Advances in pneumococcal antibiotic resistance

Abstract

Antimicrobial resistance and serotypes in Streptococcus pneumoniae have been evolving with the widespread use of antibiotics and the introduction of pneumococcal conjugate vaccines (PCV). Particularly, among various types of antimicrobial resistance, macrolide resistance has most remarkably increased in many parts of the world, which has been reported to be >70% among clinical isolates from Asian countries. Penicillin resistance has dramatically decreased among nonmeningeal isolates due to the changes in resistance breakpoints, although resistance to other β-lactams such as cefuroxime has increased. Multidrug resistance became a serious concern in the treatment of invasive pneumococcal diseases, especially in Asian countries. After PCV7 vaccination, serotype 19A has emerged as an important cause of invasive pneumococcal diseases which was also associated with increasing prevalence of multidrug resistance in pneumococci. Widespread use of PCV13, which covers additional serotypes 3, 6A and 19A, may contribute to reduce the clonal spread of drug-resistant 19A pneumococci.

Keywords::

• macrolide resistance
• multidrug resistance
• penicillin resistance
• pneumococcal conjugate vaccine
• serotype 19A
• Streptococcus pneumoniae

Acknowledgements

The author deeply appreciates the kind help of SoHyun Kim (ANSORP Project Manager) and DooRyeon Chung (Samsung Medical Center, Seoul, Korea) for their sincere contribution to this review paper.

Financial & competing interests disclosure

The author has no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• • Macrolide resistance in Streptococcus pneumoniae is a very prominent problem, particularly in Asian countries, leading to an increased risk of treatment failures.

• • Penicillin resistance in pneumococci is not a common problem in nonmeningeal infection according to the new Clinical and Laboratory Standards Institute breakpoints (resistant ≥8 mg/L). However, increase in disease-causing or colonizing pneumococcal strains with intermediate resistance due to selective pressure can become a clinical concern. Therefore, changing trends should be continuously monitored.

• • Multidrug resistance has remarkably increased in many countries, which could limit the antibiotic options in the treatment of pneumococcal diseases.

• • After the introduction of pneumococcal conjugate vaccine (PCV)-7, emergence of non-PCV7 serotypes, especially 19A, is prominent worldwide, which also contributes to the increase in antimicrobial resistance and MDR in S. pneumoniae.

• • PCV13 may contribute in reducing the spread of drug-resistant 19A pneumococcal clones by its coverage of serotype 19A.