| 1. |
- Bachmann, Till T., et al.
(author)
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Expert guidance on target product profile development for AMR diagnostic tests
- 2023
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In: BMJ Global Health. - : BMJ Publishing Group. - 2059-7908. ; 8:12
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Journal article (peer-reviewed)abstract
- Diagnostics are widely considered crucial in the fight against antimicrobial resistance (AMR), which is expected to kill 10 million people annually by 2030. Nevertheless, there remains a substantial gap between the need for AMR diagnostics versus their development and implementation. To help address this problem, target product profiles (TPP) have been developed to focus developers’ attention on the key aspects of AMR diagnostic tests. However, during discussion between a multisectoral working group of 51 international experts from industry, academia and healthcare, it was noted that specific AMR-related TPPs could be extended by incorporating the interdependencies between the key characteristics associated with the development of such TPPs. Subsequently, the working group identified 46 characteristics associated with six main categories (ie, Intended Use, Diagnostic Question, Test Description, Assay Protocol, Performance and Commercial). The interdependencies of these characteristics were then identified and mapped against each other to generate new insights for use by stakeholders. Specifically, it may not be possible for diagnostics developers to achieve all of the recommendations in every category of a TPP and this publication indicates how prioritising specific TPP characteristics during diagnostics development may influence (or not) a range of other TPP characteristics associated with the diagnostic. The use of such guidance, in conjunction with specific TPPs, could lead to more efficient AMR diagnostics development.
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| 2. |
- Iseri, Emre, PhD, et al.
(author)
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Performance of an innovative culture-based digital dipstick for detection of bacteriuria
- 2023
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In: Microbiology Spectrum. - : American Society for Microbiology. - 2165-0497.
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Journal article (peer-reviewed)abstract
- UTI-lizer is a recent digital format for easy-to-use culture-based detection, preliminary identification, and quantification of bacteria in urine at the point of care (PoC). This study aimed to evaluate the diagnostic accuracy of UTI-lizer tests for detection of bacteriuria caused by five common bacterial species: Escherichia coli, Klebsiella pneumoniae, Enterococcus faecalis, Proteus mirabilis, and Staphylococcus saprophyticus. We evaluated the accuracy of UTI-lizer tests by comparing test results of UTI-lizer with those of current standard bacterial culture-based diagnostics in clinical microbiology laboratories in a retrospective and a prospective study. Comparator methods were classical bacterial culture in combination with matrix-assisted laser desorption/ionization-time of flight mass spectrometry mediated bacterial identification. In the retrospective study, we tested 104 urine samples with in-panel microorganisms, plain urethral microbiota, and culture-negative samples. In the prospective study, we used 137 urine samples within 10 hours of their collection at general practitioner clinics. The retrospective study demonstrated 100% sensitivity and specificity in the detection of bacteriuria, and 98.6% sensitivity and 96.8% specificity in identifying primary pathogens with UTI-lizer when compared to clinical standards. S. saprophyticus and E. coli could not be distinguished. The combined nitrite and esterase test predicted the presence of bacteriuria in only 36.5% of cases. The prospective study demonstrated 100% sensitivity and 89.6% specificity in the detection of significant bacteriuria for in-panel microorganisms with a coverage rate of 88.3% (121/137). This study indicates that digital dipsticks are a promising alternative for the detection of the five main pathogens that cause the vast majority of urinary tract infections (UTIs). The results demonstrate that digital dipsticks have the potential to uniquely provide—in primary care or at the point of care—a UTI diagnostic quality on par with that of current gold-standard testing. The ease of testing, rapid test handling time, and time to result as well as simple test equipment make digital dipsticks an attractive solution for decentralized testing for bacteriuria and with that improvement in UTI diagnostics. These results motivate future studies to validate the use of UTI-lizer at the PoC setting.
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| 3. |
- Dzieciatkowska, Monika, et al.
(author)
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Rapid method for sensitive screening of oligosaccharide epitopes in the lipooligosaccharide from Campylobacter jejuni strains isolated from Guillain-Barre syndrome and Miller Fisher syndrome patients
- 2008
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In: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 46:10, s. 3429-3436
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Journal article (peer-reviewed)abstract
- Campylobacter jejuni lipooligosaccharide (LOS) can trigger Guillain-Barre syndrome (GBS) due to its similarity to human gangliosides. Rapid and accurate structural elucidation of the LOS glycan of a strain isolated from a GBS patient could help physicians determine the spectrum of anti-ganglioside antibodies likely to be found and therefore provide valuable assistance in establishing an appropriate course of treatment. The ability of implemented mass spectrometry-based approaches in a clinical setting has been limited by the laborious and time-consuming nature of the protocols, typically 3 to 4 days, used to prepare LOS. In order to improve the analytical throughput, microwave-assisted enzymatic digestion was investigated. In this study, the bacterial cells were suspended in 50 mu l of 20 mM ammonium acetate buffer containing DNase and RNase and treated by direct microwave irradiation for 3 min. Then, proteinase K was added and the samples were again microwaved. The intact LOS samples were analyzed using electrophoresis-assisted open-tubular liquid chromatography-mass spectrometry. The reliability of the rapid, high-throughput technique was demonstrated through analysis of LOS glycans from 73 C. jejuni strains. The structure was elucidated using material from a single colony. The total time for sample preparation and MS analysis is less than 60 min.
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| 4. |
- van Belkum, Alex, et al.
