1,720,993 research outputs found
Complete genome sequence and antimicrobial resistance analysis of ESBL-producing Shigella sonnei carrying small cryptic plasmids isolated in northern Italy.
Full text linkObjectives: Herein, we sequenced and assembled the genome of a Shigella sonnei isolate carrying several small plasmids using a hybrid approach that combined Oxford Nanopore Technologies and Illumina platforms.
Methods: Whole-genome sequencing was conducted using the Illumina iSeq 100 and Oxford Nanopore MinION systems, and the resulting reads were used for hybrid genome assembly via Unicycler. Coding sequences were annotated using RASTtk, while genes involved in antimicrobial resistance and virulence were identified using AMRFinderPlus. Plasmid nucleotide sequences were aligned to the NCBI non-redundant database using BLAST, and replicons were identified using PlasmidFinder.
Results: The genome consisted of 1 chromosome (4 801 657 bp), 3 major plasmids (212 849 bp, 86 884 bp, and 83 425 bp, respectively) and 12 small cryptic plasmids (ranging from 8390 bp to 1822 bp). BLAST analysis revealed that all plasmids were highly similar to previously deposited sequences. Genome annotation predicted 5522 coding regions, including 19 antimicrobial resistance genes and 17 virulence genes. Four of the antimicrobial resistance genes were located in small plasmids, and four of the virulence genes were located in a large virulence plasmid.
Conclusion: The presence of antimicrobial resistance genes in small cryptic plasmids may represent an overlooked mechanism for the propagation of these genes among bacterial populations. Our work provides new data on these elements that may inform the development of new strategies to control the spread of extended spectrum β-lactamase-producing bacterial strains
Complete Genome Sequence of a Klebsiella pneumoniae Strain Carrying Novel Variant blaKPC-203, Cross-Resistant to Ceftazidime/Avibactam and Cefiderocol, but Susceptible to Carbapenems, Isolated in Italy, 2023
Full text linkBackground: Klebsiella pneumoniae is a concerning pathogen, responsible for hospital-associated outbreaks. Multi drug resistant (MDR) strains are especially hard to treat. We conducted whole-genome sequencing on a MDR K. pneumoniae strain in order to identify genomic features potentially linked to its phenotype. Methods: DNA sequencing was performed on the Illumina iSeq 100 platform. Genome assembly was carried out with SPAdes. The genome was annotated with RASTtk. Typing was performed with MLST and Kaptive. Antibiotic resistance genes were detected with AMRFinderPlus and Abricate, and further verified with BLAST. Results: The strain exhibited resistance to ceftazidime/avibactam and cefiderocol, but remained susceptible to carbapenems. The strain belonged to sequence type ST101, serotype O1:K17. The analysis of antibiotic resistance genes indicated that the strain carried a novel KPC variant, designated as KPC-203, featuring a EL deletion at amino acid position 166-167, within the Omega-loop, and a nine-amino-acid insertion (LAVYTRAPM) at position 259. Sequence alterations were found in porin genes ompK35 and ompK36. Unlike molecular testing, which was able to detect the KPC-203 variant, all phenotypic carbapenemase detection methods achieved negative results. Conclusions: KPC-203, a novel KPC variant, showed a sequence modification in a cephalosporin resistance-associated hotspot. Interestingly, such alterations typically correlate with the restoration of carbapenem susceptibility. We hypothesize that KPC-203 likely led to resistance to ceftazidime/avibactam and cefiderocol, while maintaining susceptibility to carbapenems
Clonal dissemination of Klebsiella pneumoniae resistant to cefiderocol, ceftazidime/avibactam, meropenem/vaborbactam and imipenem/relebactam co-producing KPC and OXA-181 carbapenemase
Full text linkObjectives: Herein, we describe the epidemiology of carbapenemase-producing Enterobacterales (CPE) before and during the COVID-19 pandemic. Also, we report the emergence of an outbreak of Klebsiella pneumoniae strains co-producing KPC and OXA-181 carbapenemase, resistant to novel β-lactam/β-lactamase inhibitors (βL-βLICs) and cefiderocol.
