Antibakterielle In-vitro-Wirksamkeit ätherischer Öle gegen veterinärmedizinisch relevante Keime klinischer Isolate von Hunden, Katzen und Pferden

Screening of Antimicrobial Activity of Essential Oils against Bovine Respiratory Pathogens - Focusing on Pasteurella multocida

Administration of essential oils as natural plant products with antimicrobial activity might be an alternative to antibiotic treatment of bovine respiratory disease. The aim of this study was to analyse the in vitro antimicrobial activity of 11 essential oils against Pasteurella multocida isolated from the respiratory tract of calves using microdilution with determination of minimum inhibitory and bactericidal concentration as well as agar disc diffusion. Additionally, antimicrobial activity against Mannheimia haemolytica and bacteria in the Mannheimia clade was assessed by agar disc diffusion. Seven essential oil mixtures were also tested against all bacterial isolates. P. multocida was strongly inhibited by cinnamon cassia and lemongrass oil followed by coriander, winter savory, thyme, clove, and peppermint oil in the microdilution assays. Eucalyptus, wintergreen, spruce, and star anise oil showed lower activity. Comparison of both methods revealed an underestimation of cinnamon cassia oil activity by agar disc diffusion and conflicting results for wintergreen oil in microdilution, which precipitated in broth. Cinnamon cassia, thyme, wintergreen, lemongrass, and winter savory oil all showed strong antimicrobial activity against M. haemolytica. Bacteria in the Mannheimia clade were mostly inhibited by cinnamon cassia and thyme oil. Pasteurella isolates were more susceptible to inhibition by essential oils than Mannheimia isolates. Essential oil mixtures did not show stronger antibacterial activity than single essential oils. In conclusion, cinnamon cassia and lemongrass as well as coriander, winter savory, and thyme oil are promising candidates for treatment of P. multocida-associated bovine respiratory infections.

Characterization of Sunflower Oil Extracts from the Lichen Usnea barbata

The increasing global emergence of multidrug resistant (MDR) pathogens is categorized as one of the most important health problems. Therefore, the discovery of novel antimicrobials is of the utmost importance. Lichens provide a rich source of natural products including unique polyketides and polyphenols. Many of them display pharmaceutical benefits. The aim of this study was directed towards the characterization of sunflower oil extracts from the fruticose lichen, Usnea barbata. The concentration of the major polyketide, usnic acid, was 1.6 mg/mL extract as determined by NMR analysis of the crude mixture corresponding to 80 mg per g of the dried lichen. The total phenolics and flavonoids were determined by photometric assays as 4.4 mg/mL (gallic acid equivalent) and 0.27 mg/mL (rutin equivalent) corresponding to 220 mg/g and 13.7 mg/g lichen, respectively. Gram-positive (e.g., Enterococcus faecalis) and Gram-negative bacteria, as well as clinical isolates of infected chickens were sensitive against these extracts as determined by agar diffusion tests. Most of these activities increased in the presence of zinc salts. The data suggest the potential usage of U. barbata extracts as natural additives and mild antibiotics in animal husbandry, especially against enterococcosis in poultry.

Antifungal in vitro Activity of Essential Oils against Clinical Isolates of Malassezia pachydermatis from Canine Ears: A Report from a Practice Laboratory

BACKGROUND

The yeast Malassezia pachydermatis is a commensal but also the most isolated pathogenic yeast in canine otitis externa. Essential oils (EOs) exhibit antimicrobial activity and thus could be an alternative for treatment of otitis.

OBJECTIVE

The aim of this study was to analyse the in vitro efficacy of EOs against M. pachydermatis isolates from canine ears.

MATERIALS AND METHODS

Twenty-two EOs were tested for their in vitro activity against 15 M. pachydermatis isolates by agar disc diffusion. In addition, diluted EOs were tested and volatile antifungal activity was analysed by vapour assay.

RESULTS

Most EOs showed in vitro efficacy against M. pachydermatis. A different susceptibility pattern of tested isolates was found. Overall, the most potential EO was lemon grass. Also, cinnamon leaf, clove, manuka, Indian melissa, oregano, palmarosa, and winter savory oil exhibited a strong antifungal activity. Volatile activity was proven by the inhibiting effect in vapour assay.

CONCLUSION

EOs show in vitro activity against M. pachydermatis. This study gives scientific background for the use of EOs in veterinary medicine. Diverse susceptibility patterns of different M. pachydermatis strains emphasise the helpfulness of an aromatogram as one lead for the best choice of an EO for therapy.

Medicinal plants as therapeutic options for topical treatment in canine dermatology? A systematic review

Background

Medicinal plants have been used traditionally since centuries for wound care and treatment of skin diseases both in human and animals. Skin diseases are one of the most common reasons for owners to take their dog to the veterinarian. The demands for treatment and prophylaxis of these diseases are broad. A wide range of bacteria including antibiotic-resistant bacteria can be involved, making the treatment challenging and bear an anthropo-zoonotic potential. The aim of this review is to systematically evaluate based on recent scientific literature, the potential of four medicinal plants to enrich the therapeutic options in pyoderma, canine atopic dermatitis, otitis externa, wounds and dermatophytosis in dogs.

