TO THE EDITOR
Comment on “Propionibacterium acnes, Coagulase-Negative Staphylococcus, and the ‘Biofilm-Like’ Intervertebral Disc”
The prospective study by Coscia et al1 was conducted to determine the presence of microbial colonization and disc degeneration. They enrolled 87 patients (46 males, 41 females) with good health and no history of previous disc surgery. The mean age was 40 years (±15.2). A total of 169 intervertebral disc samples were obtained. They concluded that there is a significant relation between disc herniation and bacterial presence. The results of this study are similar to that of our recent study entitled “Modic changes in the adjacent vertebrae due to disc material infection with Propionibacterium acnes in patients with lumbar disc herniation.”2 According to the study by Coscia et al, of 62 samples of lumbar disc herniation and lumbar spine with discogenic pain, 35 (56%) samples were positive culture and 13 (20.9%) were positive for P. acnes.1 They did not show their results in patients of two groups (with modic changes [MCs] and without MCs) in a separate table; however, they concluded that there was no relation between the MC severity and culture results.1 In our study of 120 samples obtained from patients with lumbar disc herniation, 62 (56.6%) samples were positive culture and 36 (30%) were positive for P. acnes. The total number of positive culture and P. acnes–positive samples was higher than that in the study by Coscia et al.1 From 36 patients with MCs positive, 36 samples were positive for P. acnes, and this proves the importance of P. acnes that leads to MCs.2 According to the study by Coscia et al, of 62 samples of lumbar disc herniation and lumbar spine with discogenic pain, 17 (27.4%) were positive for coagulase-negative Staphylococcus.1 This rate was lower in our study, and from 120 samples, seven (5.83%) samples were positive for coagulase-negative Staphylococcus.2 Overall, results of these two studies are similar, but there is little difference in details. Something that may affect these details can be the time of onset. In our study, patients suffered low back pain from 2 to 6 months but in the study by Coscia et al, it is unclear.2 Based on these two studies it can be concluded that positive bacterial cultures have an important role that causes disc herniation, but the role of P. acnes is still unknown. More studies are recommended to clear the role of P. acnes in disc herniation.