Testing of inhibition activity of essential oils against Paenibacillus larvae – the causative agent of American foulbrood

Abstract

American foulbrood is a dangerous world-wide spread disease of honey bees caused by the Paenibacillus larvae bacterium. Antibiotic treatments are less effective and leave residues in bee products. It is therefore necessary to find an alternative, especially using natural ingredients such as plant essential oils, probiotics, fatty or organic acids. Two strains of P. larvae were used for this study: CCM 4488, a strain from the Czech collection of micro-organisms and a Slovak field strain which was isolated from infected bee combs and characterized on the basis of biochemical properties. Plant essential oils of sage (Salvia officinalis), anise (Pimpinella anisum), oregano (Origanum vulgare), caraway (Carum carvi), thyme (Thymus vulgaris), rosemary (Rosmarinum officinalis), clove (Syzygium aromaticum), camomile (Chamomilla recutita) and fennel (Foeniculum vulgare) were used for the testing of the inhibitory activity against P. larvae. Essential oils at amounts of 5 µl and 10 µl were applied to sterile discs on MYPGP agar; inhibition zone diameters were measured after 24-h incubation at 37 °C. The strongest inhibitory activity against both P. larvae strains was noted in case of the essential oils from oregano, thyme and clove; essential oils from camomile, rosemary and fennel showed no or weak antibacterial activity. Medium strong inhibition activity was recorded in case of previously untested essential oil from Carum carvi. There was a difference in sensitivity of both tested strains to essential oils. Our study confirmed that some essential oils can be used in the prevention of American foulbrood but further experiments aimed at their influence on physiological intestinal microflora of honey bees must be performed.

Current use of phytogenic feed additives in animal nutrition: a review

“…The authors demonstrated in their study that relatively low concentrations of carvacrol-and thymol-based feed additives had a positive effect on the growth performance of trout with apparent effects towards antioxidant defence and innate immunity status. Kuzysinova et al (2014) studied the inhibitory activity of sage (Salvia officinalis), anise (Pimpinella anisum), oregano (Origanum vulgare), caraway (Carum carvi), thyme (Thymus vulgaris), rosemary (Rosmarinum officinalis), clove (Syzygium aromaticum), camomile (Chamomilla recutita), and fennel (Foeniculum vulgare) against Paenibacillus larvae attacking honey bees. They demonstrated in an in vitro study (disc method using 5 a 10 μl essential oil) that certain essential oils (Thymus vulgaris, Origanum vulgare) have inhibitory effects on P. larvae and may be therefore used for the prevention of this disease.…”

Sea buckthorn (Hippophae rhamnoides L.) as a potential source of nutraceutics and its therapeutic possibilities - a review

“…It is therefore necessary to find an alternative, especially using natural ingredients (Kuzyšinová et al 2014). The phenolic compounds of sea buckthorn represent the main group of phytochemicals which exhibit antibacterial and also antiviral effects.…”

Phages in Therapy and Prophylaxis of American Foulbrood – Recent Implications From Practical Applications

“…This forces the development of alternative, natural strategies for the prevention and control of AFB. Therefore, studies have been published that suggest application of essential oils (Fuselli et al, 2008;Chirila et al, 2011;Maggi et al, 2011;Gende et al, 2014;Kuzyšinová et al, 2014;Santos et al, 2014;Ansari et al, 2015), plant extracts (González and Marioli, 2010;Damiani et al, 2014;Hernández-López et al, 2014;Anjum et al, 2015;Piana et al, 2015), propolis (Antúnez et al, 2008;Bastos et al, 2008;Mihai et al, 2012;Bíliková et al, 2013;Wilson et al, 2015) or probiotics (Alonso-Salces et al, 2017;Daisley et al, 2020). In addition, in vitro studies showed antimicrobial activity of royal jelly from different geographical origins against P. larvae (Bachanová et al, 2002;Bíliková et al, 2009).…”