In vitro effect of some Indian honeys on Staphylococcus aureus from wounds

Staphylococcus aureus is the most frequently isolated pathogen from wounds with multiple resistances to antibiotics. Honey has been demonstrated and reported to be effective antibacterial agent on Gram positive and Gram negative organisms. Hence, the present study was conducted to evaluate the in vitro antibacterial effect of Indian honeys on Staphylococcus aureus obtained from wounds. A total of 123 Staphylococcus aureus isolates along with ATCC 25923 were categorized as sensitive, multi drug resistant (MDR) and non-MDR strains. Out of total nine Indian honeys (three each of unifloral, multifloral and branded marketed honey) used, three unifloral and three multifloral honey samples showed antibacterial activity against all the organisms tested by Agar diffusion method but not the branded marketed honeys. The MIC values of all honey samples for all studied Staphylococcus aureus isolates ranged between 5-15% (v/v). Unifloral honey samples showed higher antibacterial activity than multifloral honey. The single sample of Jambhul honey showed the highest activity. Thus, Indian honeys were found to be effective for their antimicrobial activity on sensitive, non-MDR, MDR and ATCC strains of S. aureus.     

Diversity of honey stores and their impact on pathogenic bacteria of the honeybee,Apis mellifera

Honeybee colonies offer an excellent environment for microbial pathogen development. The highest virulent, colony killing, bacterial agents are Paenibacillus larvae causing American foulbrood (AFB), and European foulbrood (EFB) associated bacteria. Besides the innate immune defense, honeybees evolved behavioral defenses to combat infections. Foraging of antimicrobial plant compounds plays a key role for this “social immunity” behavior. Secondary plant metabolites in floral nectar are known for their antimicrobial effects. Yet, these compounds are highly plant specific, and the effects on bee health will depend on the floral origin of the honey produced. As worker bees not only feed themselves, but also the larvae and other colony members, honey is a prime candidate acting as self‐medication agent in honeybee colonies to prevent or decrease infections. Here, we test eight AFB and EFB bacterial strains and the growth inhibitory activity of three honey types. Using a high‐throughput cell growth assay, we show that all honeys have high growth inhibitory activity and the two monofloral honeys appeared to be strain specific. The specificity of the monofloral honeys and the strong antimicrobial potential of the polyfloral honey suggest that the diversity of honeys in the honey stores of a colony may be highly adaptive for its “social immunity” against the highly diverse suite of pathogens encountered in nature. This ecological diversity may therefore operate similar to the well‐known effects of host genetic variance in the arms race between host and parasite.     

Effect of hydrogen peroxide on antibacterial activities of Canadian honeys

Honey is recognized as an efficacious topical antimicrobial agent in the treatment of burns and wounds. The antimicrobial activity in some honeys depends on the endogenous hydrogen peroxide content. This study was aimed to determine whether honey's hydrogen peroxide level could serve as a honey-specific, activity-associated biomarker that would allow predicting and assessing the therapeutic effects of honey. Using a broth microdilution assay, I analyzed antibacterial activities of 42 Canadian honeys against two bacterial strains: Escherichia coli (ATCC 14948) and Bacillus subtilis (ATCC 6633). The MIC90 and MIC50 were established from the dose-response relationship between antibacterial activities and honey concentrations. The impact of H2O2 on antibacterial activity was determined (i) by measuring the levels of H2O2 before and after its removal by catalase and (ii) by correlating the results with levels of antibacterial activities. Canadian honeys demonstrated moderate to high antibacterial activity against both bacterial species. Both MIC90 and MIC50 revealed that the honeys exhibited a selective growth inhibitory activity against E. coli, and this activity was strongly influenced by endogenous H2O2 concentrations. Bacillus subtilis activity was marginally significantly correlated with H2O2 content. The removal of H2O2 by catalase reduced the honeys' antibacterial activity, but the enzyme was unable to completely decompose endogenous H2O2. The 25%-30% H2O2 "leftover" was significantly correlated with the honeys' residual antibacterial activity against E. coli. These data indicate that all Canadian honeys exhibited antibacterial activity, with higher selectivity against E. coli than B. subtilis, and that these antibacterial activities were correlated with hydrogen peroxide production in honeys. Hydrogen peroxide levels in honey, therefore, is a strong predictor of the honey's antibacterial activity.     

