title: Determinants of methicillin-susceptible Staphylococcus aureus native bone and joint infection treatment failure: a retrospective cohort study.
abstract: BACKGROUND
  Although methicillin-susceptible Staphylococcus aureus (MSSA) native bone and joint infection (BJI) constitutes the more frequent clinical entity of BJI, prognostic studies mostly focused on methicillin-resistant S. aureus prosthetic joint infection. We aimed to assess the determinants of native MSSA BJI outcomes.
  
  
  METHODS
  Retrospective cohort study (2001-2011) of patients admitted in a reference hospital centre for native MSSA BJI. Treatment failure determinants were assessed using Kaplan-Meier curves and binary logistic regression.
  
  
  RESULTS
  Sixty-six patients (42 males [63.6%]; median age 61.2 years; interquartile range [IQR] 45.9-71.9) presented an acute (n = 38; 57.6%) or chronic (n = 28; 42.4%) native MSSA arthritis (n = 15; 22.7%), osteomyelitis (n = 19; 28.8%) or spondylodiscitis (n = 32; 48.5%), considered as "difficult-to-treat" in 61 cases (92.4%). All received a prolonged (27.1 weeks; IQR, 16.9-36.1) combined antimicrobial therapy, after surgical management in 37 cases (56.1%). Sixteen treatment failures (24.2%) were observed during a median follow-up period of 63.3 weeks (IQR, 44.7-103.1), including 13 persisting infections, 1 relapse after treatment disruption, and 2 super-infections. Independent determinants of treatment failure were the existence of a sinus tract (odds ratio [OR], 5.300; 95% confidence interval [CI], 1.166-24.103) and a prolonged delay to infectious disease specialist referral (OR, 1.134; 95% CI 1.013-1.271).
  
  
  CONCLUSIONS
  The important treatment failure rate pinpointed the difficulty of cure encountered in complicated native MSSA BJI. An early infectious disease specialist referral is essential, especially in debilitated patients or in presence of sinus tract.
authors.affiliation: Service des maladies infectieuses et tropicales, Hospices Civils de Lyon, Groupement Hospitalier Nord, Lyon, France. florent.valour@chu-lyon.fr.
authors.forename: Florent
authors.initials: F
authors.lastname: Valour
authors.forename: Anissa
authors.initials: A
authors.lastname: Bouaziz
authors.forename: Judith
authors.initials: J
authors.lastname: Karsenty
authors.forename: Florence
authors.initials: F
authors.lastname: Ader
authors.forename: Sébastien
authors.initials: S
authors.lastname: Lustig
authors.forename: Frédéric
authors.initials: F
authors.lastname: Laurent
authors.forename: Christian
authors.initials: C
authors.lastname: Chidiac
authors.forename: Tristan
authors.initials: T
authors.lastname: Ferry
mesh_terms: D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D000890:Anti-Infective Agents / Q000494:pharmacology; D005260:Female; D006801:Humans; D007249:Inflammation; D016015:Logistic Models; D008297:Male; D008712:Methicillin / Q000494:pharmacology*; D016106:Methicillin Resistance / Q000187:drug effects*; D008875:Middle Aged; D016017:Odds Ratio; D010019:Osteomyelitis / Q000188:drug therapy; D011379:Prognosis; D012008:Recurrence; D012189:Retrospective Studies; D013203:Staphylococcal Infections / Q000188:drug therapy*; D013211:Staphylococcus aureus / Q000187:drug effects*; D017211:Treatment Failure; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D008712:Methicillin