233 - Improved Penicillin Susceptibility of Streptococcus pneumoniae and Increased Penicillin Consumption in Japan, 2013-18

Background: Penicillin is often recommended as the first choice for Streptococcus pneumoniae infection due to its effectiveness and narrow spectrum. However, it is not clear whether increased penicillin consumption at the population level induces penicillin resistance in S. pneumoniae. The main objective of this study was to examine the association between penicillin susceptibility of S. pneumoniae and penicillin consumption in Japan.

Methods: We used Japan Nosocomial Infection Surveillance data, which comprehensively collected all routine microbiological test results from approximately 2,000 out of 8,000 hospitals across Japan that voluntarily participated in the surveillance. on susceptibility of S. pneumoniae, and sales data obtained from IQVIA Services Japan on national penicillin and cephalosporin consumption from January 2013 to December 2018. Clinical and Laboratory Standards Institute minimum inhibitory concentration breakpoints for meningitis were used as indicators of susceptibility. We analysed both sets of data by decomposing them into seasonality components and chronological trend components. The cross-correlation function was checked using Spearman’s rank correlation coefficient to examine for correlation between susceptibility and consumption.

Results: After adjusting for the influence of seasonality, the susceptibility of S. pneumoniae to penicillin gradually improved from 0.53 in January 2013 to 0.61 in December 2018 and penicillin consumption increased in the same period from 0.67 defined daily doses per 1,000 inhabitants per day (DID) in January 2013 to 1.23 DID in December 2018, thus showing positive cross-correlation (coefficient = 0.801, p < 0.001). Conversely, cephalosporin consumption decreased from 3.80 DID in January 2013 to 3.33 DID in December 2018, showing negative cross-correlation with penicillin susceptibility of S. pneumoniae (coefficient = -0.981, p < 0.001).Figure 1. Trend of penicillin-susceptibility of Streptococcus pneumoniae in Japan, 2013-2018 (based on non-meningitis MICs)
Figure 2. Sales amount of penicillins in Japan, 2013-2018
Figure 3. Sales amount of cephalosporins in Japan, 2013-2018


Conclusion: The rate of penicillin-resistant S. pneumoniae isolate was not positively correlated with penicillin consumption at the population level. Increased penicillin consumption might not induce penicillin resistance of S. pneumoniae.