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Biomedical subjects

A Widmer

Publications and source records attributed to A Widmer.

At least 19 recordsLinked to original sources

[Optimizing surgical hand disinfection].

For more than 110 years hands of surgeons have been treated before a surgical procedure in order to reduce the bacterial density. The kind and duration of treatment, however, has changed significantly over time. Recent scientific evidence suggests a few changes with the aim to optimize both the efficacy and the dermal tolerance. Aim of this article is the presentation and discussion of new insights in surgical hand disinfection. A hand wash should be performed before the first disinfection of a day, ideally at least 10 min before the beginning of the disinfection as it has been shown that a 1 min hand wash significantly increases skin hydration for up to 10 min. The application time may be as short as 1.5 min depending on the type of hand rub. Hands and forearms should be kept wet with the hand rub for the recommended application time in any case. A specific rub-in procedure according to EN 12791 has been found to be suitable in order to avoid untreated skin areas. The alcohol-based hand rub should have a proven excellent dermal tolerance in order to ensure appropriate compliance. Considering these elements in clinical practice can have a significant impact to optimize the high quality of surgical hand disinfection for prevention of surgical site infections.

Disinfectants↗

Genetic architecture of traits associated with serpentine adaptation of Silene vulgaris.

Serpentine soils provide a difficult substrate for plant colonization and growth and therefore represent an ideal system for studying the genetics of habitat adaptation and the evolution of plant-ecotypes. Using an F2 mapping population derived from an intraspecific cross between a serpentine and a nonserpentine ecotype of Silene vulgaris, the genetic architecture of seven morphological, physiological and life-history traits was explored. A quantitative trait locus (QTL) analysis identified 23 QTLs, 15 of which were classified as major QTLs. The observed genetic architecture suggests that traits potentially involved in habitat adaptation are controlled by few genes of major effect and have evolved under consistent directional selection. Several linkage groups harboured overlapping QTLs for different traits, which can be due to either pleiotropy or linkage. The potential roles of these factors and of the time available for habitat adaptation and ecological speciation on serpentine are discussed.

Adaptation, Physiological↗

Dermatoscope as vector for transmissible diseases - no apparent risk of nosocomial infections in outpatients.

PURPOSE: To determine nonpathogenic and potentially pathogenic bacterial growth isolated from dermatoscopes of dermatologists using oil as contact medium in the daily routine at two outpatient sections in Switzerland. METHODS: We investigated the microbiologic colonization of dermatoscopes (Dermatoskop Delta 10, Heine Optotechnik, or Dermogeniusbasic, Rodenstock) during routine use in the outpatient sections of the Departments of Dermatology at the University of Basel and Kantonsspital Aarau. 112 swabs (4 from Aarau, 108 from Basel) taken under standardized conditions were microbiologically worked up in the same laboratory. Oil (101) and 63% isopropyl alcohol (11) were used as contact medium. RESULTS: 39 of 112 swabs showed no bacterial growth. 73 of 112 showed growth of nonpathogenic bacteria (skin flora). Additionally to the cultivation of nonpathogenic bacteria, 3 swabs showed growth of oxacillin-sensitive potentially pathogenic Staphylococcus aureus. Of 11 swabs taken after using 63% isopropyl alcohol as a contact medium, 6 revealed no bacterial growth and 5 showed the growth of skin flora. CONCLUSIONS: The potential risk of nosocomial infection related to the routine use of dermatoscopes in outpatients is small, and the use of oil as a contact medium for dermatoscopy to enhance the optical quality seems to be unproblematic.

Anti-Bacterial Agents↗

The training curriculum in hospital infection control.

