Publications by authors named "Tessa Block"

Unlabelled: The ResistAZM randomized controlled trial found that the receipt of ceftriaxone/azithromycin, compared to ceftriaxone was not associated with an increase in the proportion of oral commensal Neisseria spp. and streptococci with azithromycin resistance 14 days after treatment. We repeated the analyses by measuring the minimum inhibitory concentrations (MICs) of azithromycin and ceftriaxone for individual colonies of commensal Neisseria spp.

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: The use of antimicrobials to treat food animals leaves antimicrobial residues in foodstuffs. The World Health Organization (WHO) defines the acceptable daily intakes (ADIs) of these residues as the dose of these antimicrobials that is safe for an average human to consume on a daily basis. We hypothesized that the lowest dose of ciprofloxacin classified as safe by the WHO could select for ciprofloxacin-resistant strains of in a model.

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Commensal streptococci are common inhabitants of the oral microbiome and regulate its structure and function in beneficial ways for human health. They can, however, also be opportunistic pathogens and act as a reservoir of resistance genes that can be passed on to other bacteria, including pathogens. Little is known about the prevalence of these commensals in parents and their children and their antimicrobial susceptibilities in the Belgian general population.

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  • Between January and August 2024, nearly all provinces of the Democratic Republic of the Congo reported cases of mpox.
  • Genome sequencing from 11 cases in Kinshasa revealed the presence of two subclades, Ia and Ib, co-circulating in the Limete health zone.
  • Phylogenetic analyses indicated that these subclades have multiple introductions in Kinshasa, highlighting the increasing complexity of mpox outbreaks in the DRC.
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  • Scientists studied how to fight bacteria that are resistant to a medicine called ceftriaxone.
  • They tested different drugs to see if they could work together with ceftriaxone to stop the bacteria from becoming resistant.
  • The results showed that two specific drugs, zoliflodacin and pristinamycin, could help reduce the chances of ceftriaxone resistance spreading.
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  • Commensal species are commonly found in the oropharynx as part of the healthy microbiome but can also lead to serious diseases like meningococcal disease.
  • Clinical microbiology labs often use MALDI-TOF MS for species identification but can misidentify certain bacteria, which highlights the need for genomic surveillance to verify these results.
  • A study in Belgium analyzed 119 bacterial isolates using genome sequencing and different identification methods, revealing discrepancies in MALDI-TOF MS results and demonstrating the significance of comprehensive genomic analysis for correctly identifying and understanding these species.
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Background: commensal Neisseria species are part of the oropharyngeal microbiome and play an important role in nitrate reduction and protecting against colonization by pathogenic bacteria. They do, however, also serve as a reservoir of antimicrobial resistance. Little is known about the prevalence of these species in the general population, how this varies by age and how antimicrobial susceptibility varies between species.

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Environmental chemicals, such as PFAS, exist as mixtures and are frequently encountered at varying concentrations, which can lead to serious health effects, such as cancer. Therefore, understanding the dose-dependent toxicity of chemical mixtures is essential for health risk assessment. However, comprehensive methods to assess toxicity and identify the mechanisms of these harmful mixtures are currently absent.

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Background: Limited data are available on Mpox breakthrough infections.

Purpose: The purpose of this study is to investigate a Mpox breakthrough outbreak in 3 vaccinated individuals.

Methods: Study participants provided informed consent.

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Background: In antibiotic naïve populations, there is a strong association between the use of an antimicrobial and resistance to this antimicrobial. Less evidence is available as to whether this relationship is weakened in populations highly exposed to antimicrobials. Individuals taking HIV preexposure prophylaxis (PrEP) have a high intake of antimicrobials.

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One of the most promising new treatments for gonorrhoea currently in phase 3 clinical trials is zoliflodacin. Studies have found very little resistance to zoliflodacin in currently circulating N. gonorrhoeae strains, and in-vitro experiments demonstrated that it is difficult to induce resistance.

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Invasive non-typhoidal Salmonella (iNTS) disease manifesting as bloodstream infection with high mortality is responsible for a huge public health burden in sub-Saharan Africa. Salmonella enterica serovar Typhimurium (S. Typhimurium) is the main cause of iNTS disease in Africa.

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Background: No randomized controlled trial (RCT) has compared the impact on the resistome of ceftriaxone (CRO) plus azithromycin (AZM) vs CRO for the treatment of (NG).

Methods: This was an open-label, single-center, RCT comparing the effect on the resistome of CRO plus AZM vs CRO for the treatment of NG. Men who have sex with men (MSM) with genital, anorectal, or pharyngeal NG infection were randomized into the CRO/AZM and CRO arms.

