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Effect of a Diffused Essential Oil Blend on Bacterial Bioaerosols
Abstract
Thieves, a commercial blend of five essential oils, was tested for its antibacterial activity against Micrococcus luteus, Pseudomonas aeruginosa and Staphylococcus aureus bioaerosols. An aerosol suspension of each bacterial culture was sprayed into a 0.4 m3 enclosed fume hood previously sterilized by ultraviolet light. Thieves essential oil blend was then diffused into the hood for a given time. Depositional sampling results showed a significant reduction (P<0.0001) in the aerosol-borne bacterial load after diffusion of the oil blend. Controls showed no inhibitory effect of oil that may have settled on the exposed plate surfaces during bacterial depositional sampling. Inhibition levels appear to be organism specific. There was an 82% reduction in M. luteus bioaerosol, a 96% reduction in the P. aeruginosa bioaerosol, and a 44% reduction in the S. aureus bioaerosol following 10 min of exposure. Results for the time exposure threshold of diffused oil showed that after only six min a 90% reduction in M. luteus viability occurred. Diffusion of the oil blend, Thieves, can significantly reduce the number of aerosol-borne bacteria and may have application in treating air for enclosed environments and preventing transmission of aerosol-borne bacterial pathogens.
... Very few studies have been done on the antibacterial effects of EO vapors on the bacterial count in indoor air. Since very few studies have been conducted on the effects of EOs on bacterial counts in bioaerosols, the present study was compared with the studies by Lanzerstorfer et al. [16] and Chao et al. [11] in a hospital environment and invitro, respectively. Lanzerstorfer et al. stated that dispersion of EOs of Lemon (Citrus limon) and Silver fir (Abies alba) in a hospital environment had reduced the bacterial count by about 40%. ...
... [16] A study by Chao et al. stated that diffusion of EO blend of Cinnamomum zeylanicum, Rosmarinus officinalis, S. aromaticum, E. globulus labill and C. limon into the hood containing different bacterial strains at different times had reduced the bacterial count to about 30% in first 3 min, and 90% after 6 min. [11] It can be concluded that Vaporization of EO blend of Neem, Eucalyptus, Clove, Cinnamon bark, Thyme and Lemongrass near the dental units during treatments at 5 µl/min has significantly (P < 0.05) reduced the bacterial count in bioaerosols near the dental units by nearly 43.625% at all distances. ...
Background:
The aerosols generated during dental treatments contain bacteria and other microorganisms that penetrate the body through the respiratory system of dental surgeons and cause infectious diseases. Several studies have been done to reduce these hazards. The aim of the present study is to evaluate the effects of the plant extract essential oil (EO) vapors of Neem, Clove, Cinnamon bark, Thyme, Lemon Grass, and Eucalyptus on the bacterial count in bioaerosols near dental units.
Materials and methods:
Sampling was taken on nutrient blood agar plates by placing them open near dental units using passive air sampling method, before commencement of treatment for 1 h, during treatments for 2 h, and after introducing EO vapors for 2 h. The collected samples were taken for incubation at 37°C for 48 h. The colonies formed were counted in colony-forming units per cubic meter and taken for statistical analysis.
Results:
After comparing the obtained results, it was found that there was a significant reduction (P < 0.05) in the bacterial count for about 43% near the dental units after the introduction of the EO vapours.
Conclusion:
It is concluded that natural extracts like EOs can reduce bacterial contamination near dental units in the vapourized state, thereby reducing the health hazards in Dental Health Professionals.
... The antimicrobial effect of an essential oil mixture in a small chamber was reported by Chaoet et al. [13]. Chaoet et al. evaluated the antimicrobial activity of blended essential oils of cinnamon, clove, rosemary, eucalyptus, and lemon in a closed hood with an area of 0.4 m 3 . ...
Chamaecyparis obtusa (Siebold & Zucc.) Endl. (Cupressaceae) is known to produce a variety of antimicrobial substances. In the present study, components of three lots of essential oil from C. obtusa were analyzed by GCMS. It was confirmed that thujopsene and pinene were common markers. In addition, we report indoor space disinfectant effects of products containing C. obtusa essential oil (PO100, PO500, PO1000). It was confirmed that PO100 and PO500 could effectively remove airborne microorganisms in indoor spaces. Results of our study suggest that C. obtusa essential oil is effective in reducing contamination by infectious microorganisms in confined spaces.