Standardised training curricula for infection control nurses (ICNs) and recognition of the specialty exist in many European countries, but infection control physician (ICP) is not a specialty recognised by the UEMS. To gather information on curricula for ICPs, members of the ESCMID Study Group on Nosocomial Infections received a questionnaire. There is discussion about which 'professions' should be included in an infection control team. Within the 12 countries included, the average full-time equivalents (FTEs) for ICPs and ICNs per 1000 beds were 1.2 and 3.4, respectively. In addition to ICNs and ICPs, an infection control team should also include a data manager, an epidemiologist, secretarial/administrative support, and possibly, surveillance technicians. Overall, the composition of an ideal infection control team was estimated to be 9.3 FTE per 1000 beds. The background of ICPs can be clinical microbiology or infectious diseases. Among the participants, it was predominantly clinical microbiology. The ideal training curriculum for the ICP should include 6 years of postgraduate training. Of these, at least 2 years should be 'clinical training' (e.g., internal medicine) to acquire experience in the management of high-risk patients. Furthermore, training with regard to infection control and hospital epidemiology should be offered as a 'common trunk' for those being trained in clinical microbiology or infectious diseases. Important issues that remain are: implementation/standardisation of training curricula for doctors, recognition of ICP as a separate specialty or sub-specialty of clinical microbiology and/or infectious diseases, validation of on-the-job training facilities in terms of the number of doctors and nurses who can give training and the category of patients/problems present, and mandatory postgraduate education/continuing medical education specific for infection control for doctors and nurses in the field.

Cross Infection↗

Chloroplast DNA inheritance in the orchid Anacamptis palustris using single-seed polymerase chain reaction.

The modality of chloroplast inheritance in orchids has been investigated only in a few species due to the difficulties associated with the analysis of large progeny numbers from experimental crosses. To test chloroplast DNA inheritance in the orchid Anacamptis palustris, we took advantage of the presence of a highly variable minisatellite repeat located in the tRNA(LEU) intron in the chloroplast genome. Seed progeny obtained from experimental crosses between parental individuals carrying different chloroplast DNA (cpDNA) minisatellite repeat numbers were analyzed using a single-seed polymerase chain reaction (PCR) protocol. All examined seeds displayed the maternal cpDNA haplotypes, indicating that cpDNA inheritance is strictly maternal in this Mediterranean orchid species. No evidence for paternal leakage was found. This finding concurs with results obtained from PCR amplifications of pollen massulae that exclude the presence of chloroplast DNA in the pollen tetrads.

Crosses, Genetic↗

Reproductive versus floral isolation among morphologically similar Serapias L. species (Orchidaceae).

Flowers of the Mediterranean orchid genus Serapias L. form small, dark tubes that vary among taxa in diameter and depth. Visiting insects use the floral tube as shelter and act as pollinators if they touch the sticky viscidium at the rear of the tube and remove the pollinarium. It has been assumed that floral tube size and shape limit access to the flowers and thus may act as a barrier to gene flow between different Serapias species. Here we investigated floral characters and nuclear microsatellite markers in populations belonging to three morphologically similar Serapias species to test whether these species show evidence for floral or reproductive isolation. We found strong overlap of floral traits between two species, suggesting that floral isolation is nonexistent between them. Microsatellite markers applied to the same populations were highly polymorphic and revealed clear genetic differentiation among all three species. These results suggest that reproductive isolation exists, despite the lack of floral isolation between two of the species. In contrast to morphological characters, diagnostic microsatellite alleles were found for all Serapias species. The microsatellite markers could thus provide a useful tool to identify Serapias species and further investigate evolutionary relationships in this fascinating orchid lineage.

Alleles↗

Hospital infection control in Europe: evaluation of present practice and future goals.

The objective of this study was to assess current infection control practice in Europe and its structure, future research priorities, and how infection control should be organised. A questionnaire was sent to 223 hospital infection control physicians throughout Europe, of whom 54 in 18 countries responded. With respect to future research priorities in infection control in Europe, the largest proportion (69%) of the infection control specialists sampled expressed the need for standardisation of surveillance systems for international comparison of nosocomial infection rates. The results of this survey might help to create a basis for standardised guidelines which take into account European-wide interests.

Cross Infection↗

Emergence of a teicoplanin-resistant small colony variant of Staphylococcus epidermidis during vancomycin therapy.

Small colony variants of Staphylococcus aureus can cause persistent and recurrent infections. There are only a few reports of small colony variants of coagulase-negative staphylococci. Herein a case of infection with a teicoplanin-resistant small colony variant of Staphylococcus epidermidis is presented. The small colony variant was isolated from blood cultures of a patient with acute leukaemia and therapy-induced neutropenia who was treated with vancomycin for catheter-associated bloodstream infection. Despite removal of the catheter and adequate antibiotic therapy, the infection did not clear and the patient died 20 days after continuous antibiotic therapy.

