvae, one nymph, and one adult male tick collected from donkeys. This is the first study to report the detection of B. rochalimae, B. quintana, and B. elizabethae DNA in ticks from Peru. Further investigations must be performed to decipher the role ticks may play in the transmission of Bartonella species.

Bartonella spp. DNA in cardiac tissues from dogs in Colorado and Wyoming

BACKGROUND

Several Bartonella species (spp.) have been identified in dogs diagnosed with infectious endocarditis (IE) or myocarditis.

OBJECTIVE

To interrogate cardiac tissues of dogs with suspected IE for the presence of Bartonella spp. DNA of dogs in the Rocky Mountain states.

ANIMALS

Nine dogs with a clinical diagnosis of endocarditis from January 1990 to June 2008 were included.

METHODS

In this retrospective study, medical records at the Veterinary Teaching Hospital were searched. Animals were excluded if there was no diagnosis of IE in the original necropsy report. Paraffin embedded tissue blocks and medical records were available from 9 dogs. Total DNA was extracted from the cardiac tissues and assessed for Bartonella spp. DNA by 3 polymerase chain reaction (PCR) methods. For positive samples, the Bartonella spp. were determined by genetic sequencing or fluorogenic real-time PCR.

RESULTS

Bartonella henselae DNA was amplified from the tissues of 7 dogs; Bartonella vinsonii subsp berkhoffii DNA was amplified concurrently from 3 dogs. Six dogs were from Colorado and 1 was from Wyoming. Flea or tick infestations were reported in 2 dogs.

CONCLUSIONS AND CLINICAL IMPORTANCE

Bartonella spp. should be on the differential list for dogs in the Rocky Mountain states. The results emphasize the need for routine use of external parasite control products even in regions perceived to have low risk for flea and tick infestations.

Adhesins of Bartonella spp

Adhesion to host cells represents the first step in the infection process and one of the decisive features in the pathogenicity of Bartonella spp. B. henselae and B. quintana are considered to be the most important human pathogenic species, responsible for cat scratch disease, bacillary angiomatosis, trench fever and other diseases. The ability to cause vasculoproliferative disorders and intraerythrocytic bacteraemia are unique features of the genus Bartonella. Consequently, the interaction with endothelial cells and erythrocytes is a focus in Bartonella research. The genus harbours a variety of trimeric autotransporter adhesins (TAAs) such as the Bartonella adhesin A (BadA) of B. henselae and the variably expressed outer-membrane proteins (Vomps) of B. quintana, which display remarkable variations in length and modular construction. These adhesins mediate many of the biologically-important properties of Bartonella spp. such as adherence to endothelial cells and extracellular matrix proteins and induction of angiogenic gene programming. There is also significant evidence that the laterally acquired Trw-conjugation systems of Bartonella spp. mediate host-specific adherence to erythrocytes. Other potential adhesins are the filamentous haemagglutinins and several outer membrane proteins. The exact molecular functions of these adhesins and their interplay with other pathogenicity factors (e.g., the VirB/D4 type 4 secretion system) need to be analysed in detail to understand how these pathogens adapt to their mammalian hosts.

Enrichment culture and molecular identification of diverse Bartonella species in stray dogs

Using pre-enrichment culture in Bartonella alpha-Proteobacteria growth medium (BAPGM) followed by PCR amplification and DNA sequence identification that targeted a fragment of the citrate synthase gene (gltA), we provide evidence of common bartonella infections and diverse Bartonella species in the blood of stray dogs from Bangkok and Khon Kaen, Thailand. The overall prevalence of all Bartonella species was 31.3% (60/192), with 27.9% (31/111) and 35.8% (29/81) in the stray dogs from Bangkok and Khon Kaen, respectively. Phylogenetic analyzes of gltA identified eight species/genotypes of Bartonella in the blood of stray dogs, including B. vinsonii subsp. arupensis, B. elizabethae, B. grahamii, B. quintana, B. taylorii, and three novel genotypes (BK1, KK1 and KK2) possibly representing unique species with ≤ 90.2% similarities to any of the known Bartonella species B. vinsonii subsp. arupensis was the only species detected in dogs from both sites, B. quintana and BK1 were found in the dogs from Bangkok, B. elizabethae, B. taylorii, KK1 and KK2 were found in the dogs from Khon Kaen. We conclude that stray dogs in Thailand are frequently infected with Bartonella species that vary with geographic region. As some Bartonella species detected in the present study are considered pathogenic for humans, stray dogs in Thailand may serve as possible reservoirs for Bartonella causing human illnesses. Further work is needed to determine the role of those newly discovered Bartonella genotypes/species in human and veterinary medicine.

