Bacteriological and molecular characterization of temperature- and CO2-dependent Streptococcus pneumoniae serotype 24F ST162 isolated from Japanese children
ABSTRACT Streptococcus pneumoniae serotype 24F is one of the most prevalent non-vaccine serotypes that causes invasive pneumococcal disease (IPD) in many countries, including Japan. This study aimed to analyze the bacteriological and molecular characteristics of serotype 24F sequence type (ST) 162,...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
American Society for Microbiology
2023-12-01
|
| Series: | Microbiology Spectrum |
| Subjects: | |
| Online Access: | https://journals.asm.org/doi/10.1128/spectrum.02165-23 |
| _version_ | 1797393679337390080 |
|---|---|
| author | Jun Kobayashi Misako Ohkusu Takehisa Matsumoto Noriko Kubota Naruhiko Ishiwada |
| author_facet | Jun Kobayashi Misako Ohkusu Takehisa Matsumoto Noriko Kubota Naruhiko Ishiwada |
| author_sort | Jun Kobayashi |
| collection | DOAJ |
| description | ABSTRACT Streptococcus pneumoniae serotype 24F is one of the most prevalent non-vaccine serotypes that causes invasive pneumococcal disease (IPD) in many countries, including Japan. This study aimed to analyze the bacteriological and molecular characteristics of serotype 24F sequence type (ST) 162, which has been increasingly isolated from pediatric patients with IPD in Japan recently. The examination of growth conditions, sequencing of genes associated with the CO2 dependence, and antimicrobial susceptibility testing at 35°C under 5% CO2 were performed for 10 isolates obtained from Japanese children with IPD caused by serotype 24F ST162. All isolates failed to grow at 35°C in ambient air; however, they showed growth at 30°C in ambient air and at 35°C under 5% CO2. Sequencing of murF involved in cell wall synthesis indicated that all isolates had a single amino acid substitution, MurFA179V. Additionally, all isolates were sensitive to penicillin G and resistant to trimethoprim-sulfamethoxazole. Furthermore, 25 non-capnophilic strains were obtained from all CO2-dependent isolates, and their murF sequences were compared. Thirteen of the 25 non-capnophilic strains displayed a different amino acid substitution, MurFV179A, whereas the other 12 presented the previously described MurFA179V. This suggests that a proportion of the CO2-dependent phenotype of serotype 24F ST162 may have been conferred by MurFA179V; however, the mechanism for the CO2 dependence of these isolates warrants further investigation. The CO2-dependent serotype 24F ST162 pneumococcal isolates shared common characteristics in terms of growth patterns, molecular basis, and antimicrobial susceptibility; therefore, future epidemiological trends of this clone must be closely monitored. IMPORTANCE We characterized Streptococcus pneumoniae serotype 24F sequence type (ST) 162 isolated from Japanese children with invasive pneumococcal disease (IPD). Owing to its highly invasive nature, serotype 24F is expected to be isolated from clinically significant cases. Serotype 24F ST162 isolates tested in the present study did not grow at 35°C in ambient air. Therefore, antimicrobial susceptibility testing using the broth microdilution method, which is usually conducted in ambient air, cannot be performed, posing a clinical challenge. Clinical practitioners and laboratory personnel should be aware of the epidemiological, bacteriological, and molecular characteristics of serotype 24F ST162. We believe that our findings can help diagnose and treat IPD caused by serotype 24F ST162, a serotype expected to become problematic in the post-13 valent pneumococcal conjugate vaccine era. |
| first_indexed | 2024-03-09T00:06:21Z |
| format | Article |
| id | doaj.art-82c617082b1544edbee466c28a154ed5 |
| institution | Directory Open Access Journal |
| issn | 2165-0497 |
| language | English |
| last_indexed | 2024-03-09T00:06:21Z |
| publishDate | 2023-12-01 |
| publisher | American Society for Microbiology |
| record_format | Article |
| series | Microbiology Spectrum |
| spelling | doaj.art-82c617082b1544edbee466c28a154ed52023-12-12T13:17:18ZengAmerican Society for MicrobiologyMicrobiology Spectrum2165-04972023-12-0111610.1128/spectrum.02165-23Bacteriological and molecular characterization of temperature- and CO2-dependent Streptococcus pneumoniae serotype 24F ST162 isolated from Japanese childrenJun Kobayashi0Misako Ohkusu1Takehisa Matsumoto2Noriko Kubota3Naruhiko Ishiwada4Department of Laboratory Medicine, Nagano Children’s Hospital , Azumino, JapanDepartment of Infectious Diseases, Medical Mycology Research Center, Chiba University , Chiba, JapanDepartment of Laboratory Sciences, Gunma University Graduate School of Health Sciences , Maebashi, JapanDepartment of Laboratory Medicine, Nagano Children’s Hospital , Azumino, JapanDepartment of Infectious Diseases, Medical Mycology Research Center, Chiba University , Chiba, JapanABSTRACT Streptococcus pneumoniae serotype 24F is one of the most prevalent non-vaccine serotypes