Aged↗

Fine-scale phylogeographical analysis of Mediterranean Anacamptis palustris (Orchidaceae) populations based on chloroplast minisatellite and microsatellite variation.

The phylogeographical history of the rare marsh orchid Anacamptis palustris (Orchidaceae) was reconstructed using highly polymorphic chloroplast minisatellite and microsatellite loci. Allelic variation at chloroplast microsatellite loci was due to length variation in poly(A/T) repeats and was informative on a regional scale, but was not sufficient to unravel relationships among populations on a local geographical scale. The minisatellite locus, however, was found to be highly variable. Nine distinct repeat types were found and variation in repeat number occurred in five repeat types. The distribution of chloroplast haplotypes, combining microsatellite and minisatellite repeat type variation, provided a clear phylogeographical picture on a large geographical scale, whereas length variation in one highly polymorphic minisatellite repeat type provided fine-scale phylogeographical information. Mediterranean populations could be divided into four main lineages, a western European lineage, a northern and central Italian lineage, a well-isolated southern Italian (Apulian) lineage, and an eastern European lineage. Variation at the most variable minisatellite repeat type N revealed 19 alleles and allowed the study of seed-mediated gene flow and an estimation of the ratio of pollen to seed flow among neighbouring populations.

Base Sequence↗

Glacial refugia: sanctuaries for allelic richness, but not for gene diversity.

Glacial refugia are generally expected to harbor higher levels of genetic diversity than are areas that have been colonized after the retreat of the glaciers because colonization often involves only a few individuals. A new paper by Comps et al. challenges this expectation by demonstrating a more complex situation in the European beech Fagus sylvatica, for which some measures of genetic diversity are higher in newly colonized areas than in refugia. The key to understanding this counter-intuitive result rests both in the estimators used to measure genetic diversity and in the processes affecting these estimators during postglacial recolonization.

Journal Article↗

Molecular phylogenetics of the sexually deceptive orchid genus Ophrys (Orchidaceae) based on nuclear and chloroplast DNA sequences.

We present a phylogenetic analysis of the major lineages of the sexually deceptive orchid genus Ophrys based on nuclear ribosomal (nr) DNA (internal transcribed spacer region) and noncoding chloroplast (cp) DNA (trnL-trnF region) sequences. Sequence divergence within and among major Ophrys lineages was low for both nrDNA and cpDNA sequences. Separate analyses resulted in similar but poorly resolved trees. An incongruence length difference test revealed that nrDNA and cpDNA data sets were not incongruent. A combined analysis resulted in a better-resolved phylogenetic hypothesis of relationships among the major Ophrys lineages. Our data strongly support a division of Ophrys into two groups. These groups do not correspond to the earlier proposed sections Euophrys and Pseudophrys and are thus in conflict with traditional classifications. Our results support a well-resolved monophyletic group that contains the geographically widespread O. bombyliflora, O. speculum, O. tenthredinifera, and the O. fusca-lutea lineage. Relationships in the other group are poorly resolved. Based on our observations that taxa with identical sequences at presumably rapidly evolving loci clearly differ in floral morphology, we hypothesize that the diversity in the genus Ophrys is the result of a recent radiation in this orchid lineage.

Cell Nucleus↗

Characterization of a minisatellite repeat locus in the chloroplast genome of Orchis palustris (Orchidaceae).

We describe the occurrence of a tandem repeat in the chloroplast genome of the marsh orchid, Orchis palustris. The repeat unit is an AT-rich, 16-bp sequence located in the chloroplast tRNALEU intron. Southern blot analysis confirmed that the O. palustris tRNALEU intron including the minisatellite locus has not been transferred to the nucleus, but is indeed located on the chloroplast genome. The 16-bp repeat unit was found to be present in all O. palustris accessions studied, as well as in the closely related O. laxiflora. Variation in repeat numbers among individuals was found in O. palustris from central and northern Italy; and this was consistently associated with a 13-bp sequence motif preceding the repeat. This motif was absent from O. palustris from southern Italy, Greece, and from O. laxiflora. In these accessions, no variation in repeat numbers was found. Our results suggest that the O. palustris chloroplast minisatellite locus evolved relatively recently, presumably in central Italy, and may represent a valuable marker for population genetic studies.

