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Genomic identification and characterization of Streptococcus oralis group that causes intraamniotic infection
Pisut Pongchaikul1,2,3, Puntabut Warintaksa4, Thidathip Wongsurawat5
1Ramathibodi Medical School, Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Samut Prakan, 10540, Thailand.
Background:
Intraamniotic infection is a cause of spontaneous preterm labor. Streptococcus mitis is a common pathogen identified in intraamniotic infection, with the possible route of hematogenous dissemination from the oral cavity or migration from the vaginal canal. However, there are a few reports on Streptococcus oralis, a member of the S. mitis group, as a cause of pathogen in intraamniotic infection. We reported herein whole genome sequencing and comparative genomic analysis of S. oralis strain RAOG5826 that causes intraamniotic infection.
Results:
Streptococcus mitis was initially identified from amniotic fluid, vaginal swab, and fetal blood of a patient presenting with preterm prelabor rupture of membranes with intraamniotic infection by the use of conventional microbiological methods (biochemical phenotype, MALDI-ToF, 16 S rRNA). Subsequently, this strain was later identified as S. oralis RAOG5826 by whole-genome hybrid sequencing. Genes involved in macrolide and tetracycline resistance, namely ermB and tet(M), and mutations in penicillin-binding protein were present in the genome. Moreover, potential virulence genes were predicted and compared with other Streptococcal species.
Conclusion:
We reported a comprehensive genomic analysis of S. oralis, which causes intraamniotic infection. S. mitis was initially identified by conventional microbiological identification. However, whole-genome hybrid sequencing demonstrates S. oralis with complete profiles of antimicrobial resistance genes and potential virulence factors. This study highlights the limitations of traditional techniques and underscores the importance of genomic sequencing for accurate diagnosis and tailored antimicrobial treatment. The study also suggests that S. oralis may be an underestimated pathogen in intraamniotic infection.
Insights
Genomic sequencing identified Streptococcus oralis as the cause of intraamniotic infection, revealing antimicrobial resistance and virulence factors. This highlights the limitations of traditional methods for diagnosing this common cause of preterm labor.
Area of Science:
- Microbiology
- Genomics
- Infectious Diseases
Background:
- Intraamniotic infection is a significant cause of spontaneous preterm labor.
- Streptococcus mitis is a common pathogen, but Streptococcus oralis is less frequently reported in intraamniotic infections.
- Potential sources of infection include hematogenous spread from the oral cavity or vaginal migration.
Purpose of the Study:
- To perform whole genome sequencing and comparative genomic analysis of Streptococcus oralis strain RAOG5826.
- To accurately identify the causative agent of intraamniotic infection in a patient with preterm prelabor rupture of membranes.
- To characterize antimicrobial resistance genes and potential virulence factors of the identified pathogen.
Main Methods:
- Conventional microbiological methods including biochemical phenotype, MALDI-ToF, and 16S rRNA sequencing were initially used.
- Whole-genome hybrid sequencing was employed for precise identification of the bacterial strain.
- Comparative genomic analysis was performed to identify genes related to antimicrobial resistance and virulence.
Main Results:
- Initial identification suggested Streptococcus mitis, but whole-genome sequencing confirmed the pathogen as Streptococcus oralis RAOG5826.
- The genome contained genes conferring resistance to macrolides (ermB) and tetracyclines (tet(M)).
- Mutations in penicillin-binding proteins and potential virulence genes were identified and compared with other Streptococcal species.
Conclusions:
- Whole-genome sequencing provided a comprehensive genomic profile of Streptococcus oralis causing intraamniotic infection, surpassing limitations of traditional methods.
- The study identified specific antimicrobial resistance genes and virulence factors, crucial for understanding infection pathogenesis.
- Streptococcus oralis may be an underappreciated pathogen in intraamniotic infections, emphasizing the importance of genomic sequencing for accurate diagnosis and treatment.
