Fernández González, AnaPérez Gómez, AstridAyala, Juan A.Mallo Cancela, SusanaRumbo-Feal, SorayaTomás, MaríaPoza, MargaritaBou, Germán2026-03-022026-03-022012-03-16Fernández A, Pérez A, Ayala JA, Mallo S, Rumbo-Feal S, Tomás M, Poza M, Bou G.2012.Expression of OXA-Type and SFO-1 β-Lactamases Induces Changes in Peptidoglycan Composition and Affects Bacterial Fitness. Antimicrob Agents Chemother56:.https://doi.org/10.1128/aac.05402-110066-48041098-6596https://hdl.handle.net/2183/47553[Abstract] β-Lactamases and penicillin-binding proteins (PBPs) have evolved from a common ancestor. β-Lactamases are enzymes that degrade β-lactam antibiotics, whereas PBPs are involved in the synthesis and processing of peptidoglycan, which forms an elastic network in the bacterial cell wall. This study analyzed the interaction between β-lactamases and peptidoglycan and the impact on fitness and biofilm production. A representative set of all classes of β-lactamases was cloned in the expression vector pBGS18 under the control of the CTX-M promoter and expressed in Escherichia coli MG1655. The peptidoglycan composition of all clones was evaluated, and quantitative changes were found in E. coli strains expressing OXA-24, OXA-10-like, and SFO-1 (with its upstream regulator AmpR) β-lactamases; the level of cross-linked muropeptides decreased, and their average length increased. These changes were associated with a statistically significant fitness cost, which was demonstrated in both in vitro and in vivo experiments. The observed changes in peptidoglycan may be explained by the presence of residual dd-endopeptidase activity in these β-lactamases, which may result in hydrolysis of the peptide cross bridge. The biological cost associated with these changes provides important data regarding the interaction between β-lactamases and the metabolism of peptidoglycan and may provide an explanation for the epidemiology of these β-lactamases in Enterobacteriaceae.eng© 2012 American Society for Microbiology.Antibiotic ResistanceAntibiotic Targets in Cell Wall BiosynthesisBeta-lactam ResistanceCell Wall BiosynthesisCell Wall StructureCell Wall Synthesis and AssemblyEnvelope StructureMicrobial Pathogenesis and ImmunologyMicrobial Physiology and GeneticsPeptidoglycan ArchitecturePeptidoglycan LayerPeptidoglycan Synthesisjournal articleopen access10.1128/aac.05402-11