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Microbiology of Vertebral Osteomyelitis and Implications on Empiric Therapy. Abbye Clark, BS University of South Carolina School of Medicine. IDweek 2017 Abstract #65531. Disclosures. The authors have no financial disclosures. Background.
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Microbiology of Vertebral Osteomyelitis and Implications on Empiric Therapy Abbye Clark, BS University of South Carolina School of Medicine IDweek 2017 Abstract #65531
Disclosures • The authors have no financial disclosures
Background • Common organisms implicated in vertebral osteomyelitis (VO) include: • Staphylococcus aureus, coagulase-negative Staphylococcusspp., Streptococcusspp., and Enterobacteriaceae • The management of VO includes empiric antibiotics while clinical cultures are being processed • McHenry MC. Clin Infect Dis. 2002 • Weissman S. Scand J Infect Dis. 2014 • Gouliouris TJ. AntimicrobChemother 2010 • Berbari EF. Clin Infect Dis. 2015
Aims of Study • Develop institutional guidelines for empiric therapy of VO based on: • Local epidemiology and microbiology • Risk factors for VO due to gram-negative bacilli
Methods: Study Design • A retrospective cohort of hospitalized subjects ≥18 years, diagnosed with VO from 08/01/2010 to 08/31/2015 at Palmetto Health hospitals in Columbia, SC, USA • ICD-9 codes corresponding to VO, discitis, spondylodiscitis, paravertebral abscess, and sacroilitis
Methods: Criteria • Inclusion criteria • VO confirmed if 2/3 for the following accompanied ICD-9 code: • Clinical symptoms • Imaging suggestive of VO • Positive cultures from bloodstream or vertebral region biopsy • Exclusion criteria • Absence of VO on chart review • Presence of sacral decubitus ulcer adjacent to VO
Methods: Statistical Analysis • Multivariate logistic regression was used to identify the risk factors of VO due to gram-negativeinfection
Results: Associated Abscesses • 113 (75%) subjects had at least one associated abscess
Results: Microbiology • 121 (81%) subjects had positive cultures
Results: VO with Hardware In Situ • 14 subjects had VO with Hardware In Situ (HAVO) • 12 subjects had positive cultures • 11/12 (92%) were due to gram-positive bacteria
Limitations • Retrospective, single center study • Too few gram-negative bacilli affected power of predictive model • Fewer than recommended number of samples taken at the time of biopsy
Conclusions • Predominance of VO due to gram-positive bacteria (86% overall) • 84% in native VO • 92% in presence of hardware • Cancer, diverticular disease and injection drug use were associated with increased risk of VO due to gram-negative bacilli
Implications for Clinical Practice • IV vancomycin monotherapy may be reasonable for empiric therapy in non-critically ill patients while awaiting Gram stain and clinical culture results • Addition of gram-negative coverage to vancomycin may be justified in critically-ill patients or those with specific risk factors
Acknowledgments Study Team: • Neha Sharma, BS • Sharon Weissman, MD • Majdi Al-Hasan, MD • Caroline Derrick, PharmD • KamlaSanasi-Bhola, MD
Microbiology of Vertebral Osteomyelitis and Implications on Empiric Therapy Questions? Contact: Abbye Clark, BS Abbye.Clark@uscmed.sc.edu