qnrA gene diversity in Shewanella spp

Members of Shewanella are ubiquitous in aquatic environments, some of which have been implicated in human infections. The progenitors of antibiotic resistance genes with clinical relevance, such as qnrA genes, have been identified in Shewanella. qnrA code for a pentapeptide repeat protein that protects type II topoisomerases, decreasing susceptibility to quinolones and fluoroquinolones. In this study, 248 genomes of 49 Shewanella species were analysed as well as 33 environmental isolates belonging to 10 Shewanella species. The presence of the qnrA gene was detected in 22.9% of the genomes and 15.2% of the isolates. The gene was more often detected in Shewanella algae, but was also detected in Shewanella carassii, Shewanella chilikensis, Shewanella haliotis and Shewanella indica. The identified genes encoded the previously described variants QnrA3 (in 22 genomes of one species), QnrA2 (eight genomes and three species), QnrA1 (six genomes and two species), QnrA7 (five genomes and two species), QnrA10 (two genomes of one species) and QnrA4 (one genome). In addition, 11 novel variants with 3 to 7 amino acid substitutions were identified (in 13 genomes and one environmental isolate). The presence of this gene appears to be species-specific although within some species several variants were detected. The study presents a previously unknown diversity of qnrA in Shewanella, highlighting the role of this genus as progenitor and reservoir of these genes. Further studies are needed to determine the phenotypes conferred by the new variants and the mechanisms that may mediate the transfer of these genes to new hosts.

Prevalence of maxillary sinus septa: systematic review and meta-analysis

The aim of this systematic review and meta-analysis was to determine the prevalence and characteristics of maxillary sinus septa using cone beam computed tomography and computed tomography data. Publications were searched until October 5, 2020 in three electronic databases. Additionally, article bibliographies were searched, and authors were contacted if required. This review has been registered in PROSPERO (CRD42019124933). Two independent evaluators assessed methodological quality using the Joanna Briggs Institute levels of evidence; inter-rater reliability tests were performed (Cohen's κ). The prevalence of maxillary sinus septa was expressed as a proportion; differences according to sex were reported in terms of the odds ratio (OR) and 95% confidence interval (95% CI). Heterogeneity and sources of heterogeneity were evaluated by meta-regression. Publication bias was assessed by visual analysis of the funnel plot. Statistical significance was set at P < 0.05. The 62 studies identified and included in the review involved 13,701 patients (22,460 sinuses). The meta-analysis of 35 studies (14,664 sinuses) revealed an overall mean sinus septa prevalence per sinus of 33.2% (95% CI 27.8-38.5%; I² = 98.32%). The meta-analysis of 42 studies (9631 patients) found an overall mean sinus septa prevalence per patient of 41.0% (95% CI 36.0-46.0%, I² = 96.45%). The OR for the difference in septa prevalence between sexes was 0.785 (95% CI 0.590-1.046; P = 0.098, I² = 73.24%). Septa were most frequent in the middle area of the sinus and with a transverse orientation (86.0%). Within the limitations, the results suggest a high proportion of septa in the sinus, commonly in the middle area, which can interfere with the success of sinus floor elevation required for implant rehabilitation.

