Characterization of ampicillin resistance mechanisms in clinical Haemophilus influenzae strains isolated in Portugal between 2009 and 2012

Introduction: Haemophilus influenzae (Hi) is mainly responsible for respiratory infections and empirical therapy is used most of times. Ampicillin resistance is a problem of concern since some strains have diminished susceptibility to β-lactams through a non-enzymatic mechanism that involves decreased affinity of β-lactams for altered penicillin-binding proteins (PBPs). Strains exhibiting this resistance mechanism are referred as β-lactamase-negative ampicillin resistant (BLNAR). The aim of this study is to characterize ampicillin resistance mechanisms in clinical isolates of Hi in Portugal. Material and Methods: Two hundred and thirty-five isolates chosen according to their ampicillin MICs: 139 BLNAR (MIC≥1mg/L), 33 susceptible strains (BLNAS; MIC<1mg/L) and 63 β-lactamase producers (BLPAR) were analyzed. The ftsI gene encoding PBP3 was amplified and sequenced. MIC was determined for 13 antibiotics by a microdilution assay, according to CLSI guidelines. Results and Discussion: Of the 235 Hi isolates 199 had mutations in the ftsI transpeptidase domain as follow: 136 gBLNAR out of 139 BLNAR strains (98%) and 44 gBLPACR out of 63 BPLAR strains (70%). Of note, 19 out of 33 BLNAS (58%) presented mutations being designated as gBLNAR. Among gBLNAR and gBLPACR strains there were 43 different mutation patterns, that were included in the six previously described groups and subgroups (I, IIa, IIb, IIc, IId, III-like). The most common amino acid substitutions were located near KTG motif: N526K (160/199, 80.4%), V547I (140/199, 70.4%) and N569S (131/199, 65.8%). Strains with mutations were less susceptible to the β-lactam antibiotics studied. Comparing these results with previously ones, performed in our laboratory (between 2001 and 2008) we are assisting to an increase of susceptible strains (ampicillin MIC≤2mg/L) as well as resistant strains (beta-lactamase producers) with mutations in the ftsI gene, being so called gBLNAR and gBLPACR. CLSI breakpoints alone can’t characterize these strains as susceptible or resistant in the susceptibility tests performed routinely in the laboratory. In this way, a continuous research on breakpoints and methodologies to better define strains of this kind is of crucial importance. In conclusion, we emphasize the importance of continuing surveillance studies of this nature as essential tools to define trends in the antibiotic resistance of Hi

Personal Meaning Maps as an Assessment Tool for a Planetarium Session: A Study with Primary School Children

This study aims to analyse the potentialities of using Personal Meaning Maps to assess school children’s learning in a visit to a Planetarium. A total of 123 primary students were involved. They were asked to create a PMM, and a drawing, before and after the visit. The results suggest that the visit enhanced the degree to which students generate words and conceptual categories to describe their understanding of the suggested concepts. PMMs seemed to be a good tool to evaluate the impact of the activities on students’ ideas about the thematic explored. Drawings helped to understand the main misconceptions.info:eu-repo/semantics/publishedVersio

History of science and science museums: an enriching partnership for elementary school science

The activity presented in this article is intended for elementary school students and focus on the pioneering oceanographic work of the Portuguese King Carlos I. This activity involves the exploration of the exhibits belonging to two different science museums, the Aquarium Vasco da Gama and the Maritime Museum. Students were asked to study fish adaptations to deep sea, through the exploration of a fictional story, also based on historical data from the work of the King that served as a guiding script for all the subsequent tasks. In both museums, students had access to observations of: historical collections of organisms, oceanographic biological sampling instruments, fish gears and ships. They could also observe the characteristics and adaptations of diverse deep-sea fish species. The present study aimed to analyse the impact of this activity on students’ scientific knowledge, on their understanding of the nature of science and on the development of transversal skills. All students considered the project very interesting. The obtained results suggest that the activity promoted not only the understanding of scientific concepts, but also the development of knowledge about science itself and the construction of scientific knowledge. This emphasizes the relevance of creating activities informed by the history of science. As a final remark we suggest that the partnership between elementary schools and museums should be seen as an educational project approach, in which the teacher has to assume a key, mediating role between the school and the museums.info:eu-repo/semantics/publishedVersio

