Concordance of Results of Blood and Tissue Cultures from Patients with Pyogenic Spondylitis

Abstract

BackgroundThe aim of this study was to investigate the concordance of results of blood and tissue cultures in patients with pyogenic spondylitis.MethodsWe searched the patients with pyogenic spondylitis in whom micro-organisms were isolated from both blood and tissue cultures by retrospective review of medical records in three tertiary university-affiliated hospitals between January 2005 and December 2015. The species and antimicrobial susceptibility patterns of isolates from blood and tissue cultures were compared with each other.ResultsAmong 141 patients with pyogenic spondylitis in whom micro-organisms were isolated from both blood and tissue cultures, the species of blood and tissue isolates were identical in 135 patients (95.7%, 135/141). Excluding the four anaerobic isolates, we investigated antimicrobial susceptibility patterns of 131 isolates of same species from blood and tissue cultures. Antibiotic susceptibility patterns were identical in 128 patients (97.7%, 128/131). The most common isolates were Staphylococcus aureus (86 patients; 85 concordant and 1 discordant), followed by streptococcus (24 patients; 22 concordant and 2 discordant), and Escherichia coli (8 patients; all concordant).ConclusionWe suggest that a positive blood culture from patients with pyogenic spondylitis could preclude the need for additional tissue cultures, especially when S. aureus and streptococcus grew in blood cultures. Table 1. Micro-organisms isolated from blood and tissues in 135 patients with pyogenic spondylitisConcordant (n = 135) Staphylococcus aureus 85Viridans streptococci11 Streptococcus agalactiae 8 Escherichia coli 8 Enterococcus fecalis 4 Klebsiella pneumonia 2Others17Discordant (n = 6)BloodTissue Propionibacterium avidum Coagulase-negative staphylococcus Streptococcus constellatus, Actinomyces meyeri Streptococcus constellatus, Porphyromonas asaccharolytica Staphylococcus epidermidis, viridans streptococcus Staphylococcus epidermidis Staphylococcus aureus Staphylococcus aureus, Nontuberculous mycobacteria Klebsiella pneumoniae, Acinetobacter baumannii Klebsiella pneumoniae Coagulase-negative staphylococcus Staphylococcus lugdunensis, Candida parapsilosis, Pediococcus species Disclosures All authors: No reported disclosures.