Prioritisation of potential drug targets against Bartonella bacilliformis by an integrative in-silico approach

BACKGROUND Carrion's disease (CD) is a neglected biphasic illness caused by Bartonella bacilliformis, a Gram-negative bacteria found in the Andean valleys. The spread of resistant strains underlines the need for novel antimicrobials against B. bacilliformis and related bacterial pathogens. OBJECTIVE The main aim of this study was to integrate genomic-scale data to shortlist a set of proteins that could serve as attractive targets for new antimicrobial discovery to combat B. bacilliformis. METHODS We performed a multidimensional genomic scale analysis of potential and relevant targets which includes structural druggability, metabolic analysis and essentiality criteria to select proteins with attractive features for drug discovery. FINDINGS We shortlisted seventeen relevant proteins to develop new drugs against the causative agent of Carrion's disease. Particularly, the protein products of fabI, folA, aroA, trmFO, uppP and murE genes, meet an important number of desirable features that make them attractive targets for new drug development. This data compendium is freely available as a web server (http://target.sbg.qb.fcen.uba.ar/). MAIN CONCLUSION This work represents an effort to reduce the costs in the first phases of B. bacilliformis drug discovery.

Infective endocarditis due to Bartonella bacilliformis associated with systemic vasculitis: a case report

Abstract Infective endocarditis due to Bartonella bacilliformis is rare. A 64-year-old woman, without previous heart disease, presented with 6 weeks of fever, myalgias, and arthralgias. A systolic murmur was heard on the tricuspid area upon examination, and an echocardiogram showed endocardial lesions in the right atrium. Bartonella bacilliformis was isolated in blood cultures, defining the diagnosis of infective endocarditis using Duke's criteria. Subsequently, the patient developed clinical and laboratory features compatible with antineutrophil cytoplasmic antibody-associated vasculitis. This case presents an uncommon complication of B. bacilliformis infection associated with the development of systemic vasculitis.

Rapid and sensitive detection of Bartonella bacilliformis in experimentally infected sand flies by loop-mediated isothermal amplification (LAMP) of the Pap31 gene.

BACKGROUND: Carrion' disease, caused by Bartonella bacilliformis, remains truly neglected due to its focal geographical nature. A wide spectrum of clinical manifestations, including asymptomatic bacteremia, and lack of a sensitive diagnostic test can potentially lead to a spread of the disease into non-endemic regions where competent sand fly vectors may be present. A reliable test capable of detecting B. bacilliformis is urgently needed. Our objective is to develop a loop-mediated isothermal amplification (LAMP) assay targeting the pap31 gene to detect B. bacilliformis. METHODS AND FINDINGS: The sensitivity of the LAMP was evaluated in comparison to qPCR using plasmid DNA containing the target gene and genomic DNA in the absence and presence of human or sand fly DNA. The detection limit of LAMP was 1 to 10 copies/µL, depending on the sample metrics. No cross-reaction was observed when testing against a panel of various closely related bacteria. The utility of the LAMP was further compared to qPCR by the examination of 74 Lutzomyia longipalpis sand flies artificially fed on blood spiked with B. bacilliformis and harvested at days (D) 1, 3, 5, 7 and 9 post feeding. Only 86% of sand flies at D1 and 63% of flies at D3 were positive by qPCR. LAMP was able to detect B. bacilliformis in all those flies confirmed positive by qPCR. However, none of the flies after D3 were positive by either LAMP or qPCR. In addition to demonstrating the sensitivity of the LAMP assay, these results suggest that B. bacilliformis cannot propagate in artificially fed L. longipalpis. CONCLUSIONS: The LAMP assay is as sensitive as qPCR for the detection of B. bacilliformis and could be useful to support diagnosis of patients in low-resource settings and also to identify B. bacilliformis in the sand fly vector.

Skin diseases associated with Bartonella infection: facts and controversies.

The genus Bartonella is composed of a series of species and subspecies. Ten of them are responsible for human infections. The best-identified diseases are cat scratch disease (B henselae and possibly B clarridgeiae), trench fever (B quintana), bacillary angiomatosis (B quintana and B henselae), and the spectrum of verruga peruana, Carrion disease, and Oroya fever (B bacilliformis). Controversies exist about the implication of a few other microorganisms being involved in these diseases. Several other conditions have been associated with the presence of Bartonella spp, but these observations await confirmation.

Isolation and characterization of Bartonella bacilliformis from an expatriate Ecuadorian.

Carrion's disease is typically biphasic with acute febrile illness characterized by bacteremia and severe hemolytic anemia (Oroya fever), followed by benign, chronic cutaneous lesions (verruga peruana). The causative agent, Bartonella bacilliformis, is endemic in specific regions of Peru and Ecuador. We describe atypical infection in an expatriate patient who presented with acute splenomegaly and anemia 3 years after visiting Ecuador. Initial serology and PCR of the patient's blood and serum were negative for Bartonella henselae, Bartonella quintana, and B. bacilliformis. Histology of splenic biopsy was suggestive of bacillary angiomatosis, but immunohistochemistry ruled out B. henselae and B. quintana. Bacilli (isolate EC-01) were subsequently cultured from the patient's blood and analyzed using multilocus sequence typing, protein gel electrophoresis with Western blotting, and an immunofluorescence assay (IFA) against a panel of sera from patients with Oroya fever in Peru. The EC-01 nucleotide sequences (gltA and internal transcribed spacer) and protein band banding pattern were most similar to a subset of B. bacilliformis isolates from the region of Caraz, Ancash, in Peru, where B. bacilliformis is endemic. By IFA, the patient's serum reacted strongly to two out of the three Peruvian B. bacilliformis isolates tested, and EC-01 antigen reacted with 13/20 Oroya fever sera. Bacilliary angiomatosis-like lesions were also detected in the spleen of the patient, who was inapparently infected with B. bacilliformis and who presumably acquired infection in a region of Ecuador where B. bacilliformis was not thought to be endemic. This study suggests that the range of B. bacilliformis may be expanding from areas of endemicity in Ecuador and that infection may present as atypical clinical disease.