title: Impact of serology and molecular methods on improving the microbiologic diagnosis of infective endocarditis in Egypt.
abstract: BACKGROUND
  Conventional diagnosis of infective endocarditis (IE) is based mainly on culture-dependent methods that may fail because of antibiotic therapy or fastidious microorganisms.
  
  
  OBJECTIVE
  We aimed to evaluate the added values of serological and molecular methods for diagnosis of infective endocarditis.
  
  
  METHODS
  One hundred and fifty-six cases of suspected endocarditis were enrolled in the study. For each patient, three sets of blood culture were withdrawn and serum sample was collected for Brucella, Bartonella and Coxiella burnetii antibody testing. Galactomannan antigen was added if fungal endocarditis was suspected. Broad range PCR targeting bacterial and fungal pathogens were done on blood culture bottles followed by sequencing. Culture and molecular studies were done on excised valve tissue when available.
  
  
  RESULTS
  One hundred and thirty-two cases were diagnosed as definite IE. Causative organisms were detected by blood cultures in 40 (30.3 %) of cases. Blood culture-negative endocarditis (BCNE) represented 69.7 %. Of these cases, PCR followed by sequencing on blood and valvular tissue could diagnose five cases of Aspergillus flavus. Eleven patients with BCNE (8.3 %) were diagnosed as zoonotic endocarditis by serology and PCR including five cases of Brucella spp, four cases of Bartonella spp and two cases of Coxiella burnetii. PCR detected three cases of Brucella spp and two cases of Bartonella spp, while cases of Coxiella burnetii were PCR negative. The results of all diagnostic tools decreased the percentage of non-identified cases of BCNE from 69.7 to 49.2 %.
  
  
  CONCLUSIONS
  Our data underline the role of serologic and molecular tools for the diagnosis of blood culture-negative endocarditis.
authors: Clinical Pathology Department, Faculty of Medicine, Cairo University, Giza, Egypt.
authors: Amany Aly
authors: AA
authors: El-Kholy
authors: Clinical Pathology Department, Faculty of Medicine, Cairo University, Giza, Egypt.
authors: Nevine Gamal El-din
authors: NG
authors: El-Rachidi
authors: Clinical Pathology Department, Faculty of Medicine, Cairo University, Giza, Egypt.
authors: Mervat Gaber
authors: MG
authors: El-Enany
authors: Clinical Pathology Department, Faculty of Medicine, Cairo University, Giza, Egypt. eimanmousa@yahoo.com.
authors: Eiman Mohammed
authors: EM
authors: AbdulRahman
authors: Clinical Pathology Department, Faculty of Medicine, Cairo University, Giza, Egypt.
authors: Reem Mostafa
authors: RM
authors: Mohamed
authors: Cardiology Department, Faculty of Medicine, Cairo University, Giza, Egypt.
authors: Hussien Hasan
authors: HH
authors: Rizk
mesh_terms: D000293:Adolescent; D000328:Adult; D004534:Egypt; D004696:Endocarditis / Q000175:diagnosis*; D006801:Humans; D008828:Microbiological Techniques / Q000379:methods*; D008875:Middle Aged; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D012680:Sensitivity and Specificity; D012698:Serologic Tests / Q000379:methods*; D055815:Young Adult
keywords: Blood culture-negative endocarditis; Broad range PCR; Brucella spp.