Hypervirulent antibiotic-resistantClostridium difficilein Europe

Recently, several Clostridium difficile outbreaks due to PCR ribotype 027, associated with increased disease severity and death, have been reported in North America and in several European countries. This strain is toxinA/toxinB-positive, contains the genes for binary toxin and has an 18 bp deletion and a frameshift mutation in the gene tcdC hypothesized to result in a deregulated expression of toxins A and B. These strains are high producers of toxins in vitro compared with other toxinotypes. Moreover, these strains show a high level of resistance to fluoroquinolones, possibly due to the presence of a transition mutation (C to T) in the gyr A, resulting in the amino acid substitution Th82->IIe. A 2 month prospective study was conducted in 38 hospitals in 14 different European countries to get an overview of the phenotypic and genotypic features of C. difficile isolates in 2005. In all, 411 isolates of C. difficile were obtained from diarrhoeic patients with suspected C. difficile -associated diarrhoea (CDAD); the prevalence of the 027 epidemic strain was 6.2%. All 027 strains were positive for binary toxin genes, had an 18 bp deletion in tcdC gene and were resistant to erythromycin and moxifloxacin. Patients infected with an 027 strain were likely to have a more severe disease (OR=2.52, 95% CI 0.92-6.85, p=0.04) and to have been more specifically treated by metronidazole or vancomycin (OR=7.23, CI 0.99-149, p=0.02). Ongoing epidemiological surveillance of CDAD cases with periodic characterization of the strains is needed to detect clustering of cases in time and space and to monitor the emergence of a specific hypervirulent clone. Key words: Clostridium difficile, toxins A and B, hypervirulence, C. difficile-associated diarrhoe

Clostridium difficile erm(B)-containing elements and the burden on the in vitro fitness

In Clostridium difficile, resistance to the macrolide-lincosamide-streptogramin B group of antibiotics generally relies on erm(B) genes. In this study, we investigated elements with a genetic organization different from Tn5398, the mobilizable non-conjugative element identified in C. difficile strain 630. Our results suggested that the elements most frequently found in strains isolated during the European surveillance study in 2005 were related to Tn6194, the conjugative transposon recently detected in different C. difficile types, including PCR-ribotype 027. We characterized a Tn6194-like and a novel element rarely found in clinical isolates. A burden on the in vitro fitness of C. difficile was observed after the acquisition of these elements as well as of Tn5398

Survey, characterization and antimicrobial susceptibility of Clostridium difficile from marine bivalve shellfish of North Adriatic Sea

Abstract Clostridium difficile is a major cause of infectious diarrhea associated to healthcare settings. Community-acquired infections are increasingly reported in the last decade and exposure other than to symptomatic patients rather to contaminated foods or animals is feasible. Occurrence of C. difficile in shellfish raises concern because spores can survive the cooking temperatures given that shellfish is often consumed poorly cooked or raw. Aim of our study was to investigate whether shellfish represents a reservoir of C. difficile human PCR-ribotypes (RTs). 702 shellfish samples of farmed and wild bivalve mollusc species were collected over the 2015–2017 period in North Adriatic Italian Sea to investigate contamination with C. difficile and characterize the isolates in terms of genotypic variability and antimicrobial resistance profile. C. difficile was detected in 16.9% (CI: 14.1%–19.8%) samples: 11.6% mussels and 23.2% clams. Compared to mussels, clams were significantly associated with detection of C. difficile (OR = 2.4, P   ECOFF for vancomycin. C. difficile strains showed high variety in RTs, most of them already detected in other animals or known as highly virulent and epidemic in humans. These results prompt towards investigating on specific risk mitigation measures against C. difficile and are preliminary for any source attribution and risk assessment study

Surface-layer (S-layer) of Human and Animal Clostridium Difficile Strains and Their Behaviour in Adherence to Epithelial Cells and Intestinal Colonization

Clostridium difficile is a frequent cause of severe, recurrent post-antibiotic diarrhoea and pseudomembranous colitis. The surface layer (S-layer) is the predominant outer surface component of C. difficile which is involved in pathogen-host interactions critical to pathogenesis. In this study, we characterized the S-layer protein A (SIpA) of animal and human strains belonging to different PCR-ribotypes (PR) and compared the in vitro adherence and in vivo colonization properties of strains showing different SIpA variants. Since each SIpA variant has been recently associated with an S-layer cassette, we were able to deduce the cassette for each of our strains. In this study, an identity of 99-100% was found among the SIpA of isolates belonging to PR 012, 014/020, 045 and 078. One exception was the SIpA of a poultry isolate, PR 014/020, which showed 99% identity with that of strain 0160, another PR 014/020 which contains an S-layer cassette 6. Interestingly, this cassette has also been found in a PR 018 strain, an emerging virulent type currently predominant in Italy. Five other SIpA variants (v014/020a-e) were identified in strains PR 014/020. In vitro adherence assays and in vivo colonization experiments were performed on five PR 014/020 strains: human 1064 (v014/020e), human 4684/08 (v014/020b), human Ill 106 (v078a), poultry P30 (v014/020d) and poultry PB90 (v014/020b) strains. Adhesion assays indicate that C. difficile strains vary in their capacity to adhere to cells in culture and that adhesion seems to be independent of the SIpA variant. Colonization properties were assessed in vivo using a dixenic mouse model of colonization. The kinetics of faecal shedding and caecal colonization were similar when human 4684/08 (v014/020b) strain was compared with human 1064 (v014/020e) and poultry PB90 (v014/02013) strain. In contrast, poultry P30 (v014/020d) strain outcompeted both human 4684/08 (v014/020b) and IT1106 (v078a) strains and its adherence to caeca at day 7 was significantly higher. The peculiar characteristics of C. difficile P30 seem to advantage it in colonizing the intestinal mice niche, increasing its ability to compete and adapt. The results obtained underline the need of an increased attention to the genetic evolution of C. difficile to prevent and limit the consequences of the emergence of increasingly virulent strains

