Group B<i>Streptococcus</i>Capsular Serotype Alters Vaginal Colonization Fitness

Dammann, Allison N; Chamby, Anna B.; González, Francisco J.; Sharp, Molly E; Flores, Karina; Shahi, Ifrah; Dongas, Sophia; Hooven, Thomas A.; Ratner, Adam J.

doi:10.1093/infdis/jiab559

Cited by 7 publications

(4 citation statements)

References 48 publications

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“…Type III is the most virulent and infectious, causing more than half of serious infections. Type Ia was common in pregnant women; types Ia, Ib, II, and III were common in early neonatal infection; and type II and III were common in late neonatal infection (Russell et al, 2017;Dammann et al, 2022;Wadilo et al, 2023). Considering the multiple serotypes of GBS, the antigen-antibody test is prone to the risk of being false negative, leading this study to focus on the molecular diagnosis.…”

Section: Discussionmentioning

confidence: 99%

Establishment and application of a rapid molecular diagnostic platform for the isothermal visual amplification of group B Streptococcus based on recombinase polymerase

Liu,

Wang,

Chu

et al. 2024

Front. Cell. Infect. Microbiol.

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With growing concerns about Group B streptococcal (GBS) infections and their adverse effects on perinatal pregnancies, including infection, premature delivery, neonatal septicemia, and meningitis, it is urgent to promote GBS screening at all pregnancy stages. The purpose of this study is to establish a device-independent, fast, sensitive, and visual GBS detection method. Taking advantage of the characteristics of the recombinase polymerase isothermal amplification (RPA), the activity of the nfo nuclease cleavage base analog (tetrahydrofuran, THF) site, and the advantages of visual reading of the lateral flow chromatography strip (LFS), a GBS detection method was developed. This method focused on the conservative region of the Christie–Atkins–Munch–Petersen factor encoded by the cfb gene, a virulence gene specific to GBS. Two forward primers, two biotin-labeled reverse primers, and one fluorescein isothiocyanate (FITC)-labeled and C3spacer-blocked probe were designed. The study involved optimizing the primer pair and probe combination, determining the optimal reaction temperature and time, evaluating specificity, analyzing detection limits, and testing the method on 87 vaginal swabs from perinatal pregnant women. The results showed that the visual detection method of GBS-RPA-LFS, using the cfb-F1/R2/P1 primer probe, could detect GBS within 15 min at the temperature ranging from 39°C to 42°C. Furthermore, the method specifically amplified only GBS, without cross-reacting with pathogens like Lactobacillus iners, Lactobacillus crispatus, Candida albicans, Listeria monocytogenes, Yersinia enterocolitica, Klebsiella Pneumoniae, Enterobacter cloacae, Citrobacter freundii, Vibrio alginolyticus, Vibrio parahaemolyticus, Salmonella typhimurium, Staphylococcus aureus, Pseudomonas aeruginosa, or Trichomonas vaginalis. It could detect a minimum of 100 copies per reaction. In clinical 98 samples of vaginal swabs from pregnant women, the agreement rate between the GBS-RPA-LFS method and TaqMan real-time fluorescence quantification method was 95.92%. In conclusion, this study successfully established a combined RPA and LFS GBS in situ detection platform, with short reaction time, high sensitivity, high specificity, portability, and device independence, providing a feasible strategy for clinical GBS screening.

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Section: Discussionmentioning

confidence: 99%

Establishment and application of a rapid molecular diagnostic platform for the isothermal visual amplification of group B Streptococcus based on recombinase polymerase

Liu,

Wang,

Chu

et al. 2024

Front. Cell. Infect. Microbiol.

