Impact of Preoperative Occult-Bacterial Translocation on Surgical Site Infection in Patients Undergoing Pancreatoduodenectomy

Background: Occult-bacterial translocation (O-BT) has been reported as the condition in which microorganisms are detected in blood or lymph nodes by a highly sensitive method. However, the clinical impact of preoperative O-BT on postoperative complication is unclear. Study design: A prospective observational study with patients undergoing pancreatoduodenectomy for periampullary diseases was conducted. Blood samples were collected immediately after induction of anesthesia. The status of O-BT was investigated using bacterium-specific ribosomal RNA-targeted reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR). The impact of O-BT on surgical site infection (SSI) was analyzed. Results: A total of 155 patients were included. The positive rate in preoperative blood samples detected by RT-qPCR was significantly higher than that obtained by the culture method (32 of 155 vs 4 of 155, p < 0.001). Preoperative blood samples were contaminated with 1.0 to 19.2 bacterial cells/mL in positive patients, and 30 of the 41 detected microorganisms were obligate anaerobes. No differences in preoperative factors were observed between patients with positive and negative RT-qPCR results. The incidence of any SSI was significantly higher in patients with contaminated preoperative blood (≥1.2 bacterial cells/mL) than in other patients (14 of 27 vs 35 of 128, p = 0.013). Multivariable analysis indicated that contaminated preoperative blood was identified as one of the independent risk factors for SSI (odds ratio 2.71, 95% CI 1.04 to 7.24, p = 0.041). Conclusions: O-BT, predominantly with obligate anaerobes, was commonly observed in preoperative blood samples. In addition to the previously known risk factors, O-BT may be one of the risk factors for SSI after pancreatoduodenectomy.