Septic arthritis is rarely caused by anaerobic bacteria, which is mostly secondary to hematogenous dissemination among the immunocompromised host. We report a patient of septic arthritis on the right knee joint caused by Bacteroides thetaiotaomicron. To the best of knowledge, this is the first report of septic arthritis caused by Bacteroides spp. in Korea.
Arthritis, Infectious* ; Bacteremia* ; Bacteria, Anaerobic ; Bacteroides* ; Humans ; Immunocompromised Host ; Knee Joint ; Korea ; Multiple Myeloma*

Purpose: The coronavirus disease 2019 (COVID-19) pandemic continues. It has been reported that patients with bacterial coinfection have a higher mortality rate than patients without coinfection. However, there are no clear standard guidelines for the use of antibacterial drugs. Therefore, the purpose of this study was to determine the usefulness of procalcitonin, a specific indicator of bacterial infection, as a biomarker for predicting death in COVID-19 patients. Methods: This was a retrospective study of confirmed COVID-19 patients (N = 283) between December 2020 and February 2021 who survived or died. Logistic regression analysis was performed to determine whether there was an association between the level of procalcitonin and death. In addition, receiver operating characteristic curve analysis was performed to determine the usefulness of procalcitonin as a predictor of death. Results: In the non-survivor group, age, the number of patients transferred from a health care center, segment neutrophil ratio, C reactive protein, ferritin, and procalcitonin were significantly higher in the survivor group. In multivariate analysis, procalcitonin was identified as an independent factor associated with death (hazard ratio 6.162, confidential interval 2.285-26.322, p = 0.014). In addition, the predictive power of procalcitonin level and mortality was statistically significant using receiver operating characteristic curve analysis which gave an area under the curve value of 0.823, a cut-off value of 0.05, a sensitivity of 72.2%, a specificity of 87.5% (p < 0.001). Conclusion Measurement of procalcitonin and other biomarkers may be useful to determine whether to use or discontinue use of antibacterial drugs in patients with COVID-19.