Methods: CPE were collected during a period of 3 years from 2019 to 2021. Antimicrobial susceptibility testing for novel βL-βLICs and cefiderocol was performed by MIC test strips and microdilution with iron-depleted broth. WGS was performed on 10 selected isolates using the Illumina platform, and resistome analysis was carried out by a web-based pipeline.
Results: Between January 2019 and December 2021, we collected 1430 carbapenemase producers from 957 patients with infections due to CPE. KPC was the most common carbapenemase, followed by VIM, OXA-48 and NDM. During 2021, we identified 78 K. pneumoniae co-producing KPC and OXA-181 carbapenemases in 60 patients, resistant to meropenem/vaborbactam and imipenem/relebactam. Resistance to ceftazidime/avibactam and cefiderocol was observed respectively in 7 and 8 out of the 10 sequenced K. pneumoniae. Genome analysis showed that all isolates were clonally related, shared a common porin and plasmid content, and carried blaOXA-181 and blaKPC carbapenemases. Specifically, 4 out of 10 isolates carried blaKPC-3, while 6 harboured mutated blaKPC. Of note, KPC producers resistant to ceftazidime/avibactam and harbouring mutated blaKPC exhibited higher MICs of cefiderocol (median MIC 16 mg/L, IQR 16-16) than strains harbouring WT blaKPC-3 (cefiderocol 9 mg/L, IQR 1.5-16).
Conclusions: Our results highlight the need for continuous monitoring of CPE to limit widespread MDR pathogens carrying multiple mechanisms conferring resistance to novel antimicrobial molecule
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Complete genome sequence of a Listeria monocytogenes serotype 1 isolated from a critically ill patient in Italy, 2023.
Full text linkListeria monocytogenes, a concerning foodborne pathogen, causes severe infections in vulnerable subjects such as pregnant women and the elderly. In this article, we present the complete genome sequence of P4_LIS, an L. monocytogenes isolated from a patient with invasive bacteria infection
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
1999, Pharmacological characterisation of the first non-peptide bradykinin B2 receptor agonist FR 190997: an in vitro study on human, rabbit and pig vascular B2 receptors
No full textFR 190997, a new kinin B2 receptor agonist of non-peptide nature, has been studied in three isolated vessels: the human umbilical vein (hUV), the rabbit jugular vein (rbJV), and the pig coronary artery (pCA). Bradykinin (BK) contracts the hUV and rbJV through smooth muscle B2 receptors, while it relaxes the pCA through endothelial receptors of the B2 type. Contractions of the hUV and rbJV in response to FR 190997 show slow onset and are not reproducible compared to the rapid and reproducible effect of BK. They reach only 70% and 30% of the BK-induced maximal contractions in the hUV and rbJV, respectively. The effects of FR 190997 are antagonised by HOE 140 and this antagonist shows similar pK(B) values against BK and FR 190997, indicating that the non-peptide agent interacts with the kinin B2 receptor. FR 190997 is inactive as relaxant of the pCA; in this tissue, it acts as a pure and competitive antagonist, with a pK(B) value of 7.6, while HOE 140 acts as an insurmountable antagonist (pK(B) 9.3). When tested as an antagonist, FR 190997 inhibits also the contractile effects of BK in the hUV (pK(B) 7.8) and in the rbJV (pK(B) 7.6). FR 190997 is selective for the B2 receptor since it does not interact with the B1, and is specific since it does not affect the contraction evoked by 5-hydroxytryptamine, endothelin-1, and noradrenaline in the hUV, or the relaxation induced by substance P in the pCA. FR 190997 shows therefore different pharmacological profiles in various preparations, acting as a partial agonist in the hUV and especially in the rbJV and as a pure antagonist in the pCA. This new compound could be of interest in understanding how non-peptide agonists may activate receptors for peptides
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