Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2019 Dec 21;9(1):14.
doi: 10.3390/pathogens9010014.

Bactericidal Effect of Clove Oil against Multidrug-Resistant Streptococcus suis Isolated from Human Patients and Slaughtered Pigs

Kanruethai Wongsawan  1 , Wasana Chaisri  2 , Sahatchai Tangtrongsup  3   4 , Raktham Mektrirat  1   5
Affiliations

Bactericidal Effect of Clove Oil against Multidrug-Resistant Streptococcus suis Isolated from Human Patients and Slaughtered Pigs

Kanruethai Wongsawan et al. Pathogens. .

Abstract

Streptococcus suis is a zoonotic pathogen that is currently considered an emerging multidrug-resistant (MDR). Increasing antibiotic resistance can lead to the unsuccessful treatment of S. suis infection. Recently, many investigations of medicinal plants were conducted for the treatment of infection as a result of the increase of antibiotic-resistant bacteria. The aims of this study were to determine the chemical composition of essential oil from Syzygium aromaticum (L.) Merr. & L.M. Perry and the antibacterial activities of clove oil on MDR S. suis. Using gas chromatography coupled to a mass spectrometer, eugenol (97.76%) was found to be the major active ingredient of clove oil. In vitro antibacterial activities of clove oil against MDR S. suis were evaluated. Using the agar disc diffusion test, the clove oil showed a maximum zone of inhibition at 15% (v/v) oil concentration. In a broth microdilution method, the minimum bactericidal concentration of clove oil against all MDR S. suis isolates was 0.1% (v/v). A time-kill analysis was performed, and the killing kinetics of clove oil showed that MDR S. suis was completely reduced after 15 min of exposure to clove oil. In addition, clove oil exhibited a strong antibacterial activity at all pH values applied following incubation of MDR S. suis in pH-adjusted media with clove oil. Moreover, scanning electron microscopy revealed the nonviable S. suis isolates clearly showed atypical form and cell membrane lysis after incubation with clove oil. This study confirms the efficacy of clove oil as a natural antimicrobial against MDR S. suis and suggests the possibility of employing it as a promising alternative product for control of infectious diseases caused by S. suis in animal and human patients.

Keywords: Streptococcus suis; antibacterial activity; bactericidal activity; clove oil.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

Figures

Figure 1
Figure 1
Gas chromatography-mass spectrometry (GC-MS) chromatograph for essential oil of S. aromaticum (L.) Merr. & L.M. Perry.
Figure 2
Figure 2
Effect of clove oil on MDR S. suis viability. Bacteria were suspended in phosphate-buffered saine (PBS) and incubated with or without oil (control) at MBC. Error bars represent the standard deviations from three independent experiments. * p < 0.05.
Figure 3
Figure 3
Effect of pH on the bactericidal activity of clove oil against MDR S. suis. Error bars represent the standard deviations from three independent experiments.
Figure 4
Figure 4
Scanning electron microscopic: (a) Image of MDR S. suis untreated cell; (b) after treatment with clove oil at the MIC, (c) and (d) after treatment with clove oil at the MBC. Scale: 1 µm (a), 100 nm (b–d).
See this image and copyright information in PMC

References

    1. Takeuchi D., Kerdsin A., Pienpringam A., Loetthong P., Samerchea S., Luangsuk P., Khamisara K., Wongwan N., Areeratana P., Chiranairadul P., et al. Population-based study of Streptococcus suis infection in humans in Phayao province in Northern Thailand. PLoS ONE. 2012;7:e31265. doi: 10.1371/journal.pone.0031265. - DOI - PMC - PubMed
    1. Wisselink H.J., Veldman K.T., Van den Eede C., Salmon S.A., Mevius D.J. Quantitative susceptibility of Streptococcus suis strains isolated from diseased pigs in seven European countries to antimicrobial agents licenced in veterinary medicine. Vet. Microbiol. 2006;113:73–82. doi: 10.1016/j.vetmic.2005.10.035. - DOI - PubMed
    1. Hendriksen R.S., Mevius D.J., Schroeter A., Teale C., Jouy E., Butaye P., Franco A., Utinane A., Amado A., Moreno M., et al. Occurrence of antimicrobial resistance among bacterial pathogens and indicator bacteria in pigs in different European countries from YEAR 2002–2004: The ARBAO-II study. Acta Vet. Scand. 2008;50:19. doi: 10.1186/1751-0147-50-19. - DOI - PMC - PubMed
    1. Zhang C., Ning Y., Zhang Z., Song L., Qiu H., Gao H. In vitro antimicrobial susceptibility of Streptococcus suis strains isolated from clinically healthy sows in China. Vet. Microbiol. 2008;131:386–392. doi: 10.1016/j.vetmic.2008.04.005. - DOI - PubMed
    1. Princivalli M.S., Palmieri C., Magi G., Vignaroli C., Manzin A., Camporese A., Barocci S., Magistrali C., Facinelli B. Genetic diversity of Streptococcus suis clinical isolates from pigs and humans in Italy (2003–2007) EuroSurveillance. 2009;14:19310. doi: 10.2807/ese.14.33.19310-en. - DOI - PubMed

LinkOut - more resources