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Volume 32, Number 11—November 2026
Research
Microbial Etiology of Postoperative Spinal Fusion Infections and Factors Associated with Gram-Negative Infections, United States, 2021–2022
Table 2
Distribution of causative microorganisms in postoperative spinal infections after spinal fusion in study of microbial etiology of postoperative spinal fusion infections and factors associated with gram-negative infections, United States, 2021–2022*
| Microorganism | No. (%) cases, N = 7,187 |
|---|---|
| Staphylococcus species | 3,044 (42.4) |
| Staphylococcus aureus | 2,200 (30.6) |
| Coagulase-negative staphylococci (except S. lugdunensis) | 824 (11.5) |
| S. lugdunensis |
73 (1.0) |
| Enterococcus species |
340 (4.7) |
| Streptococcus species, including nutritionally variant streptococci |
191 (2.7) |
| Other commensal gram-positive bacteria (e.g., Corynebacterium species) |
143 (2.0) |
| Enterobacterales | 1,786 (24.9) |
| Escherichia coli | 565 (7.9) |
| Proteus mirabilis | 362 (5.0) |
| Klebsiella pneumoniae | 297 (4.1) |
| Enterobacter cloacae complex | 275 (3.8) |
| Serratia marcescens |
255 (3.5) |
| Nonfermenting gram-negative bacilli | 560 (7.8) |
| Pseudomonas aeruginosa |
501 (7.0) |
| Other mucosal gram-negative bacilli (e.g., Hemophilus species) |
16 (0.2) |
| Cutibacterium species |
274 (3.8) |
| Other anaerobic bacteria (e.g., Bacteroides, Finegoldia species) |
214 (3.0) |
| Fungi | 139 (1.9) |
| Candida species |
131 (1.8) |
| Mycobacteria |
8 (0.1) |
| Organism not fully identified | 144 (2.0) |
*All organisms represent unique organisms identified in all cultures across cases. The total number of unique organisms, (7,512), is greater than the total number of reported cases (N = 7,187) due to the number of polymicrobial cases reported. Organism frequency is reported as the percent of organisms involved across cases. Enterobacterales category includes additional species not individually listed. Non-fermenting gram-negative bacilli include species other than Pseudomonas aeruginosa. Percentages do not sum to 100% because not all organisms are listed in this table.