that causes invasive pneumococcal disease (IPD) in many countries, including Japan. This study aimed to analyze the bacteriological and molecular characteristics of serotype 24F sequence type (ST) 162, which has been increasingly isolated from pediatric patients with IPD in Japan recently. The examination of growth conditions, sequencing of genes associated with the CO2 dependence, and antimicrobial susceptibility testing at 35°C under 5% CO2 were performed for 10 isolates obtained from Japanese children with IPD caused by serotype 24F ST162. All isolates failed to grow at 35°C in ambient air; however, they showed growth at 30°C in ambient air and at 35°C under 5% CO2. Sequencing of murF involved in cell wall synthesis indicated that all isolates had a single amino acid substitution, MurFA179V. Additionally, all isolates were sensitive to penicillin G and resistant to trimethoprim-sulfamethoxazole. Furthermore, 25 non-capnophilic strains were obtained from all CO2-dependent isolates, and their murF sequences were compared. Thirteen of the 25 non-capnophilic strains displayed a different amino acid substitution, MurFV179A, whereas the other 12 presented the previously described MurFA179V. This suggests that a proportion of the CO2-dependent phenotype of serotype 24F ST162 may have been conferred by MurFA179V; however, the mechanism for the CO2 dependence of these isolates warrants further investigation. The CO2-dependent serotype 24F ST162 pneumococcal isolates shared common characteristics in terms of growth patterns, molecular basis, and antimicrobial susceptibility; therefore, future epidemiological trends of this clone must be closely monitored. IMPORTANCE We characterized Streptococcus pneumoniae serotype 24F sequence type (ST) 162 isolated from Japanese children with invasive pneumococcal disease (IPD). Owing to its highly invasive nature, serotype 24F is expected to be isolated from clinically significant cases. Serotype 24F ST162 isolates tested in the present study did not grow at 35°C in ambient air. Therefore, antimicrobial susceptibility testing using the broth microdilution method, which is usually conducted in ambient air, cannot be performed, posing a clinical challenge. Clinical practitioners and laboratory personnel should be aware of the epidemiological, bacteriological, and molecular characteristics of serotype 24F ST162. We believe that our findings can help diagnose and treat IPD caused by serotype 24F ST162, a serotype expected to become problematic in the post-13 valent pneumococcal conjugate vaccine era.https://journals.asm.org/doi/10.1128/spectrum.02165-23Streptococcus pneumoniaeMurFCO2-dependentserotype 24FST162 |
| spellingShingle | Jun Kobayashi Misako Ohkusu Takehisa Matsumoto Noriko Kubota Naruhiko Ishiwada Bacteriological and molecular characterization of temperature- and CO2-dependent Streptococcus pneumoniae serotype 24F ST162 isolated from Japanese children Microbiology Spectrum Streptococcus pneumoniae MurF CO2-dependent serotype 24F ST162 |
| title | Bacteriological and molecular characterization of temperature- and CO2-dependent Streptococcus pneumoniae serotype 24F ST162 isolated from Japanese children |
| title_full | Bacteriological and molecular characterization of temperature- and CO2-dependent Streptococcus pneumoniae serotype 24F ST162 isolated from Japanese children |
| title_fullStr | Bacteriological and molecular characterization of temperature- and CO2-dependent Streptococcus pneumoniae serotype 24F ST162 isolated from Japanese children |
| title_full_unstemmed | Bacteriological and molecular characterization of temperature- and CO2-dependent Streptococcus pneumoniae serotype 24F ST162 isolated from Japanese children |
| title_short | Bacteriological and molecular characterization of temperature- and CO2-dependent Streptococcus pneumoniae serotype 24F ST162 isolated from Japanese children |
| title_sort | bacteriological and molecular characterization of temperature and co2 dependent streptococcus pneumoniae serotype 24f st162 isolated from japanese children |
| topic | Streptococcus pneumoniae MurF CO2-dependent serotype 24F ST162 |
| url | https://journals.asm.org/doi/10.1128/spectrum.02165-23 |
| work_keys_str_mv | AT junkobayashi bacteriologicalandmolecularcharacterizationoftemperatureandco2dependentstreptococcuspneumoniaeserotype24fst162isolatedfromjapanesechildren AT misakoohkusu bacteriologicalandmolecularcharacterizationoftemperatureandco2dependentstreptococcuspneumoniaeserotype24fst162isolatedfromjapanesechildren AT takehisamatsumoto bacteriologicalandmolecularcharacterizationoftemperatureandco2dependentstreptococcuspneumoniaeserotype24fst162isolatedfromjapanesechildren AT norikokubota bacteriologicalandmolecularcharacterizationoftemperatureandco2dependentstreptococcuspneumoniaeserotype24fst162isolatedfromjapanesechildren AT naruhikoishiwada bacteriologicalandmolecularcharacterizationoftemperatureandco2dependentstreptococcuspneumoniaeserotype24fst162isolatedfromjapanesechildren |