Abstract
The increasing incidence and severity of diarrhoea and colitis caused by Clostridium difficile, together with a high rate of relapse following treatment with currently recommended antimicrobials, calls for novel interventions for C. difficile infection (CDI). Rhodomyrtone, a bioactive compound derived from the leaves of the rose myrtle (Rhodomyrtus tomentosa) has demonstrated antibacterial activity against several Gram-positive bacteria. This study compared the in vitro antimicrobial activity of rhodomyrtone on C. difficile with that of vancomycin, a recommended agent for the treatment of CDI. Determination of the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of rhodomyrtone and vancomycin for ten C. difficile isolates showed that the MICs of rhodomyrtone for C. difficile vegetative cells (0.625–2.5 mg/L) were comparable with that of vancomycin (1.25 mg/L), but the MBCs of rhodomyrtone (1.25–5 mg/L) were significantly lower than those for vancomycin (5 mg/L to ˃40 mg/L; P < 0.001). Time–kill assays showed rapid bactericidal activity for rhodomyrtone, with ≥99% killing within 4 h. Rhodomyrtone was also four-fold more potent than vancomycin in inhibiting C. difficile spore outgrowth. Transmission electron microscopy of rhodomyrtone-treated C. difficile revealed cell lysis and evidence of defective cell division and spore formation. These studies indicate that rhodomyrtone should be further investigated as a potential treatment for CDI.
| Original language | English |
|---|---|
| Pages (from-to) | 724-729 |
| Number of pages | 6 |
| Journal | International Journal of Antimicrobial Agents |
| Volume | 52 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - 1 Nov 2018 |
Keywords
- Clostridium difficile
- Rhodomyrtone
- Spores
- Vancomycin
Cite this
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Antibacterial activity of rhodomyrtone on Clostridium difficile vegetative cells and spores in vitro. / Srisuwan, Sutthirat; Mackin, Kate E.; Hocking, Dianna M; Lyras, Dena; Bennett-Wood, Vicki R; Voravuthikunchai, Supayang P. ; Robins-Browne, Roy Michael.
In: International Journal of Antimicrobial Agents, Vol. 52, No. 5, 01.11.2018, p. 724-729.Research output: Contribution to journal › Article › Research › peer-review
TY - JOUR
T1 - Antibacterial activity of rhodomyrtone on Clostridium difficile vegetative cells and spores in vitro
AU - Srisuwan, Sutthirat
AU - Mackin, Kate E.
AU - Hocking, Dianna M
AU - Lyras, Dena
AU - Bennett-Wood, Vicki R
AU - Voravuthikunchai, Supayang P.
AU - Robins-Browne, Roy Michael
PY - 2018/11/1
Y1 - 2018/11/1
N2 - The increasing incidence and severity of diarrhoea and colitis caused by Clostridium difficile, together with a high rate of relapse following treatment with currently recommended antimicrobials, calls for novel interventions for C. difficile infection (CDI). Rhodomyrtone, a bioactive compound derived from the leaves of the rose myrtle (Rhodomyrtus tomentosa) has demonstrated antibacterial activity against several Gram-positive bacteria. This study compared the in vitro antimicrobial activity of rhodomyrtone on C. difficile with that of vancomycin, a recommended agent for the treatment of CDI. Determination of the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of rhodomyrtone and vancomycin for ten C. difficile isolates showed that the MICs of rhodomyrtone for C. difficile vegetative cells (0.625–2.5 mg/L) were comparable with that of vancomycin (1.25 mg/L), but the MBCs of rhodomyrtone (1.25–5 mg/L) were significantly lower than those for vancomycin (5 mg/L to ˃40 mg/L; P < 0.001). Time–kill assays showed rapid bactericidal activity for rhodomyrtone, with ≥99% killing within 4 h. Rhodomyrtone was also four-fold more potent than vancomycin in inhibiting C. difficile spore outgrowth. Transmission electron microscopy of rhodomyrtone-treated C. difficile revealed cell lysis and evidence of defective cell division and spore formation. These studies indicate that rhodomyrtone should be further investigated as a potential treatment for CDI.
AB - The increasing incidence and severity of diarrhoea and colitis caused by Clostridium difficile, together with a high rate of relapse following treatment with currently recommended antimicrobials, calls for novel interventions for C. difficile infection (CDI). Rhodomyrtone, a bioactive compound derived from the leaves of the rose myrtle (Rhodomyrtus tomentosa) has demonstrated antibacterial activity against several Gram-positive bacteria. This study compared the in vitro antimicrobial activity of rhodomyrtone on C. difficile with that of vancomycin, a recommended agent for the treatment of CDI. Determination of the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of rhodomyrtone and vancomycin for ten C. difficile isolates showed that the MICs of rhodomyrtone for C. difficile vegetative cells (0.625–2.5 mg/L) were comparable with that of vancomycin (1.25 mg/L), but the MBCs of rhodomyrtone (1.25–5 mg/L) were significantly lower than those for vancomycin (5 mg/L to ˃40 mg/L; P < 0.001). Time–kill assays showed rapid bactericidal activity for rhodomyrtone, with ≥99% killing within 4 h. Rhodomyrtone was also four-fold more potent than vancomycin in inhibiting C. difficile spore outgrowth. Transmission electron microscopy of rhodomyrtone-treated C. difficile revealed cell lysis and evidence of defective cell division and spore formation. These studies indicate that rhodomyrtone should be further investigated as a potential treatment for CDI.
KW - Clostridium difficile
KW - Rhodomyrtone
KW - Spores
KW - Vancomycin
UR - http://www.scopus.com/inward/record.url?scp=85054816199&partnerID=8YFLogxK
U2 - 10.1016/j.ijantimicag.2018.08.014
DO - 10.1016/j.ijantimicag.2018.08.014
M3 - Article
VL - 52
SP - 724
EP - 729
JO - International Journal of Antimicrobial Agents
JF - International Journal of Antimicrobial Agents
SN - 0924-8579
IS - 5
ER -