Impact of Ag2S NPs on soil bacterial community - A terrestrial mesocosm approach

Soils might be a final sink for Ag₂S nanoparticles (NPs). Still, there are limited data on their effects on soil bacterial communities (SBC). To bridge this gap, we investigated the effects of Ag₂S NPs (10 mg kg^-1 soil) on the structure and function of SBC in a terrestrial indoor mesocosm, using a multi-species design. During 28 days of exposure, the SBC function-related parameters were analysed in terms of enzymatic activity, community level physiological profile, culture of functional bacterial groups [phosphorous-solubilizing bacteria (P-SB) and heterotrophic bacteria (HB)], and SBC structure was analysed by 16S rRNA gene-targeted denaturing gradient gel electrophoresis. The SBC exposed to Ag₂S NPs showed a significative decrease of functional parameters, such as β-glucosidase activity and L-arginine consumption, and increase of the acid phosphatase activity. At the structural level, significantly lower richness and diversity were detected, but at later exposure times compared to the AgNO₃ treatment, likely because of a low dissolution rate of Ag₂S NPs. In fact, stronger effects were observed in soils spiked with AgNO₃, in both functional and structural parameters. Changes in SBC structure seem to negatively correlate with parameters related to phosphorous (acid phosphatase activity) and carbon cycling (abundance of HB, P-SB, and β-glucosidase activity). Our results indicate a significant effect of Ag₂S NPs on SBC, specifically on parameters related to carbon and phosphorous cycling, at doses as low as 10 mg kg^-1 soil. These effects were only observed after 28 days, highlighting the importance of long-term exposure experiments for slowly dissolving NPs.

The association between the 4G/5G polymorphism in the promoter of the plasminogen activator inhibitor-1 gene and deep venous thrombosis in young people

Objective: To evaluate the association between the 4G/5G polymorphism in the promoter of the plasminogen activator inhibitor-1 (PAI-1) gene and deep venous thrombosis (DVT) in young people.

Methods: Prevalence of the 4G/5G polymorphism was investigated using DNA analysis in a population of 81 consecutive and unrelated patients with an objectively documented first episode of DVT under 40 years old and in a control group of 88 healthy subjects.

Results: The frequency of genotypes among patients was 0.27 4G/4G, 0.49 4G/5G and 0.23 5G/5G, corresponding to a frequency of 0.52 for the 4G allele. In the control group the results were, respectively, 0.24, 0.44 and 0.32, corresponding to a frequency of 0.46 for the 4G allele. The odds ratio (OR) for homozygous 4G genotype was 1.5 (95% confidence interval: 0.7–3.6), which was not statistically significant ( P = 0.51).

Conclusion: In this study, the 4G/5G polymorphism in the promoter of the PAI-1 gene, including the homozygous 4G genotype, was not associated with a significantly increased risk of DVT in young people.

Regular and moderate aerobic training before allergic asthma induction reduces lung inflammation and remodeling

Experimental studies have reported that aerobic exercise after asthma induction reduces lung inflammation and remodeling. Nevertheless, no experimental study has analyzed whether regular/moderate aerobic training before the induction of allergic asthma may prevent these inflammatory and remodeling processes. For this purpose, BALB/c mice (n = 96) were assigned into non-trained and trained groups. Trained animals ran on a motorized treadmill at moderate intensity, 30 min/day, 3 times/week, for 8 weeks, and were further randomized into subgroups to undergo ovalbumin sensitization and challenge or receive saline using the same protocol. Aerobic training continued until the last challenge. Twenty-four hours after challenge, compared to non-trained animals, trained mice exhibited: (a) increased systolic output and left ventricular mass on echocardiography; (b) improved lung mechanics; (c) decreased smooth muscle actin expression and collagen fiber content in airways and lung parenchyma; (d) decreased transforming growth factor (TGF)-β levels in bronchoalveolar lavage fluid (BALF) and blood; (e) increased interferon (IFN)-γ in BALF and interleukin (IL)-10 in blood; and (f) decreased IL-4 and IL-13 in BALF. In conclusion, regular/moderate aerobic training prior to allergic asthma induction reduced inflammation and remodeling, perhaps through increased IL-10 and IFN-γ in tandem with decreased Th2 cytokines.

