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Background Enterovirus D68 (EV-D68) causes asthma-like respiratory infection in children. Several EV-D68 outbreaks have been reported worldwide since the largest outbreak occurred in the United States in 2014. We experienced an accumulation of pediatric cases with asthma-like respiratory illness in Niigata, Japan, in 2018. Study design To determine whether EV-D68 was responsible for the case accumulation, this prospective observational study evaluated children hospitalized in 1 of 8 hospitals with asthma-like respiratory illness in Niigata, Japan, during October and November 2018. Diagnoses were made by EV-D68-specific RT-PCR using nasopharyngeal samples. The clade was identified by sequence analyses, and a phylogenetic tree was created. To evaluate seasonal variation, data from pediatric cases with asthma-like respiratory illness in 2018 were retrospectively analyzed. Results In 2018, 114 children were hospitalized with asthma-like respiratory illness in October and November, and 47 nasopharyngeal samples were collected. EV-D68 was detected in 22/47 (47%) patients during the study period. The phylogenetic tree revealed that all strains belonged to the clade B3 branch, which has been detected worldwide every 2 years since 2014. Conclusions EV-D68 was the associated pathogen for asthma-like respiratory illness in children in Japan in 2018. Clade B3, the dominant clade in outbreaks worldwide, was responsible for the outbreak. Detection and detailed virologic analysis of EV-D68 is important as part of worldwide surveillance, as it will aid in understanding the epidemiologic characteristics of EV-D68 infection.

The first step in a bacterial disease is the establishment of nasopharyngeal carriage.We conducted a birth cohort study to identify factors associated with colonization in healthy children and evaluate the serotype distributions and resistances of Streptococcus pneumoniae/Haemophilus influenzae. Nasopharyngeal cultures were obtained from 349 subjects at 5 time points coinciding with health checkups (4, 7, 10, 18 and 36 months).A total of 551 S. pneumoniae (penicillin resistance rate: 46.3%) and 301 H. influenzae (ampicillin resistance rate: 44.5%) isolates were obtained from 1654 samples. In this study, 47.5% and 60.9% of S. pneumoniae isolates were included in the serotypes of 7- and 13-valent pneumococcal conjugate vaccines, respectively. Analyzing by Cox proportional hazards models, cohabiting older sibling(s) attending day-care (hazard ratios: 2.064-3.518, P0.001) and an early start of day-care attendance by the subjects themselves (2.259-2.439, P0.001) were associated with a higher risk of early colonization regardless of their susceptibility. Recent exposure to antimicrobials was also significantly associated with increased risk of colonization (odds ratios: 2.032-2.999, P0.001) but not with resistance rates. This data indicated that introduction of appropriate antimicrobial usage in areas of overuse of antimicrobials could contribute to lower colonization of S. pneumoniae/H. influenzae, resulting in a decrease in the absolute number of resistant isolates.Strategies to control transmission at day-care centers or from older sibling(s) as well as appropriate use of antimicrobials are essential for reducing colonization and the absolute number of resistant isolates.

Background: To reduce the spread of drug-resistant pathogens, appropriate use of antimicrobials is an indispensable measure. From January 2002, we undertook campaigns about antimicrobial treatment in Sado Island, Japan. Methods: The subjects were bom in 1996 (group-1996) or during 2002-2004 (group-2002-2004) and received outpatient treatment at our hospital. We evaluated the subjects' medical information from patient records during their first 3 years of life. Demographic data, duration of breast-feeding, and attending a day-care center (DCC) were evaluated using a questionnaire. Results: Average visit-based antimicrobial prescription rates significantly decreased from 535 for group-1996, to 70 for group-2002-2004 per 1000 hospital visits (P < 0.001). The rate of cephalosporin prescriptions significantly decreased (77.1%-16.7%; P < 0.001), while amoxicillin (0.8%-29.5%) and macrolides (21.0%-52.4%) significantly increased (P < 0.001). Regarding 417 nasopharyngeal cultures from group-2002-2004. 77.8% (179/ 230) of Streptococcus pneumoniae strains were nonsusceptible to penicillin. For Haemophilus inflnenzae strains, 30.6% (59/193) were nonsusceptible to ampicillin. Living with older sibling(s) and early DCC attendance were associated with carriage of resistant pathogens. Conclusions: In a closed area under controlled antimicrobial use, our data indicated that decreasing antimicrobial prescriptions alone could not achieve elimination of resistant pathogens. Strategies to control transmission at DCCs or from older sibling(s) are also essential.