Discussion:
Blood culture-negative IE has a high variation in prevalence among countries; the reports vary from 2.5- 70% of all infective endocarditis based on zoonotic agent exposure, antibiotic prescription pattern, and diagnostic tools (10).
Bartonella species are among the main microorganisms in culture-negative endocarditis. Meanwhile, among all 45 known Bartonella species, B. henselae is the second most common cause of culture-negative endocarditis(11). While cats and cat-scratch are considered the main reservoir of B. henselae, dogs could also transmit infection as accidental hosts(12).
Moreover, although Bartonella endocarditis is a worldwide issue and there are case reports from all parts of the world, most reported cases are from European countries and the Americas(11).
In this article, we are reporting a case of Bartonella endocarditis in Iran; it is notable that since Bartonella endocarditis is not common in Iran, usually physician does not put this agent on the list of their differential diagnosis, which causes several challenges to achieving a timely diagnosis and treatment of Bartonella endocarditis. Besides, the final diagnosis is even more challenging due to non-specific symptoms, which are the same as other subacute endocarditis or infective syndromes.
Moreover, the diagnosis is more challenging during the COVID-19 pandemic and the similarity between the typical symptoms of SARS-CoV-2 and endocarditis (13). Nevertheless, several diagnostic tools are available; despite their limitations, such as low specificity and cross-reactions, serology is still considered valuable in diagnosing Bartonella endocarditis(14). Also, PCR testing on whole blood or plasma specimen, with approximate sensitivity of 58% and specificity of 100%, is an effective diagnostic tool(15).
In this case, the patient had a history of contact with dogs, but based on previous studies, connection with cats is more common in most B. henselae endocarditis cases.
Moreover, in the current case, one of the first complaints of the patient was exertional dyspnea, and heart failure manifestations are considered an acute coronary syndrome. At the same time, based on the study conducted by Okaro et al., approximately 50 to 70% of Bartonella endocarditis presents symptoms of heart failure, including exertional dyspnea(11).
Low socioeconomic status is one of the underlying determinants of developing B. quintana endocarditis. While in our patient, who was diagnosed with B. henselae, the patient’s social history regarding IV-drug abuse and low socioeconomic status were the most important considerations (11). Also, prognosis and treatment must consider epidemiological exposure and alternate diagnoses for culture-negative endocarditis in individuals who don’t respond to therapy.
The authors of the article include: Sara Gaderkhani, Bahar Haghdoost, Amirhossein Eghbal, Mahsa Azadbakhsh Kanafgorabi, Saharnaz Sazgarnejad, Saber Esmaeili, Arash Seifi, Ensiyeh Rahimi.
S.Ghaderkhani, A.Seifi and E.Rahimi contributed to the conception and design of this report. The case was diagnosed and followed up by S. Sazgarnejad and S.Esmaeili. B.Haghdoost, A.Eghbal, M.Azaadbakhsh and S.Sazgarnejad participated in data collection. B.Haghdoost, A.Eghbal and M.Azaadbakhsh wrote the article. All authors contributed to data interpretation, critically reviewed the article and approved the final draft for submission.
This manuscript is original, is not published, in press, or submitted elsewhere in English or any other language and is not currently being considered for publication elsewhere.
All authors have seen and approved the content of the manuscript and have contributed significantly to the work.
This study has been approved by the ethics committee of Tehran University of Medical. Sciences, adheres to the Declaration of Helsinki and informed consent was taken.
The patient has given a written informed consent for the publication.
The authors confirm that written consent has been obtained from the patient for submission and publication.
All the patient’s data and materials are provided in the manuscript.
The authors declare that they have no competing interests.
Funding do not applicable in this manuscript.
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