title: Rapid Time to Positivity of Cerebrospinal Fluid Culture with Coagulase-Negative Staphylococcus Is More Likely to Reflect a True Infection Than Contamination.
abstract: OBJECTIVE
  Cerebrospinal fluid (CSF) culture is the gold standard for diagnosing postoperative central nervous system infection. The time to positivity (TTP) of an automated continuous blood culture system may indicate the original concentration of the organism. Coagulase-negative Staphylococcus (CoNS), the common organism recovered in CSF, poses difficulty in differentiating infection from contamination. This study investigated the TTP of CSF culture with CoNS and its relationship to clinical parameters and prognosis.
  
  
  METHODS
  Adult neurosurgical patients with CoNS who recovered via the use of CSF culture in BacT/ALERT Pediatric FAN blood culture bottles and were admitted from September 2013 to July 2015 were enrolled. The demographics, clinical and microbiological data, and treatment were reviewed, and the TTP of each culture was retrieved.
  
  
  RESULTS
  Thirty-nine adult patients with CoNS recovered from CSF culture were included. The TTP ranged from 7.68 to 57.36 hours. A univariate logistic regression analysis indicated patients with rapid TTP (<21.5 hours) compared with those with longer TTP were more likely to be female, show an effective response to antibiotic therapy within 7 days, have clean-contaminated surgical incisions, and show CSF leak. A multivariate logistic regression analysis indicated that being female, an effective antibiotic therapy within 7 days, and clean-contaminated surgical incisions were independent predictors of rapid TTP.
  
  
  CONCLUSIONS
  Targeted antibiotic therapy was more likely to be beneficial to patients with a rapid TTP within 7 days, which suggested that CoNS with a rapid TTP represents the pathogen of central nervous system infection rather than contamination in neurosurgical patients.
authors.affiliation: Department of Clinical Laboratory, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China.
authors.forename: Rong
authors.initials: R
authors.lastname: Da
authors.affiliation: Department of Clinical Laboratory, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China.
authors.forename: Youwei
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Clinical Laboratory, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China.
authors.forename: Wanjing
authors.initials: W
authors.lastname: Liu
authors.affiliation: Department of Clinical Laboratory, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China.
authors.forename: Hong
authors.initials: H
authors.lastname: Shi
authors.affiliation: Department of Neurosurgery, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China. Electronic address: wei_wangdoc@163.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D001431:Bacteriological Techniques / Q000379:methods; D001921:Brain / Q000382:microbiology*; D020806:Central Nervous System Bacterial Infections / Q000134:cerebrospinal fluid* / Q000000981:diagnostic imaging / Q000382:microbiology*; D003030:Coagulase; D004866:Equipment Contamination; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013203:Staphylococcal Infections / Q000134:cerebrospinal fluid* / Q000175:diagnosis / Q000382:microbiology*; D013997:Time Factors; D055815:Young Adult
chemical_list: D003030:Coagulase
keywords: Cerebrospinal fluid culture; Clean-contaminated surgical incisions; Coagulase-negative Staphylococcus; Neurosurgery; Time to positivity