田中 保平

BACKGROUND: In tropical to subtropical regions, centipede bites may prompt medical attention, with manifestations largely reflecting venom-related discomfort, although infections, including rare fatal necrotizing soft tissue infection (NSTI), have been reported. However, no reports are available on the commensal bacteria on centipede forcipules. OBJECTIVES: This study aimed to investigate bacterial species residing on and in centipede forcipules and their potential role in post-bite infections. METHODS: Nine Scolopendra mutilans, three Scolopendra japonica, and two Bothropolys rugosus were collected from three regions in Japan. The bacterial composition of their forcipules was analyzed using 16S ribosomal ribonucleic acid gene sequencing and microbiome analysis. FINDINGS: A diverse bacterial community was observed on the centipede forcipules. Among the NSTI-associated genera examined (Escherichia, Staphylococcus, and Streptococcus), only Staphylococcus was identified as a minor population. CONCLUSION: This study provides the first evidence that some bacteria found on centipede forcipules have been previously isolated from centipede bite infections. The risk of infection from bacteria on centipede forcipules during a centipede bite appears low. However, the presence of diverse bacterial species emphasizes the importance of thoroughly cleaning centipede bite wounds to prevent secondary infection.

BACKGROUND Inferior vena cava (IVC) injury is a potentially fatal injury with a high mortality rate of 34-70%. In cases in which the patient's condition is stable, diagnosis by computed tomography (CT) is the criterion standard. Findings on CT include retroperitoneal hematoma around the IVC, extravasation of contrast medium, and abnormal morphology of the IVC. We report a case of an IVC injury that could not be diagnosed by preoperative CT examination and could not be immediately detected during laparotomy. CASE REPORT A 73-year-old woman had stabbed herself in the neck and abdomen at home using a knife. When she arrived at our hospital, we found a stab wound several centimeters long on her abdomen and a cut approximately 15 cm long on her neck. We activated the massive transfusion protocol because she was in a condition of hemorrhagic shock. After blood transfusion and blood pressure stabilization, contrast-enhanced computed tomography (CT) revealed a small amount of fluid in the abdominal cavity. An otorhinolaryngologist performed successful drainage and hemostasis, and a laparotomy was performed. Gastric injury and mesentery injury of the transverse colon were identified and repaired with sutures. Subsequent search of the retroperitoneum revealed massive bleeding from an injury to the inferior vena cava (IVC). The IVC was repaired. Postoperative progress was good, and she was discharged from the hospital 65 days after her injuries. CONCLUSIONS We experienced a case of penetrating IVC injury, which is a rare trauma. Occult IVC injury may escape detection by preoperative CT examination or during laparotomy.