Scholarlink

<p>Subinhibitory concentrations of various antibiotics can exacerbate microbial virulence. <i>Acinetobacter baumannii</i> is often resistant to oxacillin; however, the effect of low oxacillin concentrations on oxacillinase-producing bacteria remains unclear. Herein, oxacillinase producer <i>A. baumannii</i> ATCC-strains 2093 (motile) and 19606 (non-motile) were pre-exposed to sub-bactericidal concentrations (subMBC) of oxacillin (0.25, 0.5, and 1.0&#xa0;mg/mL) and incubated at 37&#xa0;°C. Growth kinetics, twitching and swarming-like motility, biofilm formation, exopolysaccharide production, transformation capability, and gene expression were determined. All oxacillin subMBC conditions exerted bacteriostatic effects in both strains. Pre-exposing the motile strain with 0.25 and 0.5&#xa0;mg/mL of oxacillin for 1&#xa0;h increased the twitching motility (4.2 ± 0.3&#xa0;cm; control = 3.5 cm), whereas pre-exposure for 2&#xa0;h it increased swarming-like motility (2.95 ± 0.15&#xa0;cm; control = 2.7&#xa0;cm). This strain also increased the biofilm production by effect of all 6&#xa0;h-oxacillin subMBC treated bacteria (≤ 1.42 Biofilm Formation Index (BFI); control = 0.6 BFI), whereas the strain 19606 reduced biofilm up to 1 BFI (control = 2 BFI). The antibiotic also reduced the exopolysaccharide production in almost all treated cells from both strains. The transformation efficiency (TE) of strain 19606 increased X̄ = 19 ± 11% more than the control by effect of all DNA and oxacillin conditions studied; however, the TE for strain 2093 was lower than the control. The expression of genes for resistance (<i>bla-OXA</i>), twitching (<i>pilA</i>/<i>tonB</i>) and swarming-like motilities (<i>dat</i>/<i>ddc</i>), and biofilm production (<i>csuE</i>) were altered by the oxacillin subMBC. Overall, exposure of oxacillinase-producing <i>A. baumannii</i> to oxacillin subMBC increases several virulence factors, representing a potential public health risk.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Subinhibitory Concentrations of Oxacillin Alter Motility, Biofilm Production, and Transformation Capability of the Oxacillinase-Producing Acinetobacter baumannii

  • 期刊论文

  • 发表日期：

    2025年10月17日

查看全文
  • Frida Guerrero-López,
  • Yaraymi Ortiz,
  • José Ángel Merino-Mascorro,
  • Eduardo Franco-Frías,
  • Santos García,
  • Norma Heredia

摘要

Subinhibitory concentrations of various antibiotics can exacerbate microbial virulence. Acinetobacter baumannii is often resistant to oxacillin; however, the effect of low oxacillin concentrations on oxacillinase-producing bacteria remains unclear. Herein, oxacillinase producer A. baumannii ATCC-strains 2093 (motile) and 19606 (non-motile) were pre-exposed to sub-bactericidal concentrations (subMBC) of oxacillin (0.25, 0.5, and 1.0 mg/mL) and incubated at 37 °C. Growth kinetics, twitching and swarming-like motility, biofilm formation, exopolysaccharide production, transformation capability, and gene expression were determined. All oxacillin subMBC conditions exerted bacteriostatic effects in both strains. Pre-exposing the motile strain with 0.25 and 0.5 mg/mL of oxacillin for 1 h increased the twitching motility (4.2 ± 0.3 cm; control = 3.5 cm), whereas pre-exposure for 2 h it increased swarming-like motility (2.95 ± 0.15 cm; control = 2.7 cm). This strain also increased the biofilm production by effect of all 6 h-oxacillin subMBC treated bacteria (≤ 1.42 Biofilm Formation Index (BFI); control = 0.6 BFI), whereas the strain 19606 reduced biofilm up to 1 BFI (control = 2 BFI). The antibiotic also reduced the exopolysaccharide production in almost all treated cells from both strains. The transformation efficiency (TE) of strain 19606 increased X̄ = 19 ± 11% more than the control by effect of all DNA and oxacillin conditions studied; however, the TE for strain 2093 was lower than the control. The expression of genes for resistance (bla-OXA), twitching (pilA/tonB) and swarming-like motilities (dat/ddc), and biofilm production (csuE) were altered by the oxacillin subMBC. Overall, exposure of oxacillinase-producing A. baumannii to oxacillin subMBC increases several virulence factors, representing a potential public health risk.