Impact of sampling depth and plant species on local environmental conditions, microbiological parameters and bacterial composition in a mercury contaminated salt marsh

We compare the environmental characteristics and bacterial communities associated with two rushes, Juncus maritimus and Bolboschoenus maritimus, and adjacent unvegetated habitat in a salt marsh subjected to historical mercury pollution. Mercury content was higher in vegetated than unvegetated habitat and increased with sampling depth. There was also a significant relationship between mercury concentration and bacterial composition. Habitat (Juncus, Bolboschoenus or unvegetated), sample depth, and the interaction between both, however, explained most of the variation in composition (~70%). Variation in composition with depth was most prominent for the unvegetated habitat, followed by Juncus, but more constrained for Bolboschoenus habitat. This constraint may be indicative of a strong plant-microbe ecophysiological adaptation. Vegetated habitat contained distinct bacterial communities associated with higher potential activity of aminopeptidase, β-glucosidase and arylsulphatase and incorporation rates of (14)C-glucose and (14)C-acetate. Communities in unvegetated habitat were, in contrast, associated with both higher pH and proportion of sulphate reducing bacteria.

Characterization of microbial population of 'Alheira' (a traditional Portuguese fermented sausage) by PCR-DGGE and traditional cultural microbiological methods

AIMS

This study evaluates the microbial ecology of 'Alheira' by traditional microbiological analysis and a PCR-denaturing gradient gel electrophoresis (DGGE) protocol.

METHODS AND RESULTS

Total microbial DNA from 'Alheiras' was extracted directly from the products and subjected to PCR using Eubacterial primers for 16S rDNA. The amplicons were separated by DGGE. The results demonstrated that different products of the same batch display identical profiles, whereas products from different batches of the same producer could display different DGGE profiles. 'Alheiras' from different producers were distinguishable based on the respective DGGE profiles. The obtained sequences from prevalent phylotypes affiliated with order Lactobacillales and order Bacillales and class Gammaproteobacteria. The same samples were subjected to traditional microbiological analysis. In both methods, lactic acid bacteria were dominant and were present together with other organisms, mainly members of the family Micrococcaceae.

CONCLUSIONS

The approach explored in this study allowed the description of the microbial community present in 'Alheira' in particular the diversity of lactic acid bacteria.

SIGNIFICANCE AND IMPACT OF THE STUDY

This can be useful for the microbiological characterization of traditional products in order to develop new methods of quality control capable of supporting a standardization of the processes, while preserving their typical traits.

PCR-DGGE-based methodologies to assess diversity and dynamics of Aeromonas communities

AIMS

Aeromonas is ubiquitous in aquatic environments and may cause infectious diseases in fish and humans. However, reliable and specific methods to evaluate the diversity and dynamics of Aeromonas populations are currently unavailable. This study aimed to develop PCR-DGGE methodologies for culture-independent analysis of Aeromonas populations in water systems.

METHODS AND RESULTS

Three primer sets were designed to amplify selected sections of genes gyrB, rpoD and sodB from Aeromonas. Their specificity was confirmed by in silico analysis and by PCR on DNA from pure cultures. Estuarine water samples were analyzed by PCR-DGGE using those primers. DGGE patterns clearly clustered according to seasonal factors, and Aeromonas communities were surprisingly stable along a salinity gradient. Sequences of cloned amplicons affiliated to sequences belonging to seven Aeromonas species previously isolated from the same environment.

CONCLUSIONS

The three systems used showed to be useful to describe the diversity of Aeromonas communities. However, the combined use of more than one primer set is advisable.

SIGNIFICANCE AND IMPACT OF THE STUDY

The methods presented here can be applied to understand the natural pool of Aeromonas and also to monitor and control these bacteria in aquatic reservoirs.

Primary chemotherapy with sequential docetaxel followed by docetaxel and epirubicin in large operable breast cancer

Primary chemotherapy is increasingly used in patients with large operable breast cancer. Docetaxel and epirubicin are the most active agents in breast cancer treatment.

PURPOSE

To evaluate clinical response rate, breast conserving surgery and pathological response rate in patients with large operable breast cancer treated with docetaxel followed by docetaxel and epirubicin as primary chemotherapy.

PATIENTS AND METHODS

Patients with operable breast cancer more than 3 cm in the longest diameter with T2N0, T2N1 and T3N0 disease were enrolled. Patients were treated with three cycles of docetaxel 100 mg/m2 followed by three cycles of docetaxel 75 mg/m2 and epirubicin 90 mg/m2 prior to surgery.

