title: Endocarditis caused by anaerobic bacteria.
abstract: BACKGROUND
  Infective endocarditis (IE) caused by anaerobic bacteria is a rare and poorly characterized disease. Most data reported in the literature are from case reports [1-3]. Therefore, we assessed the situation of anaerobic IE (AIE) in Spain using the database of the Spanish Collaboration on Endocarditis (GAMES).
  
  
  METHODS
  We performed a prospective study from 2008 to 2016 in 26 Spanish centers. We included 2491 consecutive cases of definite IE (Duke criteria).
  
  
  RESULTS
  Anaerobic bacteria caused 22 cases (0.9%) of definite IE. Median age was 66 years (IQR, 56-73), and 19 (86.4%) patients were men. Most patients (14 [63.6%]) had prosthetic valve IE and all episodes were left-sided: aortic valves, 12 (54.5%); and mitral valves, 8 (36.4%). The most common pathogens were Propionibacterium acnes (14 [63.6%]), Lactobacillus spp (3 [13.63%]), and Clostridium spp. (2 [9.0%]), and the infection was mainly odontogenic. Fifteen of the 22 patients (68.2%) underwent cardiac surgery. Mortality was 18.2% during admission and 5.5% after 1 year of follow-up. When patients with AIE were compared with the rest of the cohort, we found that although those with AIE had a similar age and Charlson comorbidity index, they were more likely to have community-acquired IE (86.4% vs. 60.9%, p = 0.01), have undergone cardiac surgery (68.2% vs 48.7% p = 0.06), and have had lower mortality rates during admission (18.2% vs. 27.3%).
  
  
  CONCLUSIONS
  IE due to anaerobic bacteria is an uncommon disease that affects mainly prosthetic valves and frequently requires surgery. Otherwise, there are no major differences between AIE and IE caused by other microorganisms.
authors.affiliation: Servicio de Microbiología y Enfermedades Infecciosas, Hospital General Universitario Gregorio Marañón, Departamento de Medicina, Facultad de Medicina, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón, CIBERES, Spain. Electronic address: kestler.martha@gmail.com.
authors.forename: M
authors.initials: M
authors.lastname: Kestler
authors.affiliation: Servicio de Microbiología y Enfermedades Infecciosas, Hospital General Universitario Gregorio Marañón, Departamento de Medicina, Facultad de Medicina, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón, CIBERES, Spain; CIBER de Enfermedades Respiratorias -CIBERES(CB06/06/0058), Madrid, Spain. Electronic address: pmunoz@micro.hggm.es.
authors.forename: P
authors.initials: P
authors.lastname: Muñoz
authors.affiliation: Servicio de Microbiología y Enfermedades Infecciosas, Hospital General Universitario Gregorio Marañón, Departamento de Medicina, Facultad de Medicina, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón, CIBERES, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Marín
authors.affiliation: Hospital Universitario de Donosti, Spain.
authors.forename: M A
authors.initials: MA
authors.lastname: Goenaga
authors.affiliation: Hospital Universitario de Donosti, Spain.
authors.forename: P
authors.initials: P
authors.lastname: Idígoras Viedma
authors.affiliation: Hospital Universitario Virgen del Rocío, Spain.
authors.forename: A
authors.initials: A
authors.lastname: de Alarcón
authors.affiliation: Hospital Universitario Virgen del Rocío, Spain.
authors.forename: J A
authors.initials: JA
authors.lastname: Lepe
authors.affiliation: Hospital Universitario A Coruña, Spain.
authors.forename: D
authors.initials: D
authors.lastname: Sousa Regueiro
authors.affiliation: Hospital Universitario A Coruña, Spain.
authors.forename: J M
authors.initials: JM
authors.lastname: Bravo-Ferrer
authors.affiliation: Hospital Universitario Marqués de Valdecilla, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Pajarón
authors.affiliation: Hospital Universitario Central de Asturias, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Costas
authors.affiliation: Hospital Universitario Virgen de la Victoria, Spain.
authors.forename: M V
authors.initials: MV
authors.lastname: García-López
authors.affiliation: Hospital Universitario Virgen de las Nieves, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Hidalgo-Tenorio
authors.affiliation: Hospital Universitario La Paz, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Moreno
authors.affiliation: Servicio de Microbiología y Enfermedades Infecciosas, Hospital General Universitario Gregorio Marañón, Departamento de Medicina, Facultad de Medicina, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón, CIBERES, Spain; CIBER de Enfermedades Respiratorias -CIBERES(CB06/06/0058), Madrid, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Bouza
mesh_terms: D000368:Aged; D001421:Bacteria, Anaerobic / Q000145:classification* / Q000302:isolation & purification*; D004697:Endocarditis, Bacterial / Q000453:epidemiology* / Q000382:microbiology*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D016459:Prosthesis-Related Infections / Q000453:epidemiology* / Q000382:microbiology*; D013030:Spain / Q000453:epidemiology
keywords: Anaerobes; Infective endocarditis; Propionibacterium acnes