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

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.

Syzygium aromaticum L. (Myrtaceae): Traditional Uses, Bioactive Chemical Constituents, Pharmacological and Toxicological Activities

“…Additionally, Shukri et al [42] revealed that the dietary cloves in vivo reduced the tissue damages in the livers, lens, and cardiac muscles in rats. Pharmacologically, clove oil is used in a wide range as an antiseptic in oral diseases and for the treatment of toothaches, allergy disorders, asthma, acne, scars, and rheumatoid arthritis, and it showed antispasmodic and acaricidal effects toward Dermatophagoides pteronyssinus and Dermatophagoides farina [43,44]. Moreover, the CEO has shown aphrodisiac, antipyretic, appetizer, hypnotic, anxiolytic, antiemetic, analgesic, decongestant, antimicrobial, antiepileptic, myorelaxant, anti-inflammatory, and expectorant properties as well as has a medicinal influence against trophic disorder [37,45].…”

Streptococcus suis Research: Progress and Challenges

“…The work of Libante et al [18] highlights the importance of reducing the prophylactic use of antimicrobials in livestock productions and the development of alternative control measures. In this regard, Wongsawan et al [19] explored the bactericidal effect of clove oil against S. suis in vitro. It was found that eugenol is the major active ingredient of clove oil and a promising alternative product for control of infectious diseases caused by S. suis.…”

Antibacterial Activity of Syzygium aromaticum (Clove) Bud Oil and Its Interaction with Imipenem in Controlling Wound Infections in Rats Caused by Methicillin-Resistant Staphylococcus aureus

“…Earlier studies on essential oils reported antibacterial effects against Gram-negative bacterial strains causing urinary tract infections [ 41 ]. The anti-MRSA potential of clove oil has also been reported and has highlighted the need to explore bioactive constituents [ 42 ]. The phytochemicals present in clove bud oil are responsible for antimicrobial activity.…”