Respiratory pathogens - Some altered antibiotic susceptibility after implementation of pneumococcus vaccine and antibiotic control strategies.

Background/purpose: Antimicrobial resistance in Taiwan has been on the rise for two decades. The implementation of pneumococcal conjugate vaccination (PCV13) and enhanced antimicrobial control (2013-2015) by the government may have changed the antibiotic resistance.

Methods: Four respiratory pathogens (Streptococcus pneumoniae, Haemophilus influenzae, Streptococcus pyogenes, and Moraxella catarrhalis) isolated in a single medical center during 2008-2017 were studied. We defined three temporal stages: (a) the first era (2008-2012), prior to implementation of the national immunization program (PCV13 vaccination), (b) the second era (2013-2015), during which an enhanced antibiotic control strategy was implemented, and (c) the third era (2016-2017), after implementation. Antimicrobial drug sensitivities were collected from two other hospitals: one from east Taiwan, one from west-central Taiwan.

Results: S. pneumoniae was frequently isolated during the first era. It declined progressively during the second era of PCV13 vaccination. S. pyogenes and M. catarrhalis were not frequently isolated. The drug susceptibility of S. pneumoniae to ceftriaxone and vancomycin remained high. The antimicrobial susceptibility of H. influenzae to amoxillin/clavulante declined over the three temporal stages, from 91.9%-79.5%-58.5% (all p < 0.05).

Conclusion: Antimicrobial resistance of H. influenzae increased during the latter part of the study period. The PCV13 vaccination program reduced the invasive pneumococcal disease and reduced the stress on the emergent drug resistance. This enhanced antibiotic control strategy was effective in terms of nosocomial drug resistance but not for community-associated pathogens.