title: Septic arthritis of the knee: clinical and laboratory comparison of groups with different etiologies.
abstract: To clinically and epidemiologically characterize a population diagnosed with and treated for septic arthritis of the knee, to evaluate the treatment results and to analyze the differences between patients with positive and negative culture results, patients with Gram-positive and Gram-negative bacterial isolates and patients with S. aureus- and non-S. aureus-related infections.
  One hundred and five patients with septic knee arthritis were included in this study. The clinical and epidemiological data were evaluated. Statistical analysis was performed to compare patients with and without an isolated causative agent, patients with Gram-positive and Gram-negative pathogens and patients with S. aureus-related and non S. aureus-related infections.
  Causative agents were isolated in 81 patients. Gram-positive bacteria were isolated in 65 patients and Gram-negative bacteria were isolated in 16 patients. The most commonly isolated bacterium was S. aureus. Comparing cases with an isolated pathogen to cases without an isolated pathogen, no differences between the studied variables were found except for the longer hospital stays of patients in whom an etiological agent was identified. When comparing Gram-positive bacteria with Gram-negative bacteria, patients with Gram-positive-related infections exhibited higher leukocyte counts. Patients with S. aureus-related infections were more frequently associated with healthcare-related environmental encounters.
  S. aureus is the most common pathogen of septic knee arthritis. Major differences were not observed between infections with isolated and non-isolated pathogens and between infections with Gram-positive and Gram-negative bacteria. S. aureus infections were more likely to be associated with a prior healthcare environment exposure.
authors.affiliation: Faculdade de Medicina da Universidade de São Paulo, Departamento de Ortopedia e Traumatologia, Divisão de Cirurgia do Joelho, Sa˜o Paulo/SP Brazil.
authors.forename: Camilo Partezani
authors.initials: CP
authors.lastname: Helito
authors.affiliation: Faculdade de Medicina da Universidade de São Paulo, Departamento de Ortopedia e Traumatologia, Divisão de Cirurgia do Joelho, Sa˜o Paulo/SP Brazil.
authors.forename: Paulo Renan Lima
authors.initials: PR
authors.lastname: Teixeira
authors.affiliation: Faculdade de Medicina da Universidade de São Paulo, Departamento de Ortopedia e Traumatologia, Divisa˜o de Doenc¸as Infecciosas, Sa˜o Paulo/SP Brazil.
authors.forename: Priscila Rosalba de
authors.initials: PR
authors.lastname: Oliveira
authors.affiliation: Faculdade de Medicina da Universidade de São Paulo, Departamento de Ortopedia e Traumatologia, Divisa˜o de Doenc¸as Infecciosas, Sa˜o Paulo/SP Brazil.
authors.forename: Vladimir Cordeiro de
authors.initials: VC
authors.lastname: Carvalho
authors.affiliation: Faculdade de Medicina da Universidade de São Paulo, Departamento de Ortopedia e Traumatologia, Divisão de Cirurgia do Joelho, Sa˜o Paulo/SP Brazil.
authors.forename: José Ricardo
authors.initials: JR
authors.lastname: Pécora
authors.affiliation: Faculdade de Medicina da Universidade de São Paulo, Departamento de Ortopedia e Traumatologia, Divisão de Cirurgia do Joelho, Sa˜o Paulo/SP Brazil.
authors.forename: Gilberto Luis
authors.initials: GL
authors.lastname: Camanho
authors.affiliation: Faculdade de Medicina da Universidade de São Paulo, Departamento de Ortopedia e Traumatologia, Divisão de Cirurgia do Joelho, Sa˜o Paulo/SP Brazil.
authors.forename: Marco Kawamura
authors.initials: MK
authors.lastname: Demange
authors.affiliation: Faculdade de Medicina da Universidade de São Paulo, Departamento de Ortopedia e Traumatologia, Divisa˜o de Doenc¸as Infecciosas, Sa˜o Paulo/SP Brazil.
authors.forename: Ana Lucia Munhoz
authors.initials: AL
authors.lastname: Lima
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001170:Arthritis, Infectious / Q000453:epidemiology / Q000382:microbiology*; D001938:Brazil; D002097:C-Reactive Protein / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D005260:Female; D006090:Gram-Negative Bacteria / Q000302:isolation & purification*; D006094:Gram-Positive Bacteria / Q000302:isolation & purification*; D006801:Humans; D007223:Infant; D007717:Knee / Q000382:microbiology; D007719:Knee Joint / Q000382:microbiology*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D017678:Sex Distribution; D013203:Staphylococcal Infections / Q000453:epidemiology; D013211:Staphylococcus aureus / Q000302:isolation & purification; D055815:Young Adult
chemical_list: D002097:C-Reactive Protein