Mutation accumulation in Tetrahymena

<p>Abstract</p> <p>Background</p> <p>The rate and fitness effects of mutations are key in understanding the evolution of every species. Traditionally, these parameters are estimated in mutation accumulation experiments where replicate lines are propagated in conditions that allow mutations to randomly accumulate without the purging effect of natural selection. These experiments have been performed with many model organisms but we still lack empirical estimates of the rate and effects of mutation in the protists.</p> <p>Results</p> <p>We performed a mutation accumulation (MA) experiment in <it>Tetrahymena thermophila</it>, a species that can reproduce sexually and asexually in nature, and measured both the mean decline and variance increase in fitness of 20 lines. The results obtained with <it>T. thermophila </it>were compared with <it>T. pyriformis </it>that is an obligate asexual species. We show that MA lines of <it>T. thermophila </it>go to extinction at a rate of 1.25 clonal extinctions per bottleneck. In contrast, populations of <it>T. pyriformis </it>show a much higher resistance to extinction. Variation in gene copy number is likely to be a key factor in explaining these results, and indeed we show that <it>T. pyriformis </it>has a higher mean copy number per cell than <it>T. thermophila</it>. From fitness measurements during the MA experiment, we infer a rate of mutation to copy number variation of 0.0333 per haploid MAC genome of <it>T. thermophila </it>and a mean effect against copy number variation of 0.16. A strong effect of population size in the rate of fitness decline was also found, consistent with the increased power of natural selection.</p> <p>Conclusions</p> <p>The rate of clonal extinction measured for <it>T. thermophila </it>is characteristic of a mutational degradation and suggests that this species must undergo sexual reproduction to avoid the deleterious effects detected in the laboratory experiments. We also suggest that an increase in chromosomal copy number associated with the phenotypic assortment of amitotic divisions can provide an alternative mechanism to escape the deleterious effect of random chromosomal copy number variation in species like <it>T. pyriformis </it>that lack the resetting mechanism of sexual reproduction. Our results are relevant to the understanding of cell line longevity and senescence in ciliates.</p

The Portuguese Maritime Voyages of Discovery: the exploration of the history of a city with an App as an educational resource

In this paper we present an evaluation of an App for mobile devices, ‘Roteiro dos Descobrimentos’, as an educational digital resource for primary school students. The study involved the participation of 131 students and eight teachers. Data were collected from participant observation, students’ questionnaires and interviews to students and teachers. According to students, they learned new things, related with the topics explored, in an easy and funny way. Students also emphasized as positive aspects the fact that they had to face different challenges and the need to mobilize their knowledge to solve them. Teachers referred that students showed great interest and enthusiasm during the activities. As main gains, teachers stressed that the application fosters the relationship of students with the city, facilitates collaboration, and promotes students’ autonomy. In resume, it seems that the playful and interactive dimension of the App promoted the development of important skills such as the ability to interact with the environment, collaborative work, autonomy, and reading and interpretation skills. As a conclusion, there is a great receptivity to integrate mobile technologies in the teaching and learning process, but the role of the teacher can’t be dismissed, as a mediator and educator