Antimicrobial activity of honey from the stingless bee Trigona carbonaria determined by agar diffusion,agar dilution,broth microdilution and time‐kill methodology

Aims: The aim of this study was to determine the spectrum of antimicrobial activity of 11 samples of stingless bee honey compared to medicinal, table and artificial honeys. Methods and Results: Activity was assessed by agar diffusion, agar dilution, broth microdilution and time‐kill viability assays. By agar dilution, minimum inhibitory concentration (MIC) ranges were 4% to >10% (w/v) for Gram‐positive bacteria, 6% to >16% (w/v) for Gram‐negative bacteria and 6% to >10% (w/v) for Candida spp. By broth microdilution, all organisms with the exception of Candida albicans and Candida glabrata were inhibited at ≤32% (w/v). Geometric MIC (w/v) means for stingless bee honeys ranged from 7·1% to 16·0% and were 11·7% for medicinal honey and 26·5% for table honey. Treatment of organisms with 20% (w/v) stingless bee honey for 60 min resulted in decreases of 1–3 log for Staphylococcus aureus, >3 log for Pseudomonas aeruginosa and <1 log for C. albicans. Similar treatment with each control honey resulted in decreases of <1 log for all organisms. Conclusions: Stingless bee honey has broad‐spectrum antibacterial activity although activity against Candida was limited. Stingless bee honey samples varied in activity and the basis for this remains to be determined. Significance and Impact of the Study: Stingless bee honey had similar activity to medicinal honey and may therefore have a role as a medicinal agent.     

The Effect of New Zealand Kanuka,Manuka and Clover Honeys on Bacterial Growth Dynamics and Cellular Morphology Varies According to the Species

Treatment of chronic wounds is becoming increasingly difficult due to antibiotic resistance. Complex natural products with antimicrobial activity, such as honey, are now under the spotlight as alternative treatments to antibiotics. Several studies have shown honey to have broad-spectrum antibacterial activity at concentrations present in honey dressings, and resistance to honey has not been attainable in the laboratory. However not all honeys are the same and few studies have used honey that is well defined both in geographic and chemical terms. Here we have used a range of concentrations of clover honey and a suite of manuka and kanuka honeys from known geographical locations, and for which the floral source and concentration of methylglyoxal and hydrogen peroxide potential were defined, to determine their effect on growth and cellular morphology of four bacteria: Bacillus subtilis, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. While the general trend in effectiveness of growth inhibition was manuka>manuka-kanuka blend>kanuka>clover, the honeys had varying and diverse effects on the growth and cellular morphology of each bacterium, and each organism had a unique response profile to these honeys. P. aeruginosa showed a markedly different pattern of growth inhibition to the other three organisms when treated with sub-inhibitory concentrations of honey, being equally sensitive to all honeys, including clover, and the least sensitive to honey overall. While hydrogen peroxide potential contributed to the antibacterial activity of the manuka and kanuka honeys, it was never essential for complete growth inhibition. Cell morphology analysis also showed a varied and diverse set of responses to the honeys that included cell length changes, cell lysis, and alterations to DNA appearance. These changes are likely to reflect the different regulatory circuits of the organisms that are activated by the stress of honey treatment.     

Palynological characteristics of different unifloral honeys from Greece

Three hundred and twenty-nine Greek honey samples of different botanical and geographical origin were collected and examined by organoleptic evaluation, melissopalynological analysis, measurement of electrical conductivity and colour. The results showed that 208 samples were unifloral with 178 of them representing the main types of unifloral honey produced in Greece; that is fir, pine, chestnut, cotton, orange and thyme honey. All honeys had the sensory characteristics typical of their origin and complied with the electrical conductivity standards set by Council Directive 2001/110/EC.

Fir and pine honeydew honey had a low honeydew element/pollen (HDE/P) ratio and belonged to Maurizio's Classes II or III. The pollen types identified in these honeys ranged from 11 to 45%. Chestnut nectar honey contained >90% chestnut pollen, had a total number of plant elements of >245,000/10?g, and low pollen diversity. Cotton honey contained 1.2 to 16.5% cotton pollen, belonged to Maurizio's Class II, and had 22 pollen types, with Castanea sativa L. present in all samples. Orange honey contained 2.9 to 26.5% Citrus spp. pollen, belonged to Maurizio's Class II, and was characterized by the presence of Brassicaceae, Fabaceae, Olea europea L., Quercus coccifera L. and Rosaceae. In thyme honeys Thymus capitatus Hoffm. &; Link. pollen was secondary or predominant ranging from 18.3 to 69.3%. These honeys belonged to Maurizio's Classes I or II and contained greater than 30 pollen types. Other Lamiaceae, Hypericum spp., Brassicaceae, Fabaceae, Rosaceae, and Cistus spp. pollen types appeared in the greatest number of thyme samples.     

