Serotype-Dependent Inhibition of Streptococcus pneumoniae Growth by Short-Chain Fatty Acids
Suwon Lim1, Dongwook Lee1, Sungho Jeong1
1Department of Oral Microbiology Immunology, Dental Research Institute, School of Dentistry, Seoul National University, Seoul 08826, Republic of Korea.
Abstract:
Streptococcus pneumoniae (pneumococcus) is an opportunistic pathogen that can cause severe infectious diseases such as pneumonia, meningitis, and otitis media. Despite the availability of antibiotics and pneumococcal vaccines against some invasive serotypes, pneumococcal infection remains a tremendous clinical challenge due to the increasing frequency of infection by antimicrobial resistant, nonencapsulated, and/or non-vaccine serotype strains. Short-chain fatty acids (SCFAs), which are produced at various mucosal sites in the body, have potent antimicrobial activity, including inhibition of pathogen growth and/or bacterial biofilm formation. In this study, we investigated the antimicrobial activity of SCFAs (acetate, propionate, and butyrate) against various serotypes pneumococci. Propionate generally inhibited the growth of S. pneumoniae serotypes included in the pneumococcal conjugate vaccine (PCV) 13, except for serotypes 3 and 7F, though butyrate and acetate showed no or low inhibition, depending on the serotypes. Of note, butyrate showed strong inhibition against serotype 3, the most prevalent invasive strain since the introduction of the PCV. No SCFAs showed inhibitory effects against serotype 7F. Remarkably, the nonencapsulated pneumococcal strain had more sensitivity to SCFAs than encapsulated parental strains. Taken together, these results suggest that propionate showing the most potent inhibition of pneumococcal growth may be used as an alternative treatment for pneumococcal infection, and that butyrate could be used against serotype 3, which is becoming a serious threat.
Insights
Short-chain fatty acids like propionate show potent antimicrobial activity against Streptococcus pneumoniae, offering potential new treatments for infections. Butyrate is particularly effective against the concerning serotype 3 strain.
Area of Science:
- Microbiology
- Infectious Diseases
- Biochemistry
Background:
- Streptococcus pneumoniae causes severe infections like pneumonia and meningitis.
- Antimicrobial resistance and non-vaccine serotypes pose significant challenges.
- Short-chain fatty acids (SCFAs) exhibit antimicrobial properties.
Purpose of the Study:
- To investigate the antimicrobial activity of SCFAs (acetate, propionate, butyrate) against S. pneumoniae.
- To evaluate SCFA efficacy against various pneumococcal serotypes, including vaccine and non-vaccine strains.
- To assess SCFA activity against encapsulated and nonencapsulated pneumococcal strains.
Main Methods:
- In vitro testing of acetate, propionate, and butyrate against S. pneumoniae serotypes.
- Comparison of SCFA inhibition against pneumococcal conjugate vaccine (PCV) 13 serotypes.
- Assessment of SCFA activity on nonencapsulated pneumococcal strains.
Main Results:
- Propionate inhibited most PCV13 serotypes, except for serotypes 3 and 7F.
- Butyrate strongly inhibited serotype 3, a prevalent invasive strain.
- Nonencapsulated S. pneumoniae strains were more sensitive to SCFAs than encapsulated strains.
Conclusions:
- Propionate demonstrates significant potential as an alternative treatment for pneumococcal infections.
- Butyrate may serve as a targeted therapy against the emerging threat of serotype 3 pneumococcus.
- SCFAs represent a promising class of compounds for combating pneumococcal disease.
