Linezolid is an important therapeutic option for treatment of infections caused by glycopeptide- and beta-lactam-resistant gram-positive organisms. Linezolid resistance is caused by mutations within the domain V region of the 23S ribosomal RNA (rRNA) gene, which is present in multiple copies in most bacteria. Among clinical Staphylococcus aureus isolates, there has been only 1 reported case of linezolid resistance. In the present study, this isolate was further characterized by determination of the number of mutant 23S rRNA copies, assessment of the stability of the resistant phenotype, and comparison of its growth characteristics with those of linezolid-susceptible S. aureus. All 5 copies of the 23S rRNA gene contained a G2576U mutation in the domain V region. After serial passage on antibiotic-free medium, the isolate maintained resistance to high concentrations of linezolid. Compared with 2 linezolid-susceptible S. aureus isolates, the linezolid-resistant S. aureus isolate demonstrated no significant differences in in vitro growth characteristics.
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http://dx.doi.org/10.1086/345368 | DOI Listing |
PLoS Biol
January 2025
Department of Biophysics, University of Michigan, Ann Arbor, Michigan, United States of America.
As failure rates for traditional antimicrobial therapies escalate, recent focus has shifted to evolution-based therapies to slow resistance. Collateral sensitivity-the increased susceptibility to one drug associated with evolved resistance to a different drug-offers a potentially exploitable evolutionary constraint, but the manner in which collateral effects emerge over time is not well understood. Here, we use laboratory evolution in the opportunistic pathogen Enterococcus faecalis to phenotypically characterize collateral profiles through evolutionary time.
View Article and Find Full Text PDFMicroorganisms
December 2024
Servicio de Microbiología, University Hospital Virgen de las Nieves, 18014 Granada, Spain.
The incidence of infections caused by the complex (MAC) has risen significantly, posing diagnostic and therapeutic challenges. This study analyzed 134 clinical isolates of the complex from southern Spain, performing in vitro antimicrobial susceptibility testing using a commercial microdilution technique to generate additional data, refine treatment strategies, and improve patient outcomes. Phenotypic susceptibility testing revealed clarithromycin and amikacin as the most effective antibiotics, with susceptibility rates exceeding 90%, while linezolid and moxifloxacin exhibited limited activity, with resistance rates of 49.
View Article and Find Full Text PDFAntibiotics (Basel)
December 2024
Department of Mother and Baby, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania.
This study investigates bacterial etiology and antibiotic resistance in pediatric leukemia patients to determine the impact of chronic pathology on treatment efficacy. : Thirty cases of children aged 1-16 years (18 boys, 12 girls) were analyzed, identifying 13 pathogens, including 8 Gram-positive and 5 Gram-negative bacteria. : Among the patients, 11 girls presented with acute lymphoblastic leukemia (ALL) type B, while one boy and one girl had acute myeloid leukemia, and, as for boys, three had ALL type T and two had pre-B ALL.
View Article and Find Full Text PDFAntibiotics (Basel)
December 2024
Department of Geriatrics, Evangelisches Krankenhaus Göttingen-Weende, 37075 Göttingen, Germany.
In hospital- and community-acquired central nervous system infections, resistant Gram-positive bacteria are an increasing therapeutic challenge. The present approach does not attempt to identify rapidly bactericidal therapies for susceptible pathogens but aims to improve methods to find antibiotic regimens for multi-resistant pathogens that are effective in vivo in spite of reduced in vitro susceptibility in culture media. Antibiotic susceptibility was tested in cerebrospinal fluid (CSF) and Mueller-Hinton broth (, methicillin-resistant , ) or brain-heart infusion ().
View Article and Find Full Text PDFAntibiotics (Basel)
December 2024
Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties "G. D'Alessandro", University of Palermo, 90127 Palermo, Italy.
Infections caused by S. aureus strains encoding Panton-Valentine leukocidin (PVL-SA) have become increasingly relevant in community settings and can cause severe conditions in pediatric populations. We present the pediatric case of an invasive disease caused by PVL-SA and provide a literature review of severe manifestations caused by these strains in children.
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