Antibacterial Activity of Apple Cider Vinegar against Clinical Isolates of Enterococcus Spp.
Karthik A1, Dr. P. Gopinath2*
1BDS 4th Year, Saveetha Dental College, Chennai.
2Assistant Professor, Department of Microbiology, Saveetha Dental College, Chennai.
*Corresponding Author E-mail: gopu.myco@gmail.com
ABSTRACT:
Enterococci have transformed over the past century from being an intestinal commensal organism of little clinical importance to becoming the second most widespread nosocomial pathogen and is related with considerable mortality and morbidity. Apple cider vinegar (ACV) has various benefits like eliminating bad cholesterol, weight reduction, anti-aging and most importantly has anti-fungal, anti-bacterial, anti-viral and anti-cancer effects. However, the FDA has not recognised ACV as a potent anti-microbial as there isn’t scientific evidence for it. This study aims to determine its antibacterial activity against clinical isolates of E. faecalis. A sum of 20 clinical isolates of E. faecalis were detected for antibiotic sensitivity pattern followed by the determination of antibacterial efficacy using MIC method. In our study, we did not find any inhibitory activity against clinical isolates of Enterococcus species using these dilutions. In this study we did not find any inhibitory activity against Enterococcus spp using these diltutions. Perhaps, increased number of isolates with different concentrations should be incorporated to validate the result.
KEYWORDS: Enterococcus faecalis, Apple cider vinegar, MIC.
INTRODUCTION:
Enterococci have transformed over the past century from being an intestinal commensal organism of little clinical importance to becoming the second most widespread nosocomial pathogen and is related with considerable mortality and morbidity.[1,2] The rate of infection and colonization of patients with vancomycin resistant enterococci (VRE) has been increasing significantly and the resistance can be intrinsic or acquired via gene transfer.[1] The occurrence of VRE has vividly increased globally. [2] Extensive usage of vancomycin and extended spectrum cephalosporins in hospitals has likely contributed to the emergence and remarkable increase of VRE over the past 20 years.[3] The National Nosocomial Infection Surveillance (NNIS) system in the USA has reported a significant increase in the percentage of invasive nosocomial Enterococcus strains displaying high-level vancomycin resistance.[4]
Among the different species of Enterococci which have been identified, Enterococcus faecalis, was the most common species associated with the nosocomial infections, followed by Enterococcus faecium, and together they are responsible for 95% of infections caused by Enterococci.[4] Enterococcus faecium and Enterococcus faecalis are of the normal gastrointestinal flora of humans, but they can cause serious infections such as bacterial endocarditis and bacteremia and are often difficult to treat because of inherent resistance to antimicrobial agents.[5,6] There are other species which account for less than 5% of clinical isolates such as E.gallinarum, E.hirae, E.casseliflavus, E.avium, E.durans.[1] Some of the adverse outcomes associated with the infections caused by VRE are extended length of hospital stay, increased cost and increased mortality.[2,4]
In recent studies, essential oils and extracts derived from natural plant species have been known to produce anti-microbial property against virulent genus of micro-organisms. Investigations concerning the evaluation of the biological activities of essential oils of some medicinal plantshave revealed that some of them exhibited antibacterial,antifungal and insecticidal properties. [7] Because of the antimicrobial properties showed by essential oils, thearomatherapy has been used for treatment of serious skindiseases, in special, superficial mycoses. [8] Similarly, in this study the antibacterial activity of apple cider vinegar against Enterococcus spp was assessed.
Apple cider vinegar (ACV) isa solution of acidic acid produced byfermentation of apples. Scientists have measured ninety different substances in apple cider vinegarsuch as thirteen types of carbolic acids,four aldehydes, twenty ketones, eighteentypes of alcohols, eight ethyl acetates etc.It also contains important minerals, trace elements and vitamins (as listedunderneath) as well acetic acid, propionicacid, lactic acid and malic acid, enzymes,amino acids as well as roughage in theform of potash and apple pectin. [9] ACV has various benefits like eliminating bad cholesterol, weight reduction, anti-aging and most importantly has anti-fungal, anti-bacterial, anti-viral and anti-cancer effects. However, the FDA has not recognised ACV as a potent anti-microbial as there isn’t scientific evidence for it. This study aims to create awareness among people about the various benefits of ACV, a household ingredient
MATERIALS AND METHODS:
Clinical isolates:
A total of 20 different non-repetitive clinic isolates of Enterococci were collected from different clinical specimens were included in this study. These isolates were identified by standard biochemical parameters as described by elsewhere. Isolates were preserved in semi-solid brain heart infusion medium and stored at 4şC until further use.
Antimicrobial susceptibility test:
Antibiotic susceptibility test was determined for these strains to routinely used antibiotics such as ampicillin (10µ), vancomycin (30µ), teicoplanin (30µ), erythromycin (15µ), ciprofloxacin (5µ), amikacin (200µ), gentamycin (10µ), tetracycline (30µ) and linezolid (30µ) (Hi Media, Mumbai) by kirby-bauer disc diffusion method.[10]
Detection of antibacterial activity of apple cider vinegar against clinical
isolates of Enterococcus species:
Antifungal activity of apple cider vinegar was tested against enterococcal isolates by minimum inhibitory concentration method. Agar dilution method was performed to attain the different concentrations of apple cider vinegar such as 0.03%, 0.06%, 0.125%, 0.25%, 0.5%, 1% and 2% SDA. Media containing various concentrations of vinegar were poured over the sterile petri dishes and allowed to dry. Media without vinegar was served as control plate. Spot inoculation of 0.5 McFarland standard turbidity adjusted isolates were made on the plates and incubated at 37şC for overnight. The lowest concentration of the apple cider vinegar that completely inhibited the growth of isolates was considered as MIC. [11]
RESULTS:
Sample wise distribution of clinical isolates
of Enterococci:
Of the 20 clinical isolates of Enterococci, 12/20 (60%) were obtained from urine, 4/20 (20%) were from blood, 2/20 (10%) and 2/20 (10%) were from stool samples and wound swabs respectively. Figure 1 depicts sample wise distribution of clinical isolates of Enterococci.