... Ce produit se présente sous forme de bombe qui diffuse un brouillard de particules de l'ordre de 10µm composé d'une solution volatile à base d'essences naturelles (citron, lilas, citronelle), d'alcools (salol, terpinéol) d'acide benzoïque et surtout d'huile hydrogénée (75%). Le pouvoir bactéricide, acaricide et fongistatique de Paragerm est bien établi et il s'est révélé sans aucune toxicité pour l'homme aux doses utilisées(Chao et al., 1998 ; Charai, 1999). ...
RESUME
Les huiles essentielles renferment de nombreuses molécules biologiquement actives et occupent pour cela une place considérable sur le marché pharmaceutique et dans l’industrie cosmétique et agro-alimentaire. Le but de ce travail est d’étudier la cytotoxicité des huiles essentielles de trois plantes aromatiques (Rosmarinus officinalis, Mentha pulegium et Eucalyptus golobulus) par des tests biologiques variés : les effets histopathologiques chez le modèle animal, l’effet antibactérien et l’effet antiprolifératif.
Les huiles essentielles ont été extraites par hydrodistillation et analysées par chromatographie en phase gazeuse. Les lésions histopathologiques ont été recherchées au niveau des organes de souris traitées par l’huile essentielle de Rosmarinus officinalis et de Mentha pulegium. Des coupes à la paraffine ont été confectionnées, colorées à l’hématèine-éosine et observées au microscope photonique.
L’activité antibactérienne des huiles essentielles a été étudiée sur sept souches bactériennes, par deux techniques différentes : la technique de micro-atmosphère et la technique de contact direct. L’activité antiproliférative des huiles essentielles a été déterminée par le test de viabilité sur des cellules de myélome P3X63Ag8. Les altérations cellulaires ont été recherchées après coloration des cellules par le May-Grünwald-Giemsa.
Nos résultats ont montré que les constituants majoritaires des huiles essentielles de Rosmarinus officinalis et de Mentha pulegium sont respectivement le 1,8-cinéole (42%) et la R-(+)-pulégone (82%). Aucune toxicité n’a été observée chez les souris traitées par l’huile essentielle de Rosmarinus officinalis. En revanche, l’huile essentielle de Mentha pulegium a présenté une forte toxicité. Au plan histopathologique, une dilatation alvéolaire, une hypertrophie des cellules corticales et médullaires de la surrénale et une dilatation des vaisseaux hépatiques ont été notées au niveau des organes de souris traitées par les huiles essentielles.
Les trois huiles essentielles étudiées ont révélé d’une activité antibactérienne sur les souches utilisées.
Le test de viabilité a montré un effet cytotoxique des trois huiles essentielles sur les cellules de myélome P3X63Ag8 en culture. L’étude de la morphologie des cellules tumorales traitées a révélé une lyse cellulaire avec éclatement membranaire, une hypertrophie et une condensation de la chromatine.
Nous avons conclu que les trois huiles essentielles sont douées d’une activité antibactérienne, d’une activité antiproliférative et présentent des effets histopathologiques notables dans différents organes vitaux.
Les tests biologiques proposés par cette étude évaluent de manière efficace la cytotoxicté des huiles essentielles étudiées. Ils peuvent être utilisés comme outil fiable et faisable pour l’étude de la cytotoxicité d’autres huiles essentielles, voire d’autres substances.
... The Eucalyptus camaldulensis phytochemical analysis shows that all the parts of the plant were rich in saponins and tannins, alkaloids, anthraquinone though cardiac glycosides are not present (Ghareeb et al., 2018;Roger, 1999). Eucalyptus oil has various uses such as antifungal, antiseptic, sterilizing, aromatic and food seasoning (Shaighal et al., 2012;Mehraban et al., 2005;Essien and Akpan, 2004;Chao and Young, 1998 ...
Plant components have been extensively evaluated for their pharmacological activities. This study provides scientific rationale towards the therapeutic effect of Eucalyptus camaldulensis aqueous bark extract against induced atherosclerosis and hyperlipidemia in pigeons. Phytochemical components of Eucalyptus bark extract possess a great antioxidant activity that potentially reduced the risk of heart diseases. A total of 42 Pigeons of both sexes were distributed into negative control (fed normal grain diet), hyperlipidemic control (fed HFD 1% animal fat oil and 0.1% cholesterol for 3 months), test groups of variable doses (0.05, 0.1, 0.2 to 0.4 gms/kg BW for 21 days) and the group received atorvastatin daily after induction used. At the end of the experiment biochemical and histological evaluation has been performed. After HFD induction the serum levels of liver enzyme AST, glucose, urea, cholesterol, LDL, VLDL, and TG were significantly increased with the reduction in HDL levels. The atherogenic index was also found significantly raised. Microscopic examination of the liver and aorta showed the appearance of lipid-filled foam cells all over the liver parenchyma and intima after the HFD induction. Thus it was concluded that Eucalyptus aqueous bark extract can be effective against atherosclerosis and hyperlipidemia.