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“…A909 is a sequence-type 7 GBS strain that expresses capsular serotype Ia. It was originally isolated from an infected neonate and has been used in many laboratory studies of GBS pathogenesis ( 22 , 51 , 61 , 63 – 69 ). GBS was grown in liquid cultures in tryptic soy (TS) broth (Fisher Scientific cat.…”

Section: Methodsmentioning

confidence: 99%

A group B Streptococcus indexed transposon mutant library to accelerate genetic research on an important perinatal pathogen

Bhavana,

Hillebrand,

Gopalakrishna

et al. 2023

Microbiol Spectr

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Group B Streptococcus (GBS) is a major contributor to sepsis, meningitis, and pneumonia in newborns. Indexed bacterial mutant libraries accelerate pathogenesis research by allowing rapid screening of genes that contribute to disease. In this study, we created and characterized a large-scale GBS indexed library of Himar1 mini-transposon mutant strains grown as monocultures from a mixed transposon insertion library that we had previously used for transposon-genome junction sequencing. We used a high-throughput workflow to identify transposon insertion sites in chromosomal DNA purified from individual mutants. Following quality control steps and the removal of isogenic duplicate strains, we isolated 1,919 monocultures of unique transposon insertion mutants with even dispersion across the GBS genome. Our final library, stored in barcoded, traceable glycerol stocks, contains interruptions of 878 genes and 253 intergenic regions. We also validated select library mutants with confirmatory PCR and, when possible, specific phenotypic testing. While the library contains only sparse interruptions of essential or near-essential genes, the genes represented in the set span a wide range of predicted functional categories, including roles in metabolism, structure, and virulence. In conclusion, we developed and applied a high-throughput molecular analysis and bioinformatic pipeline to generate a GBS indexed library of unprecedented scale that we believe will be a useful genetic tool for fellow GBS researchers. IMPORTANCE Group B Streptococcus (GBS) is a significant global cause of serious infections, most of which affect pregnant women, newborns, and infants. Studying GBS genetic mutant strains is a valuable approach for learning more about how these infections are caused and is a key step toward developing more effective preventative and treatment strategies. In this resource report, we describe a newly created library of defined GBS genetic mutants, containing over 1,900 genetic variants, each with a unique disruption to its chromosome. An indexed library of this scale is unprecedented in the GBS field; it includes strains with mutations in hundreds of genes whose potential functions in human disease remain unknown. We have made this resource freely available to the broader research community through deposition in a publicly funded bacterial maintenance and distribution repository.

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“…Parent measurements which fell below the limit of detection, 1000 CFU/mL, were not included in competitive index calculations. Competitive index was calculated as below and results were summarized using the geometric mean and a 95% confidence interval for each timepoint and ratio 61 .…”

Section: Cloning and Expression Of Bacteriocin T8 Bacteriocin T8 And ...mentioning

confidence: 99%

Bacteriocin production facilitates nosocomial emergence of vancomycin-resistantEnterococcus faecium

Mills,

Smith,

Griffith

et al. 2024

Preprint

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Vancomycin-resistantEnterococcus faecium(VREfm) is a prevalent healthcare-acquired pathogen. Gastrointestinal colonization can lead to difficult-to-treat bloodstream infections with high mortality rates. Prior studies have investigated VREfm population structure within healthcare centers. However, little is known about how and why hospital-adapted VREfm populations change over time. We sequenced 710 healthcare-associated VREfm clinical isolates from 2017-2022 from a large tertiary care center as part of the Enhanced Detection System for Healthcare-Associated Transmission (EDS-HAT) program. Although the VREfm population in our center was polyclonal, 46% of isolates formed genetically related clusters, suggesting a high transmission rate. We compared our collection to 15,631 publicly available VREfm genomes spanning 20 years. Our findings describe a drastic shift in lineage replacement within nosocomial VREfm populations at both the local and global level. Functional and genomic analysis revealed, antimicrobial peptide, bacteriocin T8 may be a driving feature of strain emergence and persistence in the hospital setting.SummaryThis study shows local and global lineage replacement of vancomycin-resistantEnterococcus faecium. Bacteriocin T8 is enriched in emergent lineages and provides a strong competitive advantagein vitroandin vivo.

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Group BStreptococcusCapsular Serotype Alters Vaginal Colonization Fitness

Cited by 7 publications

References 48 publications

Establishment and application of a rapid molecular diagnostic platform for the isothermal visual amplification of group B Streptococcus based on recombinase polymerase

Establishment and application of a rapid molecular diagnostic platform for the isothermal visual amplification of group B Streptococcus based on recombinase polymerase

A group B Streptococcus indexed transposon mutant library to accelerate genetic research on an important perinatal pathogen

Bacteriocin production facilitates nosocomial emergence of vancomycin-resistantEnterococcus faecium

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