The effects of postoperative antibiotics in endoscopic sinus surgery

Previous research into post-operative antibiotic usage for chronic rhinosinusitis (CRS) patients generated contradictory results. Some studies found that post-operative antibiotics did not improve the short-term clinical outcomes, while some did. Those studies had also focused primarily on the clinical outcomes of the surgery, overlooking the potential impact of prophylactic antibiotics on the sinonasal microbiome. Using cultivation-independent methods, this study aimed to examine the impact of post-operative antibiotics on the sinonasal microbiome alongside short-term clinical outcomes of CRS patients undergoing endoscopic sinus survey (ESS). Twelve patients undergoing ESS to treat their CRS were enrolled in this study and randomly distributed into two groups: an antibiotic treatment group and a placebo treatment group. The antibiotic treatment group received doxycycline for 28 days after surgery. Clinical information, including computed tomography scans, symptom questionnaires, and nasal endoscopy, were collected for each patient before and after ESS. Swab and tissue samples were collected and underwent DNA extraction, PCR amplification of the bacterial 16S rRNA gene, and amplicon sequencing analysis to longitudinally characterise each patient's sinonasal microbiome. There were no differences in symptom scores or endoscopic/radiological scores between treatment groups before or after the surgery, and there was no significant difference in the microbiome between the treatment groups after surgery. Our preliminary study showed that post-operative antibiotics did not improve short-term clinical outcomes for CRS patients undergoing ESS, and there was no significant difference in the microbiome between treatments, either. However, our preliminary findings reflect only short-term effects, and many of our analyses were statistically underpowered due to the modest sample size. A larger study is needed to explore specific patterns observed in our data with greater confidence.