Q Fever Endocarditis in Romania: The First Cases Confirmed by Direct Sequencing

International Journal of Molecular Sciences

Ani Ioana Cotar²  Daniela Badescu²  Mihaela Oprea²  Sorin Dinu²  Otilia Banu⁴  Dan Dobreanu⁵  Minodora Dobreanu³  Adina Ionac¹  Mirela Flonta⁶ 

[1] Institute for Cardiovascular Diseases Timisoara, Str. Gheorghe Adam, 13A, 300310, Timişoara, Timis, Romania; E-Mail:;National Institute for Research in Microbiology and Immunology, Cantacuzino, Spl. Independentei 103, 050096, Bucharest, Romania; E-Mails:;University of Medicine and Pharmacy Targu Mures, Str. Gheorghe Marinescu 38, 540139, Targu Mures, Mures, Romania; E-Mail:;Institute for Emergency Cardiovascular Diseases Prof. C.C. Iliescu, Sos. Fundeni 258, 022328, Bucharest, Romania; E-Mail:;Institute for Cardiovascular Diseases and Transplant Targu Mures, Str. Gheorghe Marinescu 50, 540136, Targu Mures, Mures, Romania; E-Mail:;Clinical Hospital for Infectious Diseases Cluj-Napoca, Str. Iuliu Moldovan 23, 400348, Cluj-Napoca, Cluj, Romania; E-Mail:

关键词: chronic Q fever;    blood culture-negative endocarditis;    molecular diagnosis;   

DOI  :  10.3390/ijms12129504

来源: mdpi

【 摘 要 】

Infective endocarditis (IE) is a serious, life-threatening disease with highly variable clinical signs, making its diagnostic a real challenge. A diagnosis is readily made if blood cultures are positive, but in 2.5 to 31% of all infective endocarditis cases, routine blood cultures are negative. In such situations, alternative diagnostic approaches are necessary. Coxiella burnetii and Bartonella spp. are the etiological agents of blood culture-negative endocarditis (BCNE) most frequently identified by serology. The purpose of this study is to investigate the usefulness of molecular assays, as complementary methods to the conventional serologic methods for the rapid confirmatory diagnostic of Q fever endocarditis in patients with BCNE. Currently, detection of C. burnetii by culture or an antiphase I IgG antibody titers >800 represents a major Duke criterion for defining IE, while a titers of >800 for IgG antibodies to either B. henselae or B. quintana is used for the diagnosis of endocarditis due to Bartonella spp. We used indirect immunofluorescence assays for the detection of IgG titers for C. burnetii, B. henselae and B. quintana in 57 serum samples from patients with clinical suspicion of IE. Thirty three samples originated from BCNE patients, whereas 24 were tested before obtaining the blood cultures results, which finally were positive. The results of serologic testing showed that nine out of 33 BCNE cases exhibited antiphase I C. burnetii IgG antibody titer >800, whereas none has IgG for B. henselae or B. quintana. Subsequently, we used nested-PCR assay for the amplification of C. burnetii DNA in the nine positive serum samples, and we obtained positive PCR results for all analyzed cases. Afterwards we used the DNA sequencing of amplicons for the repetitive element associated to htpAB gene to confirm the results of nested-PCR. The results of sequencing allowed us to confirm that C. burnetii is the causative microorganism responsible for BCNE. In conclusion, the nested PCR amplification followed by direct sequencing is a reliable and accurate method when applied to serum samples, and it may be used as an additional test to the serological methods for the confirmatory diagnosis of BCNE cases determined by C. burnetii.

【 授权许可】

CC BY   
© 2011 by the authors; licensee MDPI, Basel, Switzerland.