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Updated: Dec 18, 2025
A Murine Model of Group B Streptococcus Vaginal Colonization
Published on: November 16, 2016
Antibiotic Susceptibility Patterns and Prevalence of Streptococcus Agalactiae Rectovaginal Colonization Among
Mina Dashtizade1, Mohammad Reza Zolfaghari1, Masoud Yousefi2
1Department of Microbiology, Qom Branch, Islamic Azad University, Qom, Iran.
Insights
Group B Streptococcus (GBS) colonization affects 6.7% of pregnant women in Iran, posing risks for neonatal infections. Screening pregnant mothers for GBS is recommended to guide antibiotic prophylaxis and prevent serious infant complications.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Public Health
Background:
- Group B Streptococcus (GBS) is a significant pathogen causing life-threatening infections in neonates and pregnant women.
- Preventive strategies against GBS infections are crucial for maternal and infant health.
Purpose of the Study:
- To determine the prevalence of rectovaginal GBS colonization in pregnant women in Iran.
- To identify risk factors associated with GBS colonization.
- To analyze the antibiotic resistance patterns of GBS isolates.
Main Methods:
- A study involving 240 pregnant women.
- Collection of vaginal and rectal swabs for GBS isolation and identification using standard microbiological tests and PCR.
- Antimicrobial susceptibility testing via Kirby-Bauer disk diffusion.
- Detection of *ermB* and *mefA* genes in erythromycin-nonsusceptible isolates using PCR.
Main Results:
- GBS colonization was identified in 16 out of 240 pregnant women (6.7%).
- No significant association was found between demographic-obstetric factors and GBS colonization.
- Linezolid, vancomycin, and ampicillin demonstrated the highest effectiveness against GBS isolates.
- The *ermB* gene was detected in 35.29% of isolates, while the *mefA* gene was not found.
Conclusions:
- The prevalence of GBS colonization necessitates screening pregnant mothers to mitigate risks of neonatal infections.
- Findings underscore the importance of antibiotic prophylaxis during pregnancy to prevent early-onset GBS-neonatal infections and associated comorbidities.
Objective:
Streptococcus agalactiae is an important pathogen in neonates and pregnant women. Neonatal invasive infections due to S. agalactiae are life-threatening and preventive strategies for this challenge of human have become a concern. The aim of the present study was to determine the prevalence of rectovaginal colonization, related risk factors and antibiotic resistance pattern of S. agalactiae among pregnant women in Iran.
Methods:
The present study was performed on 240 pregnant women. Vaginal and rectal swabs were obtained from all of the women and then were transferred to the laboratory. The isolation and identification of S. agalactiae was performed by standard microbiological tests and polymerase chain reaction (PCR) assay. The antimicrobial susceptibility patterns of the isolates were determined by the Kirby-Bauer disk diffusion. Polymerase chain reaction was used to detect ermB and mefA genes in erythromycin-nonsusceptible isolates.
Results:
Out of 240 pregnant women, 16 cases (6.7%) were colonized by S. agalactiae. There is no significant association between demographic-obstetric factors and maternal S. agalactiae colonization in the pregnant women. Linezolid, vancomycin and ampicillin were the most effective antibiotics against S. agalactiae. The ermB gene was present in 6 (35.29%) S. agalactiae isolates. However, the mefA gene was not detected in any of the isolates.
Conclusion:
Given the relatively significant prevalence of S. agalactiae colonization in the pregnant women in the present study and the risk of serious neonatal infections, the screening of pregnant mothers for the bacteria seems necessary. Our findings highlight the importance of appropriate antibiotic prophylaxis during pregnancy for the prevention of early onset S. agalactiae-neonatal infection and comorbidity.
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