Biofilms: A developmental niche for vancomycin-intermediate Staphylococcus aureus.

Autor: Chapman JE; Department of Medical Microbiology, Immunology, and Cell Biology, Southern Illinois University School of Medicine, USA., George SE; Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Germany., Wolz C; Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Germany., Olson ME; Department of Medical Microbiology, Immunology, and Cell Biology, Southern Illinois University School of Medicine, USA. Electronic address: molson39@siumed.edu.
Jazyk: angličtina
Zdroj: Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases [Infect Genet Evol] 2024 Jan; Vol. 117, pp. 105545. Date of Electronic Publication: 2023 Dec 29.
DOI: 10.1016/j.meegid.2023.105545
Abstrakt: Staphylococcus aureus are gram-positive bacteria responsible for a wide array of diseases, ranging from skin and soft tissue infections to more chronic illnesses such as toxic shock syndrome, osteomyelitis, and endocarditis. Vancomycin is currently one of the most effective antibiotics available in treating patients infected with methicillin-resistant S. aureus (MRSA), however the emergence of vancomycin-resistant S. aureus (VRSA), and more commonly vancomycin-intermediate S. aureus (VISA), threaten the future efficacy of vancomycin. Intermediate resistance to vancomycin occurs due to mutations within the loci of Staphylococcal genes involved in cell wall formation such as rpoB, graS, and yycG. We hypothesized the VISA phenotype may also arise as a result of the natural stress occurring within S. aureus biofilms, and that this phenomenon is mediated by the RecA/SOS response. Wildtype and recA null mutant/lexAG94E strains of S. aureus biofilms were established in biofilm microtiter assays or planktonic cultures with or without the addition of sub-inhibitory concentrations of vancomycin (0.063 mg/l - 0.25 mg/L ciprofloxacin, 0.5 mg/l vancomycin). Efficiency of plating techniques were used to quantify the subpopulation of biofilm-derived S. aureus cells that developed vancomycin-intermediate resistance. The results indicated that a greater subpopulation of cells from wildtype biofilms (4.16 × 10 2 CFUs) emerged from intermediate-resistant concentrations of vancomycin (4 μg/ml) compared with the planktonic counterpart (1.53 × 10 1 CFUs). Wildtype biofilms (4.16 × 10 2 CFUs) also exhibited greater resistance to intermediate-resistant concentrations of vancomycin compared with strains deficient in the recA null mutant (8.15 × 10 1 CFUs) and lexA genes (8.00 × 10 1 CFUs). While the VISA phenotype would be an unintended consequence of genetic diversity and potentially gene transfer in the biofilm setting, it demonstrates that mutations occurring within biofilms allow for S. aureus to adapt to new environments, including the presence of widely used antibiotics.
Competing Interests: Declaration of Competing Interest None.
(Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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