Advances in Pneumococcal Antibiotic Resistance

Jae-Hoon Song


Expert Rev Resp Med. 2013;7(5):491-498. 

In This Article

Abstract and Introduction


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.


Streptococcus pneumoniae causes various types of diseases including otitis media, sinusitis, pneumonia, bacteremia and meningitis.[1] Disease burden of pneumococcal infections has increased due to several factors including the increase in aged population, chronic illness and increasing prevalence of antimicrobial resistance.[2] In particular, disease burden of pneumococcal infections has increased by treatment failure due to the emergence of resistance to multiple antimicrobial agents over the past decades. Since the first report of penicillin resistance in S. pneumoniae in 1967,[3] pneumococcal resistance to macrolides,[4] quinolones[5] and multidrug resistance (MDR)[6] has emerged worldwide over the decades, which were related with the increased use of antimicrobial agents[7,8] and dissemination of resistant clones such as the Spanish 23F clone.[9] According to the published reports,[1] the prevalence rates of antimicrobial resistance in S. pneumoniae are much higher in Asian countries than in the western part of the world. In recent years, the most important event that has affected the epidemiology of pneumococcal resistance was the introduction of pneumococcal conjugate vaccine (PCV). The 7-valent PCV (PCV7) comprising the most common serotypes causing pediatric invasive pneumococcal diseases (IPD), 4, 6B, 9V, 14, 18C, 19F and 23F, has contributed to a significant decrease in the incidence of IPD caused by vaccine serotypes as well as the prevalence rates of antimicrobial resistance in developed countries where PCV7 has been extensively used.[10]

However, introduction of PCV7 has led to a prominent emergence of non-vaccine serotypes, particularly 19A, worldwide.[11] Because serotype 19A is particularly associated with antimicrobial resistance in S. pneumoniae, this could be an important factor for the changing prevalence of pneumococcal resistance. A recent introduction of 13-valent PCV (PCV13) which contains six additional serotypes including serotype 19A can prevent the emergence of serotype 19A and will further affect the epidemiology of pneumococcal diseases and antimicrobial resistance. This paper reviews the current status of antimicrobial resistance in S. pneumoniae in the era of PCV.