title: Multiple fluid collections: CT- or US-guided aspiration--evaluation of microbiologic results and implications for clinical practice.
abstract: OBJECTIVE
  To determine if patients with multiple fluid collections need every collection aspirated and if cross-contamination is a risk if separate sterile procedures are not followed for each aspiration.
  
  
  METHODS
  Records from 1,076 imaging-guided percutaneous aspirations and drainages over 39 months were retrospectively reviewed; 124 patients had multiple fluid collections drained, which yielded 287 aspirates. The patients were divided into two groups: those (n = 82) with multiple collections aspirated on any 1 day, and those (n = 61) with multiple collections aspirated over 10 days. Nineteen patients were included in both groups. Gram stain microscopy and culture results were compared between sequential aspirates in each patient, and their potential effects on antimicrobial therapy and theoretic risk for cross-contamination were evaluated.
  
  
  RESULTS
  In 82 patients undergoing multiple aspirations on any 1 day, multiple microorganisms differed in 32 patients, which indicated a need for therapy change in 18 (22%) patients. In 61 patients undergoing aspiration on different days, microorganisms differed in 32 patients, which indicated a need for therapy change in 15 (25%) patients. Cross-contamination could have occurred in 28 of 93 (30%) aspirates from patients with a second or subsequent collection if separate sterile procedures had not been undertaken.
  
  
  CONCLUSIONS
  When multiple fluid collections are identified, aspirates from all collections should be obtained through separate sterile procedures to ensure optimal antimicrobial coverage and avoid cross-contamination.
authors.affiliation: Department of Radiology, Duke University Medical Center, Durham, NC 27710, USA. heneg002@mc.duke.edu
authors.forename: J P
authors.initials: JP
authors.lastname: Heneghan
authors.forename: R J
authors.initials: RJ
authors.lastname: Everts
authors.forename: R C
authors.initials: RC
authors.lastname: Nelson
mesh_terms: D000328:Adult; D001202:Ascitic Fluid / Q000382:microbiology*; D001431:Bacteriological Techniques / Q000295:instrumentation*; D004322:Drainage / Q000295:instrumentation*; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D010538:Peritonitis / Q000188:drug therapy / Q000382:microbiology*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013396:Suction / Q000295:instrumentation*; D014057:Tomography, X-Ray Computed / Q000295:instrumentation*; D014463:Ultrasonography / Q000295:instrumentation*