Multi-locus sequence typing of a geographically and temporally diverse sample of the highly clonal human pathogen Bartonella quintana

Bartonella quintana is a re-emerging pathogen and the causative agent of a variety of disease manifestations in humans including trench fever. Various typing methods have been developed for B. quintana, but these tend to be limited by poor resolution and, in the case of gel-based methods, a lack of portability. Multilocus sequence typing (MLST) has been used to study the molecular epidemiology of a large number of pathogens, including B. henselae, a close relative of B. quintana. We developed a MLST scheme for B. quintana based on the 7 MLST loci employed for B. henselae with two additional loci to cover underrepresented regions of the B. quintana chromosome. A total of 16 B. quintana isolates spanning over 60 years and three continents were characterized. Allelic variation was detected in five of the nine loci. Although only 8/4270 (0.002%) of the nucleotide sites examined were variable over all loci, these polymorphisms resolved the 16 isolates into seven sequence types (STs). We also demonstrate that MLST can be applied on uncultured isolates by direct PCR from cardiac valve tissue, and suggest this method presents a promising approach for epidemiological studies in this highly clonal organism. Phylogenetic and clustering analyses suggest that two of the seven STs form a distinct lineage within the population.

A confusing case of canine vector-borne disease: clinical signs and progression in a dog co-infected with Ehrlichia canis and Bartonella vinsonii ssp. berkhoffii

Bartonella spp. are important pathogens in human and veterinary medicine, and bartonellosis is considered as an emerging zoonosis that is being reported with increasing frequency. Of 22 known species and subspecies of Bartonella, seven have been isolated from dogs, causing disease manifestations similar to those seen in human beings. The wide variety of clinical signs and the possible chronic progression of disease manifestations are illustrated in the case of an infected Labrador retriever. Here, the authors discuss the seemingly diverse spectrum of disease manifestations, the co-infections of Bartonella spp. with other vector-borne pathogens (mainly Ehrlichia spp. or Babesia spp.) and the difficulties in microbiological confirmation of an active Bartonella infection, all of which make the disease pathogenesis and clinical diagnosis more problematic.

Ecological fitness and strategies of adaptation of Bartonella species to their hosts and vectors

Bartonella spp. are facultative intracellular bacteria that cause characteristic hostrestricted hemotropic infections in mammals and are typically transmitted by blood-sucking arthropods. In the mammalian reservoir, these bacteria initially infect a yet unrecognized primary niche, which seeds organisms into the blood stream leading to the establishment of a long-lasting intra-erythrocytic bacteremia as the hall-mark of infection. Bacterial type IV secretion systems, which are supra-molecular transporters ancestrally related to bacterial conjugation systems, represent crucial pathogenicity factors that have contributed to a radial expansion of the Bartonella lineage in nature by facilitating adaptation to unique mammalian hosts. On the molecular level, the type IV secretion system VirB/VirD4 is known to translocate a cocktail of different effector proteins into host cells, which subvert multiple cellular functions to the benefit of the infecting pathogen. Furthermore, bacterial adhesins mediate a critical, early step in the pathogenesis of the bartonellae by binding to extracellular matrix components of host cells, which leads to firm bacterial adhesion to the cell surface as a prerequisite for the efficient translocation of type IV secretion effector proteins. The best-studied adhesins in bartonellae are the orthologous trimeric autotransporter adhesins, BadA in Bartonella henselae and the Vomp family in Bartonella quintana. Genetic diversity and strain variability also appear to enhance the ability of bartonellae to invade not only specific reservoir hosts, but also accidental hosts, as shown for B. henselae. Bartonellae have been identified in many different blood-sucking arthropods, in which they are typically found to cause extracellular infections of the mid-gut epithelium. Adaptation to specific vectors and reservoirs seems to be a common strategy of bartonellae for transmission and host diversity. However, knowledge regarding arthropod specificity/restriction, the mode of transmission, and the bacterial factors involved in arthropod infection and transmission is still limited.

Isolation and characterization of Bartonella quintana from the parotid gland of an immunocompetent man

We describe a case of the isolation of Bartonella quintana from the parotid gland of an apparently healthy man. Pathological examination showed intraparotid granulomatous abscessual lymphadenitis. Diagnosis was made on the basis of high titers of immunoglobulin G (IgG) and IgM antibodies and of culture isolation of a causative agent from parotid aspirate.

Infective endocarditis in a dog and the phylogenetic relationship of the associated "Bartonella rochalimae" strain with isolates from dogs, gray foxes, and a human

The first case of canine endocarditis caused by "Bartonella rochalimae" is reported. By PCR-restriction fragment length polymorphism, sequence, and phylogenetic analyses, Bartonella isolates from a dog with endocarditis, 22 gray foxes, and three dogs, described as B. clarridgeiae like, were confirmed to belong to the new species "B. rochalimae," suggesting canids as the natural reservoir.