Results

Based on four books and a survey among veterinarians specialized in phytotherapy, four medicinal plants were chosen as the subject of this systematic review: Calendula officinalis L. (Marigold), Hypericum perforatum L. agg. (St. John’s Wort), Matricaria chamomilla L. (syn. Matricaria recutita L., Chamomile) and Salvia officinalis L. (Sage). According to the PRISMA statement through literature research on two online databases a total of 8295 publications was screened and narrowed down to a final 138 publications for which full-text documents were analyzed for its content resulting in a total of 145 references (21 clinical, 24 in vivo and 100 in vitro references).

Conclusions

All four plants were proven to have antibacterial and antifungal effects of a rather broad spectrum including antibiotic-resistant bacteria. This makes them an interesting new option for the treatment of pyoderma, otitis externa, infected wounds and dermatophytosis. Marigold, St. John’s Wort and Chamomile showed wound-healing properties and are thus promising candidates in line to fill the therapeutic gap in canine wound-healing agents. St. John’s Wort and Chamomile also showed anti-inflammatory and other beneficial effects on healthy skin. Due to the wide range of beneficial effects of these medicinal plants, they should be taken into account for the treatment of dermatologic diseases in dogs at least in future clinical research.

Electronic supplementary material

The online version of this article (10.1186/s12917-019-1854-4) contains supplementary material, which is available to authorized users.

Ethnoveterinary contemporary knowledge of farmers in pre-alpine and alpine regions of the Swiss cantons of Bern and Lucerne compared to ancient and recent literature - Is there a tradition?

ETHNOPHARMACOLOGICAL RELEVANCE

The term "traditional" is well established in European (human) medicine and even appears in recent European regulations on herbal medicinal products connected to a simplified registration. In contrast, a scientific discussion of a Traditional European Veterinary Herbal Medicine is still lacking in spite of a rising interest, in herbal medicine for animals in particular of veterinarians. There is only limited systematic ethnoveterinary research in Europe, with exception of the Mediterranean region, Switzerland and Austria. We conducted a survey on the ethnoveterinary knowledge of farmers in the pre-alpine and alpine regions of the Swiss cantons of Bern and Lucerne. We compared the findings with earlier studies conducted in Switzerland and with recent and past human and veterinary medicinal literature.

AIM OF THE STUDY

We wanted to know to what extent (dependent to different definition of the term "traditional") the ethnoveterinary knowledge of Swiss farmers could be considered as "traditional" in a European veterinary medicinal context.

MATERIAL AND METHODS

Semistructured interviews with 44 dialog partners, mainly smallholder cattle farmers, were conducted in 2014. Detailed information about homemade herbal remedies (plant species, plant part, manufacturing process) and the corresponding use reports (target animal species, category of use, route of administration, dosage, source of knowledge, frequency of use, last time of use and farmers satisfaction) were collected. To compare our data with literature, one German book of veterinary pharmacology published in 1900, one typescript of Swiss lectures in veterinary pharmacology from 1944, four books of veterinary herbal medicine published between 1984 and 2016, and one recent publication comparing current Swiss (human) ethnomedicinal plant knowledge with modern and past literature were analyzed.

RESULTS

Information on a total of 315 homemade remedies containing one single plant species (homemade single species herbal remedy reports, HSHR) was collected from participating farmers. These HSHR were prepared from 83 plant species belonging to 46 botanical families. Plants of the families Asteraceae, Lamiaceae and Rosaceae were most frequently used. Matricaria recutita L., Calendula officinalis L., Quercus robur L., Thymus vulgaris L. and Symphytum officinale L. were the most frequently documented species. A total of 404 use reports (UR) were gathered for the 315 HSHR. The largest number of UR was for treatments of gastrointestinal disorders and metabolic dysfunctions, followed by skin alterations and sores. For more than half of the UR the source of knowledge was family, ancestors and friends, and for approximately one quarter the information was from courses and other educational events. For nearly 90% of the UR farmers mentioned at least one use during the last 10 years, and in more than 50% of the UR the last use was within the past year. Compared with recent and past literature and depending on different definitions of the term "traditional" as used for human medicine, between 43% and 84% of all 83 and between 57% and 100% of the most often mentioned 21 plant species show a "traditional" European veterinary use.

CONCLUSION

For the treatment of their animals farmers in the pre-alpine and alpine regions of the Swiss cantons of Bern and Lucerne mostly used plants which have a track record as medicinal herbs in Europe over several centuries. Almost half of the plant species had specific veterinary uses for about 120 years and even more for at least 30 years. The majority of the plant species thus fulfill the criteria of "traditional" according to several definitions and even more up to a certain degree the criteria of "traditional use" as defined in European regulations for human medicinal products. Ethnoveterinary research combined with data from historical sources may serve as a sound foundation for the development and definition of a Traditional European Veterinary Herbal Medicine maybe even with regard to the recent discussion about a simplified registration for Traditional Herbal Veterinary Medicinal Products.