1. Introduction
2. Results
2.1. Serotype and Multilocus Sequence Typing (MLST) Distribution
2.2. Antimicrobial Susceptibility
2.3. Genome-Based Phylogenetic Analysis

2.4. Virulence Genes and Antibiotic Resistance Genes among the Three GBS Clusters
3. Discussion
4. Materials and Methods
4.1. Bacterial Strains
4.2. GBS Serotyping and Antibiotic Susceptibility Test
4.3. Whole-Genome Sequencing of GBS Strains
5. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Serotypes | Total No. Swabs (n = 60) | Pre-Delivery Vaginal Swab (n = 28) | Post-Delivery Vaginal Swabs (n = 25) | Neonate Anal Swabs (n = 7) | p-Value (Pre- vs Post-Delivery Vaginal Swabs) ^ | p-Value (Pre-Delivery Vaginal Swabs vs Neonatal Anal Swabs) ^ | p-Value (Post-Delivery Vaginal Swabs vs Neonatal Anal Swabs) ^ |
---|---|---|---|---|---|---|---|
Ia | 7 (11.7%) | 3 (10.7%) | 1 (4%) | 3 (42.9%) | 0.6 | 0.07 | 0.03 |
Ib | 1 (1.67%) | 1 (3.57%) | 0 (0%) | 0 (0%) | N/A | N/A | N/A |
II | 12 (20%) | 9 (32.1%) | 2 (8%) | 1 (14.3%) | 0.04 | 0.6 | 1 |
III | 15 (25%) | 7 (25%) | 8 (32%) | 0 (0%) | 0.76 | N/A | N/A |
IV | 1 (1.67%) | 0 (0%) | 1 (4%) | 0 (0%) | N/A | N/A | N/A |
V | 6 (10%) | 3 (10.7%) | 2 (8%) | 1 (14.3%) | 1 | 1 | 1 |
VI | 17 (28.3%) | 5 (17.9%) | 10 (40%) | 2 (28.6%) | 0.12 | 0.6 | 0.7 |
NT # | 1 (1.67%) | 0 (0%) | 1 (4%) | 0 (0%) | N/A | N/A | N/A |
Sequence Type (ST) | Serotypes | |||||||
---|---|---|---|---|---|---|---|---|
Ia (n = 7) | Ib (n = 1) | II (n = 12) | III (n = 15) | IV (n = 1) | V (n = 16) | VI (n = 17) | NT (n = 1) # | |
ST1 | - | 1 (100%) | 4 (33.3%) | - | - | 3 (50%) | 16 (94.1%) | - |
ST23 | 2 (28.6%) | - | - | 7 (46.7%) | - | - | - | 1 (100%) |
ST335 | - | - | - | 4 (26.7%) | - | - | - | - |
ST28 | - | - | 3 (25%) | - | - | - | - | - |
ST19 | - | - | - | 2 (13.3%) | - | - | - | - |
ST4 | 3 (42.8%) | - | - | - | - | - | - | - |
ST24 | 2 (28.6%) | - | - | - | - | 1 (16.7%) | - | - |
ST10 | - | - | 2 (16.7%) | - | - | - | - | - |
ST17 | - | - | - | 2 (13.3%) | - | - | - | - |
ST14 | - | - | - | - | - | - | 1 (5.9%) | - |
ST49 | - | - | - | - | - | 1 (16.7%) | - | - |
ST1206 | - | - | - | - | 1 (16.7%) | - | - | |
Unknown STs | - | - | 3 (25%) | - | 1 (100%) | - | - |
Class of Antibiotic | Antibiotic | MIC (μg/mL) a | No. of Resistance Strains (%) | ||
---|---|---|---|---|---|
Range | MIC50 | MIC90 | |||
Penicillins | Penicillin | 2–0.0625 | 0.06 | 0.06 | 0 |
Oxacillin | 32–0.03 | 0.25 | 0.5 | 0 | |
Cephalosporins | Cefotaxime | 2–0.12 | 0.12 | 0.12 | 0 |
Ceftibuten | 32–0.03 | 16 | 16 | 0 | |
Glycopeptides | Vancomycin | 8–0.25 | ≤0.12 | ≤0.12 | 0 |
Amino glycosides | Gentamicin | 4–0.25 | >4 | >4 | 60 (100%) |
Tetracyclines | Doxycycline ^ | 32–1 | 32 | >32 | 34 (56.7%) |
Minocycline ^ | 32–1 | 32 | >32 | 34 (56.7%) | |
Tetracycline | 32–1 | 16 | 32 | 35 (58.3%) | |
Oxazolidinones | Linezolid | 64–0.06 | 1 | 1 | 0 |
Chloramphenicol | Chloramphenicol | 64–2 | ≤1 | 2 | 0 |
Macrolides | Erythromycin | 4–0.12 | ≤0.06 | 1 | 9 (15%) |
Lincosamides | Clindamycin | 4–0.12 | ≤0.06 | ≤0.06 | 0 |
Lincomycin | 32–0.03 | 0.12 | 0.25 | 0 | |
Fluoroquinolones | Ciprofloxacin | 64–0.06 | 0.25 | 0.5 | 0 |
Levofloxacin | 32–1 | ≤0.5 | 1 | 0 | |
Gatifloxacin | 4–0.25 | ≤0.5 | ≤0.5 | 0 | |
Moxifloxacin * | 2–0.12 | ≤0.12 | ≤0.12 | 0 |
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