Abstract
Purpose of study
The aim of this study was to identify the incidence of Gram negative bacterial vertebral osteomyelitis (VO) within our unit during a 3-year study period and evaluate if this corresponds to published evidence that the occurrence is increasing.
Methods
Between May 2007 and May 2010, all patients, over the age of 18 years, suffering from Gram-negative VO were identified and their microbiological diagnoses were evaluated. All patients were treated within a large tertiary spinal surgery unit in Leeds.
Results
This study identified 79 patients with haematogenous VO. Of these 79 patients, 10 patients (12.66%) had Gram-negative organisms isolated. These organisms included E. Coli (4), Pseudomonal aeruginosa (3), Klebsiella pneumonia (1), Haemophilus influenza (1) and Enterobacter cloacae (1). Four patients had the causative organism isolated on =2 positive blood cultures, three from biopsy and =2 positive blood culture, one from biopsy alone and two were diagnosed from 1 positive blood culture.
Conclusion
VO is a common manifestation of osteomyelitis in adults, representing 2-7% of all cases of osteomyelitis. Staphylococcus aureus is the most common causative aetiological agent in haematogenous spinal infections, accounting for between 40 - 60% of cases. Despite the fact that Gram negative bacteria infections represent a minor proportion of all cases of VO, around 15 - 23%, recent evidence suggests that the microbiology of this disease may be changing and the incidence of Gram-negative bacterial infections are increasing. This has been attributed a variety of factors including, an increasing proportion of individuals with predisposing risk factors such as advanced age, diabetes mellitus, malignancy and better diagnostic techniques. Results from our study show an incidence of Gram-negative VO of 12%, which is less than results quoted in the literature and does not confirm recent evidence that these types of spinal infections are increasing in incidence.
