Scholarlink

Background <p>Colistin-resistant <i>Klebsiella pneumoniae</i> (CR <i>K. pneumoniae</i>) is considered one of the bacteria with the highest levels of antibiotic resistance, necessitating the discovery of alternative therapeutic strategies. This study aimed to evaluate the ability of eugenol, carvacrol, and cinnamaldehyde to inhibit CR <i>K. pneumoniae</i> and the biofilm community of this bacterium.</p> Method <p>The minimum inhibitory concentration (MIC) and antibiofilm effects of compounds were assessed using broth macrodilution and microtiter plate assays, respectively. Time-kill assays determined the bactericidal effects of natural compounds on CR <i>K. pneumoniae</i> isolates. Protein and nucleic acid leakage were examined to assess metabolic disruption and cell membrane integrity. Real-time PCR was used to evaluate the effect of natural compounds on the expression of biofilm-related genes (<i>mrkA</i>, <i>treC</i>, and <i>luxS</i>).</p> Results <p>In the disk diffusion test, the inhibition zones of eugenol, carvacrol, and cinnamaldehyde were 15 ± 1, 29 ± 2, and 30 ± 1&#xa0;mm, respectively. The MIC of eugenol, carvacrol, and cinnamaldehyde were 260, 119, and 128&#xa0;µg/mL, respectively. The time-kill assay demonstrated the rapid bactericidal effects of eugenol, carvacrol, and cinnamaldehyde at 2× MIC, with kill times of 6, 2, and 3&#xa0;h, respectively. At the MIC, the kill times were 12, 10, and 12&#xa0;h, respectively. These compounds significantly released proteins and nucleic acids from the treated bacteria. They also inhibited biofilm formation and disrupted mature biofilms. Furthermore, <i>mrkA</i> and <i>treC</i> expression levels were significantly reduced in the presence of eugenol and cinnamaldehyde.</p> Conclusion <p>These natural compounds demonstrated significant antibacterial and antibiofilm activity against CR <i>K. pneumoniae</i>, emerging as a promising natural alternative for treatment.</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

Antibacterial and antibiofilm efficacy of eugenol, carvacrol, and cinnamaldehyde against colistin-resistant Klebsiella pneumoniae

  • 期刊论文

  • 发表日期：

    2025年5月21日

查看全文
  • Milad Kashi,
  • Abbas Farahani,
  • Azam Ahmadi,
  • Aref Shariati,
  • Majid Akbari

摘要

Background

Colistin-resistant Klebsiella pneumoniae (CR K. pneumoniae) is considered one of the bacteria with the highest levels of antibiotic resistance, necessitating the discovery of alternative therapeutic strategies. This study aimed to evaluate the ability of eugenol, carvacrol, and cinnamaldehyde to inhibit CR K. pneumoniae and the biofilm community of this bacterium.

Method

The minimum inhibitory concentration (MIC) and antibiofilm effects of compounds were assessed using broth macrodilution and microtiter plate assays, respectively. Time-kill assays determined the bactericidal effects of natural compounds on CR K. pneumoniae isolates. Protein and nucleic acid leakage were examined to assess metabolic disruption and cell membrane integrity. Real-time PCR was used to evaluate the effect of natural compounds on the expression of biofilm-related genes (mrkA, treC, and luxS).

Results

In the disk diffusion test, the inhibition zones of eugenol, carvacrol, and cinnamaldehyde were 15 ± 1, 29 ± 2, and 30 ± 1 mm, respectively. The MIC of eugenol, carvacrol, and cinnamaldehyde were 260, 119, and 128 µg/mL, respectively. The time-kill assay demonstrated the rapid bactericidal effects of eugenol, carvacrol, and cinnamaldehyde at 2× MIC, with kill times of 6, 2, and 3 h, respectively. At the MIC, the kill times were 12, 10, and 12 h, respectively. These compounds significantly released proteins and nucleic acids from the treated bacteria. They also inhibited biofilm formation and disrupted mature biofilms. Furthermore, mrkA and treC expression levels were significantly reduced in the presence of eugenol and cinnamaldehyde.

Conclusion

These natural compounds demonstrated significant antibacterial and antibiofilm activity against CR K. pneumoniae, emerging as a promising natural alternative for treatment.