Publications by authors named "Stephanie Lo"

Article Synopsis
  • The polysaccharide capsule of pneumococcus protects the bacteria from the host immune system and is the main target for existing vaccines; however, the effectiveness of these vaccines can be compromised by variations in the capsule structure.
  • Recent research has identified a new capsule type, 20C, which differs from the previously known B subtype due to gene inactivation affecting the capsule structure.
  • There is a need for advanced genetic screening and bioinformatics to monitor mutations in capsule-related genes, which could influence vaccine effectiveness and the emergence of new capsule variants.
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  • Virulence studies on the one-carbon metabolism pathway and proline synthesis indicate their importance in the infection process, particularly in Δ and Δ mutant strains of capsular serotype 6B BHN418.* -
  • These mutant strains showed significantly reduced virulence in models of mouse sepsis and pneumonia despite being able to colonize the nasopharynx and grow normally in nutrient-rich environments.* -
  • Differences in metabolic profiles and gene transcription under various stress conditions revealed strain-specific effects on virulence and metabolism, underscoring the need for rapid adaptation to host physiological conditions.*
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  • Invasive pneumococcal disease (IPD) remains a serious global issue, particularly concerning non-vaccine serotypes, even after the introduction of pneumococcal conjugate vaccines (PCV) in South Africa.
  • The study analyzed over 3,000 IPD genomes from children between 2005-2020, observing a drop in incidence for vaccine-type bacteria in the late-PCV13 period, but some continued to pose a threat.
  • Notably, non-vaccine serotypes showed rising drug resistance and lineage diversity, indicating the need for ongoing genomic surveillance to inform health policies and future vaccine developments.
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Defining the population structure of a pathogen is a key part of epidemiology, as genomically related isolates are likely to share key clinical features such as antimicrobial resistance profiles and invasiveness. Multiple different methods are currently used to cluster together closely related genomes, potentially leading to inconsistency between studies. Here, we use a global dataset of 26 306  genomes to compare four clustering methods: gene-by-gene seven-locus MLST, core genome MLST (cgMLST)-based hierarchical clustering (HierCC) assignments, life identification number (LIN) barcoding and k-mer-based PopPUNK clustering (known as GPSCs in this species).

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  • The study aimed to evaluate the risk and prevalence of hospital-acquired bacterial infections in intensive care units during the first wave of COVID-19 by using advanced deep-sequencing techniques.
  • Conducted in a hard-hit region in northern Italy, the research involved collecting and analyzing samples from patients in both regular wards and ICUs to identify specific bacterial pathogens.
  • The findings highlighted the effectiveness of this novel sequencing approach in tracking bacterial transmission and understanding antimicrobial resistance during a time of increased patient load.
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Background: In early 2021, the 10-valent Pneumococcal conjugate vaccine (PCV10) was replaced with 13-valent (PCV13) by the federal directorate of immunization (FDI), Pakistan. We assessed the impact of a higher valent vaccine, PCV13, on the serotype distribution of nasopharyngeal carriage in rural Pakistan.

Methods: Children <2 years were randomly selected from two rural union councils of Matiari, Sindh in Pakistan between September-October,2022.

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The Southampton pneumococcal carriage study of children under 5 years old continued during the coronavirus disease 2019 (COVID-19) pandemic. Here, we present data from October 2018 to March 2023 describing prevalence of pneumococci and other pathobionts during the winter seasons before, during, and after the introduction of non-pharmaceutical interventions (NPIs) to prevent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission. Nasopharyngeal swabs were collected from children attending outpatient clinics at a secondary care hospital and community healthcare sites.

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Streptococcus pneumoniae is a leading cause of pneumonia and meningitis worldwide. Many different serotypes co-circulate endemically in any one location. The extent and mechanisms of spread and vaccine-driven changes in fitness and antimicrobial resistance remain largely unquantified.

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Pakistan is amongst the four countries with the highest number of pneumococcal deaths. While the PCV10 vaccine was introduced in Pakistan in October 2012, data regarding the impact of the vaccine on the population dynamics of in Pakistan remain obscure. Using whole genome sequencing of 190 isolates (nasopharyngeal carriage=75, disease=113, unknown sites=2) collected between 2002 and 2020, this study presents characteristics of pneumococcal strains in Pakistan in the pre- and post-vaccine era.

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Whole genome sequencing (WGS)-based approaches for pneumococcal capsular typing have become an alternative to serological methods. serotyping from WGS has not yet been applied to long-read sequences produced by third-generation technologies. The objective of the study was to determine the capsular types of pneumococci causing invasive disease in Catalonia (Spain) using serological typing and WGS and to compare the performance of different bioinformatics pipelines using short- and long-read data from WGS.

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(the pneumococcus) is a bacterial pathogen with the greatest burden of disease in Asia and Africa. The pneumococcal capsular polysaccharide has biological relevance as a major virulence factor as well as public health importance as it is the target for currently licensed vaccines. These vaccines have limited valency, covering up to 23 of the >100 known capsular types (serotypes) with higher valency vaccines in development.

