Publications by authors named "Frank H Schuren"

Background: To date, women are most often diagnosed with bacterial vaginosis (BV) using microscopy based Nugent scoring or Amsel criteria. However, the accuracy is less than optimal. The aim of the present study was to confirm the identity of known BV-associated composition profiles and evaluate indicators for BV using three molecular methods.

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Background: The observed association between Depo-Provera injectable use and increased HIV acquisition may be caused by hormone-induced increased susceptibility to other sexually transmitted infections (STIs) or changes in the cervicovaginal microbiota (VMB), accompanied by genital immune activation and/or mucosal remodeling.

Methods: Rwandan female sex workers (n = 800) were interviewed about contraceptive use and sexual behavior and were tested for STIs, bacterial vaginosis by Nugent score and pregnancy, at baseline. A subset of 397 HIV-negative, nonpregnant women were interviewed and tested again at regular intervals for 2 years.

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Cervicovaginal microbiota not dominated by lactobacilli may facilitate transmission of HIV and other sexually transmitted infections (STIs), as well as miscarriages, preterm births and sepsis in pregnant women. However, little is known about the exact nature of the microbiological changes that cause these adverse outcomes. In this study, cervical samples of 174 Rwandan female sex workers were analyzed cross-sectionally using a phylogenetic microarray.

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Prebiotics are considered to have potential to reduce disturbances in the gut microbiota induced by antibiotics. Results in literature are, however, not consistent. The current in vitro study conducted in a fermentation screening platform allowed to unambiguously compare the impact of galacto-oligosaccharides (GOS) on adult gut microbiota composition and activity upon treatment with four antibiotics at two doses.

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Vaginal lactobacilli assessed by PCR-based microarray and PCR-based genotyping of HPV in South African women at risk for HIV and BV. Vaginal lactobacilli can be defined by microarray techniques in fixed cervical samples of South African women. Cervical brush samples suspended in the coagulant fixative BoonFix of one hundred women attending a health centre for HIV testing in South Africa were available for this study.

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Article Synopsis
  • Thermostable spores from the Bacillaceae family often cause food preservation failures due to their resistance to cleaning methods and preservation treatments.
  • A mixed-species genotyping array was developed for 6 Bacillus and 4 Geobacillus species to effectively track food spoilage from ingredients to final products.
  • The array can differentiate between species and even individual isolates, making it a fast and economical tool for identifying Bacillus-related food spoilage bacteria in various food items.
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Objective: The objective was to examine the use of a tailor-made DNA microarray containing probes representing the vaginal microbiota to examine bacterial vaginosis.

Study Design: One hundred one women attending a health center for HIV testing in South Africa were enrolled. Stained, liquid-based cytology slides were scored for bacterial vaginosis.

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Although their exact function remains enigmatic, bifidobacteria are among the first colonizers of the newborn infant gut and further develop into abundant communities, notably in response to diet. Therefore, the transcriptional responses of bifidobacteria in rapidly processed fecal samples from young infants that were fed either breast milk or a formula containing a mixture of galacto- and fructo-oligosaccharides were studied. The presence and diversity of the bifidobacterial fecal communities were determined using PCR-denaturing gradient gel electrophoresis and quantitative real-time PCR for specific species.

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A genomic DNA-based microarray was constructed containing over 6000 randomly cloned genomic fragments of approximately 1-2 kb from six mammalian intestinal Bifidobacterium spp. including B. adolescentis, B.

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Background: In bacteriology, the ability to grow in selective media and to form colonies on nutrient agar plates is routinely used as a retrospective criterion for the detection of living bacteria. However, the utilization of indicators for bacterial viability-such as the presence of specific transcripts or membrane integrity-would overcome bias introduced by cultivation and reduces the time span of analysis from initiation to read out. Therefore, we investigated the correlation between transcriptional activity, membrane integrity and cultivation-based viability in the Gram-positive model bacterium Bacillus subtilis.

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Article Synopsis
  • The study focuses on the Aspergillus niger protease mutant AB1.13, where several major secreted protease genes, including the pepA gene, show altered expression.
  • The researchers used a cloning technique to identify and complement a gene responsible for the mutation, which revealed a gene (PrtT) coding for a fungal-specific protein.
  • Notably, PrtT has homologues among Aspergillus species but is absent in non-Aspergillus species, suggesting a unique regulatory role specific to this genus.
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  • The Enterobacter cloacae complex is increasingly recognized as a nosocomial pathogen, but its traditional identification methods are unreliable.
  • Multilocus sequence analysis and comparative genomic hybridization show that this complex is divided into two distinct genetic clades, with one clade being more homogeneous and containing the most commonly found species in hospitals.
  • The study suggests that some existing classifications of (sub)species within this complex need to be revised, and new genetic markers can aid in more accurate identification.
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Invasive group A streptococcal (GAS) disease re-emerged in The Netherlands in the late 1980s. To seek an explanation for this resurgence, the genetic compositions of 22 M1 and 19 M28 GAS strains isolated in The Netherlands between 1960s and the mid-1990s were analyzed by using a mixed-genome DNA microarray. During this four-decade period, M1 and especially M28 strains acquired prophages on at least eight occasions.

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Article Synopsis
  • Group A streptococci (GAS) are linked to diverse diseases, including severe conditions like toxic-shock-like syndrome (TSS), with M types M1 and M3 particularly associated with TSS.
  • Researchers analyzed genomic differences among 76 GAS strains in The Netherlands using microarray technology, finding that variations between M types were much greater than those within a single type, with phages playing a significant role in this genetic diversity.
  • Four novel genes were identified that may influence disease manifestations in specific M types, alongside unique virulence factors found in M1 and M3 strains that could enhance their ability to cause TSS, although no common virulence profile was found for TSS across all M types.
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Enterococcus faecium, an ubiquous colonizer of humans and animals, has evolved in the last 15 years from an avirulent commensal to the third most frequently isolated nosocomial pathogen among intensive care unit patients in the United States. E. faecium combines multidrug resistance with the potential of horizontal resistance gene transfer to even more pathogenic bacteria.

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Background: Clone-based microarrays, on which each spot represents a random genomic fragment, are a good alternative to open reading frame-based microarrays, especially for microorganisms for which the complete genome sequence is not available. Since the generation of a genomic DNA library is a random process, it is beforehand uncertain which genes are represented. Nevertheless, the genome coverage of such an array, which depends on different variables like the insert size and the number of clones in the library, can be predicted by mathematical approaches.

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Lactobacillus plantarum is a versatile and flexible species that is encountered in a variety of niches and can utilize a broad range of fermentable carbon sources. To assess if this versatility is linked to a variable gene pool, microarrays containing a subset of small genomic fragments of L. plantarum strain WCFS1 were used to perform stringent genotyping of 20 strains of L.

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