RESULTS

Sixty-five patients were enrolled between 09/2002 and 12/2005. The median age was 48.9 years and 72.3% were premenopausal. Median tumour size was 4.26 cm, 10.8% were T3 tumours and 38.5% had clinical positive lymph nodes. Of the tumours 58.5% were grade 1/2, 33.9% ER positive and 21.5% c-erb negative. All six cycles were administered to 62 patients; six cycles were delayed and five had dose reductions. Complete clinical response occurred in 41.5% of patients and partial response in 49.2%. Breast conserving surgery was performed in 30% of patients however it was feasible in 57%. Complete pathological response occurred in both primary tumour and nodes in 28%, and in 34% just in the primary tumour. Nine percent of cases had neutropenia and 7.7% febrile neutropenia, and two cases had a hypersensitivity reaction to docetaxel. One associated treatment death occurred.

CONCLUSION

Docetaxel followed by epirubicin and docetaxel as primary chemotherapy results in a high clinical and pathological response rate. The majority of adverse events were predictable and manageable.

Blood group antigen profile predicted by molecular biology-use of real-time polymerase chain reaction to genotype important KEL, JK,RHD, and RHCE alleles

The most clinically important blood group systems in transfusion medicine, excluding the ABO system, are the RH, Kell, and Kidd systems. Alloantibodies to antigens of these systems may be produced following blood transfusion or during pregnancy and can result in serious hemolytic transfusion reactions and hemolytic disease of the newborn. We developed rapid and robust techniques for RHD, RHCE, KEL, and JK genotyping with the use of a real-time polymerase chain reaction instrument. Two fluorescence-based methods for the detection of amplification products were used: for KEL1/KEL2, JK1/JK2, and RHE/RHe (exon 5) we used the hybridization probes protocol; for RHC/RHc the analysis was done in sequences of exon 1 for RHC and exon 2 for RHc; and for RHD, analysis was done in sequences of intron 4, exon 7, and exon 4 pseudogene using the SYBR Green I protocol. The genotyping tests were validated with samples from 85 Caucasian Portuguese and 15 Black European blood donors. Complete phenotype-genotype correlations were obtained. The potential use of the presented methods can be predicted in clinical transfusion medicine, allowing appropriate monitoring, early intervention, and improved care. When blood group genotyping techniques are necessary, this methodology is highly competitive for a routine laboratory.

Rapid genotyping of the major alleles at the Duffy (FY) blood group locus using real-time fluorescence polymerase chain reaction

The Duffy blood group system has clinical importance due to involvement in transfusion reactions and hemolytic disease of the newborn. Recently, the molecular basis of the two alleles, FY*A and FY*B (125G>A), and the mutation situated in the promoter region of the FY gene (-33T>C), have been elucidated. In order to develop an accurate, easy, and rapid genotyping method, we describe a procedure using the LightCycler. Samples from 53 Caucasian Portuguese blood donors and 7 black, healthy, European individuals were phenotyped with commercial antisera. DNA was extracted from blood samples and the relevant sequences were amplified with the same cycling conditions, using real-time polymerase chain reaction. The melting point of the FY*A allele was 63 degrees C and of the FY*B allele, 55 degrees C. The allele without mutation at the promoter region had a melting point at 64 degrees C and the FY*B silent allele at 58 degrees C. The results in Caucasian individuals were similar to those found in European and American populations. When FY genotyping techniques are necessary, the methodology described is preferable to conventional methods as it is reliable, high speed, and uses small volumes, providing a highly competitive technology for use by a routine laboratory.

Genetic risk factors in acute coronary disease

OBJECTIVE

We investigate whether each of the following: HPA-1, Factor V Leiden, prothrombin gene variant and the methylene tetrahydrofolate reductase gene (MTHFR) mutation, are risk factors for acute coronary disease in Portuguese patients.

