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. 2025 Mar 31;17(3):e81519.
doi: 10.7759/cureus.81519. eCollection 2025 Mar.

Assessing the Effectiveness of Antibiotic Irrigation to Reduce Bacterial Load at the Spinal Surgical Site: An In-Vitro Study

Rawan Masarwa  1 , Ofir Uri  1 , Abed Athamna  1 , Sarit Freimann  1 , Ali Yassin  1 , Elie Najjar  1 , Rodrigo Muscogliati  2   1 , Weronika Nocun  1   3 , Eyal Behrbalk  1
Affiliations

Assessing the Effectiveness of Antibiotic Irrigation to Reduce Bacterial Load at the Spinal Surgical Site: An In-Vitro Study

Rawan Masarwa et al. Cureus. .

Abstract

Introduction Intra-operative surgical site irrigation with antibiotics is believed to reduce the risk of infection in spine surgeries involving instrumentation. However, despite its frequent use, there is limited supporting evidence for this practice. This prospective in-vitro study aims to evaluate the effect of short-term antibiotic exposure on the growth of common pathogens associated with wound infections. Furthermore, this study aims to determine the optimal duration of antibiotic exposure to eradicate common surgical site infection organisms. Methods A suspension of one of three micro-organisms: (1) Staphylococcus aureus, (2) Staphylococcus epidermidis, or (3) Pseudomonas aeruginosa was added to 2-ml vials of an enriched medium, containing one of three antibiotics: (a) Vancomycin, (b) Gentamicin, or (c) Cefazolin. The final inoculum of each micro-organism was 103 CFU/ml, representing a contaminated surgical wound in spine surgery. Antibiotics were washed out from the suspension by a centrifugation technique after (i) 5 minutes, or (ii) 8 hours. The recovery of growth of the micro-organisms was monitored by laser light scattering technology. Results P. aeruginosa inoculated in vials with Gentamicin showed no 24-hour bacterial growth after 5-minute and 8-hour exposure to the antibiotic. Vials of all other bacteria-antibiotic combinations showed bacterial growth curves similar to the control vials after both 5-minute and 8-hour exposures to antibiotics, with no signs of bacterial growth inhibition. Conclusion The study demonstrated that Gentamicin effectively inhibited P. aeruginosa growth after both short-term (5-minute) and long-term (8-hour) exposures. However, no significant bacterial growth inhibition was observed with other bacteria-antibiotic combinations, regardless of the exposure time. These findings suggest that while Gentamicin may be effective against P. aeruginosa in the context of surgical site irrigation, the use of Vancomycin and Cefazolin does not appear to provide the same level of effectiveness for the other tested pathogens. Further studies are needed to evaluate alternative antibiotic strategies for broader infection control in spine surgeries.

Keywords: in-vitro study; intra-operative antibiotic prophylaxis; post-operative wound infections; spine surgery; surgical site infection; surgical site irrigation.

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Conflict of interest statement

Human subjects: All authors have confirmed that this study did not involve human participants or tissue. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.

Figures

Figure 1
Figure 1. Growth curves of Pseudomonas aeruginosa and Staphylococcus aureus 24 hours after 5-minute exposure to gentamicin.
See this image and copyright information in PMC

References

    1. Surgical site infection: incidence and impact on hospital utilization and treatment costs. de Lissovoy G, Fraeman K, Hutchins V, Murphy D, Song D, Vaughn BB. Am J Infect Control. 2009;37:387–397. - PubMed
    1. Reducing surgical site infection in spinal surgery with betadine irrigation and intrawound vancomycin powder. Tomov M, Mitsunaga L, Durbin-Johnson B, Nallur D, Roberto R. Spine (Phila Pa 1976) 2015;40:491–499. - PMC - PubMed
    1. Intrawound vancomycin decreases the risk of surgical site infection after posterior spine surgery: a multicenter analysis. Devin CJ, Chotai S, McGirt MJ, et al. Spine (Phila Pa 1976) 2018;43:65–71. - PubMed
    1. Risk factors for surgical site infection after instrumented fixation in spine trauma. Cooper K, Glenn CA, Martin M, Stoner J, Li J, Puckett T. J Clin Neurosci. 2016;23:123–127. - PMC - PubMed
    1. Intra-wound antibiotics and infection in spine fusion surgery: a report from Washington State's SCOAP-CERTAIN Collaborative. Ehlers AP, Khor S, Shonnard N, et al. Surg Infect (Larchmt) 2016;17:179–186. - PMC - PubMed

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