Examinando por Autor "Mahler, Graciela S."
Mostrando 1 - 3 de 3
Resultados por página
Opciones de ordenación
Ítem Acceso Abierto 2-Mercaptomethyl-thiazolidines use conserved aromatic–S interactions to achieve broad-range inhibition of metallo-β-lactamases(Royal Society of Chemistry, 2021-01-05) Rossi, María Agustina; Martínez, Verónica; Hinchliffe, Philip; Mojica, María F.; Castillo, Valerie; Moreno, Diego M.; Smith, Ryan; Spellberg, Brad; Drusano, George L.; Banchio, Claudia; Bonomo, Robert A.; Spencer, James; Vila, Alejandro J.; Mahler, Graciela S.; https://orcid.org/0000-0003-4720-4070; https://orcid.org/0000-0002-3697-5219; https://orcid.org/0000-0001-8611-4743; https://orcid.org/0000-0002-1380-9824; https://orcid.org/0000-0001-5493-8537; https://orcid.org/0000-0002-4602-0571; https://orcid.org/0000-0002-7978-3233; https://orcid.org/0000-0003-0612-0516Infections caused by multidrug resistant (MDR) bacteria are a major public health threat. Carbapenems are among the most potent antimicrobial agents that are commercially available to treat MDR bacteria. Bacterial production of carbapenem-hydrolysing metallo-β-lactamases (MBLs) challenges their safety and efficacy, with subclass B1 MBLs hydrolysing almost all β-lactam antibiotics. MBL inhibitors would fulfil an urgent clinical need by prolonging the lifetime of these life-saving drugs. Here we report the synthesis and activity of a series of 2-mercaptomethyl-thiazolidines (MMTZs), designed to replicate MBL interactions with reaction intermediates or hydrolysis products. MMTZs are potent competitive inhibitors of B1 MBLs in vitro (e.g., Ki = 0.44 μM vs. NDM-1). Crystal structures of MMTZ complexes reveal similar binding patterns to the most clinically important B1 MBLs (NDM-1, VIM-2 and IMP-1), contrasting with previously studied thiol-based MBL inhibitors, such as bisthiazolidines (BTZs) or captopril stereoisomers, which exhibit lower, more variable potencies and multiple binding modes. MMTZ binding involves thiol coordination to the Zn(II) site and extensive hydrophobic interactions, burying the inhibitor more deeply within the active site than D/L-captopril. Unexpectedly, MMTZ binding features a thioether–π interaction with a conserved active-site aromatic residue, consistent with their equipotent inhibition and similar binding to multiple MBLs. MMTZs penetrate multiple Enterobacterales, inhibit NDM-1 in situ, and restore carbapenem potency against clinical isolates expressing B1 MBLs. Based on their inhibitory profile and lack of eukaryotic cell toxicity, MMTZs represent a promising scaffold for MBL inhibitor development. These results also suggest sulphur–π interactions can be exploited for general ligand design in medicinal chemistry.Ítem Acceso Abierto Impact of tebipenem pivoxil on the intestinal microbiota and on establishment of colonization with carbapenem-resistant Klebsiella pneumoniae in mice(American Society for Microbiology, 2025-03-14) Mojica, María F.; Hausman, Bryan S.; Pearlmutter, Basya S.; Zink, Elizabeth G.; Wilson, Brigid M.; Villamil, Valentina; Saiz, Cecilia; Mahler, Graciela S.; Vila, Alejandro J.; Sangwan, Naseer; Donskey, Curtis J.; Bonomo, Robert A.; https://orcid.org/0000-0002-1380-9824; https://orcid.org/0000-0002-7978-3233; https://orcid.org/0000-0003-0990-4498; https://orcid.org/0000-0002-3299-894XTebipenem pivoxil has potent in vitro activity against Enterobacterales pathogens, but requires combination with β-lactamase inhibitor to achieve activity against carbapenemase producers, including metallo-β-lactamases (MBLs). Herein, we evaluate the potential of tebipenem pivoxil, alone and in combination with the prodrug of the experimental MBL inhibitor CS319 (CS319-piv-SAc), to disrupt the indigenous mice microbiota of the colon and promote colonization by pathogens. The effect of antibiotic treatment (daily for 3 days with subcutaneous saline [control], subcutaneous clindamycin, oral tebipenem pivoxil alone and in combination with CS319-piv-Sac, or oral CS319-piv-Sac) on the intestinal microbiota was assessed by culture for enterococci and facultative Gram-negative bacilli and by 16S rRNA amplicon sequencing. Mice were also challenged with 10,000 colony-forming units (CFU) of multidrug-resistant (MDR) strain Klebsiella pneumoniae blaNDM-1, 6 h after the second dose. The concentrations of the MDR K. pneumoniae in stool were measured on days 1, 3, and 6 after challenge. In comparison to saline controls, clindamycin (P = 0.001) and tebipenem pivoxil plus CS319-piv-SAc (P = 0.02) treatment resulted in significant changes in the alpha diversity patterns, whereas tebipenem pivoxil and CS319-piv-SAc individual treatments did not (P > 0.05). Moreover, clindamycin treatment resulted in substantial overgrowth of MDR K. pneumoniae (mean concentration after 6 days of infection, 6.1 vs 2.9 log10 CFU/g stool), whereas the other treatments did not (≤3.6 log10 CFU/g). Although tebipenem pivoxil alone or in combination with an MBL inhibitor, CS319, caused alteration of the mice intestinal microbiota, neither treatment promoted overgrowth of carbapenem-resistant K. pneumoniae. IMPORTANCE: in this work, we used a mouse model to determine the impact of tebipenem pivoxil alone and in combination with a prodrug of an experimental metallo-β-lactamase inhibitor, CS319, on the intestinal microbiota and on the establishment of colonization with carbapenem-resistant Klebsiella pneumoniae. We found that while treatment with tebipenem pivoxil plus the prodrug of CS319 caused alteration of the intestinal microbiota, it did not promote the overgrowth of carbapenem-resistant K. pneumoniae. Although additional studies are needed to examine the impact of tebipenem pivoxil treatment on other multidrug-resistant Gram-negative bacilli, Clostridioides difficile, and Candida spp., our study is a step forward in the understanding of the potential effect of this oral carbapenem on the indigenous microbiota of the colon and on the promotion of colonization by pathogens.Ítem Acceso Abierto Metallo-β-lactamase inhibitors inspired on snapshots from the catalytic mechanism(MDPI, 2020-06-03) Palacios, Antonela R.; Rossi, María Agustina; Mahler, Graciela S.; Vila, Alejandro J.