Analysis of a novel insect cell culture medium-based growth medium for Bartonella species

Human- and animal-pathogenic Bartonella species are fastidious and slow-growing bacteria difficult to isolate and cultivate. We describe a novel, easy-to-prepare liquid medium for the fast and reliable growth of several Bartonella spp. that does not affect bacterial protein expression patterns or interactions with host cells.

Molecular evidence for Bartonella spp. in cat and dog fleas from Germany and France

Nine hundred and fifty-two fleas were collected from 148 cats and 133 dogs at 18 widely distributed geographic locations in Germany and France and examined for the presence of six different Bartonella spp. (Bartonella bacilliformis, Bartonella clarridgeiae, Bartonella elizabethae, Bartonella henselae, Bartonella quintana, Bartonella vinsonii subsp. berkhoffii) by PCR. Thirty-five specimens (3.7%) tested positive for either B. henselae (14 positive fleas) or B. clarridgeiae (21 positive fleas). DNA of other Bartonella spp. were not detected. Bartonella clarridgeiae was the dominating species in samples from France (19 out of 22 positive fleas), whereas B. henselae was more frequent in Germany (11 out of 13 positive fleas). With 3.5% (22 out of 632 fleas) in France and 4.1% (13 out of 320 fleas) in Germany, the overall prevalences of pathogen did not vary significantly between the flea populations of both countries. 5.4% of cats in France versus 16.1% of cats from Germany were infested by fleas carrying Bartonella, whereas 9.5% of dogs in France but none of the examined dogs from Germany were infested by Bartonella positive fleas. The molecular evidence of Bartonella infections reveals that agents of zoonotic potential are established in flea populations in Germany and France and that the spectrum of species can vary significantly from country to country.

Vector transmission of Bartonella species with emphasis on the potential for tick transmission

Bartonella species are gram-negative bacteria that infect erythrocytes, endothelial cells and macrophages, often leading to persistent blood-borne infections. Because of the ability of various Bartonella species to reside within erythrocytes of a diverse number of animal hosts, there is substantial opportunity for the potential uptake of these blood-borne bacteria by a variety of arthropod vectors that feed on animals and people. Five Bartonella species are transmitted by lice, fleas or sandflies. However, Bartonella DNA has been detected or Bartonella spp. have been cultured from numerous other arthropods. This review discusses Bartonella transmission by sandflies, lice and fleas, the potential for transmission by other vectors, and data supporting transmission by ticks. Polymerase chain reaction (PCR) or culture methods have been used to detect Bartonella in ticks, either questing or host-attached, throughout the world. Case studies and serological or molecular surveys involving humans, cats and canines provide indirect evidence supporting transmission of Bartonella species by ticks. Of potential clinical relevance, many studies have proposed co-transmission of Bartonella with other known tick-borne pathogens. Currently, critically important experimental transmission studies have not been performed for Bartonella transmission by many potential arthropod vectors, including ticks.

Detection ofBartonella henselaeDNA in two dogs with pyogranulomatous lymphadenitis

CASE DESCRIPTION

1 dog evaluated because of inappetence and lameness of the left hind limb of 1 day's duration and 1 dog evaluated because of inappetence, fever, and lymphadenopathy of 2 weeks' duration.

CLINICAL FINDINGS

Histologic examination of excisional biopsy specimens from lymph nodes revealed pyogranulomatous lymphadenitis in both dogs. Quantitative real-time PCR assays detected Bartonella henselae DNA in blood samples and affected lymph node specimens from both dogs. Antibodies against B. henselae were not detected via immunofluorescent antibody testing during active disease in either dog.

TREATMENT AND OUTCOME

1 dog recovered after 6 weeks of treatment with doxycycline (5 mg/kg [2.3 mg/lb], p.o., q 12 h), whereas the other dog recovered after receiving a combination of azithromycin (14.5 mg/kg [6.6 mg/lb], p.o., q 24 h for 21 days), doxycycline (17.3 mg/kg [7.9 mg/lb], p.o., q 24 h for 4 weeks), and immunosuppressive corticosteroid (prednisone [3 mg/kg {1.4 mg/lb}, p.o., q 24 h], tapered by decreasing the daily dose by 25% every 2 weeks) treatment.

CLINICAL RELEVANCE

B. henselae is implicated as a possible cause or a cofactor in the development of pyogranulomatous lymphadenitis in dogs. In dogs with pyogranulomatous lymphadenitis, immunofluorescent assays may not detect antibodies against B. henselae. Molecular testing, including PCR assay of affected tissues, may provide an alternative diagnostic method for detection of B. henselae DNA in pyogranulomatous lymph nodes.

Isolation of Bartonella quintana from a woman and a cat following putative bite transmission

We report here the detection of Bartonella quintana, after putative bite transmission, in pre-enrichment blood cultures from a woman and from two feral barn cats. Prospective molecular epidemiological studies are necessary to characterize the risk of human Bartonella quintana infection following cat bites.