MDR carbapenemase-producing Klebsiella pneumoniae of the hypervirulence-associated ST23 clone in Poland, 2009-19.

OBJECTIVES: To characterize carbapenemase-producing isolates of the Klebsiella pneumoniae hypervirulent (hvKp) clone ST23 in Poland. METHODS: Fifteen K. pneumoniae ST23 isolates were identified by the Polish surveillance of carbapenemase-producing Enterobacterales. These comprised a cluster with KPC-2 + NDM-1 (n = 7), KPC-2 (n = 1) or NDM-1 (n = 1) enzymes from one hospital from 2018, and sporadic isolates with KPC-2 (n = 1), NDM-1 (n = 1), VIM-1 (n = 1) or OXA-48 (n = 3), recovered from 2009 to 2019 in different towns. The isolates were sequenced by Illumina MiSeq, followed by MinION for six representatives. Clonality, phylogeny, serotypes, virulomes, resistomes and plasmids of the isolates were analysed and compared with international ST23 strains, using various bioinformatic tools. RESULTS: Only two diverse isolates with KPC-2 or VIM-1 were of typical hvKp ST23 serotypes K1 and O1v.2, and its predominant phylogenetic clade. These contained multiple chromosomal (ybt, clb) and pK2044/KpVP-1 plasmid (iuc, iro, rmpADC, rmpA2) virulence loci, whereas carbapenemase and other antimicrobial resistance (AMR) genes were on single additional plasmids. All remaining isolates were of K57 and O2v.2 serotypes, and a minor, distant clade of unclear phylogeny, including also ∼10 isolates from other European countries. These had fewer virulence loci (ybt, iuc, rmpADC, rmpA2) but abounded in plasmids, which with several chromosomal AMR mutations conferred more extensive MDR phenotypes than in K1 O1v.2. Lower clonal diversity than in K1, and numerous common characteristics of the isolates supported the hypothesis of the emerging character of the ST23 K57 clade. CONCLUSIONS: A new MDR ST23 lineage has emerged in Europe, causing a potential threat to public health.

The synergism of natural compounds in the pursuit of safe and healthier food.

Food producers apply modern processing techniques and use a variety of preservative additives to guarantee safe food and a longer shelflife. Regrettably many of these impact the sensory characteristics of the foodstuffs, such as colour, texture, and flavour, which can result in low consumer acceptance. Additionally, strategies used to reduce growth of spoilage and pathogenic bacteria are not selective enough and may inactivate also desired microbiota. Food is usually overdosed with antimicrobials that are supplemented 'just in case.' Consequently, food producers are searching for natural preservation methods that are not harmful to humans. Nature offers a wide spectrum of biologically active (phyto) chemicals that can be used as potential natural preservatives. Compounds with bacterial growth-limiting properties are detected in all parts of plants, including their leaves, flowers, fruits, roots, etc. These are mostly acids, alcohols, medium and long-chain organic acids, terpenic compounds, and their derivatives. This study focused on the effectiveness of plant extracts, i.e., synergism between terpenoids and medium chain fatty acids in cured cooked meat. Bacterial strains that were tested include typical members of the spoilage microflora in vacuum (Lactobacillus curvatus) and MA-packed meats (Brochothrix thermosphacta). These were isolated and identified in a separate study. L. curvatus was observed to be very resistant against either terpenoids or fatty acids when used separately, whereas its growth was strongly inhibited when both chemicals were combined. Growth of B. thermosphacta was significantly inhibited when antimicrobial compounds were solely applied, whereas a blend of terpenoids and fatty acids showed an almost bactericidal effect.

Surface modification of cyclic olefin copolymers for osteochondral defect repair can increase pro-destructive potential of human chondrocytes in vitro.

