Ambient NO2 is associated with Streptococcus pneumoniae-induced pneumonia in children and increases the minimum inhibitory concentration of penicillin

The present study aimed to assess the correlation between ambient air pollutants and Streptococcus pneumoniae (S. pneumoniae)-induced pneumonia in children and retrospectively reviewed the daily data regarding S. pneumoniae from children with pneumonia in a tertiary hospital of Hangzhou City, between January 1st, 2018, and December 31st, 2018. The excess risk (ER) of NO_{2} with regard to the daily number of S. pneumoniae isolates obtained from the respiratory tract specimens of children with pneumonia was 13.31% (95% confidence interval [CI]: 3.12-24.51%, P = 0.010) in the single-pollutant model. An increase of 10 μg/m^{3} in NO_{2} exposure was associated with a 23.30% increased risk for the acquisition of S. pneumoniae-induced pneumonia in children (95% CI: 2.02-49.02%; P = 0.031) according to the multi-pollutant model. The ER of NO_{2} with regard to the daily number of S. pneumoniae isolates (1 μg/ml ≤ minimum inhibitory concentration (MIC) to penicillin ≤ 2 μg/ml) obtained from the respiratory tract specimens of children with pneumonia was 15.80% (95% CI: 2.02-31.45%; P = 0.024) in the single-pollutant model. According to the multi-pollutant model, the ER of NO_{2} with regard to the daily number of S. pneumoniae isolates (1 μg/ml ≤ MIC to penicillin ≤ 2 μg/ml) obtained from the respiratory tract specimens of children with pneumonia was 37.09% (95% CI: 5.70-77.81%; P = 0.018). In conclusion, ambient NO_{2} is associated with S. pneumoniae-induced pneumonia in children. More importantly, NO_{2} exposure is associated with the increased MICs of penicillin against S. pneumoniae from children with pneumonia.