Hypo- and Hyper-Virulent Listeria monocytogenes Clones Persisting in Two Different Food Processing Plants of Central Italy.

A total of 66 Listeria monocytogenes (Lm) isolated from 2013 to 2018 in a small-scale meat processing plant and a dairy facility of Central Italy were studied. Whole Genome Sequencing and bioinformatics analysis were used to assess the genetic relationships between the strains and investigate persistence and virulence abilities. The biofilm forming-ability was assessed in vitro. Cluster analysis grouped the Lm from the meat plant into three main clusters: two of them, both belonging to CC9, persisted for years in the plant and one (CC121) was isolated in the last year of sampling. In the dairy facility, all the strains grouped in a CC2 four-year persistent cluster. All the studied strains carried multidrug efflux-pumps genetic determinants (sugE, mdrl, lde, norM, mepA). CC121 also harbored the Tn6188 specific for tolerance to Benzalkonium Chloride. Only CC9 and CC121 carried a Stress Survival Islet and presented high-level cadmium resistance genes (cadA1C1) carried by different plasmids. They showed a greater biofilm production when compared with CC2. All the CC2 carried a full-length inlA while CC9 and CC121 presented a Premature Stop Codon mutation correlated with less virulence. The hypo-virulent clones CC9 and CC121 appeared the most adapted to food-processing environments; however, even the hyper-virulent clone CC2 warningly persisted for a long time. The identification of the main mechanisms promoting Lm persistence in a specific food processing plant is important to provide recommendations to Food Business Operators (FBOs) in order to remove or reduce resident Lm.

Detection of Astrovirus in a Cow with Neurological Signs by Nanopore Technology, Italy.

In this study, starting from nucleic acids purified from the brain tissue, Nanopore technology was used to identify the etiological agent of severe neurological signs observed in a cow which was immediately slaughtered. Histological examination revealed acute non-suppurative encephalomyelitis affecting the brainstem, cerebrum, cerebellum, and medulla oblongata, while by using PCR-based assays, the nucleic acids of major agents for neurological signs were not detected. By using Nanopore technology, 151 sequence reads were assigned to Bovine Astrovirus (BoAstV). Real-time RT-PCR and in situ hybridization (ISH) confirmed the presence of viral RNA in the brain. Moreover, using the combination of fluorescent ISH and immunofluorescence (IF) techniques, it was possible to detect BoAstV RNA and antigens in the same cells, suggesting the active replication of the virus in infected neurons. The nearly whole genome of the occurring strain (BoAstV PE3373/2019/Italy), obtained by Illumina NextSeq 500, showed the highest nucleotide sequence identity (94.11%) with BoAstV CH13/NeuroS1 26,730 strain, an encephalitis-associated bovine astrovirus. Here, we provide further evidence of the role of AstV as a neurotropic agent. Considering that in a high proportion of non-suppurative encephalitis cases, which are mostly indicative of a viral infection, the etiologic agent remains unknown, our result underscores the value and versatility of Nanopore technology for a rapid diagnosis when the PCR-based algorithm gives negative results.

Redescription of the larva of Gynacantha cylindrata Karsch (Insecta: Odonata: Aeshnidae).

The ultimate stadium larva of Gynacantha cylindrata Karsch, 1891 is described and illustrated based on fifteen male and female exuviae from Bundibugyo, Uganda. The larva resembles those of the few described African species of the genus but shows a denser coverage of spine-like setae on body surface and abundance of hair-like setae on mouthparts. The female gonapophyses appear to be the longest described in the genus up to now and similar to those of G. villosa, a species included in the same group of African species.