Journal of Infection and Chemotherapy最新文献

Background: Differences in the clinical manifestation of pediatric coronavirus disease 2019 (COVID-19) across Omicron variants in emergency departments (EDs) remain unclear.

Patients and methods: This retrospective observational study characterized the clinical features of pediatric patients with COVID-19 for each variant period at a primary ED in Kobe City, Japan. The variant-dominant periods comprised BA.1/BA.2 (sixth wave, January-June 2022), BA.5/BQ.1 (seventh-eighth waves, July 2022-March 2023), and XBB (ninth wave, April-December 2023). COVID-19 was diagnosed by rapid antigen testing.

Results: Among the 46,719 pediatric ED visits, 4,085 were COVID-19 cases; 599 (9.0%), 2,943 (15.4%) and 543 (2.6%) cases were diagnosed in the sixth, seventh-eighth, and ninth waves, respectively. During the XBB period, cough was significantly more frequent than in other periods and nasal discharge was more common compared with the BA.5/BQ.1 period. Vomiting occurred more frequently in the BA.5/BQ.1 period than in the BA.1/BA.2 period. Among children aged <1 year, vomiting was significantly more common during the XBB period. No significant differences were observed between patients aged 1-4 years. Dyspnea was more common in the BA.1/BA.2 than in the BA.5/BQ.1 period. In adolescents, fever occurred more frequently during the BA.5/BQ.1 period.

Conclusion: This study compared pediatric COVID-19 cases across the BA.1/BA.2, BA.5/BQ.1, and XBB waves. Although evidence for the XBB wave remains limited, upper respiratory symptoms such as nasal discharge and cough were observed more frequently during this period. Distinct differences in clinical presentations according to variant type and age group were identified.

Introduction: With the rapid advancement of artificial intelligence (AI) technology, AI has been applied to the detection of pathogens that cause infectious diseases. This study evaluated the newly developed AI-based software, the BiTTE-iE, based on Gram-stained specimen images captured with smartphones, assessing not only its ability to accurately identify bacterial species but also its capability to classify pathogens morphologically.

Methods: Gram-stained slides were prepared from 177 positive blood culture bottles as part of routine clinical practice. This study evaluated the match rate between the results of "Major Pathogen Classification" (GPCs, GPRs, GNCs, GNRs, and Yeast) performed by the BiTTE-iE and the microscopic findings of microbiology-trained medical technologists. Furthermore, the match rate between the pathogen classifications identified by the BiTTE-iE at the "Group-level" and "Species-level" and the final species identification results obtained using culture methods and MALDI-TOF MS was evaluated.

Results: Overall, the match rate for the "Major Pathogen Classification" exceeded 85% in all classification categories except GNCs, where data collection was impossible. For GPCs, a high match rate of 93.8% (166/177) was observed. In contrast, the match rate for "Species-level" classification was relatively low, generally ranging from 0% to 80%. In particular, the match rates for Enterococcus spp. and non-fermentative Gram-negative rods were especially low, resulting in an overall "Species-level" match rate of 41.5% (66/159).

Conclusions: The BiTTE-iE demonstrated potential utility in selecting antimicrobial agents for empirical treatment. By comprehensively accumulating image data for all microbials, it is expected that diagnostic performance using the BiTTE-iE will be further improved.

Streptococcus agalactiae sequence type (ST) 283 is an emerging, hypervirulent lineage predominantly identified in Southeast Asia and strongly associated with foodborne transmission linked to raw freshwater fish consumption. While ST283 was responsible for the 2015 outbreak in Singapore, no human infections have been reported in Japan to date. We describe a travel-associated case of invasive ST283 disease in a Japanese man residing in Vietnam in 2010, representing the earliest documented S. agalactiae ST283 infection in a Japanese individual. A 67-year-old previously healthy man developed progressive lower back pain and fever while living in Vietnam and presented to our institution nine days after symptom onset. Computed tomography and magnetic resonance imaging revealed L2-L3 pyogenic spondylitis with bilateral psoas abscesses. Blood cultures grew S. agalactiae susceptible to β-lactams, and targeted intravenous penicillin followed by ampicillin resulted in complete clinical and radiological resolution after six weeks of therapy. Whole-genome sequencing of the bloodstream isolate demonstrated serotype III-ST283 harboring tetM, pilus islands 1 and 2a, AlphaC, and Srr1. Phylogenetic comparison with a publicly available regional dataset showed close relatedness to isolates recovered in Vietnam during 2015-2016, supporting local acquisition in Vietnam in 2010, predating the 2015 Singapore outbreak. This case highlights that ST283 infections may occur outside recognized endemic settings and may be imported into non-prevalent countries through international travel. Clinicians should consider ST283 in invasive S. agalactiae infections with meningoencephalitis, septic arthritis, and/or spinal infections among travelers returning from Southeast Asia and obtain relevant exposure histories, including consumption of raw/undercooked freshwater fish.