RESUMEN
It turns out that the more than trillion microorganisms living in the host's digestive tract are crucial for maintaining nutrient intake, environmental suitability, and physiological mechanism. Xinjiang fine-wool sheep is an exclusive breed for wool in China, which has excellent stress tolerance. In this study, we collected feces and blood samples of 20 Xinjiang fine-wool sheep under the same genetic characteristics, the Fine-Wool Sheep (FWS) group and the Control Fine-Wool Sheep (CFWS) group were set up according to the differs in phenotypic characteristics of their wool. By 16S rRNA amplicon sequence, ITS1 region amplicons and Targeted Metabolomics, we analyzed the microbial community structure of fecal microorganisms and Short Chain Fatty Acids (SCFAs) in serum of the Xinjiang fine-wool sheep. Fecal microbial sequencing showed that the bacterial composition and structure were similar between the two groups, whereas there were significant differences in the composition and structure of the fungal community. It was also found that the abundant of Neocallimastigomycota in the intestinal fungal community of FWS was higher. In addition, the results of the serum SCFAs content analysis showed that butyric acid was significantly differences than those two groups. Correlation analysis between SCFAs and bacteria found that butyric acid metabolism had positively correlated (P < 0.05) with Ruminococcus and UCG-005. Overall, our data provide more supplement about the gut microbes community composition and structure of the Xinjiang fine-wool sheep. These results might be useful for improving gut health of sheep and taking nutritional control measure to improve production traits of animals in future.
Asunto(s)
Bacterias , Ácidos Grasos Volátiles , Heces , Microbioma Gastrointestinal , Secuenciación de Nucleótidos de Alto Rendimiento , ARN Ribosómico 16S , Animales , Ovinos/microbiología , Heces/microbiología , Bacterias/clasificación , Bacterias/genética , Bacterias/metabolismo , Bacterias/aislamiento & purificación , China , ARN Ribosómico 16S/genética , Ácidos Grasos Volátiles/metabolismo , Hongos/genética , Hongos/clasificación , Hongos/metabolismo , Lana/microbiología , FilogeniaRESUMEN
BACKGROUND: With the advent of affordable next-generation sequencing (NGS) technologies, major progress has been made in the understanding of the population structure and evolution of the B. anthracis species. Here we report the use of whole genome sequencing and computer-based comparative analyses to characterize six strains belonging to the A.Br.Vollum lineage. These strains were isolated in Switzerland, in 1981, during iterative cases of anthrax involving workers in a textile plant processing cashmere wool from the Indian subcontinent. RESULTS: We took advantage of the hundreds of currently available B. anthracis genomes in public databases, to investigate the genetic diversity existing within the A.Br.Vollum lineage and to position the six Swiss isolates into the worldwide B. anthracis phylogeny. Thirty additional genomes related to the A.Br.Vollum group were identified by whole-genome single nucleotide polymorphism (SNP) analysis, including two strains forming a new evolutionary branch at the basis of the A.Br.Vollum lineage. This new phylogenetic lineage (termed A.Br.H9401) splits off the branch leading to the A.Br.Vollum group soon after its divergence to the other lineages of the major A clade (i.e. 6 SNPs). The available dataset of A.Br.Vollum genomes were resolved into 2 distinct groups. Isolates from the Swiss wool processing facility clustered together with two strains from Pakistan and one strain of unknown origin isolated from yarn. They were clearly differentiated (69 SNPs) from the twenty-five other A.Br.Vollum strains located on the branch leading to the terminal reference strain A0488 of the lineage. Novel analytic assays specific to these new subgroups were developed for the purpose of rapid molecular epidemiology. CONCLUSIONS: Whole genome SNP surveys greatly expand upon our knowledge on the sub-structure of the A.Br.Vollum lineage. Possible origin and route of spread of this lineage worldwide are discussed.