... The oil can also be rubbed on the skin as an insect repellent. Eucalyptus oil is also rich in cineole (a potent antiseptic that kills bacteria responsible for bad breath), so some professional herbalists may also recommend diluted eucalyptus tinctures to treat bad breath (Bluementhal M et al, 2000, Chao S C et al, 1998, Cermelli C et al, 2008). Withania somnifera: It is used for tumors, inflammation (including arthritis), and a wide range of infectious diseases. ...
The study was conducted to determine the phytoconstituents and to determine antibacterial potential including the minimum inhibitory concentration (MIC) of the leaf extracts of Withania somnifera and Eucalyptus melliodora against pathogenic strains of bacteria viz. Nocardia asteroids and Streptococcus pyogenes. Aqueous and methanolic plant extracts were screened for their antibacterial activity by in vitro agar well diffusion and disc diffusion methods against the microbial strains collected from MTCC, Chandigarh. MIC was determined by dilution series test. The zones of inhibition against N. asteroids by methanolic extracts of E. melliodora and W. somnifera by agar well diffusion were 16 and 20 mm whereas in case of disc diffusion method they were 10 and 15 mm respectively. Zones of inhibition noted against S. pyogenes were 22 mm and 23 mm via agar well diffusion method and 11 mm and 13 mm by disc diffusion method with extracts of E. melliodora and W. somnifera respectively. The aqueous extracts were not showed any reliable results against both the pathogens using disc diffusion method. Minimum Inhibitory Concentration (MIC) obtained were 31µg/mL and 62µg/mL against both the pathogens viz. N asteroids and S. pyogenes with E. melliodora and W. somnifera respectively. The phytochemicals viz. alkaloids, flavanoids, saponins, tannins, carbohydrates and proteins were found to be present in extracts of both the plants.
Currently, due to the global pandemic caused by severe acute respiratory syndrome coronavirus SARS-CoV-2, new procedures and devices for effective disinfection of indoor air are of obvious interest. Various studies demonstrated quite broad ranges of the efficiency of essential oils in the control of biological aerosols. This project reports the results of investigation of the antimicrobial activity of essential oils natural for Australia (tea tree oil, eucalyptus oil and lemon myrtle) distributed by newly developed VaxiPod device for various scenarios, including bacterial, viral and fungal inactivation on various surfaces and in aerosol form. It was found that the device was capable of operating continuously over 24-h periods, providing sufficient aerosol concentration to efficiently inactivate microorganisms both on the surface and in airborne form. Twenty-four to forty-eight hours were required to achieve inactivation above 90% of most of the tested microbes on solid surfaces (stainless steel discs and agar plates), whilst similar efficiency of inactivation on fibrous filter surface as well as in aerosol form was achieved over 30–60 min of the process run. The results look very promising for further development of bioaerosol inactivating procedures and technologies for air quality control applications.
