Microbiological spectrum of SSI pathogens in patients with chronic infectious spondylitis requiring revision surgery: results of continuous monocentric 5-year monitoring

Abstract

Objective. To analyze the results of the continuous monocentric 5-year microbiological monitoring of causative agents of surgical site infection (SSI) in patients who underwent primary surgery for chronic infectious spondylitis and required revision surgery.Material and Methods. The study included patient data from 2018 to 2022. The primary cohort included 569 consecutively operated patients with chronic infectious spondylitis of nonspecific (n1 = 214) and tuberculous (n2 = 355) etiology. The analyzed sample was formed taking into according to inclusion and exclusion criteria. Thus, in 99 patients who required revision surgical interventions due to the development of SSI, a continuous microbiological monitoring of pathogens was performed, including the assessment of drug resistance and the timing of the development of infectious complications. Periodization of the time of SSI development was performed according to the accepted classification of Prinz et al. (2020), the assessment of drug resistance spectrum was performed according to the EUCAST recommendations (2020) and taking into account the approved methodological recommendations.Results. In the general structure of surgical interventions for chronic infectious spondylitis, the share of revision interventions due to the development of SSI was 17.4 %. The highest incidence of complications was noted in the late postoperative period (χ2 = 9.237; p = 0.009). Bacterial detection from the material of vertebral localization was noted in 43 cases (48.3 %), pathogen strains were isolated in urine in 28 (60.8 %), in decubital ulcers in 11 (23.9 %) and in hemoculture in 7 (15.2 %) patients. Culture negative SSI was detected in 10 cases (10.1 %) in the late period. Infectious complications in the setting of chronic non-specific spondylitis were detected more frequently than in spondylitis of tuberculous etiology (χ2 = 21.345; p < 0.001). Gram-positive multidrug-resistant and Gram-negative bacteria with extreme resistance prevailed in the microbiological landscape of late SSI, and Gram-positive strains without drug resistance in that of early and delayed SSI (χ2 = 17.516; p = 0.0032).Conclusion. Drug-resistant Gram-positive bacteria predominate in the structure of SSI with a significantly higher frequency of complication development. Nonspecific etiology of spondylitis is associated with a significantly higher incidence of SSI. In the absence of a positive result of bacteriological examination of the material of vertebral localization, it is advisable to collect blood, decubital ulcer secretion and urine sampling.