title: Time-to-positivity of blood culture: An independent prognostic factor of monomicrobial Pseudomonas aeruginosa bacteremia.
abstract: OBJECTIVE
  Pseudomonas aeruginosa bacteremia is an important cause of nosocomial infections with high morbidity and mortality. Time-to-positivity (TTP) of blood cultures is considered to be a predictor of the clinical outcome for bacteremia. The aim of the study is to investigate the relationship between TTP and clinical outcomes in patients with monomicrobial P. aeruginosa bacteremia.
  
  
  METHODS
  From January 2013 to June 2014, a retrospective cohort study was conducted in a 1200-bed tertiary care hospital. The cases of monomicrobial P. aeruginosa bacteremia were studied. TTP and clinical parameters were determined and analyzed.
  
  
  RESULTS
  In 139 cases of P. aeruginosa bacteremia, TTP ≤ 13 hours was associated with higher Pitt bacteremia scores (5.3 ± 4.2 vs. 2.3 ± 2.8, p < 0.001), severe sepsis (66.1% vs. 35.0%, p < 0.001), higher 30-day mortality rate (54.2% vs. 15.0%, p < 0.001), longer hospitalization in the survivors (25.6 ± 48.5 days vs. 16.3 ± 15.3 days, p = 0.16), and more admission to intensive care unit (27.2% vs. 16.3%, p = 0.14). Risk factors for 30-day mortality in the univariate analysis included corticosteroid exposure, primary bacteremia, concurrent pneumonia, a high Pitt bacteremia score, severe sepsis, and TTP ≤ 13 hours. In the multivariate analysis, primary bacteremia, a pulmonary origin of bacteremia, severe sepsis, and TTP ≤ 13 hours were independent risk factors for 30-day mortality.
  
  
  CONCLUSIONS
  In cases of monomicrobial P. aeruginosa bacteremia, a short TTP (≤ 13 hours) provides prognostic information, in addition to clinical parameters.
authors.affiliation: Division of Infectious Diseases, Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan; Division of Infectious Diseases, Department of Internal Medicine, Tainan Municipal Hospital, Tainan, Taiwan.
authors.forename: Poh-Chang
authors.initials: PC
authors.lastname: Tang
authors.affiliation: Division of Infectious Diseases, Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan; Center for Infection Control, National Cheng Kung University Hospital, Tainan, Taiwan.
authors.forename: Ching-Chi
authors.initials: CC
authors.lastname: Lee
authors.affiliation: Division of Infectious Diseases, Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan; Center for Infection Control, National Cheng Kung University Hospital, Tainan, Taiwan.
authors.forename: Chia-Wen
authors.initials: CW
authors.lastname: Li
authors.affiliation: Division of Infectious Diseases, Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan; Center for Infection Control, National Cheng Kung University Hospital, Tainan, Taiwan.
authors.forename: Ming-Chi
authors.initials: MC
authors.lastname: Li
authors.affiliation: Division of Infectious Diseases, Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan; Center for Infection Control, National Cheng Kung University Hospital, Tainan, Taiwan. Electronic address: winston3415@gmail.com.
authors.forename: Wen-Chien
authors.initials: WC
authors.lastname: Ko
authors.affiliation: Division of Infectious Diseases, Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan; Center for Infection Control, National Cheng Kung University Hospital, Tainan, Taiwan. Electronic address: nanyao@mail.ncku.edu.tw.
authors.forename: Nan-Yao
authors.initials: NY
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016470:Bacteremia / Q000175:diagnosis* / Q000382:microbiology; D001769:Blood / Q000382:microbiology*; D000071997:Blood Culture / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011552:Pseudomonas Infections / Q000175:diagnosis* / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000302:isolation & purification*; D012189:Retrospective Studies; D062606:Tertiary Care Centers; D013997:Time Factors; D055815:Young Adult
keywords: Pseudomonas aeruginosa; bacteremia; time-to-positivity