Detection rate of pathogenic bacteria and its potential risk factors in deep infection after spinal instrumented surgery

English Keywords:Spinal disease  Instrumented surgery  Deep infection  Pathogenicity  Detection rate

English Abstract:

  【Abstract】 Objectives: To analyze the distribution of pathogenic bacteria deep surgical site infection after spinal instrumented surgery and the potential risk factors affecting the detection rate. Methods: All patients diagnosed with deep surgical site infection after spinal instrumented surgery were selected between January 2009 and January 2019. Distributionand detection rate of pathogenic bacteriawere analyzed. Data including age, sex, surgical indication, surgical region, number of operated vertebrae, operative time, type of infection(early and late onset infection), specimen collection time span(time from the initial operation to sample collection), antibiotic intervention before specimen collection, and antibiotic intervention time span were compared to assess the potential risk factors for reducing detection rate. Results: 89 patients met the enrollment criteria, and 38 patients had positive culture result, among which 31 patients suffered mono-infection and 7 patients suffered multi-infection. The detection rate was 42.7%. 47 strains of pathogenic bacteria were collected, with 26 strains of Gram-positive bacteria, 20 strains of Gram-negative bacteria and 1 strain of fungus. The main pathogens were Staphylococcus aureus(13 strains, 27.7%), Escherichia coli(8 strains, 17.0%), Staphylococcus epidermidis(5 strains, 10.6%), Pseudomonas aeruginosa(5 strains, 10.6%). Type of infection(P=0.002), specimen collection time span(P=0.044) and antibiotic intervention(P<0.001) all affected the detection rate of pathogenic bacteria, the difference were statistically significant. Surgical indication, surgical region, number of operated vertebrae, operative time, and antibiotic intervention time span had no effect on the detection rate (P<0.05). Conclusions: The detection rate of pathogenic bacteria was 42.7%. Staphylococcus aureus and Escherichia coliwere the main pathogens. Antibiotic intervention and the time span of specimen collection could affect the detection rate, and the pathogenic bacteria could be more easily cultivated in late-onset infection.