Hot weather is likely to increase further due to climate change. Previous studies have found that hotter months corresponded to a higher risk of in-hospital bacterial infections. However, the short-term association between high temperatures and bacterial infections, as well as the related vulnerable populations, is unclear. The meteorological data were sourced from the National Meteorological Data Sharing Platform. All hospitalized patients who underwent bacterial testing at Henan Provincial People's Hospital between January 2017 and December 2019 were included in the analysis, encompassing 195,630 test results from 82,070 patients. No missing data were observed for basic information such as gender, age, and surgical status. We adopted a time-stratified case-crossover design and a distributed lag nonlinear model to assess the short-term associations between temperature and the specific bacterial positive detection rate. Relative humidity and PM 2.5 concentration were incorporated as covariates into the model. We further conducted subgroup analyses by gender, age group, and surgical or invasive treatment status to identify relevant vulnerable populations. There were six types of bacteria with high positive detection rates, namely Enterococcus spp, Staphylococcus aureus , Pseudomonas aeruginosa , Escherichia coli , Klebsiella pneumoniae , and Acinetobacter spp, with positive cases (positive detection rates) of 1,928 (0.99 %), 2,056 (1.05 %), 3,279 (1.68 %), 6,563 (3.35 %), 6,979 (3.57 %), and 7,115 (3.64 %). Summer was one of the seasons with a high bacterial positive detection rate; the risk of positive detections for Pseudomonas aeruginosa , Acinetobacter spp, and Klebsiella pneumoniae increased with increasing temperatures in the summer. At a lag of 0–3 days, compared with the 5th percentile of summer temperatures, high temperatures (the 95th percentile) were associate with the increase of positive detection rates of Pseudomonas aeruginosa , Pseudomonas spp., and Klebsiella pneumoniae , with relative risk values (95% CIs) of 1.799 (1.225, 2.640), 1.382 (1.052, 1.816), and 1.692 (1.274, 2.246), respectively. The harmful effects of high temperatures occurred mainly among the elderly and those who had undergone surgical or invasive procedures. High summer temperatures may increase the risk of detecting Pseudomonas aeruginosa , Acinetobacter spp, and Klebsiella pneumoniae , with the elderly population and patients undergoing surgery as relevant vulnerable populations. • This study assessed the short-term association between ambient temperature and specific bacterial positive detection rate. • There were six types of bacteria with high positive detection rates, namely Enterococcus spp, Staphylococcus aureus , Pseudomonas aeruginosa , Escherichia coli , Klebsiella pneumoniae , and Acinetobacter spp. • The risk of positive detections for Pseudomonas aeruginosa , Acinetobacter spp, and Klebsiella pneumoniae increased with increasing temperatures in the summer. • The harmful effects of high temperature occurred mainly in the elderly population and in those who had undergone surgical or invasive operations.
Li et al. (Sun,) studied this question.