A quality improvement study on the relationship between intranasal povidone-iodine and anesthesia and the nasal microbiota of surgery patients

INTRODUCTION

The composition of the nasal microbiota in surgical patients in the context of general anesthesia and nasal povidone-iodine decolonization is unknown. The purpose of this quality improvement study was to determine: (i) if general anesthesia is associated with changes in the nasal microbiota of surgery patients and (ii) if preoperative intranasal povidone-iodine decolonization is associated with changes in the nasal microbiota of surgery patients.

MATERIALS AND METHODS

One hundred and fifty-one ambulatory patients presenting for surgery were enrolled in a quality improvement study by convenience sampling. Pre- and post-surgery nasal samples were collected from patients in the no intranasal decolonization group (control group, n = 54). Pre-decolonization nasal samples were collected from the preoperative intranasal povidone-iodine decolonization group (povidone-iodine group, n = 97). Intranasal povidone-iodine was administered immediately prior to surgery and continued for 20 minutes before patients proceeded for surgery. Post-nasal samples were then collected. General anesthesia was administered to both groups. DNA from the samples was extracted for 16S rRNA sequencing on an Illumina MiSeq.

RESULTS

In the control group, there was no evidence of change in bacterial diversity between pre- and post-surgery samples. In the povidone-iodine group, nasal bacterial diversity was greater in post-surgery, relative to pre-surgery (Shannon's Diversity Index (P = 0.038), Chao's richness estimate (P = 0.02) and Inverse Simpson index (P = 0.027). Among all the genera, only the relative abundance of the genus Staphylococcus trended towards a decrease in patients after application (FDR adjusted P = 0.06). Abundant genera common to both povidone-iodine and control groups included Staphylococcus, Bradyrhizobium, Corynebacterium, Dolosigranulum, Lactobacillus, and Moraxella.

CONCLUSIONS

We found general anesthesia was not associated with changes in the nasal microbiota. Povidone-iodine treatment was associated with nasal microbial diversity and decreased abundance of Staphylococcus. Future studies should examine the nasal microbiota structure and function longitudinally in surgical patients receiving intranasal povidone-iodine.

PSIX-25 Documenting succession of the rumen microbial community in dairy calves

Dairy cattle rely exclusively on the microbiota within their gastrointestinal tract for nutrient provisioning as they lack the endogenous enzymes needed to convert their plant-based diet into an accessible form. The acquisition of a fully functioning gut microbiome early in life is critical to survival of these animals. The establishment of a calf’s gut microbiota has previously been characterized using proxies such as fecal sampling and destructive sampling methods, but it is unclear how accurate these methods are over time in the same animals. To address this, 10 dairy calves were cannulated at 3 weeks of age. Rumen liquid and rumen solid samples were collected biweekly in congruence with buccal swabs and fecal samples from 7–17 weeks of age and characterized using Illumina 16S rRNA V4 amplicon sequencing. Fecal and buccal samples contained similar amounts of shared operational taxonomic units (OTUs) to the rumen pre-weaning but separated post-weaning such that buccal samples contained nearly double the number of shared OTUs. Beta diversity showed that fecal communities more closely resemble the rumen than buccal but shift as the animals begin ruminating such that buccal communities more closely resemble the rumen. This suggests that fecal samples would serve as a more accurate proxy prior to weaning whereas buccal samples would more accurately represent the rumen after weaning. These data will be invaluable for researchers interested in understanding the acquisition, succession, and establishment of the calf rumen microbiota using non-invasive approaches.