The definition of aromatherapy is the controlled use of essential oils (2). Essential oils are steam distillates obtained from aromatic plants. Aromatherapy is a fairly new complementary therapy, although its roots are in herbal medicine, one of the oldest known forms of medicine. Aromatherapy is an accepted part of nursing care in the United Kingdom, Switzerland, Germany, Australia, and Canada, and many nurses in the United States are beginning to use aromatherapy. Aromatherapy is particularly useful in cardiology (see Table 1), because the use of familiar smells and gentle touch can be deeply reassuring. Essential oils have many other properties that can be useful in cardiology-hypotensor, sedative, antiinflammatory, antispasmodic, analgesic, antibiotic, antifungal, and antiviral. This chapter covers the use of aromatherapy for borderline hypertension and for fear and anxiety associated with myocardial infarction (MI) or cardiac surgery and outlines interesting case and small clinical studies addressing the effect of essential oils on methicillin-resistant Staphylococcus aureus (MRSA)
Table 1
Essential Oils for Specific Diagnosis
Diagnosis
Essential oil
Research
Reference
Borderline hypertension
Ylang ylang
Lavender
Rose
Neroli
Lemon
Clary sage
Freund, 2000
Saeki and Shiohara, 2001
Nathan, 2000
Tiran, 1996
Tiran, 1996
Tiran, 1996
28
30
31
34
34
34
Reducing fear and anxiety
Lavender
Roman chamomile
Rose
Hadfiele, 2001
Yamada et al., 1996
Manly, 1993
41
46
51
Methicillin-resistant Staphylococcus aureaus
Tea tree
Lavender
Juniper
Peppermint
Lemongrass
Eucalyptus
Clove
Thyme
Nelson, 1997
Nelson, 1997
Nelson, 1997
Nelson, 1997
Sherry et al., 2001
Sherry et al., 2001
Sherry et al., 2001
Sherry et al., 2001
22
22
22
22
26
26
26
26
Antibacterial effects of essential oils obtained from medicinal plants viz., Trachyspermum ammi, Cinnamomum zeylanicum, Syzygium aromaticum, Zingiber officinale, Curcuma longa and Acorus calamus were studied in vitro against Salmonella typhi, Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus and Bacillus subtilis. T. ammi and C. zeylanicum oils exhibited maximum activity as compared to the other oils, while A. calamus displays negligible effect.
Eucalyptus is a fast growing tree which has shown to possess high degree of resistance against stressed environmental conditions. Eucalyptus tereticornis is widely cultivated in various parts of the world even in Pakistan. The medicinal properties of this tree reside in its oil. The main aim of our study is to check the antimicrobial activity of this valuable tree and to compare it with commercially available antibiotics. Eucalyptus tereticornis oil was extracted from the fresh leaves and branch tips during flowering season from surrounding areas of Hazara University, Pakistan. Different concentrations of oil were checked against Gram positive bacteria Staphylococcus aureus (ATCC 6538), Enterococcus faecalis (ATCC 49452), Gram negative bacteria including Escherichia coli (ATCC 25922), Salmonella typhimurium (ATCC 14028) and Pseudomonas aeruginosa (ATCC 27853), and also against yeast Candiada albican (ATCC 2091). The oil was significantly active against all the microbes studied. The activity of E. tereticornis oil was compared with standard antibiotics Ciprofloxacin (CIP-5 μg), Chloramphenicol (C-30 μg), Tetracycline (TE-30 μg) and Ampicillin (AMP 25-μg). The comparison gives the significant results and proves the antimicrobial efficiency of this valuable plant.
Hydrodistillation of Amomum subulatum, Cinnamomum verum, Coriandrum sativum, Cuminum cyminum, Elettaria cardamomum, Myristica fragrans (Mace), and Myristica fragrant (Nutmeg) purchased from local markets yielded essential oils which contained 1,8-cineole (72.7%), cinnamaldehyde (79.8%), linalool (78.1%), cuminaldehyde (37.4%), 1,8-cineole (30.7%), terpinen-4-ol (20.0% and 31.3%), respectively as main constituents analyzed by GC/MS. Antifungal activity of the resulting essential oils against various pathogenic fungi (Aspergillus flavus, A. niger, Candida albicans, Fusarium oxysporum var. lycopersici, Microsporum canis, Pseudallescheria boydii, Trichophyton mentagrophytes, T. simii) was investigated.
Of 73 essential oils tested for antibacterial activity against Streptococcus pneumoniae R36A (an unencapsulated strain) with a paper disk diffusion assay, three oils were highly inhibitory, fifteen moderately inhibitory and the remainder weakly or non-inhibitory. Three oils from each group were selected and tested with a broth assay in which each oil was added to growing cultures of S. pneumoniae R36A and optical densities (OD) were measured over time. The oils with high antibacterial activity; oregano, thyme and rosewood, induced rapid lysis of R36A as indicated by a decrease in OD, and appearance of dechaining and considerable cell debris within 30 min of addition. The lytic response of R36A to the three oils with moderate activity was variable but all induced some lysis. Oils that were weak inhibitors generally caused slowing of growth but little or no lysis. Several oils were also tested against an encapsulated isolate, S. pneumoniae IC2. Both disk assay and broth results were similar to those obtained with R36A, except that the oils were slightly less effective. Disk assay results showed some correlation with the broth assay, but were not always predictive of an oil's ability to induce bacterial lysis. Essential oils that induce lysis in S. pneumoniae may have potential as an alternative treatment for infections caused by drug resistant pneumococci.