(author)
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Host-pathogen adhesion as the basis of innovative diagnostics for emerging pathogens
- 2021
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In: Diagnostics. - : MDPI AG. - 2075-4418. ; 11:7
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Research review (peer-reviewed)abstract
- Infectious diseases are an existential health threat, potentiated by emerging and re-emerging viruses and increasing bacterial antibiotic resistance. Targeted treatment of infectious diseases re-quires precision diagnostics, especially in cases where broad-range therapeutics such as antibiotics fail. There is thus an increasing need for new approaches to develop sensitive and specific in vitro diagnostic (IVD) tests. Basic science and translational research are needed to identify key microbial molecules as diagnostic targets, to identify relevant host counterparts, and to use this knowledge in developing or improving IVD. In this regard, an overlooked feature is the capacity of pathogens to adhere specifically to host cells and tissues. The molecular entities relevant for pathogen–surface interaction are the so-called adhesins. Adhesins vary from protein compounds to (poly-)saccharides or lipid structures that interact with eukaryotic host cell matrix molecules and receptors. Such interactions co-define the specificity and sensitivity of a diagnostic test. Currently, adhesin-receptor binding is typically used in the pre-analytical phase of IVD tests, focusing on pathogen enrichment. Further exploration of adhesin–ligand interaction, supported by present high-throughput “omics” technolo-gies, might stimulate a new generation of broadly applicable pathogen detection and characterization tools. This review describes recent results of novel structure-defining technologies allowing for detailed molecular analysis of adhesins, their receptors and complexes. Since the host ligands evolve slowly, the corresponding adhesin interaction is under selective pressure to maintain a constant receptor binding domain. IVD should exploit such conserved binding sites and, in particular, use the human ligand to enrich the pathogen. We provide an inventory of methods based on adhesion factors and pathogen attachment mechanisms, which can also be of relevance to currently emerging pathogens, including SARS-CoV-2, the causative agent of COVID-19.
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| 5. |
- Verhaegh, Suzanne J. C., et al.
(author)
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Comparative Analysis of the Humoral Immune Response to Moraxella catarrhalis and Streptococcus pneumoniae Surface Antigens in Children Suffering from Recurrent Acute Otitis Media and Chronic Otitis Media with Effusion
- 2012
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In: Clinical and Vaccine Immunology. - 1556-6811. ; 19:6, s. 914-918
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Journal article (peer-reviewed)abstract
- A prospective clinical cohort study was established to investigate the humoral immune response in middle ear fluids (MEF) and serum against bacterial surface proteins in children suffering from recurrent acute otitis media (rAOM) and chronic otitis media with effusion (COME), using Luminex xMAP technology. The association between the humoral immune response and the presence of Moraxella catarrhalis and Streptococcus pneumoniae in the nasopharynx and middle ear was also studied. The levels of antigen-specific IgG, IgA, and IgM showed extensive interindividual variation. No significant differences in anti-M. catarrhalis and anti-S. pneumoniae serum and MEF median fluorescence intensity (MFI) values (anti-M. catarrhalis and antipneumococcal IgG levels) were observed between the rAOM or COME groups for all antigens tested. No significant differences were observed for M. catarrhalis and S. pneumoniae colonization and serum IgG levels against the Moraxella and pneumococcal antigens. Similar to the antibody response in serum, no significant differences in IgG, IgA, and IgM levels in MEF were observed for all M. catarrhalis and S. pneumoniae antigens between OM M. catarrhalis-or S. pneumoniae-positive and OM M. catarrhalis-or S. pneumonia-negative children suffering from either rAOM or COME. Finally, results indicated a strong correlation between antigen-specific serum and MEF IgG levels. We observed no significant in vivo expressed anti-M. catarrhalis or anti-S. pneumoniae humoral immune responses using a range of putative vaccine candidate proteins. Other factors, such as Eustachian tube dysfunction, viral load, and genetic and environmental factors, may play a more important role in the pathogenesis of OM and in particular in the development of rAOM or COME.
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| 6. |
- Verhaegh, Suzanne J. C., et al.
(author)
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Temporal development of the humoral immune response to surface antigens of Moraxella catarrhalis in young infants
- 2011
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In: Vaccine. - : Elsevier BV. - 1873-2518 .- 0264-410X. ; 29:34, s. 5603-5610
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Journal article (peer-reviewed)abstract
- The primary Moraxella catarrha/is-specific humoral immune response, and its association with nasopharyngeal colonization, was studied in a cohort of infants from birth to 2 years of age. Results indicated that the levels of antigen-specific IgG, IgA and IgM showed extensive inter-individual variability over time, with IgM and IgA levels to all 9 recombinant domains, from 7 different OMPs, being relatively low throughout the study period. In contrast, the level of antigen-specific IgG was significantly higher for the recombinant domains Hag(385-863), MID764-913, MID962-1200, UspA1(557-704) and UspA2(165-318) in cord blood compared to 6 months of age (P <= 0.001). This was a most likely a consequence of maternal transmission of antigen-specific IgG to newborn babies, possibly indicating a future role for these 3 surface antigens in the development of an effective humoral immune response to M. catarrhalis. Finally, at 2 years of age, the levels of antigen-specific IgG still remained far below that obtained from cord blood samples, indicating that the immune response to M. catarrhalis has not matured at 2 years of age. We provide evidence that a humoral antibody response to OMPs UspA1,UspA2 and Hag/MID may play a role in the immune response to community acquired M. catarrhalis colonization events. (C) 2011 Elsevier Ltd. All rights reserved.
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