Determinants of the Sympatric Host-Pathogen Relationship in Tuberculosis

Major contributions from pathogen genome analysis and host genetics have equated the possibility of Mycobacterium tuberculosis co-evolution with its human host leading to more stable sympatric host-pathogen relationships. However, the attribution to either sympatric or allopatric categories depends on the resolution or grain of genotypic characterization. We explored the influence on the sympatric host-pathogen relationship of clinical (HIV infection and multidrug-resistant tuberculosis [MDRTB]) and demographic (gender and age) factors in regards to the genotypic grain by using spacer oligonucleotide typing (spoligotyping) for classification of M. tuberculosis strains within the Euro-American lineage. We analyzed a total of 547 tuberculosis (TB) cases, from six year consecutive sampling in a setting with high TB-HIV coinfection (32.0%). Of these, 62.0% were caused by major circulating pathogen genotypes. The sympatric relationship was defined according to spoligotype in comparison to the international spoligotype database SpolDB4. While no significant association with Euro-American lineage was observed with any of the factors analyzed, increasing the resolution with spoligotyping evidenced a significant association of MDRTB with sympatric strains, regardless of the HIV status. Furthermore, distribution curves of the prevalence of sympatric and allopatric TB in relation to patients' age showed an accentuation of the relevance of the age of onset in the allopatric relationship, as reflected in the trimodal distribution. On the contrary, sympatric TB was characterized by the tendency towards a typical (standard) distribution curve. Our results suggest that within the Euro-American lineage a greater degree of genotyping fine-tuning is necessary in modeling the biological processes behind the host-pathogen interplay. Furthermore, prevalence distribution of sympatric TB to age was suggestive of host genetic determinisms driven by more common variants.Luso-American Development Foundation: (LACR Award program - 2007), European Community fund: (FEDER)

GLYCOSAMINOGLYCANS AND PROTEOGLYCANS IN PALMAR FASCIA OF PATIENTS WITH DUPUYTREN

Objective: To evaluate and compare the behavior of glycosaminoglycans (GAGs) in Dupuytren disease (DD). Methods: This is an experimental study with 23 patients diagnosed with DD. Tissue collected through fasciectomy with incision type Brunner or McCash were evaluated by electrophoresis for identification of GAGs. The quantification was carried out by immunofluorescence and dosage of proteins for different types of glycosaminoglycans. The results were expressed in percentage and statistically evaluated. Results: A significant increase was observed through eletrophoresis in GAGs, as compared to the control (p<0.05). Immunofluorescence of hyaluronic acid was reduced (23 times) when compared to the control (p<0.0001). Conclusion: An increase of sulfated GAGs in Dupuytren's disease, mainly dermatan sulfate, was evident from our results, as well as a pronounced decrease of hyaluronic acid in the palmar aponeurosis from the same patients.Univ Fed Sao Paulo Unifesp, Escola Paulista Med, Dept Orthoped & Traumatol, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Dept Orthoped & Traumatol, Sao Paulo, SP, BrazilUniv Fed Sao Paulo Unifesp, Escola Paulista Med, Dept Orthoped & Traumatol, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Dept Orthoped & Traumatol, Sao Paulo, SP, BrazilWeb of Scienc

Ex vivo exposure to titanium dioxide and silver nanoparticles mildly affect sperm of gilthead seabream (Sparus aurata) - A multiparameter spermiotoxicity approach

Nanoparticles (NP) are potentially repmtoxic, which may compromise the success of populations. However, the reprotoxicity of NP is still scarcely addressed in marine fish. Therefore, we evaluated the impacts of environmentally relevant and supra environmental concentrations of titanium dioxide (TiO2: 10 to 10,000 mu g.L-1) and silver NP (Ag: 0.25 to 250 mu g.L-1) on the sperm of gilthead seabream (Sparus aurata). We performed short-term direct exposures (ex vivo) and evaluated sperm motility, head morphometry, mitochondrial function, antioxidant responses and DNA integrity. No alteration in sperm motility (except for supra environmental Ag NP concentration), head morphometry, mitochondrial function, and DNA integrity occurred. However, depletion of all antioxidants occurred after exposure to TiO2 NP, whereas SOD decreased after exposure to Ag NP (lowest and intermediate concentration). Considering our results, the decrease in antioxidants did not indicate vulnerability towards oxidative stress. TiO2 NP and Ag NP induced low spermiotoxicity, without proven relevant ecological impacts.info:eu-repo/semantics/publishedVersio