Molecular detection of Coxiella burnetii in heart valve tissue from patients with culture-negative infective endocarditis.

Abstract

Coxiella burnetii is a common cause of blood culture-negative infective endocarditis (IE). Molecular detection of C burnetii DNA in clinical specimens is a promising method of diagnosing Q fever endocarditis. Here, we examined the diagnostic utility of Q fever polymerase chain reaction (PCR) of formalin-fixed heart valve tissue from patients with blood culture-negative IE who underwent heart valve surgery. Clinical and laboratory data of patients with blood culture-negative IE who underwent heart valve surgery during a 6-year period and for whom biopsy tissues were available were reviewed retrospectively. Blood culture-positive IE patients who underwent heart valve surgery within the last 3 years were used as controls. Heart valve samples were cultured and also subjected to histological examination and PCR for Q fever, brucellosis, and bartonellosis. Data from 20 patients with blood culture-negative IE and 20 with blood culture-positive IE were analyzed. Eight cases of blood culture-negative IE were PCR-positive for C burnetii (40%; 95% confidence interval, 19-64). No specimen was PCR-positive for brucellosis or bartonellosis. Histologically, 4 of 8 specimens with a positive Q fever PCR result were characterized by clusters of multinucleated giant cells without a fibrin ring. None of 20 patients with blood culture-negative IE received anti-Coxiella antibiotic therapy due to lack of clinical suspicion. Six-month mortality was higher in the Q fever PCR-positive group than in the Q fever PCR-negative group [38% (3/8) vs 0% (0/12), P = .049). Of the 20 patients with blood culture-positive IE, none yielded a positive Q fever PCR result for valve tissue. Approximately 40% of patients with culture-negative IE who received heart valve surgery were PCR-positive for Q fever; patients without clinical suspicion suffered high mortality. These data suggest that Q fever IE in patients with culture-negative IE is often missed in routine clinical practice.

• Authors: Young-Rock Jang, Joon Seon Song, Choong Eun Jin, Byung-Han Ryu, Se Yoon Park, Sang-Oh Lee, Sang-Ho Choi, Yang Soo Kim, Jun Hee Woo, Jae-Kwan Song, Yong Shin, Sung-Han Kim
• Journal: Medicine (Medicine (Baltimore)) Vol. 97 Issue 34 Pg. e11881 (Aug 2018) ISSN: 1536-5964 [Electronic] United States
• PMID: 30142785 (Publication Type: Journal Article, Observational Study)

Topics

• Adult
• Aged
• Blood Culture
• Cardiac Surgical Procedures (adverse effects)
• Coxiella burnetii (genetics)
• Endocarditis (diagnosis, etiology, microbiology)
• Female
• Heart Valves (microbiology)
• Humans
• Male
• Middle Aged
• Polymerase Chain Reaction (methods)
• Q Fever (complications, diagnosis)
• Retrospective Studies
• Survival Rate