Direct identification of chlamydiae from clinical samples using a DNA microarray assay: a validation study

While DNA microarrays have become a widely accepted tool for mRNA expression monitoring, their use in rapid diagnosis of bacterial and viral pathogens is only emerging. So far, insufficient sensitivity and high costs have been the major limiting factors preventing more widespread use of microarray platforms in direct testing of clinical samples. In the present study, a total of 339 samples, among them 293 clinical specimens from animals and humans, were examined by the ArrayTube (AT) DNA microarray assay to detect chlamydial DNA and identify the species of Chlamydia and Chlamydophila involved. Samples included nasal and conjunctival swabs, formalin-fixed, paraffin-embedded and fresh organ tissue, milk, feces and cell culture. Notably, the AT test was shown to detect mixed infections in clinical samples. The calculated median sensitivity of 0.81 over the entire panel of clinical samples was comparable to conventional 16S PCR, but slightly lower than real-time PCR and other PCR assays. However, when a panel of long-time stored swab samples was excluded from the calculation, the sensitivity was clearly higher (0.87) and equivalent to that of real-time PCR. Altogether, the data demonstrate the suitability of this DNA microarray assay for routine diagnosis.     

Beeinflussung der psychosozialen Entwicklung von Kindern und Jugendlichen durch das Tragen von Gesichtsmasken im öffentlichen Raum zur Prävention von Infektionskrankheiten: Ein systematischer Review

Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz - Zur Prävention tröpfchenübertragener Infektionskrankheiten wird das Tragen einer Maske im öffentlichen Raum...     

Removing barriers to knowing HIV status: same-day mobile HIV testing in Zimbabwe

OBJECTIVES: We developed a mobile HIV voluntary counseling testing (VCT) strategy. Our aims were (1) to describe those using the services, (2) to assess the acceptability of such services, (3) to assess reasons for not testing previously, and (4) to compare those who used the services with those who did not to determine how to increase acceptability. METHODS: We provided free anonymous mobile VCT using 2 rapid HIV tests in 12 marketplaces in Epworth and Seke, Zimbabwe. Qualitative interviews were conducted to assess motivations for and barriers to testing. A subsample of HIV testers and individuals near testing vans who declined testing (nontesters) completed a questionnaire. RESULTS: A total of 1099 individuals participated in mobile VCT between March 2002 and August 2003. The proportion of participants infected with HIV was 29.2%. Overall, 98.8% of participants elected to receive HIV test results the same day. Reasons for not testing previously were often logistic (eg, inconvenience of hours [25.6%] and location [20.7%] or cost [8%]). Those who used the same-day mobile testing services (testers vs. nontesters) perceived themselves at higher risk for HIV infection (adjusted odds ratio [AOR] = 1.8) but were less likely to have known people with HIV (AOR = 0.49) or where to get tested (AOR = 0.57). CONCLUSIONS: Same-day HIV testing in community settings seems to be acceptable in sub-Saharan Africa. Barriers to HIV testing are often logistic and can be overcome with community-based strategies. These strategies need to be refined to address the needs of those not using mobile testing services.     

Candidate DNA replication initiation regions at human trinucleotide repeat disease loci

The positions of DNA replication initiation regions (IRs) at three human trinucleotide repeat (TNR) disease loci were examined in order to characterize the role played by IRs in explaining the known locus-specific variation in TNR instability levels. Using three different normal cell lines, candidate IRs were identified at the HD, SCA-7 and SBMA loci. At each locus the IR is less than 3.6 kb from the CAG/CTG repeat tract. Preliminary studies with a cell line homozygous for an HD disease mutation indicated no change in the position of the candidate IR in spite of the mutation. Comparison with experimental results from model systems suggests that a complex relationship may exist between instability and the proximity and/or orientation of the repeats with respect to an IR.     

SpA, ClfA, and FnbA genetic variations lead to Staphaurex test-negative phenotypes in bovine mastitis Staphylococcus aureus isolates

Staphylococcus aureus encodes many proteins that act as virulence factors, leading to a variety of diseases, including mastitis in cows. Among these virulence factors, SpA, ClfA, ClfB, FnbA, and FnbB are important for the ability of S. aureus to adhere to and invade host cells as well as to evade host immune responses. The interaction between these S. aureus surface proteins and human immunoglobulin G and fibrinogen that are coupled to latex particles is utilized to induce latex agglutination reactions, which are used widely in diagnostic kits for confirmation of presumptive S. aureus isolates. In this study, the Staphaurex latex agglutination test was performed on a collection of confirmed bovine mastitis S. aureus isolates. Notably, 54% (43/79 isolates) of these isolates exhibited latex agglutination-negative phenotypes (Staphaurex-negative result). To gain insights into the reasons for the high frequency of Staphaurex-negative bovine mastitis S. aureus isolates, the spa, clfA, clfB, fnbA, and fnbB genes were examined. Specific genetic changes in spa, clfA, and fnbA, as well as a loss of fnbB, which may impair SpA, ClfA, FnbA, and FnbB functions in latex agglutination reactions, were detected in Staphaurex-negative S. aureus isolates. The genetic changes included a premature stop codon in the spa gene, leading to a truncated SpA protein that is unable to participate in S. aureus cell-mediated agglutination of latex particles. In addition, clfA and fnbA genetic polymorphisms were detected that were linked to ClfA and FnbA amino acid changes that may significantly reduce fibrinogen-binding activity. The genetic variations in these S. aureus isolates might also have implications for their bovine mastitis virulence capacity.     

Suppression of Caco-2 and HEK-293 cell proliferation by Kigelia africana, Mimusops zeyheri and Ximenia caffra seed oils

Animal-derived oils and purified fatty acids, but not indigenous fruit-tree-derived seed oils, have been used to study cell growth and differentiation. In this study, we determined the effects of the Kigelia africana, the Mimusops zeyheri and the Ximenia caffra seed-oil on cell proliferation in culture. Human colon adenocarcinoma (Caco-2) and human embryonic kidney (HEK-293) cells were maintained and treated with various concentrations (0, 20, 40, 80, 100 and 120 mg/l) of K. africana, M. zehyeri and X. caffra seed oil. The trypan blue dye exclusion method was used to determine cell growth 48-hours after oil treatment. All three tree seed oils suppressed both Caco-2 and HEK-293 cell growth in a dose-dependent manner. Importantly, the tree seed oils did not cause increased cell death as the number of dead cells remained unchanged under control and oil-treated conditions. K. africana oil significantly suppressed Caco-2 cell growth compared to HEK-293 cell growth at all oil concentrations, whereas M. zeyheri and X. caffra seed oils significantly suppressed HEK-293 and Caco-2 cell growth, only at a concentration of 80 mg/l. The suppression of Caco-2 and HEK-293 cell proliferation by K. africana, M. zeyheri and X. caffra seed oils suggest a potential antiproliferative effect of these tree seed oils on the two cell lines.