A case of Bacillus subtilis var. natto bacteremia caused by ingestion of natto during COVID-19 treatment in a maintenance hemodialysis patient with multiple myeloma.

A 70-year-old woman, who started on hemodialysis 7 months before for end-stage renal disease due to diabetic nephropathy and was diagnosed with symptomatic multiple myeloma 1 month before, was admitted to our hospital with critical coronavirus disease 2019 and treated with long-term immunosuppressive therapy such as steroids and tocilizumab. During treatment, Bacillus subtilis was detected in the blood cultures. We could not exclude the association of natto (fermented soybeans) with B. subtilis var. natto, which the patient had been eating every day from 8 days after admission. She was prohibited from eating natto and treated with vancomycin. Later, B. subtilis detected in the blood culture was identified as B. subtilis var. natto, which was identical with those contained in the natto that the patient consumed daily using a next-generation sequencer. Gut dysbiosis due to old age, malignant tumor, diabetes mellitus, end-stage renal disease, and intestinal inflammation caused by severe acute respiratory syndrome coronavirus 2 increased intestinal permeability and the risk of bacterial translocation, causing B. subtilis var. natto bacteremia. Therefore, careful consideration might be given to the intake of fermented foods containing live bacteria in patients with severe immunocompromised conditions.

[Investigation of the procalcitonin and microbiology test and antibiotics situation from our hospital].

Procalcitonin (PCT) was first described as a sepsis-associated protein in 1993. PCT is increased in the blood at the time of infection by bacteria. Therefore, it is used as an auxiliary indicator of sepsis diagnosis. In addition, PCT is reduced quickly by antibiotics. And use as a stop or change marker is also expected. We have investigated the antimicrobial use and microbial testing of measurement patient and PCT running performance. Number of requests was 3,387 cases (inpatient 2,649 and outpatient 742 cases) for one year. It was subject to the 820 cases that had inspection request to July to October 2012. In 820 cases, 57 cases had exhibited a PCT >0.5 ng/ml and diagnosed with infectious diseases. In 57 cases, 44 cases (77%) were performed microbiology and blood culture. And only blood culture performed in 8 (14%), blood culture and microbiology is not performed for 5 cases (9%), In 21 (40%) cases of 52 cases performed the blood culture shown positive. Detecting bacteria accounted for more than half in 17 cases of Gram-negative bacilli. Also, it had exhibited a systemic inflammatory response syndrome (SIRS) in 18 cases. Antibiotics have been used in all cases regardless of implementation of the microbiology test. If sepsis is suspected, it is necessary for diagnosis is done correctly and quickly. Therefore, PCT has been suggested high usefulness by examining in the hospital. It is required that the reference identification and drug susceptibility results of the pathogenic bacterium combination of microbiology test and the PCT. We considered useful to PCT monitoring that as an indicator of antimicrobial agents change or shorten of antibiotic use period. Future, proactive use of clinical practice is expected.