TY - JOUR A1 - Umstätter, Florian A1 - Werner, Julia A1 - Zerlin, Leah A1 - Mühlberg, Eric A1 - Kleist, Christian A1 - Klika, Karel D. A1 - Hertlein, Tobias A1 - Beijer, Barbro A1 - Domhan, Cornelius A1 - Zimmermann, Stefan A1 - Ohlsen, Knut A1 - Haberkorn, Uwe A1 - Mier, Walter A1 - Uhl, Philipp T1 - Impact of linker modification and PEGylation of vancomycin conjugates on structure-activity relationships and pharmacokinetics JF - Pharmaceuticals N2 - As multidrug-resistant bacteria represent a concerning burden, experts insist on the need for a dramatic rethinking on antibiotic use and development in order to avoid a post-antibiotic era. New and rapidly developable strategies for antimicrobial substances, in particular substances highly potent against multidrug-resistant bacteria, are urgently required. Some of the treatment options currently available for multidrug-resistant bacteria are considerably limited by side effects and unfavorable pharmacokinetics. The glycopeptide vancomycin is considered an antibiotic of last resort. Its use is challenged by bacterial strains exhibiting various types of resistance. Therefore, in this study, highly active polycationic peptide-vancomycin conjugates with varying linker characteristics or the addition of PEG moieties were synthesized to optimize pharmacokinetics while retaining or even increasing antimicrobial activity in comparison to vancomycin. The antimicrobial activity of the novel conjugates was determined by microdilution assays on susceptible and vancomycin-resistant bacterial strains. VAN1 and VAN2, the most promising linker-modified derivatives, were further characterized in vivo with molecular imaging and biodistribution studies in rodents, showing that the linker moiety influences both antimicrobial activity and pharmacokinetics. Encouragingly, VAN2 was able to undercut the resistance breakpoint in microdilution assays on vanB and vanC vancomycin-resistant enterococci. Out of all PEGylated derivatives, VAN:PEG1 and VAN:PEG3 were able to overcome vanC resistance. Biodistribution studies of the novel derivatives revealed significant changes in pharmacokinetics when compared with vancomycin. In conclusion, linker modification of vancomycin-polycationic peptide conjugates represents a promising strategy for the modulation of pharmacokinetic behavior while providing potent antimicrobial activity. KW - glycopeptide antibiotics KW - antimicrobial resistance KW - vancomycin KW - polycationic peptides KW - linker influence KW - pharmacokinetics KW - PEGylation Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-255197 SN - 1424-8247 VL - 15 IS - 2 ER - TY - JOUR A1 - Kurotschka, Peter Konstantin A1 - Fulgenzio, Chiara A1 - Da Cas, Roberto A1 - Traversa, Giuseppe A1 - Ferrante, Gianluigi A1 - Massidda, Orietta A1 - Gágyor, Ildikó A1 - Aschbacher, Richard A1 - Moser, Verena A1 - Pagani, Elisabetta A1 - Spila Alegiani, Stefania A1 - Massari, Marco T1 - Effect of fluoroquinolone use in primary care on the development and gradual decay of Escherichia coli resistance to fluoroquinolones: a matched case-control study JF - Antibiotics N2 - The reversibility of bacterial resistance to antibiotics is poorly understood. Therefore, the aim of this study was to determine, over a period of five years, the effect of fluoroquinolone (FQ) use in primary care on the development and gradual decay of Escherichia coli resistance to FQ. In this matched case–control study, we linked three sources of secondary data of the Health Service of the Autonomous Province of Bolzano, Italy. Cases were all those with an FQ-resistant E. coli (QREC)-positive culture from any site during a 2016 hospital stay. Data were analyzed using conditional logistic regression. A total of 409 cases were matched to 993 controls (FQ-sensitive E. coli) by the date of the first isolate. Patients taking one or more courses of FQ were at higher risk of QREC colonization/infection. The risk was highest during the first year after FQ was taken (OR 2.67, 95%CI 1.92–3.70, p < 0.0001), decreased during the second year (OR 1.54, 95%CI 1.09–2.17, p = 0.015) and became undetectable afterwards (OR 1.09, 95%CI 0.80–1.48, p = 0.997). In the first year, the risk of resistance was highest after greater cumulative exposure to FQs. Moreover, older age, male sex, longer hospital stays, chronic obstructive pulmonary disease (COPD) and diabetes mellitus were independent risk factors for QREC colonization/infection. A single FQ course significantly increases the risk of QREC colonization/infection for no less than two years. This risk is higher in cases of multiple courses, longer hospital stays, COPD and diabetes; in males; and in older patients. These findings may inform public campaigns and courses directed to prescribers to promote rational antibiotic use. KW - drug resistance KW - bacterial KW - antimicrobial resistance KW - anti-bacterial agents KW - primary care KW - quinolones KW - fluoroquinolones KW - information storage and retrieval KW - Escherichia coli Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-278771 SN - 2079-6382 VL - 11 IS - 6 ER - TY - JOUR A1 - Masota, Nelson E. A1 - Ohlsen, Knut A1 - Schollmayer, Curd A1 - Meinel, Lorenz A1 - Holzgrabe, Ulrike T1 - Isolation and characterization of galloylglucoses effective against multidrug-resistant strains of Escherichia coli and Klebsiella pneumoniae JF - Molecules N2 - The search for new antibiotics against multidrug-resistant (MDR), Gram-negative bacteria is crucial with respect to filling the antibiotics development pipeline, which is subject to a critical shortage of novel molecules. Screening of natural products is a promising approach for identifying antimicrobial compounds hosting a higher degree of novelty. Here, we report the isolation and characterization of four galloylglucoses active against different MDR strains of Escherichia coli and Klebsiella pneumoniae. A crude acetone extract was prepared from Paeonia officinalis Linnaeus leaves, and bioautography-guided isolation of active compounds from the extract was performed by liquid–liquid extraction, as well as open column, flash, and preparative chromatographic methods. Isolated active compounds were characterized and elucidated by a combination of spectroscopic and spectrometric techniques. In vitro antimicrobial susceptibility testing was carried out on E. coli and K. pneumoniae using 2 reference strains and 13 strains hosting a wide range of MDR phenotypes. Furthermore, in vivo antibacterial activities were assessed using Galleria mellonella larvae, and compounds 1,2,3,4,6-penta-O-galloyl-β-d-glucose, 3-O-digalloyl-1,2,4,6-tetra-O-galloyl-β-d-glucose, 6-O-digalloyl-1,2,3,4-tetra-O-galloyl-β-d-glucose, and 3,6-bis-O-digalloyl-1,2,4-tri-O-galloyl-β-d-glucose were isolated and characterized. They showed minimum inhibitory concentration (MIC) values in the range of 2–256 µg/mL across tested bacterial strains. These findings have added to the number of known galloylglucoses from P. officinalis and highlight their potential against MDR Gram-negative bacteria. KW - antimicrobial resistance KW - Enterobacteriaceae KW - Paeonia KW - gallotannins KW - isolation KW - structural elucidation KW - Escherichia coli KW - Klebsiella pneumoniae Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-286179 SN - 1420-3049 VL - 27 IS - 15 ER -