Characterization of Scardovia wiggsiae biofilm by original scanning electron microscopy protocol

Early childhood caries (ECC) is a severe manifestation of carious pathology with rapid and disruptive progression. The ECC microbiota includes a wide variety of bacterial species, among which is an anaerobic newly named species, Scardovia wiggsiae, a previously unidentified Bifidobacterium. Our aim was to provide the first ultrastructural characterization of S. wiggsiae and its biofilm by scanning electron microscopy (SEM) using a protocol that faithfully preserved the biofilm architecture and allowed an investigation at very high magnifications (order of nanometers) and with the appropriate resolution. To accomplish this task, we analyzed Streptococcus mutans’ biofilm by conventional SEM and VP-SEM protocols, in addition, we developed an original procedure, named OsO4-RR-TA-IL, which avoids dehydration, drying and sputter coating. This innovative protocol allowed high-resolution and high-magnification imaging (from 10000× to 35000×) in high-vacuum and high-voltage conditions. After comparing three methods, we chose OsO4-RR-TA-IL to investigate S. wiggsiae. It appeared as a fusiform elongated bacterium, without surface specialization, arranged in clusters and submerged in a rich biofilm matrix, which showed a well-developed micro-canalicular system. Our results provide the basis for the development of innovative strategies to quantify the effects of different treatments, in order to establish the best option to counteract ECC in pediatric patients

Designing and implementing a multi-scalar approach to Maritime Spatial Planning: The case study of Italy

The Italian coastal and marine space includes areas with remarkable differences in terms of oceanographic characteristics, maritime uses, natural habitats, species distribution, landscape and cultural heritage. In Italy, coastal and marine management competencies are shared among national, regional, and for some aspects even local authorities. This geographic heterogeneity and governance complexity required the adoption of a multiscalar approach to Maritime Spatial Planning (MSP). Such an approach aims at implementing decision-making and spatial planning at multiple and nested scales. In the case of Italy, the multi-scalar approach included the definition of national guidelines and the development of three maritime spatial (MS) plans, one for each maritime area (Adriatic, Ionian and Central Mediterranean, and Tyrrhenian and Western Mediterranean), including subareas and nested planning units. The development of the MS plans involved competent Ministries, the coastal Regions and several researchers. Based on the description of the adopted six-phase methodology and the exemplification of results of the Italian MSP process, this paper discusses the most relevant features and common challenges of multi-scalar MSP (i.e. co-planning, vertical and horizontal integration, multi-level governance, scalability, flexibility, integration of data and knowledge with different resolution, multi-scalar stakeholder engagement). Finally, the paper reflects on some novel aspects of the adopted multi-scalar approach and identifies actions to grant efficacy to this approach during the next phases of the Italian MSP proces

Стан та перспективи конкурентоспроможності галузі національного господарства в умовах глобалізації

Метою дослідження є узагальнення нових теоретичних положень розвитку галузей економіки в умовах глобалізації, визначення загальних конкурентних переваг хімічної галузі України та практичних напрямів сучасного розвитку економіки країни

Genome analysis of Legionella pneumophila ST23 from various countries reveals highly similar strains

© 2022 Ricci et al. This article is available under a CreativeCommons License (Attribution 4.0 International, as described at https://creativecommons.org/licenses/by/4.0/).Legionella pneumophila serogroup 1 (Lp1) sequence type (ST) 23 is one of the most commonly detected STs in Italy where it currently causes all investigated outbreaks. ST23 has caused both epidemic and sporadic cases between 1995 and 2018 and was analysed at genomic level and compared with ST23 isolated in other countries to determine possible similarities and differences. A core genome multi-locus sequence typing (cgMLST), based on a previously described set of 1,521 core genes, and single-nucleotide polymorphisms (SNPs) approaches were applied to an ST23 collection including genomes from Italy, France, Denmark and Scotland. DNAs were automatically extracted, libraries prepared using NextEra library kit and MiSeq sequencing performed. Overall, 63 among clinical and environmental Italian Lp1 isolates and a further seven and 11 ST23 from Denmark and Scotland, respectively, were sequenced, and pangenome analysed. Both cgMLST and SNPs analyses showed very few loci and SNP variations in ST23 genomes. All the ST23 causing outbreaks and sporadic cases in Italy and elsewhere, were phylogenetically related independent of year, town or country of isolation. Distances among the ST23s were further shortened when SNPs due to horizontal gene transfers were removed. The Lp1 ST23 isolated in Italy have kept their monophyletic origin, but they are phylogenetically close also to ST23 from other countries. The ST23 are quite widespread in Italy, and a thorough epidemiological investigation is compelled to determine sources of infection when this ST is identified in both LD sporadic cases and outbreaks.info:eu-repo/semantics/publishedVersio