Effects of Selected Egyptian Honeys on the Cellular Ultrastructure and the Gene Expression Profile of Escherichia coli

The purpose of this study was to: (i) evaluate the antibacterial activities of three Egyptian honeys collected from different floral sources (namely, citrus, clover, and marjoram) against Escherichia coli; (ii) investigate the effects of these honeys on bacterial ultrastructure; and (iii) assess the anti-virulence potential of these honeys, by examining their impacts on the expression of eight selected genes (involved in biofilm formation, quorum sensing, and stress survival) in the test organism. The minimum inhibitory concentration (MIC) of the honey samples against E. coli ATCC 8739 were assessed by the broth microdilution assay in the presence and absence of catalase enzyme. Impacts of the honeys on the cellular ultrastructure and the expression profiles of the selected genes of E. coli were examined using transmission electron microscopy (TEM) and quantitative real-time polymerase chain reaction (qPCR) analysis, respectively. The susceptibility tests showed promising antibacterial activities of all the tested honeys against E. coli. This was supported by the TEM observations, which revealed “ghost” cells lacking DNA, in addition to cells with increased vacuoles, and/or with irregular shrunken cytoplasm. Among the tested honeys, marjoram exhibited the highest total antibacterial activity and the highest levels of peroxide-dependent activity. The qPCR analysis showed that all honey-treated cells share a similar overall pattern of gene expression, with a trend toward reduced expression of the virulence genes of interest. Our results indicate that some varieties of the Egyptian honey have the potential to be effective inhibitor and virulence modulator of E. coli via multiple molecular targets.     

Honey as an apitherapic product: its inhibitory effect on urease and xanthine oxidase

The aim of this study was to evaluate new natural inhibitor sources for the enzymes urease and xanthine oxidase (XO). Chestnut, oak and polyfloral honey extracts were used to determine inhibition effects of both enzymes. In addition to investigate inhibition, the antioxidant capacities of these honeys were determined using total phenolic content (TPC), ferric reducing antioxidant power (FRAP), and DPPH radical scavenging activity assays. Due to their high phenolic content, chestnut and oak honeys are found to be a powerful source for inhibition of both enzymes. Especially, oak honeys were efficient for urease inhibition with 0.012–0.021?g/mL IC₅₀ values, and also chestnut honeys were powerful for XO inhibition with 0.028–0.039?g/mL IC₅₀ values. Regular daily consumption of these honeys can prevent gastric ulcers deriving from Helicobacter pylori and pathological disorders mediated by reactive oxygen species.     

Palynological evaluation of selected honeys from Romania

Fifty-four honey samples collected over two consecutive harvest seasons (2009–2010) from different floristic areas of Romania were analysed. A melissopalynological analysis including qualitative and quantitative analyses was carried out in order to identify the principal pollen types in Romanian honeys and therefore, the important plants exploited by Apis mellifera in this country. Seventy-seven pollen types from 35 botanical families were identified. The main pollen forms were: Brassica napus-type, Tilia, Helianthus annuus, Robinia pseudoacacia, Prunus, Castanea sativa, Fragaria-type and Plantago-type. Honey samples were classified as: acacia honey (Robinia pseudoacacia), lime honey (Tilia), rape honey (Brassica napus-type), sunflower honey (Helianthus annuus), cherry honey (Prunus). Three of them were honeydew honeys whereas the others were all polyfloral. The results from this study can be used as a palynological baseline data of Romanian artisanal honeys.     

