Metagenomic Analysis of Microdissected Valvular Tissue for Etiologic Diagnosis of Blood Culture Negative Endocarditis

Matthieu Million (1, 2) , Maxime Gaudin (1, 2) , Clea Melenotte (1, 2) , Lionel Chasson (3, 2) , Sophie Edouard (1, 2) , Constance Verdonk (4) , Elsa Prudent (1, 2) , Bernard Amphoux (1, 2) , Stéphane Meresse (3, 2) , Richard Dorent (5) , Hubert Lepidi (1, 2, 6) , Bernard La Scola (7, 1, 2) , Jean-Pierre Gorvel (3, 2) , Christelle Desnues (1, 8, 2) , Didier Raoult (1, 2)

1 MEPHI - Microbes évolution phylogénie et infections
2 AMU - Aix Marseille Université
3 CIML - Centre d'Immunologie de Marseille - Luminy
4 Hospital Bichat Paris
5 AP-HP - Hôpital Bichat - Claude Bernard [Paris]
6 TIMONE - Hôpital de la Timone [CHU - APHM]
7 APHM - Assistance Publique - Hôpitaux de Marseille
8 MIO - Institut méditerranéen d'océanologie

Background Etiological diagnosis is a key to therapeutic adaptation and improved prognosis, particularly for infections such as endocarditis. In blood culture–negative endocarditis (BCNE), 22% of cases remain undiagnosed despite an updated comprehensive syndromic approach. This prompted us to develop a new diagnostic approach. Methods Eleven valves from 10 BCNE patients were analyzed using a method that combines human RNA bait-depletion with phi29 DNA polymerase-based multiple displacement amplification and shotgun DNA sequencing. An additional case in which a microbe was serendipitously visualized by immunofluorescence was analyzed using the same method, but after laser capture microdissection. Results Background DNA prevented any diagnosis in cases analyzed without microdissection because the majority of sequences were contaminants. Moraxella sequences were dramatically enriched in the stained microdissected region of the additional case. A consensus genome sequence of 2.4 Mbp covering more than 94% of the Moraxella osloensis KSH reference genome was reconstructed with 234X average coverage. Several antibiotic-resistance genes were observed. Etiological diagnosis was confirmed using Western blot and specific polymerase chain reaction with sequencing on a different valve sample. Conclusions Microdissection could be a key to the metagenomic diagnosis of infectious diseases when a microbe is visualized but remains unidentified despite an updated optimal approach. Moraxella osloensis should be tested in blood culture–negative endocarditis

Keywords: blood culture–negative endocarditis; laser capture microdissection; human RNA bait-depletion; Moraxella osloensis

Domains: Life Sciences [q-bio]; Microbiology and Parasitology; Bacteriology; Life Sciences [q-bio]; Human health and pathology; Infectious diseases; Life Sciences [q-bio]; Human health and pathology; Cardiology and cardiovascular system; Life Sciences [q-bio]; Bioengineering; Imaging

Matthieu Million, Maxime Gaudin, Clea Melenotte, Lionel Chasson, Sophie Edouard, et al.. Metagenomic Analysis of Microdissected Valvular Tissue for Etiologic Diagnosis of Blood Culture Negative Endocarditis. Clinical Infectious Diseases, 2019, 70 (11), ⟨10.1093/cid/ciz655⟩. ⟨hal-02195898⟩