Theoretical Study of Triafulvene, Fulvene, Heptafulvene, and Their 0- and N-Heteroanalogs

The geometry, electronic structure, and the aromatic stability of triafulvene, fulvene, heptafulvene, and their 0- and N-heteroanalogs have been investigated by t;he PPP-CI MO method. Energy minimization with respect to bond lengths has been carried out in order to find the optimal geometry of the studied compounds. Aromatic stability predictions are based on the topological resqnance energy, TRE, approach. Theoretical results are in very good agreement with experimental measurements

Circular Dichroism of Optically Active 1,4-Benzodiazepines

Assignment of the CD-bands of 1,4-benzodiazepin-2-one derivatives (1-14, 26), and their 2-deoxo-congeners (15-25) has been performed by applying the qualitative MO theory and the exc1iton coupling theory. It has been found that the longest wavelength band (about 310 nm), as well as that around 250 nm correspond to the B2u and B1u transition of the chiral partial chromophore A, respectively, while the corresponding transitions for the partial chromophore C give rise to the bands at 285 nm and 250 nm (Figures 2-4). The CD-signs for several of these Cotton effects can be derived in a nonempirical manner. 7-Nitro derivatives, 23-25 scape above analysis, however, since the nitro-group is a very strong perturber, which has its own absorption bands in the same region. Model cyclic and acyclic compounds 27-36 have been prepared, and their CD-spectra analysed in the same way

Circular Dichroism of Optically Active 1,4-Benzodiazepines

Assignment of the CD-bands of 1,4-benzodiazepin-2-one derivatives (1-14, 26), and their 2-deoxo-congeners (15-25) has been performed by applying the qualitative MO theory and the exc1iton coupling theory. It has been found that the longest wavelength band (about 310 nm), as well as that around 250 nm correspond to the B2u and B1u transition of the chiral partial chromophore A, respectively, while the corresponding transitions for the partial chromophore C give rise to the bands at 285 nm and 250 nm (Figures 2-4). The CD-signs for several of these Cotton effects can be derived in a nonempirical manner. 7-Nitro derivatives, 23-25 scape above analysis, however, since the nitro-group is a very strong perturber, which has its own absorption bands in the same region. Model cyclic and acyclic compounds 27-36 have been prepared, and their CD-spectra analysed in the same way

Comparison of PCR methods and culture for the detection of Borrelia spp. in patients with erythema migrans

ABSTRACTThe sensitivities of two PCR assays and culture were compared for the detection of Borrelia spp. in skin specimens of 150 patients with typical erythema migrans. In addition, the accuracy of the methods for the identification of Borrelia spp. was compared by analysing culture isolates and material obtained directly from skin biopsy specimens. Borrelia burgdorferi sensu lato was isolated from 73 (49%) of 150 skin biopsy specimens. Using a nested PCR targeting the rrf–rrl region and a PCR targeting the flagellin gene, 107 (71%) and 36 (24%) specimens, respectively, were positive. With both PCRs, positive results were more frequent with culture-positive samples (67/73 (92%) and 24/73 (33%) for the nested and flagellin PCRs, respectively) than with culture-negative samples (40/77 (52%) and 12/77 (16%) for nested and flagellin PCR, respectively). Pulsed-field gel electrophoresis after MluI restriction identified 69/73 (95%) isolates, of which 58/69 (84%) were Borrelia afzelii and 11/69 (16%) were Borrelia garinii. After MseI restriction of PCR products amplified from the intergenic rrf–rrl region, B. afzelii was identified in 73/107 (68%) samples, B. garinii in 22/107 (21%) samples, and both species in 11/107 (10%) samples. The corresponding results for culture-positive specimens were 41/69 (59%), 14/69 (20%), and 7/69 (10%). Comparison of the results for specimens positive according to both approaches revealed complete uniformity in 80% of the cases. Overall, nested PCR was the most sensitive method for the demonstration of Borrelia spp. in erythema migrans skin lesions, followed by culture and PCR targeting the flagellin gene. The congruence of identification results obtained by analyzing culture isolates and material obtained directly from skin biopsies was relatively high but incomplete

Whole genome sequencing characterization of Slovenian carbapenem-resistant Klebsiella pneumoniae, including OXA-48 and NDM-1 producing outbreak isolates

Objectives The first hospital outbreak of carbapenemase-producing Enterobacteriaceae in Slovenia occurred in 2014-2016. Whole genome sequencing was used to analyse the population of carbapenem-resistant Klebsiella pneumoniae collected in Slovenia in 2014-2017, including OXA-48 and/or NDM-1 producing strains from the outbreak. Methods A total of 32 K. pneumoniae isolates were analysed using short-read sequencing. Multilocus sequence typing and core genome multi-locus sequence typing were used to infer genetic relatedness. Antimicrobial resistance markers, virulence factors, plasmid content and wzi types were determined. Long-read sequencing was used for six isolates for detailed analysis of plasmids and their possible transmission. Results Overall, we detected 10 different sequence types (STs), the most common being ST437 (40.6%). Isolates from the initial outbreak belonged to ST437 (12/16) and ST147 (4/16). A second outbreak of four ST15 isolates was discovered. A new ST (ST3390) and two new wzi types (wzi-556, wzi-559) were identified. blaOXA-48 was found in 17 (53.1%) isolates, blaNDM-1 in five (15.6%), and a combination of blaOXA-48/NDM-1 in seven (21.9%) isolates. Identical plasmids carrying blaOXA-48 were found in outbreak isolates sequenced with long-read sequencing technology. Conclusions Whole genome sequencing of Slovenian carbapenem-resistant K. pneumoniae isolates revealed multiple clusters of STs, two of which were involved in the first hospital outbreak of carbapenem producing K. pneumoniae in Slovenia. Transmission of the plasmid carrying blaOXA-48 between two STs was likely to have occurred. A previously unidentified second outbreak was also discovered, highlighting the importance of whole genome sequencing in detection and/or characterization of hospital outbreaks and surveillance of drug-resistant bacterial clones