Botanical characterisation of Mexican honeys from a subtropical region (Oaxaca) based on pollen analysis

Melissopalynological analysis of 39 honey samples from Oaxaca, Mexico, enabled us to establish the important plant sources exploited by bees during the principal harvest in four districts of the State of Oaxaca, Mexico. A total of 64 taxa belonging to 29 families were recorded. These subtropical honeys were characterised by their botanical origin as follows: (a) monofloral honeys of Bursera simaruba, Clethra mexicana, Cordia alliodora, Lonchocarpus sp., Mangifera indica, Miconia argentea, Orbignya cohune and Quercus sp.; (b) bifloral honeys with an association of Heliocarpus donnell-smithii and Ceiba sp., Lonchocarpus sp. and Mimosa pudica, H. donnell-smithii and Mangifera indica, Miconia argentea and Miconia tenuiflora; (c) oligofloral honeys of Asteraceae; and (d) multifloral honeys with three or four species ≥10%. Monofloral honeys were placed in classes I, II, III, IV and V. Oligofloral were class II, bifloral were classes I and II, and polyfloral honeys were assigned to classes I, II and III. Honey samples of Apis mellifera had a diversity index range of 0.3 to 2.7. It is well known that this bee is polylectic and has a heterogeneous foraging behaviour. In the State of Oaxaca, it prefers resources of secondary vegetation from low deciduous forest, although taxa of economic importance were also utilised, for instance, Mangifera indica and Citrus sinensis. Oaxaca has important and diverse native resources, and beekeeping activity needs to be promoted because of its potential to develop new types of honey.     

Two major medicinal honeys have different mechanisms of bactericidal activity

Honey is increasingly valued for its antibacterial activity, but knowledge regarding the mechanism of action is still incomplete. We assessed the bactericidal activity and mechanism of action of Revamil® source (RS) honey and manuka honey, the sources of two major medical-grade honeys. RS honey killed Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa within 2 hours, whereas manuka honey had such rapid activity only against B. subtilis. After 24 hours of incubation, both honeys killed all tested bacteria, including methicillin-resistant Staphylococcus aureus, but manuka honey retained activity up to higher dilutions than RS honey. Bee defensin-1 and H₂O₂ were the major factors involved in rapid bactericidal activity of RS honey. These factors were absent in manuka honey, but this honey contained 44-fold higher concentrations of methylglyoxal than RS honey. Methylglyoxal was a major bactericidal factor in manuka honey, but after neutralization of this compound manuka honey retained bactericidal activity due to several unknown factors. RS and manuka honey have highly distinct compositions of bactericidal factors, resulting in large differences in bactericidal activity.     

Thyme and suico essential oils: promising natural tools for potato common scab control

• Potato common scab is a worldwide disease mainly caused by Streptomyces scabiei. It seriously affects potato crops by decreasing tuber quality. Essential oils (EO) are natural products with recognised antimicrobial properties. In this research, the antibacterial activities of thyme, oregano, suico and mint EO against S. scabiei were analysed.
• Infected tubers and soil samples were used for bacterial isolation; the obtained isolates were genetically identified. The chemical composition of the EO was determined by GC‐MS. The broth microdilution method was used to analyse antibacterial properties of EO.
• Thirty‐one bacterial isolates were obtained. The isolate chosen for antibacterial assays was morpho‐physiologically and genetically identified as S. scabiei. Thyme EO was mainly composed of thymol and o‐cymene; suico EO of dihydrotagetone, trans‐tagetone and verbenone; oregano EO of trans‐sabinene hydrate, thymol and ?‐terpinene; and mint EO of menthone and menthol. All the EO tested were effective against S. scabiei, but thyme and suico EO were the most successful, with a minimum inhibitory concentration of 0.068 g·l^?1 and 0.147 g·l^?1, respectively, and a minimum bactericidal concentration of 0.137 g·l^?1 and 0.147 g·l^?1, respectively. Scanning electron microscopy showed similar damage caused by both thyme and suico EO to the bacterial envelope. Total phenolic content of EO was not related to their antibacterial activity.
• Thyme and suico EO are effective antibacterial agents against S. scabiei, impeding bacterial viability and disturbing the bacterial cell envelope. These EO are promising tools for control of potato common scab.

     

Antibacterial potential of some Saudi honeys from Asir region against selected pathogenic bacteria

Honey is a nutrient rich natural product and has been utilized as traditional and complementary medicine since ancient times. In this study, antibacterial activity of Sider (Ziziphus spina-christi), Dharm (Lavandula dentata), and Majra (Hypoestes forskaolii) honey samples collected from Asir region of Saudi Arabia was in vitro evaluated at 80% and 50% w/v concentrations against five pathogenic bacteria i.e. Escherichia coli, Proteus mirabilis, Staphylococcus aureus, Shigella flexneri, and Staphylococcus epidermidis. Well diffusion assays to measure the average zone of inhibition (ZOI) and minimum inhibitory concentration (MIC) values were employed in the experiments. All the tested honey samples showed antibacterial activity in a dose-dependent manner. Sider and Dharm exhibited a good antibacterial activity at high concentrations while, Majra honey of Apis mellifera jemenitica and of Apis florea showed comparatively low antibacterial activity. The average MIC values of Sider, Dhram from Rijal Alma, Dharm from Al-Souda, Majra (A.m. jemenitica), and Majra (A. florea) honey against all tested bacteria were 22%, 16%, 18%, 32%, and 28% (v/v) respectively. Dharm and Sider honeys showed better antibacterial activity than Majra honey. Saudi honey can be considered as a promising future antimicrobial agent and should be further investigated as an alternative candidate in the management of resistant bacterial pathogens.     

