title: Abdominal actinomycosis in the last 10 years and risk factors for appendiceal actinomycosis: review of the literature.
abstract: Actinomycosis is a granulomatous disease caused by filamentous, gram-positive, anaerobic bacteria. Actinomycetes are commensal inhabitants of the oral cavity and intestinal tract but acquire pathogenicity through invasion of breached or necrotic tissue.1397645907In abdominal actinomycosis (AA), the appendix and ileocecal region are usually involved. The aim of this study was to characterize patients diagnosed with AA and to establish the risk factors for appendiceal actinomycosis, including a short review of the literature.
  
  
  
  We conducted a prospective cohort study of all patients diagnosed with AA in the University Hospital Marques de Valdecilla (Santander-Cantabria) from January 2003 to October 2013. We also conducted a short review of the literature.
  
  
  
  We characterized the epidemiological features of patients diagnosed with AA and risk factors for the involvement of the appendix, as most of the cases were misdiagnosed as appendicitis. Risk factors for appendiceal actinomycosis are no antecedents of carcinoma (P = 0.034) and previous incorrect diagnosis (P = 0.006).
  
  
  
  AA is a rare and chronic infection. It is only reported in case reports in the literature. We present the largest series of patients diagnosed with AA. Half of the patients had morbidities, mostly carcinoma, and penicillin was the preferred treatment. More studies are needed to characterize patients affected with AA and to establish the correct treatment.
authors.affiliation: Department of General Internal Medicine, Hospital Universitario Marqués de Valdecilla, Santander, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Lisa-Gracia
authors.affiliation: Department of General Internal Medicine, Hospital Universitario Marqués de Valdecilla, Santander, Spain.
authors.forename: Berta
authors.initials: B
authors.lastname: Martín-Rivas
authors.affiliation: Home Care Unit, Hospital Universitario Marqués de Valdecilla, Santander, Spain.
authors.forename: Marcos
authors.initials: M
authors.lastname: Pajarón-Guerrero
authors.affiliation: Infectious Diseases Unit, Hospital Universitario Marqués de Valdecilla, Santander, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Arnáiz-García
mesh_terms: D000196:Actinomycosis / Q000175:diagnosis / Q000453:epidemiology; D000368:Aged; D001064:Appendicitis / Q000175:diagnosis / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology