Phenotypical and molecular assessment of the virulence potential of KPC-3-producing Klebsiella pneumoniae ST392 clinical isolates

Klebsiella pneumoniae is a Gram-negative bacterium of clinical importance, due to its resistance to several antibiotic classes. We have identified 4 clinical isolates of K. pneumoniae sequence type (ST) 392 KPC-3-producing strains from patients at the Istituto Mediterraneo per i Trapianti e Terapie ad Alta Specializzazione (IRCCS-ISMETT), a Southern Italian transplantation health facility, during a routine surveillance for carbapenemase-producing Enterobacterales from in-house clinical samples. Since those were among, to the best of our knowledge, the first KPC-producing K. pneumoniae ST392 isolated in Europe, we assessed their virulence potential, to understand if this particular ST can become an endemic clinical threat. ST392 isolates were investigated to assess their virulence potential, namely resistance to human sera, formation of abiotic biofilms, adhesion to biotic surfaces, exopolysaccharide production and in vivo pathogenesis in the wax moth Galleria mellonella animal model. ST392-belonging strains were highly resistant to human sera. These strains also have a high capacity to form abiotic biofilms and high levels of adhesion to the human epithelial colorectal adenocarcinoma HT-29 cell line. An increase of transcriptional levels of genes involved in serum resistance (aroE and traT) and adhesion (pgaA) was observed when compared with the Klebsiella quasipneumoniae subsp. similipneumoniae strain ATCC 700603 reference strain. Infection of G. mellonella larvae with ST392 clinical isolates showed that the latter were not highly pathogenic in this model. Together, our results indicate that ST392 isolates have the potential to become a strain of clinical relevance, especially in health settings where patients are immunosuppressed, e.g., transplant recipients

Caratterizzazione delle proprietà del Regalrez 1126 e del Paraloid B72 nel consolidamento del legno

Questo lavoro è incentrato sullo studio dell’efficacia di due prodotti consolidanti applicati sia singolarmente che congiuntamente su due differenti specie lignee: l’abete rosso ed il pioppo bianco. Lo studio prosegue una ricerca già sviluppata e trattata in letteratura sulla sperimentazione delle caratteristiche consolidanti di due resine sintetiche e sulla loro possibile azione sinergica sul legno, potenzialmente determinata dai differenti livelli di penetrazione: il Paraloid B72, copolimero di durezza media a base di metilacrilato ed etilmetacrilato, e il Regalrez 1126, polimero a basso peso molecolare della famiglia degli idrocarburi saturi composto da monomeri di stirene idrogenato. I trattamenti sono stati effettuati su serie di provini delle due diverse specie lignee attraverso applicazioni sia con i consolidanti da soli che con un doppio trattamento che prevede una prima applicazione di Regalrez e successivamente di Paraloid. Sono state valutate le variazioni di porosità mediante porosimetria ad intrusione di mercurio e sono state effettuare misure delle variazioni dimensionali in seguito a cicli di invecchiamento accelerato gelo/disgelo. Parallelamente sono state effettuate misure colorimetriche e misure di spettroscopia infrarossa prima e dopo invecchiamento da radiazione solare al fine di verificare un’eventuale azione di rallentamento dei processi fotodegradativi del legno. I risultati ottenuti confermano la possibile differente localizzazione dei due prodotti, con un’evidente selezione funzionale, e mostrano come il doppio trattamento Regalrez- Paraloid rappresenti un significativo vantaggio in termini sia di resistenza meccanica che di resistenza alle variazioni dimensionali del legno. Non si osservano invece vantaggi del doppio trattamento nella resistenza ai processi fotossidavi e alle variazioni cromatiche

Changes in the Transcriptome Profiles of Human Amnion-Derived Mesenchymal Stromal/Stem Cells Induced by Three-Dimensional Culture: A Potential Priming Strategy to Improve Their Properties

Mesenchymal stromal/stem cells (MSCs) are believed to function in vivo as a homeostatic tool that shows therapeutic properties for tissue repair/regeneration. Conventionally, these cells are expanded in two-dimensional (2D) cultures, and, in that case, MSCs undergo genotypic/phenotypic changes resulting in a loss of their therapeutic capabilities. Moreover, several clinical trials using MSCs have shown controversial results with moderate/insufficient therapeutic responses. Different priming methods were tested to improve MSC effects, and three-dimensional (3D) culturing techniques were also examined. MSC spheroids display increased therapeutic properties, and, in this context, it is crucial to understand molecular changes underlying spheroid generation. To address these limitations, we performed RNA-seq on human amnion-derived MSCs (hAMSCs) cultured in both 2D and 3D conditions and examined the transcriptome changes associated with hAMSC spheroid formation. We found a large number of 3D culture-sensitive genes and identified selected genes related to 3D hAMSC therapeutic effects. In particular, we observed that these genes can regulate proliferation/differentiation, as well as immunomodulatory and angiogenic processes. We validated RNA-seq results by qRT-PCR and methylome analysis and investigation of secreted factors. Overall, our results showed that hAMSC spheroid culture represents a promising approach to cell-based therapy that could significantly impact hAMSC application in the field of regenerative medicine

Zika virus infection induces MiR34c expression in glioblastoma stem cells: new perspectives for brain tumor treatments

Zika virus (ZIKV) is a flavivirus with a marked effect on fetal nervous system development. ZIKV treatment has recently been found to also have a benefit against glioblastoma, a highly aggressive brain tumor with a poor prognosis. The reported data do not completely explain the mechanism beyond this effect. Nevertheless, in the majority of the cases no adverse effect has been found in healthy adult humans. In this study, we characterized the ZIKV infection mechanism on glioblastoma stem cells, which are considered responsible for the tumor progression and resistance to conventional therapies. Moreover, we explain why the action of this virus is directed to the stem cells in the nervous system counterpart. Our results confirm the effectiveness of ZIKV treatment against glioblastoma, indicating novel molecular targets that can be introduced for more powerful therapies

A retrospective molecular epidemiological scenario of carbapenemase-producing Klebsiella pneumoniae clinical isolates in a Sicilian transplantation hospital shows a swift polyclonal divergence among sequence types, resistome and virulome

In this work, we assessed and characterized the epidemiological scenario of carbapenem-resistant Klebsiella pneumoniae strains (CR-Kp) at IRCCS-ISMETT, a transplantation hospital in Palermo, Italy, from 2008 to 2017. A total of 288 K. pneumoniae clinical isolates were selected based on their resistance to carbapenems. Molecular characterization was also done in terms of the presence of virulence and resistance genes. All patients were inpatients from our facility and clinical isolates were collected from several sources, either from infection or colonization cases. We observed that, in agreement with the Italian epidemiological scenario, initially only ST258 and ST512 clade II (but not from clade I) were identified from 2008 to 2011. From 2012 onwards, other STs have been observed, including the clinically relevant ST101 and ST307, but also others not previously observed in other Italian health settings, such as ST220 and ST753. The presence of genes involved in resistance and virulence was confirmed, and a heterogeneous genetic resistance profile throughout the years was observed. Our work highlights that resistance genes are rapidly disseminating between different and novel K. pneumoniae clones which, combined with resistance to multiple antibiotics, can derive into more aggressive and pathogenic multidrug-resistant strains of clinical importance. Our results stress the importance of continuous surveillance of CR Enterobacterales in health facilities so that novel STs carrying resistance and virulence genes that may become increasingly pathogenic can be identified and adequate therapies to adopted to avoid their dissemination and derived pathologies