Background:

Previous studies show an increasing incidence of gram-negative organisms in surgical site infections after spine surgery. This study is looking for the association of the post-operative prophylactic use of Bactrim and the gram-negative surgical site infection after lumbar spine surgery.

Methods:

Patients who underwent lumbar spine surgery between August 2010 and December 2019 at the institution were retrospectively reviewed.

Results:

There were 11 infections out of 511 cases where no oral antibiotics were given (2.2%). There were 2 infections out of 84 cases where Bactrim was given (2.4%). This was not statistically significant (P=0.89). The organisms cultured from the no oral antibiotic group were 8 cases of methicillin sensitive Staphylococcus aureus (MSSA), 1 case of E. coli, 1 case of Pseudomonas aeruginosa, 1 case of MRSA. The organisms cultured from the Bactrim group were 1 case of MRSA, and 1 case of combined Citrobacter freundii and methicillin sensitive Staphylococcus aureus (MSSA).

Conclusion:

There was no statistically significant difference in SSIs when Bactrim was given for two weeks after surgery. However, two subjects who developed infection from the Bactrim group were paradoxically affected by gram-negative and antibiotic resistant organisms. So, clinicians should be judicious in their use of oral antibiotics after spine surgery. Level of Evidence: III.