Basic research In vitro antibacterial activity of seven Indian spices against high level gentamicin resistant strains of enterococci

Abstract

IntroductionThe aim of the study was to explore the in vitro antibacterial activity of seven ethanolic extracts of spices against high level gentamicin resistant (HLGR) enterococci isolated from human clinical samples.Material and methodsTwo hundred and fifteen enterococcal strains were isolated from clinical samples. High level gentamicin resistance in ethanolic extracts of cumin (Cuminum cyminum), cinnamon (Cinnamomum zeylanicum), ginger (Zingiber officinale), fenugreek (Trigonella foenum-graecum), cloves (Syzygium aromaticum), cardamom (Elettaria cardamomum Maton) and black pepper (Piper nigrum) were prepared using Soxhlet apparatus. The antibacterial effect of the extracts was studied using the well diffusion method. Statistical analysis was carried out by χ2 test using SPSS 17 software.ResultsOnly cinnamon and ginger were found to have activity against all the isolates, whereas cumin and cloves had a variable effect on the strains. Fenugreek, black pepper and cardamom did not show any effect on the isolates. The zone diameter of inhibition obtained for cinnamon, ginger, cloves and cumin was in the range 31–34 mm, 27–30 mm, 25–26 mm and 19–20 mm respectively.ConclusionsCinnamomum zeylanicum and Z. officinale showed the maximum antibacterial activity against the enterococcal isolates followed by S. aromaticum and C. cyminum. The findings of the study show that spices used in the study can contribute to the development of potential antimicrobial agents for inclusion in the anti-enterococcal treatment regimen.

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

“…The results from the agar disc diffusion method revealed that clove oil had inhibitory effects against all test MDR S. suis isolates. This is consistent with previous studies [33][34][35][36]. Incidentally, regarding the inhibition zones obtained from the essential oil, it is notable that differences can occur among studies due to the methods used in solubilizing the oils to obtain hydrophilic molecules [33], antimicrobial assays, and tested organisms.…”

Discovery of Antibacterial Dietary Spices That Target Antibiotic-Resistant Bacteria

“…Mandal et al reported that the DIZ value obtained from ethanol extracts (20 µL, 10 mg/mL) of cinnamon, clove, and cumin against methicillin-resistant S. aureus was in the range of 22–27 mm, 19–23 mm, and 9–15 mm, respectively [38]. Similarly, Revati et al found that high level gentamicin-resistant enterococci isolates were sensitive to ethanol extracts (50 µL, 100 mg/mL) of cinnamon, ginger, clove, and cumin, with the DIZ values of 31–34, 27–30, 25–26, and 19–20 mm, respectively [14]. Even though, most of the previous investigations were carried out with a limited number of antibiotic-resistant bacterial isolates as well as the tested spice samples, thus the broad antibacterial spectra of spice extracts could not be demonstrated.…”

“…However, few studies have focused on the inhibitory effects of these spices on antibiotic-resistant bacteria. The methanolic and ethanolic extracts of cinnamon, which was the most studied spice, were reported to have inhibitory effects on high level gentamicin-resistant (HLGR) enterococci, multi-drug resistant Escherichia coli AG100, methicillin-resistant S. aureus (MRSA), as well as β-lactamase producing multi-drug Klebsiella pneumonia and Pseudomonas aeruginosa [14,15,16]. Moreover, the antibacterial properties of spices are mostly attributed to lipophilic essential oils in most previous studies [17].…”

Antibacterial and Antifungal Activities of Spices

“…rubra . Revati et al [ 77 ] explored the antimicrobial activities of seven Indian spice ethanol extracts against Enterococci (including 215 enterococcal strains) isolated from human clinical samples with the agar well diffusion method. Crude ethanol extract of cinnamon was the most effective against all the clinical isolates of Enterococci , with the DIZs ranging from 31 to 34 mm.…”