Presentation Abstract
Session: P466-P525-Trauma Posters
Date/Time: Tuesday, Mar 19, 2013, 8:00 AM - 5:30 PM
Posters occur Tuesday through Saturday.
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Location McCormick Place, Academy Hall B
Presentation Number: Poster P486
Posterboard Number: P486
Title: The Impact of Multiple Cultures on Antibiotic Usage: A Protocol for Nonunion and Hardware Infections
Classification: +Post Traumatic Reconstruction (Trauma)
Keywords: Nonunion/Malunion; Fracture Healing; Perioperative Complications; Infectious
Author(s): Michael Kuhne, MD, Portland, Oregon
Joseph Volpi, BS, Portland, Oregon
Penelope Barnes, MBBS, PhD, Portland, Oregon
Darin M. Friess, MD, Portland, Oregon
Abstract: INTRODUCTION: Skin flora organisms (SFOs) isolated from one or two biopsies in cases of fracture nonunion or possible deep implant infection are difficult to distinguish as contamination or infection. Prosthetic joint studies suggest multiple biopsies may help with definitive diagnosis. This has never been analyzed in cases with other orthopaedic implants. This study examined the change in microbiological diagnosis and resultant antibiotic treatment when the number of intra-operative biopsies was increased from 1-2 to ≥5 and incubation prolonged to 10 days to detect fastidious bacteria.
METHODS: A cohort of patient cases was constructed from a 16-month retrospective chart review. Patients undergoing either removal of hardware, irrigation and debridement with deep non-arthroplasty orthopaedic implant present, revision of nonunion, or conversion of prior surgery to total joint arthroplasty were identified. Inclusion criteria were five separate surgical biopsies, each cultured for 10 days (using separate sterile instruments). Coagulase negative Staphylococcus, Corynebacteria and Propionibacteria were defined as SFOs. Patients were categorized into four groups based upon the results of multiple cultures. Patients with (1) all cultures sterile and not treated for infection, (2) virulent infection defined as ≥1/5 biopsies growing a virulent organism (S.aureus, Pseudomonas, etc.), (3) SFO infection defined as ≥3 biopsies growing the same SFO or (4) SFO contaminant defined as one to two biopsies growing SFOs. Change in antibiotic treatment was defined as tailoring treatment from broad-spectrum coverage to organism specific coverage, avoiding treatment of a SFO contaminant or treating an SFO infection.
RESULTS: Fifty-two cases fulfilled inclusion criteria. In 21 cases, all biopsies were sterile. Seventeen cases grew virulent organism(s). However, virulent organisms were not grown in 26% of biopsies from these cases. Thus, multiple biopsies identified the virulent organism in four cases that could have been missed with one biopsy. Seven infections due to SFOs were definitively identified; that would not have been possible with one biopsy. Fourteen of 296 biopsies grew contaminant SFOs in 13 cases; thus, two patients were identified as having SFO contaminant that would not have been possible with only one to two biopsies. In summary, multiple biopsies changed microbiological diagnosis in 13/52 cases (25%, 95% Confidence Interval 14-39%). Antibiotic treatment was narrowed in four cases of virulent organism infection, targeted to an SFO infection in five cases and held in two cases of SFO contamination. In summary multiple biopsies changed postoperative antibiotic management in 11/52 cases (21%, 95% CI 11-25%) .
CONCLUSION: In comparison to one to two biopsies, five or more biopsies increased accuracy of diagnosis and altered post-operative antibiotic management in nearly one quarter of the cases.
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发表于 2013-4-18 10:14
发表于 2013-4-18 11:14