MATERIAL AND METHODS

100 blood donors and 52 patients with an established diagnosis of myocardial infarction or unstable angina were evaluated for genetic risk factors, by determining HPA-1 genotype, Factor V Leiden, Prothrombin 20210 variant and MTHFR mutation.

RESULTS

We found a prevalence of 2.0% for Factor V Leiden, 5.0% for the Prothrombin 20210 variant and 66% for the MTHFR mutation in blood donors. These values are similar to those found in the patients (1.9, 3.8 and 58%, respectively). We found that 28/100 controls had the PI(A2) polymorphism, a frequency statistically different from that in the patients (23/52). This difference was even more pronounced in patients less than 60 years old (27/96 vs. 13/24).

CONCLUSION

Factor V Leiden, Prothrombin 20210 variant and MTHFR mutation do not seem to represent risk factors for acute coronary disease. However, the PI(A2) polymorphism could have a role in the pathogenesis of this disease. The presence of multiple genetic factors, more than single ones, could influence the development and outcome of myocardial infarction and unstable angina. Larger studies are needed in order to have a better insight into the pathophysiological mechanisms of this disease, along with its prevention and the development of new treatments.

Poststroke atrial fibrillation bursts with sinus rhythm at stroke onset: what was the cause of stroke?

Intermittent atrial fibrillation may cause stroke, and acute stroke may lead to secondary bursts of atrial fibrillation. We studied with continuous ECG before, during and after stroke a patient with a history of intermittent atrial fibrillation. To our knowledge, this is the first case with continuous monitoring of atrial fibrillation bursts and their precise timing in the peristroke period.

[Cerebral-cardiac embolism. Cerebrovascular-cardiac embolic stroke]

The diagnosis of cerebral cardioembolism requires, apart from evidence of an embolic cardiopathy, a cause-effect relation to be established between the potential cardioembolic source and the occurrence of ischemic stroke. There are several arguments in favour of this reaction, namely the neurologic aspects put forward both clinicians and neuroimaging professionals, as well as the generalization of cardiologic diagnostic techniques for the etiologic investigation of ischemic stroke. Importance should be given to primary prevention of embolic cardiopathies. Oral anticoagulation should be administered in all situations where an advantage has been established when compared to antiaggregation or placebo. Cooperation between the different health structures and the different specialties probably depends on the changes in the prevalence of cerebral cardioembolism.

Stroke subtypes and hypertension. Primary hemorrhage vs infarction, large- vs small-artery disease

BACKGROUND

Hypertension is the major risk factor for stroke associated with small-artery disease and large-artery disease, but the factors behind the development of a particular stroke subtype in individual patients are not known.

METHODS

We determined risk factors potentially predictive of stroke subtype in 822 of 2760 patients consecutively admitted to a primary care stroke center with (1) first-ever stroke, (2) hypertension (blood pressure >160/90 mm Hg at least twice before the stroke), and (3) no cardioembolic source. We used logistic regression analysis to delineate factors associated with ischemic (brain infarct) vs hemorrhagic (primary hemorrhage) stroke and with large- vs small-artery disease. A scoring system was elaborated on the basis of the estimated regression coefficients. Observed proportions and calculated risks were determined.

RESULTS

Age greater than 67 years, cigarette smoking, hypercholesterolemia, and a family history of stroke or ischemic heart disease were independent predictors of ischemic vs hemorrhagic stroke. In women, diabetes mellitus was an additional risk factor for ischemic vs hemorrhagic stroke. Only one of 144 patients with primary hemorrhage had an ipsilateral carotid stenosis. In men with brain infarct, cigarette smoking, cardiac ischemia, and a family history of stroke or ischemic heart disease were significantly and independently associated with large- vs small-artery disease. In women with brain infarct, smoking was the only predictive factor for large- vs small-artery disease.

CONCLUSION

In patients with stroke and hypertension, associated risk factors influence the subtype of stroke (hemorrhage vs brain ischemia, large- vs small-artery disease).