Strong correlation of total phenotypic resistance of samples from household environments and the prevalence of class 1 integrons suggests for the use of the relative prevalence of intI1 as a screening tool for multi-resistance.

One of the biggest challenges of health care systems worldwide is the increasing number of pathogenic bacteria resistant to a growing number of antibiotics. In this respect, class 1 integrons which are part of mobile genetic elements can confer several phenotypes including resistance to a broad range of antibiotic classes, heavy metals and biocides. They are linked to common resistance genes and have penetrated pathogenic and commensal bacteria likewise. Therefore its relative prevalence can be a proxy for antimicrobial resistance and anthropogenic pollution. Household environments are areas with a high influx of bacteria from humans, animals and foods, and biocides and detergents are frequently used. In this study we aimed to investigate the relative prevalence of class 1 integrons in household environments, in relation to the number of antibiotic and benzalkonium chloride resistant phenotypes of a sample point, for the validation of the relative prevalence of class 1 integrons as a screening tool for multi-resistance. Kitchen sink and bathroom sink U-bends, dishwasher, washing machines and toothbrushes of 28 households were probed. Copies /mL of class 1 integron integrase gene and 16SrDNA gene were determined by qPCR and bacteria of the respective sample were isolated on ampicillin selective agar plates, followed by the determination of the species and phenotypic resistance profiles. The relative prevalence of class 1 integrons in relation to 16SrDNA was calculated and correlated to phenotypic resistance. Our findings show a high relative prevalence of class 1 integrons in water reticulation systems of household environments and in particular shower U-bends. Furthermore, prevalence of class 1 integrons correlates strongly (rs = 0.95) with total phenotypic resistance at a sample point and suggest that a standardized assay determining the relative prevalence of class 1 integrons could be used as a useful screening tool in the assessment of multi-resistance in environmental samples.

Evaluation of a Novel Rapid Test System for the Detection of Allergic Sensitization to Timothy Grass Pollen against Established Laboratory Methods and Skin Prick Test.

Type I hypersensitivity is driven by allergen specific immunoglobulin E (sIgE) and thus sIgE represents a marker for modern allergy diagnosis. Recently, a rapid assay for the detection of sIgE, termed as (Allergy Lateral Flow Assay) ALFA, has been developed. The objective of our study is the evaluation of a scanner-based system for the semiquantitative interpretation of ALFA results. Agreement to Skin Prick Test (SPT, Allergopharma), ALLERG-O-LIQ System (Dr. Fooke), and ImmunoCAP (Phadia) was investigated using 50 sera tested for specific IgE to timothy grass pollen (g6). 35/50 sera were positive by SPT, ALLERG-O-LIQ, and ImmunoCAP. Excellent agreement was observed between ALFA results and SPT, ImmunoCAP, and ALLERG-O-LIQ. Area under the curve (AUC) values were found at 1.0, and 100% sensitivity and specificity was found versus all other methods. Visual- and scanner-based interpretation of the ALFA results revealed excellent agreement.

The structural transition of the prion protein into its pathogenic conformation is induced by unmasking hydrophobic sites.

A series of structural intermediates in the putative pathway from the cellular prion protein PrP(C) to the pathogenic form PrP(Sc) was established by systematic variation of low concentrations (<0.1%) of the detergent sodium dodecyl sulfate (SDS) or by the interaction with the bacterial chaperonin GroEL. Most extended studies were carried out with recombinant PrP (90-231) corresponding to the amino acid sequence of hamster prions PrP 27-30. Similar results were obtained with full-length recombinant PrP, hamster PrP 27-30 and PrP(C) isolated from transgenic, non-infected CHO cells. Varying the incubation conditions, i.e. the concentration of SDS, the GroEL and GroEL/ES, but always at neutral pH and room temperature, different conformations could be established. The conformations were characterized with respect to secondary structure as determined by CD spectroscopy and to molecular mass, as determined by fluorescence correlation spectroscopy and analytical ultracentrifugation: alpha-helical monomers, soluble alpha-helical dimers, soluble but beta-structured oligomers of a minimal size of 12-14 PrP molecules, and insoluble multimers were observed. A high activation barrier was found between the alpha-helical dimers and beta-structured oligomers. The numbers of SDS-molecules bound to PrP in different conformations were determined: Partially denatured, alpha-helical monomers bind 31 SDS molecules per PrP molecule, alpha-helical dimers 21, beta-structured oligomers 19-20, and beta-structured multimers show very strong binding of five SDS molecules per PrP molecule. Binding of only five molecules of SDS per molecule of PrP leads to fast formation of beta-structures followed by irreversible aggregation. It is discussed that strongest binding of SDS has an effect identical with or similar to the interaction with GroEL thereby inducing identical or very similar transitions. The interaction with GroEL/ES stabilizes the soluble, alpha-helical conformation. The structure and their stabilities and particularly the induction of transitions by interaction of hydrophobic sites of PrP are discussed in respect to their biological relevance.

Intracellular re-routing of prion protein prevents propagation of PrP(Sc) and delays onset of prion disease.

Prion diseases are fatal and transmissible neurodegenerative disorders linked to an aberrant conformation of the cellular prion protein (PrP(c)). We show that the chemical compound Suramin induced aggregation of PrP in a post-ER/Golgi compartment and prevented further trafficking of PrP(c) to the outer leaflet of the plasma membrane. Instead, misfolded PrP was efficiently re-routed to acidic compartments for intracellular degradation. In contrast to PrP(Sc) in prion-infected cells, PrP aggregates formed in the presence of Suramin did not accumulate, were entirely sensitive to proteolytic digestion, had distinct biophysical properties, and were not infectious. The prophylactic potential of Suramin-induced intracellular re-routing was tested in mice. After intraperitoneal infection with scrapie prions, peripheral application of Suramin around the time of inoculation significantly delayed onset of prion disease. Our data reveal a novel quality control mechanism for misfolded PrP isoforms and introduce a new molecular mechanism for anti-prion compounds.

Explanatory models and help-seeking behaviour of leprosy patients in Adamawa State, Nigeria.

In northern Nigeria 60 leprosy patients, 49 outpatients and 11 in-patients, were interviewed about their help-seeking behaviour and explanatory models before their first contact with the leprosy services. Most patients showed a delay of more than 1 year. After leprosy was provisionally diagnosed by lay persons, 27% of patients found their way to the leprosy services within 3 months. Chemists (popular sector) and the professional sector frequently missed the diagnosis. If early case finding is to be improved, it is important to involve them in case finding activities and to train them in adequate diagnostic skills. No significant correlations were found between total delay and sex, age, religion or leprosy classification, except with visible deformity at the time of the interview and illiteracy. Consultation of folk healers was the major reason for delay. Most patients consulted folk healers, who, although they claimed to have a positive attitude towards modern medicine in the case of leprosy, never referred patients to the leprosy services. While many patients held a variety of causes responsible for leprosy, most patients explained the disease in traditional terms (58%), while only a minority used modern concepts (20%). This emphasizes the need for continuous attention for health education of diagnosed patients and their families. No significant difference was found between male and female patients concerning their concept of leprosy. Denial of the leprosy diagnosis was rare.