Caratterizzazione molecolare di ceppi di Listeria monocytogenes isolati da matrici alimentari e da fonti umane

Scopo del lavoro è stato la caratterizzazione molecolare di ceppi di L. monocytogenes (L.m.) isolati da alimenti e dall’uomo nel triennio 2019-2021. Un totale di 67 ceppi di L.m. sono stati isolati (norma UNI EN ISO 11290-1:2017) presso i laboratori di Microbiologia degli alimenti dell’IZS Palermo da diverse matrici alimentari con prevalenza di alimenti pronti quali prodotti lattiero-caseari, a base di carne, ittici, vegetali, prelevati nell’ambito dei campionamenti dei Servizi Veterinari delle ASP. Gli isolati batterici sono stati conservati a –20 °C in Microbank ed in seguito inviati al LNR di Teramo per la determinazione del sierogruppo (PCR-Multiplex) e successiva indagine molecolare (MLST e Whole Genome Sequencing -WGS). Il sequenziamento è stato effettuato su piattaforma NextSeq 500 Illumina e l’analisi dei dati eseguita su una piattaforma bioinformatica e di raccolta dati del LNR L.m., denominata GenPat. Presso i laboratori ospedalieri di Palermo (Ospedale Civico, Ospedali Riuniti Villa Sofia-Cervello e Azienda Ospedaliera Universitaria Policlinico, quest’ultimo anche Laboratorio di Riferimento Regionale per la listeriosi) sono stati isolati n. 39 ceppi clinici di L.m. I ceppi, insieme alle schede per la raccolta dei dati epidemiologici, sono stati inviati all’Istituto Superiore di Sanità (ISS-Operational Contact Point microbiologico per L.m.) per la caratterizzazione molecolare mediante WGS. Il sequenziamento è stato effettuato su una piattaforma IonTorrent S5 e l’analisi è stata eseguita automaticamente su una piattaforma bioinformatica e di raccolta dati, denominata IRIDA-ARIES. I risultati sulla caratterizzazione molecolare dei ceppi isolati dagli alimenti hanno mostrato una prevalenza del sierogruppo IVb (70%), seguito dal IIa (24%), dal IIb (4.5%) e dal IIc (1.5%). Il 46.3% dei ceppi, tutti appartenenti al sierogruppo IVb, sono stati isolati da mozzarella e formaggio a pasta filata, prelevati presso una stessa azienda produttrice, durante controlli ufficiali, nel periodo agosto-settembre 2020, a seguito di positività rilevata in autocontrollo. I risultati del sequenziamento effettuato dal LNR hanno evidenziato l’esistenza di cluster di ceppi appartenenti al Clonal Complex (CC) 2, CC199 e CC1. In particolare, tutti i ceppi isolati nello stesso caseificio, sia nel periodo considerato che in un successivo campionamento a gennaio 2022, appartenevano al CC2 e Sequence Type 2 (ST2). Riguardo i ceppi clinici, l’analisi filogenetica dei genomi dei 39 isolati di L.m. ha consentito l’identificazione di un Cluster_90 composto da 25 ceppi dei quali 6 isolati nel 2019, 16 nel 2020 e 1 nel 2021. I 25 ceppi sono risultati appartenere al sierogruppo IVb, ST2 e CC2 presentando tra loro una differenza allelica al core genome MLST compresa tra 0 e 12. Da sottolineare la presenza di 8 ceppi, isolati tra ottobre 2019 e agosto 2021, associati a casi materno neonatali. Le sequenze genomiche dei 39 ceppi clinici di L.m. sono state confrontate con le sequenze depositate nel database IRIDA-ARIES. Dall’analisi è emerso che al Cluster_90, ST2 appartenevano anche 3 ceppi isolati in Lombardia (2 nel 2019, 1 nel 2020), 2 in Piemonte, 1 nel Lazio, 1 in Toscana nel 2020 e 2 ceppi isolati in Sicilia (1 nel 2019 da Siracusa e 1 nel 2020 dalla provincia di Palermo). Il presente studio ha permesso di avviare la costruzione di una rete integrata medico/veterinaria tra laboratori per potenziare il sistema di sorveglianza della listeriosi nella regione Sicilia

Proresolving Lipid Mediators and Receptors in Stem Cell Biology: Concise Review

Summary Accumulating evidence indicates that stem cells (SCs) possess immunomodulatory, anti‐inflammatory, and prohealing properties. The mechanisms underlying these functions are being investigated with the final goal to set a solid background for the clinical use of SCs and/or their derivatives. Specialized proresolving lipid mediators (SPMs) are small lipids formed by the enzymatic metabolism of polyunsaturated fatty acids. They represent a leading class of molecules that actively and timely regulate the resolution of inflammation and promote tissue/organ repair. SC formation of these mediators as well as expression of their receptors has been recently reported, suggesting that SPMs may be involved in the immunomodulatory, proresolving functions of SCs. In the present review, we summarize the current knowledge on SPMs in SCs, focusing on biosynthetic pathways, receptors, and bioactions, with the intent to provide an integrated view of SPM impact on SC biology. Stem Cells Translational Medicine 2019;8:992–99

Molecular characterization of Listeria monocytogenes strains isolated from food and human sources

