Hartrossi2602

Introduction. Carbapenemase-producing Enterobacterales (CPE) are an increasing threat to global health. Fast detection is crucial for patient management and outbreak control.Hypothesis/Gap statement. Recently, a new commercial colorimetric test, CARBA PAcE, was released that has not yet been scientifically evaluated.Aim. Our goals were to evaluate the performance of CARBA PAcE using a large variety of different CPE.Methodology. CARBA PAcE was challenged with 107 molecularly characterized CPE and 53 non-CPE controls. Isolates were grown on Mueller-Hinton agar (MHA); in the case of a false-negative result, isolates were additionally inoculated on Columbia blood agar (CBA) and CARBA PAcE was repeated. The test was performed according to the manufacturer's protocol.Results. CARBA PAcE showed an overall sensitivity and specificity of 72 % [confidence interval (CI) 62-80 %] and 91 % (CI 79-97 %), respectively, when isolates were grown on MHA. With growth on CBA, detection improved (especially of metallo-β-lactamases), resulting in an extrapolated sensitivity of 89 % (CI 81-94 %) for all carbapenemases and 96 % (CI 89-99 %) for the four major carbapenemases (NDM, OXA-48-like, KPC, VIM).Conclusion. CARBA PAcE is a simple and very rapid test for the detection of CPE which performs well for the major carbapenemases when isolates are grown on CBA. Laboratories should be aware of the limitations of this assay, such as moderate sensitivity when isolates are grown on more challenging agars such as MHA and the poor detection of some rare carbapenemases (e.g. IMI, OXA-58).Transposons are genetic elements that change their intracellular genomic position by transposition and are spread horizontally between bacteria when located on plasmids. It was recently discovered that transposition from fully heterologous DNA also occurs in the course of natural transformation. Here, we characterize the molecular details and constraints of this process using the replicative transposon Tn1 and the naturally competent bacterium Acinetobacter baylyi. We find that chromosomal insertion of Tn1 by transposition occurs at low but detectable frequencies and preferably around the A. baylyi terminus of replication. We show that Tn1 transposition is facilitated by transient expression of the transposase and resolvase encoded by the donor DNA. RecA protein is essential for the formation of a circular, double-stranded cytoplasmic intermediate from incoming donor DNA, and RecO is beneficial but not essential in this process. Absence of the recipient RecBCD nuclease stabilizes the double-stranded intermediate. Based on these results, we suggest a mechanistic model for transposition during natural transformation.A Gram-negative, rod-shaped bacterium, strain Duganella callida DN04T, was isolated from the soil of a maize field in North Carolina, USA. Based on the 16S rRNA gene sequence, the most similar Duganella species are D. sacchari Sac-22T, D. ginsengisoli DCY83T, and D. radicis Sac-41T with a 97.8, 97.6, or 96.9 % sequence similarity, respectively. We compared the biochemical phenotype of DN04T to D. sacchari Sac-22T and D. zoogloeoides 115T and other reference strains from different genera within the Oxalobacteraceae and while the biochemical profile of DN04T is most similar to D. sacchari Sac-22T and other Duganella and Massilia strains, there are also distinct differences. DN04T can for example utilize turanose, N-acetyl-d-glucosamine, inosine, and l-pyroglutamic acid. The four fatty acids found in the highest percentages were C15  0 iso (24.6 %), C15  1 isoG (19.4 %), C17  0 iso3-OH (16.8 %), and summed feature 3 (C161 ⍵7c and/or C161 ⍵6c) (12.5 %). We also applied whole genome sequencing to determine if DN04T is a novel species. The most similar AAI (average amino acid identity) score was 70.8 % (Massilia plicata NZ CP038026T), and the most similar ANI (average nucleotide identity) score was 84.8 % (D. Tertiapin-Q radicis KCTC 22382T), which indicates that DN04T is a novel species. The genome-to-genome-distance calculation (GGDC) revealed a DDH of 28.3 % to D. radicis KCTC 22382T, which is much lower than the new species threshold. Based on the morphological, phenotypic, and genomic differences, we propose Duganella callida sp. nov. as a novel species within the Duganella genus (type strain DN04T=NRRL B-65552T=LMG 31736T).A Gram-stain-negative, aerobic, short rod-shaped, motile, brownish-coloured bacterium, termed strain LPB0137T, was isolated from a squid. Its cells could grow weakly on marine agar 2216 with 0.04 % 2,3,5-triphenyl tetrazolium chloride (TTC). Each cell of strain LPB0137T has a circular chromosome with a length of 2.87 Mb and 27.7 mol% DNA G+C content. The genome includes 2698 protein-coding genes and six rRNA operons. In 16S rRNA gene sequence trees, strain LPB0137T formed a robust monophyletic clade with Poseidonibacter antarcticus SM1702T with a sequence similarity of 98.3 %. However, the average nucleotide identity and in silico DNA-DNA hybridization values between the two type strains were low (83.9 and 28.1 %, respectively). The overall phenotypic and genomic features of strain LPB0137T supported its assignment to the genus Poseidonibacter. However, the relatively low gene and genome sequence similarity between this strain and other type strains of the genus Poseidonibacter and several enzymatic characteristics indicated the taxonomic novelty of the isolated strain as a new member of the genus Poseidonibacter. Therefore, based on the phylogenetic and phenotypic characteristics of LPB0137T, we proposed a novel species of the genus Poseidonibacter for it, with the name Poseidonibacter parvus sp. nov. The type strain of this new species is thus LPB0137T (=KACC 18888T=JCM 31548T).A novel, slightly halophilic bacterium, designated TBZ202T, was isolated from water of Urmia Lake, in the Azerbaijan region of north-west Iran. The strain was facultatively anaerobic, Gram-stain-negative, rod-shaped and motile. Colonies were creamy, circular, convex and shiny. It grew at NaCl concentrations of 0-12 % (w/v) (optimum 3-5 % w/v), at temperatures of 20-45 °C (optimum 30 °C) and at pH 5.0-10.0 (optimum pH 7.0). Based on the 16S rRNA gene sequence, strain TBZ202T belongs to the genus Halomonas in the Halomonadaceae and the most closely related species are Halomonas gudaonensis CGMCC 1.6133T (98.6 % similarity), Halomonas ventosae Al12T (96.8 %) and Halomonas rambilicola RS-16T (96.6%). The G+C content was 67.9 % and the digital DNA-DNA hybridization and average nucleotide identity values with H. gudaonensis were 35.8 and 83.8 %, respectively, indicating that the isolate differs from all species described. The major fatty acids were C18 1ω7c, C16 0 and C16 1ω7c. The only respiratory quinone detected was Q-9 and polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, aminophospholipid and three unknown phospholipids.