A seven-year prospective study on spondylodiscitis: epidemiological and microbiological features

Abstract

Background: The aim of this paper was to enlarge the available knowledge on clinical and etiological aspects of patients affected by spondylodiscitis.

Patients and methods: All patients with spondylodiscitis admitted between January 2001 and December 2007 at the 1,300-bed University Hospital "Policlinico Umberto I" of Rome, Italy, were followed. Demographic characteristics, underlying diseases, invasive procedures, imaging studies, isolated microorganisms, treatment, complications, and outcome were recorded.

Results: Eighty-one patients of mean age 57.7 +/- 14.7 years with lumbosacral (72.8%), thoracic (14.8%), and cervical tract (12.3%) site of infection were included, of which 38 developed community-acquired (CA) spondylodiscitis and 43 developed hospital-acquired (HA) spondylodiscitis. Underlying disease was present in 49.4% of patients. HA spondylodiscitis was diagnosed earlier (46.8 +/- 49.7 days) than CA spondylodiscitis (65.0 +/- 55.4 days) (P < 0.05). The most frequently isolated microorganisms were Staphylococcus aureus (28 strains, 43.1%), coagulase-negative staphylococci (CNS) (eight strains, 12.3%), Pseudomonas aeruginosa (eight strains, 12.3%), and three methicillin-resistant S. aureus (MRSA) strains were isolated in CA spondylodiscitis. Fungi and yeasts, isolated in six patients, represented 9.2% of all strains but 17.6% when considering only HA spondylodiscitis. Over 85% of patients were managed by conservative treatment alone, and the treatment time depended on clinical and laboratory evidence. Poor outcome was recorded in 12 (14.8%) patients, and was associated with neurological deficit symptoms (relative risk [RR] 2.87; 95% confidence interval [CI] 1.02-8.07; P < 0.05) and the time between diagnosis and the onset of symptoms > or = 60 days (RR 2.65; 95% CI 0.92-7.59; P < 0.05).

Conclusions: Infectious spondylodiscitis affects most frequently the elderly population, who are more exposed to healthcare contacts. Consequently, the infection etiology includes a growing proportion of multi-resistant bacteria and fungi.