title: Staphylococcus aureus bacteremia: comparison of two periods and a predictive model of mortality.
abstract: Staphylococcus aureus is an important pathogen causing bacteremia, primarily affecting hospitalized patients. We studied the epidemiology of S. aureus bacteremia, comparing two periods (early and mid 1990s) and developed a predictive model of mortality. A nested case-control was done. All 251 patients over 14 years old with positive blood cultures for S. aureus were selected. MRSA (methicillin resistant S. aureus) was isolated in 63% of the cases. When comparing the two periods MRSA community-acquired bacteremia increased from 4% to 16% (p=0.01). There was no significant difference in the mortality rate between the two periods (39% and 33%, p=0.40). Intravascular catheters provoked 24% of the cases of bacteremia and were associated with the lowest rate of mortality. In a logistic regression analysis, three variables were associated with death: septic shock, source of bacteraemia and resistance to methicillin. The probability of dying among patients with MRSA and those with methicillin sensitive S. aureus bacteraemia ranged from 10% to 90% and from 4% to 76%, respectively, depending on the source of the bacteraemia and the occurrence of septic shock. The MRSA found in Brazil may be a particularly virulent strain.
authors.affiliation: Division of Infectious Disease of Marília Medical School, Division of Infectious Disease of Federal University of São Paulo, SP, Brazil. lucien@famema.br
authors.forename: Lucieni
authors.initials: L
authors.lastname: de Oliveira Conterno
authors.forename: Sérgio Barsanti
authors.initials: SB
authors.lastname: Wey
authors.forename: Adauto
authors.initials: A
authors.lastname: Castelo
mesh_terms: D000328:Adult; D016470:Bacteremia / Q000188:drug therapy / Q000209:etiology / Q000382:microbiology* / Q000401:mortality*; D001938:Brazil / Q000453:epidemiology; D017714:Community-Acquired Infections / Q000382:microbiology / Q000401:mortality; D003428:Cross Infection / Q000382:microbiology / Q000401:mortality; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D016106:Methicillin Resistance; D008875:Middle Aged; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000209:etiology / Q000401:mortality*; D013211:Staphylococcus aureus