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T-cell-based diagnostic tools identify pathogen exposure but lack differentiation between recent and historical exposures in acute infectious diseases. Here, T-cell receptor (TCR) RNA sequencing was performed on HLA-DR+/CD38+CD8+ T-cell subsets of hospitalized coronavirus disease 2019 (COVID-19) patients (n = 30) and healthy controls (n = 30; 10 of whom had previously been exposed to severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2]). CDR3α and CDR3β TCR regions were clustered separately before epitope specificity annotation using a database of SARS-CoV-2-associated CDR3α and CDR3β sequences corresponding to >1000 SARS-CoV-2 epitopes.

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Article Synopsis
  • - The study focuses on analyzing the genetic diversity of plague-causing bacteria in Brazil, despite the country currently experiencing low plague incidence, as indicated by the presence of antibodies in local wildlife.
  • - Researchers examined 407 bacterial genomes from the Fiocruz Collection and identified four main clades (C, E, G, and H) with varying absences of virulence genes, indicating a potential reduction in the bacteria's effectiveness as a pathogen over time.
  • - The findings also highlight connections between genetic data and historical epidemiological patterns, enhancing the understanding of plague evolution and the potential for future genomic applications in tracking disease outbreaks.
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Although transmitted mainly through direct (sexual) contact, mpox virus (MPXV) can be detected in ambient air. We explored the use of air sampling for diagnosis or (genomic) surveillance of mpox in a sexual health clinic. For six out of six patients who were infected with MPXV, all four of our ambient air PCR tests were positive.

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Salmonella enterica serovar Typhi (S. Typhi) is the cause of typhoid fever, presenting high rates of morbidity and mortality in low- and middle-income countries. The H58 haplotype shows high levels of antimicrobial resistance (AMR) and is the dominant S.

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Despite the general agreement on the significance of T cells during SARS-CoV-2 infection, the clinical impact of specific and cross-reactive T-cell responses remains uncertain. Understanding this aspect could provide insights for adjusting vaccines and maintaining robust long-term protection against continuously emerging variants. To characterize CD8+ T-cell response to SARS-CoV-2 epitopes unique to the virus (SC2-unique) or shared with other coronaviruses (CoV-common), we trained a large number of T-cell receptor (TCR) - epitope recognition models for MHC-I-presented SARS-CoV-2 epitopes from publicly available data.

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Antimicrobial resistant Salmonella enterica serovar Concord (S. Concord) is known to cause severe gastrointestinal and bloodstream infections in patients from Ethiopia and Ethiopian adoptees, and occasional records exist of S. Concord linked to other countries.

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Antibiotic tolerance is associated with antibiotic treatment failure, and molecular mechanisms underlying tolerance are poorly understood. We recently succeeded in inducing tolerance to ceftriaxone (CRO) in an reference isolate. In a prior in vitro study, six biological replicates of WHO P strains were exposed to CRO (10× the MIC) followed by overnight growth, and tolerance was assessed using a modified Tolerance Disc (T.

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The effect of sequential exposure to different antibiotics is an underexplored topic. Azithromycin can be detected in humans for up to 28 days post-ingestion and may prime bacterial responses to subsequently ingested antibiotics. In this study, we assessed if preexposure to azithromycin could accelerate the acquisition of resistance to ciprofloxacin in reference strain, WHO-F.

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Article Synopsis
  • Some men who have sex with men (MSM) using HIV prevention medicine called PrEP have high levels of germs that resist antibiotics in their mouths.
  • A study compared these MSM to regular people and found that the MSM had much more antibiotic resistance, especially to certain types of antibiotics.
  • It's suggested that reducing the use of antibiotics in these high-risk groups could help prevent the spread of infections that are hard to treat.
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Vaccination is important in containing the 2022 mpox (formerly monkeypox) epidemic. We describe five Belgian patients with localised severe symptoms of proctitis and penile oedema, occurring between 4 and 35 days after post-exposure preventive vaccination or after one- or two-dose off-label pre-exposure preventive vaccination with MVA-BN vaccine. Genome sequencing did not reveal evidence for immune escape variants.

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In addition to antimicrobial resistance, bacteria contain other mechanisms to survive antibiotic exposure such as tolerance, defined as the ability to slow metabolism by the extension of the lag phase without altering antimicrobial susceptibility. In a number of bacterial species, tolerance has been associated with treatment failure and infection chronicity and is found to precede and facilitate antimicrobial resistance. It is unknown if tolerance can be induced in .

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