Fig 1: Pie chart showing the sample wise distribution of clinical isolates of Enterococcus spp.
Bacterial isolates:
Out of 20 Enterococci isolates, 14/20 (70%) were found to be E.faecalis, whereas 6/20 (30%) were E. faecium. Figure 2 denotes the species wise distribution of Enterococci from clinical samples.
We found increased percentage of isolates were shown to be resistant to all the antibiotics used in this study. For ampicillin, amikacin, erythromycin, gentamicin, our isolates were found to resistant between 80-90%. Better sensitivity was observed in linezolid, teicoplanin and vancomycin antibiotics. The detailed results of antibiotic sensitivity patter of Enterococci was given in table 1.
Table 1: Results of antibiotic sensitivity patter of Enterococci
Antibiotics |
Sensitivity |
Intermediate |
Resistance |
Ampicillin |
1(5%) |
2(10%) |
17(85%) |
Vancomycin |
15(75%) |
1(5%) |
4(20%) |
Teicoplanin |
12(60%) |
3(15%) |
5(25%) |
Erythromycin |
2(10%) |
0 |
18(90%) |
Ciprofloxacin |
6(30%) |
0 |
14(70%) |
Amikacin |
1(5%) |
1(5%) |
18(90%) |
Gentamycin |
2(10%) |
2(10%) |
16(80%) |
Tetracycline |
4(20%) |
4(20%) |
12(60%) |
Linezolid |
18(90%) |
1(5%) |
1(5%) |
Result of antibacterial activity of apple cider vinegar against clinical isolates of Enterococcus species:
In our study, we did not find any inhibitory activity against clinical isolates of Enterococcus species using these dilutions.
DISCUSSION:
Vinegar, alone, has been used for cleaning and treating nail fungus, head lice, warts and ear infections. Consumers typically prefer natural preservative methods for inhibiting the growth of foodbornepathogenic microorganisms in food. [14] Several problems might be encountered with antifungal drugs, first; resistance; as fungi may become resistant to antifungaldrugs due to target gene mutations, enzymemodification or to development of pumpsystem that expels the drug out of thefungal cell [15] second; toxicity; as antifungal drugs can cause systemic toxicities as hepatotoxicity and nephrotoxicity. Theseproblems necessitate searching for safereffective remedies with known antifungal activity. [12]
Apple cider vinegar is a commonlyprescribed antifungal agent in folkmedicine for treatment of fungal skin, earand vaginal infections. [12] The antifungal activity of apple cider vinegarmight be attributed to its malic acid, acetic acid contents or to other non-identifiedingredients.The mechanism of inhibition fungi growth by organic acids is generally not considered a pH phenomenon. It is known that, growth and morphology of fungi are influenced by the pH of media. [16] Organic acids resulting a decreasing in pH value, this may influence the growth by acidifying the cell, which will consume a great amount of energy to maintain the intracellular pH homeostasis. [17] Other explanations have also been proposed including the membrane disruption, the interruption of metabolic reactions, and the accumulation of toxic anions. [18]
The inhibition of microbial growth increases by lowering pH of the media, and most microorganisms are susceptible to antimicrobial effects in the presence of organic acids. This phenomenon is due to the hydrophobic feature of most organic acids, which allows free diffusion of the protonized form through cell membrane. This diffusion process takes place spontaneously due to pH and osmolarity gradients that exist between the inner and outer sides of the cell. The intracellular pH is higher than the extracellular, and the acid undergoes dissociation as soon as it enters the cytoplasm and then decreases the intracellular pH by releasing the proton. To counter the decrease of cytoplasmic pH, resulting from the ionization of the entered acid, the cell allocates the main part of its energy content to eliminate these newly formed protons which results in slower growth kinetics. [19]
According to Hassan. R et al. [19], acetic acid shows strongest inhibition of fungal growth among other organic acids. Whereas, in our study we used apple cider vinegar to prove its antibacterial activity against Enterococcus by MIC method, but it did not showed any promising result.
CONCLUSION:
Enterococcus is one of the commonest nosocomial pathogen that causes disease in both immunocompromised and competent hosts. Natural oils and products seem to be more efficient in their antibacterial and antifungal property. It is also a safer treatment modality with almost no side-effects. In this study we did not find any inhibitory activity against Enterococcus spp using these diltutions. Perhaps, increased number of isolates with different concentrations should be incorporated to validate the result.
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Received on 03.06.2018 Modified on 07.07.2018
Accepted on 20.07.2018 © RJPT All right reserved
Research J. Pharm. and Tech 2018; 11(8): 3259-3262.
DOI: 10.5958/0974-360X.2018.00599.1