Multiple fluid collections: CT- or US-guided aspiration - Evaluation of microbiologic results and implications for clinical practice

PURPOSE: To determine if patients with multiple fluid collections need ever y collection aspirated and if cross-contamination is a risk if separate ste rile procedures are not followed for each aspiration. MATERIALS AND METHODS: Records from 1,076 imaging-guided percutaneous aspir ations and drainages over 39 months were retrospectively reviewed; 124 pati ents had multiple fluid collections drained, which yielded 287 aspirates. T he patients were divided into two groups: those (n = 82) with multiple coll ections aspirated on any 1 day, and those (n = 61) with multiple collection s aspirated over 10 days. Nineteen patients were included in both groups. G ram stain microscopy and culture results were compared between sequential a spirates in each patient, and their potential effects on antimicrobial ther apy and theoretic risk for cross-contamination were evaluated. RESULTS: In 82 patients undergoing multiple aspirations on any 1 day, multi ple microorganisms differed in 32 patients, which indicated a need for ther apy change in 18 (22%) patients. In 61 patients undergoing aspiration on di fferent days, microorganisms differed in 32 patients, which indicated a nee d for therapy change,in 15 (25%) patients. Cross-contamination could have o ccurred in 28 of 93 (30%) aspirates from patients with a second or subseque nt collection if separate sterile procedures had not been undertaken. CONCLUSION: When multiple fluid collections are identified, aspirates from all collections should be obtained through separate sterile procedures to e nsure optimal antimicrobial coverage and avoid cross-contamination.