The lack of solubility and the high degree of volatility of essential oils present significant problems to determining the biological effects of these oils. The activity of 10 essential oils and 4 essential oil blends against a Gram-positive bacterium, Staphylococcus aureus., and a yeast, Candida albicans., was compared using a dilution assay and two diffusion methods. The tube dilution assay, using a 0.2% agar solution to provide a stable homogeneous dispersion of oils, was used to measure minimum inhibitory concentrations (MICs). The relative merits of using p.-iodonitro tetrazolium dye (INT) or optical density (OD) in measuring MIC of essential oils also were evaluated. All 14 oils were active against both microorganisms. Thyme, mountain savory, and Turkish oregano were the most active oils against S. aureus. with MICs of 0.31–0.42 µl/ml. Thyme, Turkish oregano, and mountain savory also were the most active against C. albicans. with MICs of 0.31–0.42 µl/ml. The MIC values as determined by INT or OD methods are strongly correlated for both microorganisms, and both give an accurate estimation of MIC. In the disk diffusion assay, thyme, Turkish oregano, Melissa, mountain savory, and the Exodus II (E2) blend were most active against S. aureus.. In the hole-plate assay, the same oils were active against S. aureus. except for Melissa. For C. albicans., thyme, Melissa, mountain savory, Turkish oregano, rosewood, E2 blend, and the T1 blend were most active in the disk diffusion assay. The same oils were active against C. albicans. in the hole-plate diffusion assay except for the T1 blend. Of the methods tested, the tube dilution assay best addresses the solubility and volatility concerns of essential oils. We favor the determination of MIC using INT because of several eliminated steps. Although there were differences in the way in which some essential oils responded in the two diffusion methods, the correlations between the disk and hole-plate diffusion methods were high and yielded comparable results. However, results from the dilution assay were weakly correlated with agar diffusion results. Diffusion assays are useful as a qualitative assessment of biological activity of essential oils but are not appropriate in assessing quantitative effects.
Ninety-one essential oils, each distilled from a single plant source, and 64 blended essential oils obtained from a commercial source were screened using the disc diffusion assay for inhibitory activity against methicillin-resistant Staphylococcus aureus (MRSA). Of the 91 single essential oils, 78 exhibited zones of inhibition against MRSA, with lemongrass, lemon myrtle, mountain savory, cinnamon and melissa essential oils having the highest levels of inhibition. Of 64 blended essential oils, 52 exhibited inhibitory activity against MRSA, with R.C. (a combination of myrtle, Eucalyptus globulus, Eucalyptus australiana, Eucalyptus radiata, marjoram, pine, cypress, lavender, spruce, peppermint and Eucalyptus citriodora oils), Motivation (a combination of Roman chamomile, ylang ylang, spruce and lavender oils) and Longevity (a combination of frankincense, clove, orange and thyme oils) blended essential oils having the highest inhibitory activity. These results indicate that essential oils alone and in combination can inhibit MRSA in vitro. Application of these results may include the potential use of essential oils as an alternative therapy for various diseases sustained by S. aureus MRSA. Copyright © 2008 John Wiley & Sons, Ltd.
Six spice essential oils (sage, rosemary, caraway, cumin, clove, and thyme) and their basic ingredients were tested for their inhibitory effect against 3 strains of Gram-negative bacteria, 4 strains of Gram-positive bacteria, one acid fast bacterium, and one yeast. Preliminary screening of antimicrobial activity of the essential oils was done using the filter paper disc agar diffusion method. The minimum inhibitory concentration for each essential oil against various micro-organisms was also measured. Very low concentrations (0.25-12 mg/ml) of the various essential oils were sufficient to prevent microbial growth. The data show that Gram-positive bacteria were more sensitive to the antimicrobial compounds in spices than Gram-negative. The inhibition zones of different microbial growth produced by various essential oils were similar to those produced by their basic compounds. Thyme and cumin oils possessed very strong antimicrobial activity compared with the other essential oils. There was a relationship between the chemical structures of the most abundant compounds in the essential oils under investigation and the antimicrobial activity. Copyright © International Association of Milk, Food and Environmental Sanitarians.
