Healthcare-associated infections (HAIs) pose significant challenges to healthcare systems worldwide. Epidemiological data are essential for effective HAI control; however, comprehensive information on HAIs in Japanese hospitals is limited. This study aimed to provide an overview of HAIs in Japanese hospitals.

A multicenter point-prevalence survey (PPS) was conducted in 27 hospitals across the Aichi Prefecture between February and July 2020. This study encompassed diverse hospital types, including community, university, and specialized hospitals. Information on the demographic data of the patients, underlying conditions, devices, HAIs, and causative organisms was collected.

A total of 10,199 patients (male: 5,460) were included in this study. The median age of the patients was 73 (interquartile range [IQR]: 56–82) years, and the median length of hospital stay was 10 (IQR: 4–22) days. HAIs were present in 6.6% of patients, with pneumonia (1.83%), urinary tract infection (1.09%), and surgical site infection (SSI) (0.87%) being the most common. The prevalence of device-associated HAIs was 0.91%. Staphylococcus aureus (17.3%), Escherichia coli (17.1%), and Klebsiella pneumoniae (7.2%) were the primary pathogens in 433 organisms; 29.6% of the Enterobacterales identified showed resistance to third-generation cephalosporins. Pneumonia was the most prevalent HAI in small-to-large hospitals (1.69%–2.34%) and SSI, in extra-large hospitals (over 800 beds, 1.37%).

This study offers vital insights into the epidemiology of HAIs in hospitals in Japan. These findings underscore the need for national-level PPSs to capture broader epidemiological trends, particularly regarding healthcare challenges post-COVID-19.

Pregnant women require increased levels of n-3 polyunsaturated fatty acids (PUFAs) due to the demands of the growing fetus. Although some evidence indicates that maternal intake of fish and n-3 PUFAs is associated with reduced risk of postpartum depression, the results are inconsistent.

We investigated whether dietary consumption of fish and/or n-3 PUFAs during pregnancy is associated with a reduced risk of maternal postpartum depression at 6 months after delivery and of serious mental illness at 1 year in a Japanese population. After exclusion and multiple imputation from a dataset comprising 103 062 pregnancies obtained in the Japan Environment and Children's Study, we evaluated 84 181 and 81 924 women at 6 months and 1 year after delivery, respectively.

Multivariable logistic regression showed a reduced risk of postpartum depression at 6 months in the second to fifth quintiles v. the lowest quintile for fish and n-3 PUFA intake, with trend tests also revealing a significant linear association. At 1 year after delivery, fish intake was associated with a reduced risk of serious mental illness in the second to fifth quintiles v. the lowest quintile for fish and in the third to fifth quintiles v. the lowest quintile for n-3 PUFA intake, with trend tests also revealing a significant linear association.

Women with higher fish and/or n-3 PUFA intake showed reduced risk of postpartum depression at 6 months after delivery and of serious mental illness at 1 year after delivery.