Introduction: The aim of the work was the molecular characterization of L. monocytogenes (L.m.) isolated from food and humans in the period 2019-2021. Materials and methods: A total of 67 L.m. isolates have been collected (UNI EN ISO 11290-1: 2017) at the Food Microbiology laboratories of the IZS Palermo from different food matrices with a prevalence of ready-to-eat food products such as dairy, fresh cheese, meat, fish sampled by Veterinary Services. The bacterial isolates were stored at -20 ° C in Microbank and sent to the LNR of Teramo for the determination of the serogroup (PCR-Multiplex) and molecular investigation (MLST and Whole Genome Sequencing -WGS). The sequencing was carried out on the Illumina NextSeq 500 platform and the data analysis was performed on a bioinformatics and data collection platform of the LNR L.m, called GenPat. N. 39 clinical strains of L.m. were collected at Palermo hospital laboratories (Regional Reference Laboratory for listeriosis). The strains, together with the sheets for the collection of epidemiological data, were sent to the Istituto Superiore di Sanità (ISS- Operational Microbiological Contact Point for L.m.) for molecular characterization by WGS. The sequencing was carried out on an IonTorrent S5 platform and the analysis was performed automatically on a bioinformatics and data collection platform, called IRIDA-ARIES. Results: The results on the molecular characterization of the strains isolated from food showed a prevalence of serogroup IVb (70%), followed by IIa (24%), IIb (4.5%) and IIc (1.5%). The 46.3% of the strains, all belonging to serogroup IVb, have been isolated from milk products (mozzarella and string cheese) taken from the same producer during official controls, in the period August- September 2020, following a positivity detected in self-control. The results of the sequencing carried out by the LNR highlighted the existence of clusters of strains belonging to Clonal Complex (CC) 2, CC199 and CC1. In particular, all the strains isolated in the same cheese factory, both in the period considered and in a subsequent sampling in January 2022, belonged to CC2 and Sequence Type 2 (ST2). Regarding the 39 clinical L.m. strains, the phylogenetic analysis of the genomes allowed the identification of a Cluster_90 composed of 25 strains of which 6 were isolated in 2019, 16 in 2020 and 1 in 2021. The 25 strains were found to belong to serogroup IVb, ST2 and CC2, presenting between them an allelic difference in the MLST core genome between 0 and 12. It has been noted the presence of 8 strains, isolated between October 2019 and August 2021, associated with maternal and neonatal cases. The genomic sequences of the 39 clinical strains of L.m. were compared with the sequences deposited in the IRIDA-ARIES database. From the analysis, it emerged that the Cluster_90, ST2 also included 3 isolated strains in Lombardy (2 in 2019, 1 in 2020), 2 in Piedmont, 1 in Lazio, 1 in Tuscany in 2020 and 2 isolated strains in Sicily (1 in 2019 from Syracuse and 1 in 2020 from the province of Palermo). Conclusion: This study allowed to start the construction of an integrated medical/veterinary network between laboratories to enhance the listeriosis surveillance system in the Sicily region

Novel Translational Read-through-Inducing Drugs as a Therapeutic Option for Shwachman-Diamond Syndrome

Shwachman-Diamond syndrome (SDS) is one of the most commonly inherited bone marrow failure syndromes (IBMFS). In SDS, bone marrow is hypocellular, with marked neutropenia. Moreover, SDS patients have a high risk of developing myelodysplastic syndrome (MDS), which in turn increases the risk of acute myeloid leukemia (AML) from an early age. Most SDS patients are heterozygous for the c.183-184TA>CT (K62X) SBDS nonsense mutation. Fortunately, a plethora of translational read-through inducing drugs (TRIDs) have been developed and tested for several rare inherited diseases due to nonsense mutations so far. The authors previously demonstrated that ataluren (PTC124) can restore full-length SBDS protein expression in bone marrow stem cells isolated from SDS patients carrying the nonsense mutation K62X. In this study, the authors evaluated the effect of a panel of ataluren analogues in restoring SBDS protein resynthesis and function both in hematological and non-hematological SDS cells. Besides confirming that ataluren can efficiently induce SBDS protein re-expression in SDS cells, the authors found that another analogue, namely NV848, can restore full-length SBDS protein synthesis as well, showing very low toxicity in zebrafish. Furthermore, NV848 can improve myeloid differentiation in bone marrow hematopoietic progenitors, enhancing neutrophil maturation and reducing the number of dysplastic granulocytes in vitro. Therefore, these findings broaden the possibilities of developing novel therapeutic options in terms of nonsense mutation suppression for SDS. Eventually, this study may act as a proof of concept for the development of similar approaches for other IBMFS caused by nonsense mutations

Novel Translational Read-Through–Inducing Drugs as a Therapeutic Option for Shwachman-Diamond Syndrome

Shwachman-Diamond syndrome (SDS) is one of the most commonly inherited bone marrow failure syndromes (IBMFS). In SDS, bone marrow is hypocellular, with marked neutropenia. Moreover, SDS patients have a high risk of developing myelodysplastic syndrome (MDS), which in turn increases the risk of acute myeloid leukemia (AML) from an early age. Most SDS patients are heterozygous for the c.183-184TA>CT (K62X) SBDS nonsense mutation. Fortunately, a plethora of translational read-through inducing drugs (TRIDs) have been developed and tested for several rare inherited diseases due to nonsense mutations so far. The authors previously demonstrated that ataluren (PTC124) can restore full-length SBDS protein expression in bone marrow stem cells isolated from SDS patients carrying the nonsense mutation K62X. In this study, the authors evaluated the effect of a panel of ataluren analogues in restoring SBDS protein resynthesis and function both in hematological and non-hematological SDS cells. Besides confirming that ataluren can efficiently induce SBDS protein re-expression in SDS cells, the authors found that another analogue, namely NV848, can restore full-length SBDS protein synthesis as well, showing very low toxicity in zebrafish. Furthermore, NV848 can improve myeloid differentiation in bone marrow hematopoietic progenitors, enhancing neutrophil maturation and reducing the number of dysplastic granulocytes in vitro. Therefore, these findings broaden the possibilities of developing novel therapeutic options in terms of nonsense mutation suppression for SDS. Eventually, this study may act as a proof of concept for the development of similar approaches for other IBMFS caused by nonsense mutations