The performances of various bioaerosol samplers have previously been compared in different field settings. The results are contradictory because of the arbitrarily chosen samplers, detection methods and sampling environments. In this paper, bioaerosol samplers are analyzed as to their operating principles and the different elements of the bioaerosol sampling process. The concepts of stopping distance as an estimate of sampler cut-off size, particle surface density on the collection surface and an example sampling time are introduced. Several presently available samplers are evaluated as to their collection characteristics and calculated optimal sampling times.
Heterotrophic bacteria from structural surfaces, drain pan water, and the airstream of a well-maintained air-handling system with no reported building-related illness were enumerated. Visually the system appeared clean, but large populations of bacteria were found on the fin surface of the supply-side cooling coils (10(5) to 10(6) CFU cm-2), in drain pan water (10(5) to 10(7) CFU ml-1), and in the sump water of the evaporative condenser (10(5) CFU ml-1). Representative bacterial colony types recovered from heterotrophic plate count cultures on R2A medium were identified to the genus level. Budding bacteria belonging to the genus Blastobacter dominated the supply surface of the coil fins, the drain pan water, and the postcoil air. These data and independent scanning electron microscopy indicated that a resident population of predominantly Blastobacter bacteria was present as a biofilm on the supply-side cooling coil fins.
The three major forms of skin cancer (melanoma, squamous cell carcinoma, and basal cell carcinoma) are all epidemic in the Caucasian population of North America, and each has therefore been the subject of numerous investigations. This chapter reviews the descriptive and analytic epidemiology of melanoma and nonmelanoma skin cancer. The data reviewed are based primarily on populations in the United States and Canada; the (largely parallel) results that characterize the Scandinavian and Australasian literature are reviewed in Chapters 9 and 10.
Higher plants have been exploited as a source of biologically active compounds since antiquity. In particular, the ability to inhibit the growth of spoilage and food poisoning bacteria, human and animal pathogens and a number of filamentous fungi has been of immense importance to man over the centuries (Zaika 1989; Deans and Svoboda 1990a; Deans et al. 1990). It is worth noting that even with today’s battery of synthetic and semi-synthetic antibiotics, over 25% of pharmaceutical preparations in the West contain at least one component originating from plant sources: in the East this percentage is far higher. That some of these plant antimicrobials also possess antioxidant properties is a welcome bonus in the quest to preserve the food reserves of the world.
The solubility in water of essential oil constituents is directly related to their ability to penetrate the cell walls of a bacterium or fungus. The antimicrobial activity of essential oils is due to their solubility in the phospholipid bilayer of cell membranes. Terpenoids which are characterized by their lability have been found to interfere with the enzymatic reactions of energy metabolism.
The bacteriostatic and bactericidal activities of 22 essential oils (anise, calamint, celery, coriander, cornmint, cumin, dill, fennel, Laser, laurel, lemon peel, lemon leaf, orange peel, oregano, parsley, rosemary, sage, savory, tarragon, thyme, wild thyme, and Ziziphora) from Turkish spice and citrus plants against seven bacteria (Aerobacter aerogenes, Bacillus subtilis, Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa, Staphylococcus albus, and Staphylococcus aureus) were evaluated.
The results showed that the essential oils tested varied in their antibacterial activity. Anise, celery, coriander, parsley, and sage were inactive or had little activity; while cornmint, cumin, laurel, lemon peel, orange, oregano, and Ziziphora were active against all tested bacteria to a variable extent. S. aureus and P. vulgaris were the most sensitive organisms, while P. aeruginosa was the most resistant except towards thyme oil. Fifteen essential oils had MBC lower than MIC and only seven were at about the same level. The results also showed that the bacteriostatic data obtained by agar diffusion and serial dilution methods were not always comparable; therefore, in testing the biostatic effects of essential oils it is advisable to carry out both techniques.
Fifty plant essential oils were examined for their antibacterial properties against 25 genera of bacteria. Four concentrations of each oil were tested using an agar diffusion technique. The ten most inhibitory oils were thyme, cinnamon, bay, clove, almond (bitter), lovage, pimento, marjoram, angelica and nutmeg. The most comprehensively inhibitory extracts were angelica (against 25 genera), bay (24), cinnamon (23), clove (23), thyme (23), almond (bitter) (22), marjoram (22), pimento (22), geranium (21) and lovage (20).