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Historically, epidemiological investigation and surveillance for bacterial antimicrobial resistance (AMR) has relied on low-resolution isolate-based phenotypic analyses undertaken at local and national reference laboratories. Genomic sequencing has the potential to provide a far more high-resolution picture of AMR evolution and transmission, and is already beginning to revolutionise how public health surveillance networks monitor and tackle bacterial AMR. However, the routine integration of genomics in surveillance pipelines still has considerable barriers to overcome.

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Article Synopsis
  • Despite advances in vaccine development, the emergence of non-vaccine serotypes like serotype 16F in vaccinated populations presents a significant global health challenge, particularly in South Africa where it's prevalent among infants.
  • A study analyzed over 10,000 isolates from South African infants, finding that 9% of these were serotype 16F, with most isolates globally collected from Africa and associated with distinct genetic lineages.
  • Certain lineages, such as GPSC33 and GPSC46, demonstrated a concerning prevalence of antimicrobial resistance genes, indicating a potential rise in resistant strains that could complicate treatment options.
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() is a leading vaccine-preventable cause of childhood invasive disease. Nigeria has the second highest pneumococcal disease burden globally, with an estimated ~49 000 child deaths caused by pneumococcal infections each year. Ten-valent pneumococcal conjugate vaccine (GSK; PCV10) was introduced in December 2014 in a phased approach.

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Introduction: Due to the emergence of non-vaccine serotypes in vaccinated populations, remains a major global health challenge despite advances in vaccine development. Serotype 16F is among the predominant non-vaccine serotypes identified among vaccinated infants in South Africa (SA).

Aim: To characterise lineages and antimicrobial resistance in 16F isolates obtained from South Africa and placed the local findings in a global context.

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In this Q&A, Stephanie Lo and Robert Paulino-Ramírez answer questions about their research fields and share insights into their role as editorial board members at the journal.

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The polysaccharide (PS) capsule is essential for immune evasion and virulence of Streptococcus pneumoniae. Existing pneumococcal vaccines are designed to elicit anticapsule antibodies; however, the effectiveness of these vaccines is being challenged by the emergence of new capsule types or variants. Herein, we characterize a newly discovered capsule type, 33E, that appears to have repeatedly emerged from vaccine type 33F via an inactivation mutation in the capsule glycosyltransferase gene, wciE.

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  • Subtotal skin electron beam therapy can help patients with cutaneous lymphoma by focusing radiation on large skin areas while protecting others that have had prior treatment or are cosmetically sensitive.* -
  • A customizable shield was developed using acrylic blocks mounted on a steel frame to tailor the treatment and was tested for its effectiveness in shielding patients during therapy.* -
  • The shield proved to be user-friendly and effective, reducing electron transmission and maintaining safety without increasing x-ray exposure, making it suitable for personalized treatment in over 30 patients.*
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  • The introduction of pneumococcal conjugate vaccines (PCVs) has effectively reduced invasive pneumococcal diseases but led to the rise of non-vaccine serotypes, notably serotype 15A, linked to clonal complex 63 (CC63).
  • A study analyzed 865 isolates of CC63 from the USA and globally, focusing on their serotypes and resistance to antibiotics, revealing a significant increase in serotype 15A after PCV implementation.
  • The research indicates that the CC63 lineage, especially the 15A sub-lineage, is widely distributed and predominantly multidrug-resistant, emphasizing the need for ongoing monitoring of these strains.
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or group B streptococcus (GBS) is a leading cause of neonatal sepsis and increasingly found as an invasive pathogen in older patient populations. Beta-lactam antibiotics remain the most effective therapeutic with resistance rarely reported, while the majority of GBS isolates carry the tetracycline resistance gene in fixed genomic positions amongst five predominant clonal clades. In the UK, GBS resistance to clindamycin and erythromycin has increased from 3% in 1991 to 11.

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Decisions are often made under uncertainty. The most that one can do is use prior knowledge (e.g.

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Streptococcus pneumoniae can produce a wide breadth of antigenically diverse capsule types, a fact that poses a looming threat to the success of vaccines that target pneumococcal polysaccharide (PS) capsule. Yet, many pneumococcal capsule types remain undiscovered and/or uncharacterized. Prior sequence analysis of pneumococcal capsule synthesis () loci suggested the existence of capsule subtypes among isolates identified as "serotype 36" according to conventional capsule typing methods.

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Serotype 3 pneumococci remains a significant cause of disease despite its inclusion in PCV13. Whilst clonal complex 180 (CC180) represents the major clone, recent studies have refined the population structure into three clades: Iα, Iβ and II, with the last being a recent divergent and more antibiotic-resistant. We present a genomic analysis of serotype 3 isolates from paediatric carriage and all-age invasive disease, collected between 2005 and 2017 in Southampton, UK.

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is a leading cause of pneumonia and meningitis worldwide. Many different serotypes co-circulate endemically in any one location. The extent and mechanisms of spread, and vaccine-driven changes in fitness and antimicrobial resistance (AMR), remain largely unquantified.

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