Natto intake is a risk factor of Bacillus subtilis bacteremia among children undergoing chemotherapy for childhood cancer: A case-control study.

BACKGROUND: Natto, a popular, daily food in Japan, is made from soybeans fermented by Bacillus subtilis. The aim of this retrospective case-control study (matched 1: 4) is to determine whether natto intake is a risk factor of B. subtilis bacteremia in this population. METHODS: The retrospective, matched case-control study was conducted at Tokyo Metropolitan Children's Medical Center between April 2012 and June 2020 and included pediatric patients younger than 15 years who received chemotherapy for cancer. Patients who received hematopoietic stem cell transplantation were excluded. Patients with B. subtilis bacteremia were compared with controls matched for age and underlying diseases. Dietary information within seven days from the date of blood culture collection was extracted from medical records. Multivariate logistic regression was performed to define the risk factors of B. subtilis bacteremia. RESULTS: In total, 23 patients with B. subtilis bacteremia were identified and matched to 92 controls. The percentage of patients and controls who ingested natto within seven days from the date of blood culture collection was 78% and 50%, respectively. On univariate analysis, the odds ratio of natto intake for B. subtilis bacteremia was 3.6 (95% confidence interval [CI]: 1.2-10.5). Multivariable logistic regression tests after controlling for neutropenia revealed that B. subtilis bacteremia was associated significantly with natto intake at odds ratio 3.3 (95% CI: 1.1-9.6). CONCLUSION: Natto intake was associated with B. subtilis bacteremia during chemotherapy for childhood cancer.

Impact of Introducing a Multiplex Polymerase Chain Reaction Blood Culture Panel on Anti-Methicillin-Resistant Staphylococcus aureus (MRSA) and Carbapenem Antimicrobial Agents in a Children's Hospital.

BACKGROUND: With the advent of multiplex polymerase chain reaction (PCR) using samples from a positive blood culture, the time required to identify a pathogen has significantly shortened to a few hours. It can help us select appropriate antimicrobial agents more quickly. The present study aimed to assess the impact of using a multiplex PCR blood culture panel on the appropriate administration of antimicrobial agents. METHODS: Patients aged <16 years with culture-confirmed bacteremia at Tokyo Metropolitan Children's Medical Center were enrolled. A pre-intervention period (period I: December 2016 to December 2018) and a post-intervention period with multiplex PCR use for the confirmation of positive blood cultures (period II: December 2019 to December 2021) were compared for their effect on the use of antimicrobial agents for gram-positive cocci (GPC) and gram-negative rod (GNR) bacteremia. Data on patient background, blood culture results, and antimicrobial use were retrospectively collected from electronic medical records. RESULTS: Periods I and II had 174 and 154 patients, respectively. The median age at periods I and II was 14 (IQR 2-82) months and 12 (IQR 1-78) months, respectively. GPC bacteremia during periods I and II occurred in 140 and 115 patients, respectively. GNR during periods I and II occurred in 34 and 39 patients, respectively. Neither the vancomycin-resistance genes A/B nor the carbapenem-resistance gene were detected. The use of antimicrobial agents against anti-methicillin-resistant Staphylococcus aureus (MRSA) for GPC bacteremia decreased from 103/140 cases (73%) in period I to 56/115 cases (49%) in period II (p=0.047). The use of carbapenems for GNR bacteremia did not change significantly, at 23/34 (68%) in period I and 34/39 (87%) in period II (p=0.47). CONCLUSION: Introducing multiplex PCR for pediatric bacteremia decreased the use of anti-MRSA antimicrobial agents but not of carbapenems.