Base Composition↗

Phylogeny and classification of poison frogs (Amphibia: dendrobatidae), based on mitochondrial 16S and 12S ribosomal RNA gene sequences.

An analysis of partial sequences of the 16S ribosomal rRNA gene (582 bp) of 20 poison frog species (Dendrobatidae) confirmed their phylogenetic relationships to bufonid and leptodactylid frogs. Representatives of the ranoid families and subfamilies Raninae, Mantellinae, Petropedetinae, Cacosterninae, Arthroleptidae, Astylosternidae, and Microhylidae did not cluster as sister group of the Dendrobatidae. Similar results were obtained in an analysis using a partial sequence of the 12S gene (350 bp) in a reduced set of taxa and in a combined analysis. Within the Dendrobatidae, our data supported monophyly of the genus Phyllobates but indicated paraphyly of Epipedobates and Colostethus. Minyobates clustered within Dendrobates, contradicting its previously assumed phylogenetic position. Phobobates species clustered as a monophyletic unit within Epipedobates. Allobates was positioned in a group containing two Colostethus species, indicating that lack of amplexus, presence of skin alkaloids, and aposematic coloration evolved independently in Allobates and the remaining aposematic dendrobatids.

Amphibians↗

Genetic evidence for host specificity in the hemi-parasitic Viscum album L. (Viscaceae).

Nuclear ribosomal DNA (nrDNA) ITS sequences and partial sequences of three non-coding chloroplast DNA (cpDNA) introns and spacers were used to assess genetic variation within and among three presumed host races of the hemi-parasite Viscum album L. Currently, identification of host races occurs via the host trees, and morphological differences are minute at best. cpDNA and nrDNA ITS sequences revealed little sequence variation, but the variation found consistently supported the distinction of three host races. cpDNA and ITS sequences were not incongruent, as assessed by the incongruence length difference test. A combined analysis supported the sister group relationship between mistletoes from deciduous trees and fir.

Cycadopsida↗

Molecular analysis of orchid pollinaria and pollinaria-remains found on insects.

Direct observations of pollinator visits to orchids are often difficult and time consuming, especially in orchids with a deceptive pollination system where seed set is typically pollinator-limited. This lack of direct observations greatly inhibits our understanding of orchid-pollinator relationships and especially the degree of pollinator-specificity. Here we describe a molecular approach to the study of orchid-pollinator relationships based on the analysis of DNA recovered from pollinaria found on insects. The insects were collected from nectar-rich plants flowering near natural orchid populations, or taken from museum collections. Sequence analysis of the nuclear ribosomal ITS region allowed the identification of the orchid species or species-group from which the pollinaria originated. Four out of eight orchid-pollinator relationships established with this approach have not been reported previously, which highlights the value of molecular tools for the study of orchid pollination biology.

Animals↗

Evolution of gall morphology and host-plant relationships in willow-feeding sawflies (Hymenoptera: Tenthredinidae).

There are over 200 species of nematine sawflies that induce galls on willows (Salix spp.). Most of the species are mono- or oligophagous, and they can be separated into seven or eight different groups based on the type of gall that they induce. We studied the evolution of different gall types and host plant associations by reconstructing the phylogeny of five outgroup and 31 ingroup species using DNA sequence data from the mitochondrial cytochrome b gene. Maximum-parsimony and maximum-likelihood analyses resulted in essentially the same phylogeny with high support for important branches. The results show that: (1) the galling species probably form a monophyletic group; (2) true closed galls evolved only once, via leaf folders; (3) with the possible exception of leaf rollers, all gall type groups are mono- or paraphyletic; (4) similar gall types are closer on the phylogeny than would be expected by a random process; (5) there is an apparent evolutionary trend in galling site from the leaf edge towards the more central parts of the host plant; and (6) many willow species have been colonized several times, which excludes the possibility of parallel cladogenesis between willows and the gallers; however, there are signs of restrictions in the evolution of host use. Many of the patterns in the evolutionary history of nematine gallers have also been observed in earlier studies on other insect gallers, indicating convergent evolution between the independent radiations.

Animals↗