Materials on the basis of cycloolefin copolymers (COC) are suitable for subchondral defect repairs. The objective of this study was to evaluate the influence of surface modification of COC and COC/LLDPE blends on the viability and gene expression of chondrocytes. Human chondrocytes were incubated on the surface of the studied materials. Half of the materials were plasmatically modified with a subsequent type II collagen application. The gene expression of matrix metalloproteinases (MMP-1,-3,-13), pro-inflammatory cytokines (IL-1, TNF-alpha) and apoptotic molecules (BAX, Bcl-2) was evaluated using quantitative Taq-Man PCR after 48 h incubation. Chondrocyte viability was evaluated by the MTT test after 2, 4 and 8 days of incubation. The synthesis of MMPs was measured by ELISA assay in cell culture medium after 48 h of incubation. Chondrocytes incubated on plasmatically modified in contrast to unmodified materials demonstrated significantly increased gene expression of IL-1 (p<0.05), MMP-1 and MMP-3 (p<0.05 for both comparisons) as well as MMP-13 (p<0.001). Increased gene expression was confirmed by significantly increased production of active forms of particular MMPs into the cell culture medium. Unlike surface unmodified polymers, the modified materials showed time-dependent reduction of chondrocyte viability. The gene expression of TNF-alpha and apoptotic molecules by chondrocytes was not significantly changed by different materials. Cycloolefin copolymers and their blends may represent suitable materials for tissue engineering, however, their surface modification followed by collagen type II application may, at least under in vitro conditions, reduce the viability of chondrocytes and induce their pro-destructive behavior. The potential benefit or disadvantage of surface modifications of materials for osteochondral defect repairs needs to be further elucidated.

Immunolocalisation of crustacean-SIFamide in the median brain and eyestalk neuropils of the marbled crayfish.

Crustacean-SIFamide (GYRKPPFNGSIFamide) is a novel neuropeptide that was recently isolated from crayfish nervous tissue. We mapped the localisation of this peptide in the median brain and eyestalk neuropils of the marbled crayfish (Marmorkrebs), a parthenogenetic crustacean. Our experiments showed that crustacean-SIFamide is strongly expressed in all major compartments of the crayfish brain, including all three optic neuropils, the lateral protocerebrum with the hemiellipsoid body, and the medial protocerebrum with the central complex. These findings imply a role of this peptide in visual processing already at the level of the lamina but also at the level of the deeper relay stations. Immunolabelling is particularly strong in the accessory lobes and the deutocerebral olfactory lobes that receive a chemosensory input from the first antennae. Most cells of the olfactory globular tract, a projection neuron pathway that links deuto- and protocerebrum, are labelled. This pathway plays a central role in conveying tactile and olfactory stimuli to the lateral protocerebrum, where this input converges with optic information. Weak labelling is also present in the tritocerebrum that is associated with the mechanosensory second antennae. Taken together, we suggest an important role of crustacean-SIFamidergic neurons in processing high-order, multimodal input in the crayfish brain.

[Bone marrow cellularity in acute lymphoblastic leukemia of children]. / Komórkowosc szpiku kostnego w ostrej bialaczce limfoblastycznej u dzieci.

The early response to therapy in childhood acute lymphoblastic leukemia (ALL) is typically assessed by bone marrow status. The clearance of blast cells in peripheral blood and bone marrow during induction therapy was analysed in 38 children (27 precursor-B-ALL and 11 precursor T-ALL) treated according to BFM90 or New York 93 protocols. Leukocyte count and peripheral blood smear taken at diagnosis, day 8, day 14 and day 33 as well as bone marrow cellularity and percentage of blasts on days: 0, 14, 33 were analysed. The number of blasts in bone marrow was correlated to bone marrow cellularity (Spearman's rho = 0.72, p = 0.001). Patients with T-ALL were more frequently resistant to steroids in vivo and reached remission later in comparison to precursor-B-ALL children (p = 0.019), however blasts reduction ratio was comparable in both lineages. Bone marrow cellularity on days 14 and 33 of induction therapy was similar.