Antibacterial components of honey

The antibacterial activity of honey has been known since the 19th century. Recently, the potent activity of honey against antibiotic-resistant bacteria has further increased the interest for application of honey, but incomplete knowledge of the antibacterial activity is a major obstacle for clinical applicability. The high sugar concentration, hydrogen peroxide, and the low pH are well-known antibacterial factors in honey and more recently, methylglyoxal and the antimicrobial peptide bee defensin-1 were identified as important antibacterial compounds in honey. The antibacterial activity of honey is highly complex due to the involvement of multiple compounds and due to the large variation in the concentrations of these compounds among honeys. The current review will elaborate on the antibacterial compounds in honey. We discuss the activity of the individual compounds, their contribution to the complex antibacterial activity of honey, a novel approach to identify additional honey antibacterial compounds, and the implications of the novel developments for standardization of honey for medical applications.     

Effect of Carbon Source on the Antimicrobial Activity of the Air Flora

Summary In an attempt to screen for air flora producing new potent antimicrobial substances, Bacillus megaterium NB-3, Bacillus cereus NB-4, Bacillus cereus NB-5, Bacillus subtilis NB-6 and Bacillus circulans NB-7, were isolated and were found to be antagonistic to bacteria and/or fungi. Production of antimicrobial substances by the bacterial strains was greatly influenced by variation of carbon sources. Glycerol strongly enhanced the antimicrobial activity of strains NB-3 and NB-6, whereas glucose increased the antimicrobial activity of strains NB-4 and NB-5. The maximum antibiotic yield of NB-7 was achieved with fructose as a carbon source. Starch (Bacillus megaterium NB-3), maltose (Bacillus cereus NB-5), glycerol (Bacillus circulans NB-7), arabinose, ribose (Bacillus cereus NB-4) and arabinose, fructose, glucose, ribose and sucrose (Bacillus subtilis NB-6) repressed the production of antimicrobial substances by the respective bacterial strains.     

Mineral salt requirements of Bacillus globisporus subsp. marinus strains

The mineral salt requirements of four isolates of Bacillus globisporus subsp. marinus and of two terrestrial strains of B. globisporus were investigated. In contrast to the terrestrial reference strains the marine isolates showed an obligate requirement for sodium and potassium. The sodium ion could not be replaced by potassium or by osmotically equivalent concentrations of mannitol. None of the strains proved to be dependent upon Mg²⁺ or Ca²⁺. The B. globisporus subsp. marinus strains are considered true marine bacteria. The criteria used to distinguish between marine and terrestrial Gram-negative bacteria can also be applied for Gram-positive bacteria.     

Phenolic Acid Composition,Antiatherogenic and Anticancer Potential of Honeys Derived from Various Regions in Greece

The phenolic acid profile of honey depends greatly on its botanical and geographical origin. In this study, we carried out a quantitative analysis of phenolic acids in the ethyl acetate extract of 12 honeys collected from various regions in Greece. Our findings indicate that protocatechuic acid, p-hydroxybenzoic acid, vanillic acid, caffeic acid and p-coumaric acid are the major phenolic acids of the honeys examined. Conifer tree honey (from pine and fir) contained significantly higher concentrations of protocatechuic and caffeic acid (mean: 6640 and 397 µg/kg honey respectively) than thyme and citrus honey (mean of protocatechuic and caffeic acid: 437.6 and 116 µg/kg honey respectively). p-Hydroxybenzoic acid was the dominant compound in thyme honeys (mean: 1252.5 µg/kg honey). We further examined the antioxidant potential (ORAC assay) of the extracts, their ability to influence viability of prostate cancer (PC-3) and breast cancer (MCF-7) cells as well as their lowering effect on TNF- α-induced adhesion molecule expression in endothelial cells (HAEC). ORAC values of Greek honeys ranged from 415 to 2129 µmol Trolox equivalent/kg honey and correlated significantly with their content in protocatechuic acid (p<0.001), p-hydroxybenzoic acid (p<0.01), vanillic acid (p<0.05), caffeic acid (p<0.01), p-coumaric acid (p<0.001) and their total phenolic content (p<0.001). Honey extracts reduced significantly the viability of PC-3 and MCF-7 cells as well as the expression of adhesion molecules in HAEC. Importantly, vanillic acid content correlated significantly with anticancer activity in PC-3 and MCF-7 cells (p<0.01, p<0.05 respectively). Protocatechuic acid, vanillic acid and total phenolic content correlated significantly with the inhibition of VCAM-1 expression (p<0.05, p<0.05 and p<0.01 respectively). In conclusion, Greek honeys are rich in phenolic acids, in particular protocatechuic and p-hydroxybenzoic acid and exhibit significant antioxidant, anticancer and antiatherogenic activities which may be attributed, at least in part, to their phenolic acid content.     

