Associations between blood cultures after surgery for colorectal cancer and long-term oncological outcomes

Significance of blood culture testing after pancreatoduodenectomy

Aim

The aim of this study was to clarify the significance of blood culture testing in the postoperative period of pancreatoduodectomy (PD), a highly invasive surgery.

Methods

Rates of blood culture sampling and positivity were investigated for febrile episodes (FEs) in patients who underwent PD (2016-2021). FEs were defined as body temperature of 38.0°C or higher occurring on or after the 4th postoperative day. Fever origin was diagnosed retrospectively, and FEs were classified as pancreatic fistula (PF)-related or PF-unrelated FEs. Factors correlated with blood culture positivity were explored.

Results

Among 339 patients who underwent PD, 99 experienced 202 FEs. Blood culture testing was performed on 160 FEs occurring in 89 patients. The sampling and positivity rates were 79.2% and 17.5%, respectively, per episode and 89.9% and 28.1%, respectively, per patient. Thirty-six FEs were classified as PF-related and 124 were classified as PF-unrelated FEs. The blood culture positivity rate was significantly lower in PF-related vs. PF-unrelated FEs (1/36 vs. 27/124, respectively, p = 0.006). The blood culture positivity rate was significantly higher in patients with cholangitis, catheter-related blood stream infection, and urinary tract infection than PF-related FEs. Multivariate analysis showed that blood culture positivity was negatively associated with PF-related FEs and positively associated with accompanying symptoms of shivering, Pitt Bacteremia Score, and preoperative biliary drainage.

Conclusions

Patients who underwent PD showed relatively high blood culture positivity rates. Based on these results, it may be possible to distinguish PF-related and -unrelated FEs.

Alterations in blood microbiota after colonic cancer surgery

BACKGROUND

Mechanisms contributing to the perioperative stress response remain poorly understood. This study investigated changes in the amount of bacterial DNA in blood and the diversity of blood microbiota in the perioperative period in patients undergoing minimally invasive surgery for colonic cancer in an enhanced recovery after surgery setting.

METHODS

DNA encoding the bacterial 16S ribosomal RNA gene (16S rDNA) in whole blood obtained the day before surgery, and on postoperative day (POD) 1 and POD 10-14 was amplified and quantified by PCR before sequencing for taxonomic assignment. Richness, evenness and similarity measures were calculated to compare microbiota between days. Differences in relative abundance were analysed using the linear discriminant analysis effect size (LEfSe) algorithm.

RESULTS

Thirty patients were included between January and July 2016. The concentration of bacterial 16S rDNA in blood increased between the day before surgery and POD 1 (P = 0.025). Bacterial richness was lower on POD 10-14 than on the day before surgery and POD 1 (both P < 0·001). LEfSe analysis comparing the day before surgery and POD 10-14 identified changes in the abundance of several bacteria, including Fusobacterium nucleatum, which was relatively enriched on POD 10-14.

CONCLUSION

These findings suggest that the blood of patients with colonic cancer harbours bacterial 16S rDNA, which increases in concentration after surgery.