Determination of the minimum inhibitory concen-trations (MIC) of 212 common soap fragrance raw materials demonstrated that
the paper disc-petri plate technique does not reflect the relative anti-microbial activity of these materials. Commonly used
soap bacteriostats were shown to be 100 to 1000 times more effective than the most active fragrance materials. Of 521 fragrance
materials initially screened by the petri plate method, 44% were inhibitory against one of the three test organisms, and 15%
were effective against all three(Staphylococcus aureus, Escherichia coli, Candida albicans). Of a selected number (212) of these positive materials, subsequently screened against a lipophilic diphtheroid organism(Corynebacterium sp.), 64 materials (30%) were positive against all four test organisms. However, only nine materials (4%) had a MIC as low
as 50 ppm compared to the common soap bacteriostat TCC, which had a MIC of 0.08 ppm (vs.S. aureus). In hand-degerming tests, no reduction of bacterial counts was obtained with a soap containing the most active fragrance materials.
These results demonstrate that creation of a practical antimicrobial soap fragrance does not appear to be possible.
Essential oil of clove, dispersed (0.4%v/v) in a concentrated sugar solution, had a marked germicidal effect against various bacteria and Candida albicans. Staphyloccus aureus (five strains), Klebsiella pneumoniae, Pseudomonas aeruginosa, Clostridium perfringens , and Escherichia coli inoculated at a level of 10 ⁷ cfu/ml, and C. albicans (inoculum 4.0×10 ⁵ cfu/ml) were killed (< 99.999%) after 2–7 min in a laboratory broth supplemented with 63% (v/w) of sugar, and containing 0.4% (v/w) of essential oil of clove. Added organic matter (i.e. human or bovine serum) did not impair its antimicrobial activity.
Sugar was not necessary for the antimicrobial activity of clove oil, but the concentrated sugar solution provided a good vehicle for obtaining an oil dispersion that is relatively stable for certain practical applications.
Several clinical observations suggest the necessity of protective measures to prevent eye damage from solar ultraviolet radiation. Recommendations for protection are given.
The antimicrobial properties of essential oils, terpineol, and orange oil, in particular, varied according to the type of bacteria tested. Terpineol and other terpeneless fractions of citrus oils appeared to have greater inhibitory effect on food-borne bacteria than the other citrus oils or derivatives. Gram-positive bacteria were, in general, more sensitive to essential oils than gram-negative bacteria. Terpineol extended the shelf life of commercially pasteurized skim milk, low-fat milk, and whole milk for more than 56 days at 4 C. Orange oil extended the shelf life of skim milk and low-fat milk for the same period.
The primary objective of this study was to determine quantitatively and qualitatively the predominant types of microbial contamination occurring in conventional and laminar flow clean rooms. One horizontal laminar flow, three conventional industrial clean rooms, and three open factory areas were selected for microbiological tests. The results showed that as the environment and personnel of a clean room were controlled in a more positive manner with respect to the reduction of particulate contamination, the levels of airborne and surface microbial contaminants were reduced accordingly. The chief sources of microbial contamination were associated with the density and activity of clean room personnel. In addition, the majority of microorganisms isolated from the intramural air by air samplers were those indigenous to humans. Studies on the fallout and accumulation of airborne microorganisms on stainless-steel surfaces showed that, although there were no significant differences in the levels of microbial contamination among the conventional clean rooms, the type of microorganism detected on stainless-steel surfaces was consistently and significantly different. In addition, the "plateau phenomenon" occurred in all environments studied. It was concluded that the stainless-steel strip method for detecting microbial accumulation on surfaces is efficient and sensitive in ultra-clean environments and is the most reliable and practical method for monitoring microbial contamination in future class 100 clean rooms to be used for the assembly of spacecraft which will be sterilized.
In: Maiziial of Etzviro?zme?ital Microbiology
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Antimicrobial activit)? of c10i.e oil clispe?~ed in a concerztrated sugarsoliitioti
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Antibacterial activities of eserztia/ oils from Turkish spices arid CitriLs. F~Jv. Fragr Aiitiiiticrobialactiorz ofsotiiecit/i~fi~itoi/so?zselectecl food-borne bacteria
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M. Kivanc and A. Akgiil, Antibacterial activities of eserztia/ oils from Turkish spices arid CitriLs. F~Jv. Fragr. J., 9. R. Dabbah, V. M. Edwards and W. A. Moats, Aiitiiiticrobialactiorz ofsotiiecit/i~fi~itoi/so?zselectecl food-borne bacteria. Appl. Microbiol., 19, 27-31 (1970).
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