Diversity and exploration of bioactive marine actinomycetes in the Bay of Bengal of the Puducherry coast of India

The present study was designed to investigate the Puducherry coast of the Bay of Bengal, India for the diversity of bioactive actinomycetes. A total of 50 actinomycete strains were isolated from the marine sediments and most of the strains were belongs to Streptomyces. These strains were identified by means of morphological physiological, biochemical and cultural characteristics. The isolates were subjected to shake flask fermentation and the secondary metabolites were extracted with ethyl acetate and screened for cytotoxicity, hemolytic activity and antimicrobial activity against selected bacterial and fungal pathogens. The cytotoxic activity was evaluated using HeLa cell lines by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, a tetrazole (MTT) assay, hemolytic activity on mouse erythrocytes and the antifungal activity was evaluated by MTT cytotoxic assay against Aspergillus niger, Aspergillus fumigatus and Candida albicans. The antibacterial activity was studied against Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Klebsiella pneumoniae. The cytotoxicity and antimicrobial activity of secondary metabolite was found to be concentration dependent and nearly 24% of isolates showed significant antimicrobial, hemolytic and cytotoxic activity. The results of our study indicate the diversity and bioactive potential of marine actinomycetes isolated in the Puducherry coast.     

Spectrum of plant species foraged by Apis mellifera adansonii Latreille in the North Sudanian phytogeographical region of Burkina Faso

Melissopalynological analysis of 60 honey samples collected from 50 Kenyan Top Bar Hives in the North Sudanian phytogeographical region of Burkina Faso established the plant species foraged by honeybees Apis mellifera adansonii. Forty-three pollen types from 29 families were identified in the honey samples. The most common families were Mimosaceae (9.30%), Asteraceae (6.98%) and Anacardiaceae (6.98%). The most frequently visited plants were Combretum (66.66%), Tridax procumbens (66.66), Acacia seyal-group (50%), Cleome viscosa-group (50%) and Cyperus esculentus (41.67%). The results showed that Apis mellifera adansonii is polylectic with a heterogeneous foraging behaviour. Pollen analysis showed that the honeys from the two main honey flows of Burkina Faso were polyfloral.     

Analysis of <Emphasis Type="Italic">cry</Emphasis> Gene Profiles in <Emphasis Type="Italic">Bacillus Thuringiensis</Emphasis> Strains Isolated During Epizootics in <Emphasis Type="Italic">Cydia pomonella</Emphasis> L.

The crystal morphology and the profiles of genes encoding protein toxins (Cry and Cyt) were analyzed in 12 Bacillus thuringiensis strains isolated during epizootics in laboratory culture lines of Cydia pomonella, 2 isolates cultured from Leucoma salicis larvae, and 9 reference strains. Epizootic isolates produced crystals of the same bipyramidal shape; however, they revealed a variety of number and type of cry genes. Genes cry1I, cry2Ab, and cry9B were the most frequently observed in epizootic strains. Gene cry1I was noted in of 50% epizootic isolates. Eighty-three percent of them harbored gene cry2Ab. Gene cry9B was found for 42% of strains isolated during epizootics. Three isolates showed the largest number of cry genes and their variety; hence, they were chosen for the toxicity assay of their crystals and spores on C. pomonella larvae. One of them had approximately sixfold higher insecticidal activity than the reference strain B. thuringiensis subsp. kurstaki BTK STANDARD.