Asunto(s)
Carbunco/microbiología , Bacillus anthracis/clasificación , Bacillus anthracis/genética , Genoma Bacteriano/genética , Polimorfismo de Nucleótido Simple/genética , Lana/microbiología , Animales , Bovinos , Análisis por Conglomerados , Genómica , Humanos , India , Tipificación Molecular , Pakistán , Filogenia , Análisis de Secuencia de ADN , Industria TextilRESUMEN
INTRODUCTION: Shiga toxin-producing Escherichia coli (STEC) are an important group of emerging zoonotic pathogens carried in the intestinal tracts of ruminants. They can cause mild diarrhea and fatal disease characterized by hemolytic uremic syndrome, especially in children, the elderly, and immune-compromised individuals. METHODOLOGY: The aim of this study was to determine if sheep harbor STEC. Sheep feces (n = 40), brisket wool (n = 40), and 150 meat samples were collected from the flank (n = 35), rump (n = 35), brisket (n = 20), shank (n = 25), diaphragm (n = 10), and neck (n = 25) of slaughter-age sheep at a high-throughput abattoir and tested for STEC using a combination of culture and real-time polymerase chain reaction techniques. RESULTS: E. coli O103 (5/40) and O145 (5/40) strains were isolated from the feces and E. coli O157:H7 was isolated from brisket wool (10/40) and flank meat (5/35). The results of this study provide the first report of STEC infections in sheep in Namibia. CONCLUSIONS: The results of this study show that sheep, like cattle, can shed STEC strains in their feces, which can contaminate meat and expose humans to infections.
Asunto(s)
Infecciones por Escherichia coli/veterinaria , Ovinos/microbiología , Escherichia coli Shiga-Toxigénica/aislamiento & purificación , Animales , Infecciones por Escherichia coli/microbiología , Heces/microbiología , Carne/microbiología , Namibia , Serogrupo , Escherichia coli Shiga-Toxigénica/clasificación , Lana/microbiologíaRESUMEN
Novel naphthalimide-poly(amidoamine) dendrimer fluorescent dyes were synthesized, and their structures were identified and confirmed using different characterization methods such as Fourier transform infrared, (1) H NMR, (13) C NMR, differential scanning calorimetry, elemental analysis and UV-vis spectroscopy. The spectrophotometric studies demonstrated absorption maxima (λmax ) and extinction coefficient (εmax ) values in the ranges of 429-438 nm and 25,635-88,618 L/mol/cm, respectively. The dyeing, fastness and antimicrobial properties of dyed wool fibers were examined. Colorimetric measurements demonstrated a greenish-yellow hue with remarkable fluorescence intensity on dyed wool. Although the fastness properties of naphthalimide dye on wool fibers were poor/moderate, color fastness was appreciably improved through modification of the dye using dendrimers. The results revealed that the newly synthesized dyes are potent antimicrobial agents on wool fibers. Overall, it was deduced that poly(amidoamine) (PAMAM) dendrimers could be exploited as a promising tool in tailoring the different properties of naphthalimide dyes, being suitable for dyeing and antimicrobial finishing agents for wool fibers. Copyright © 2015 John Wiley & Sons, Ltd.
Asunto(s)
Antibacterianos/farmacología , Dendrímeros/farmacología , Fluorescencia , Colorantes Fluorescentes/farmacología , Naftalimidas/farmacología , Poliaminas/farmacología , Lana/efectos de los fármacos , Lana/microbiología , Animales , Antibacterianos/síntesis química , Antibacterianos/química , Dendrímeros/síntesis química , Dendrímeros/química , Relación Dosis-Respuesta a Droga , Escherichia coli/efectos de los fármacos , Colorantes Fluorescentes/síntesis química , Colorantes Fluorescentes/química , Pruebas de Sensibilidad Microbiana , Nanoestructuras/química , Naftalimidas/química , Poliaminas/química , Staphylococcus aureus/efectos de los fármacos , Relación Estructura-ActividadRESUMEN
Psoroptes ovis mites, which cause psoroptic mange (sheep scab), were investigated to identify potential bacterial targets for endosymbiont control of sheep scab. In addition, transmission of bacteria to the sheep skin was investigated through the characterisation of bacteria present in P. ovis faecal trails and on the fleece environment by internal transcribed spacer (ITS) sequencing. A diverse range of bacteria was identified in addition to a potential endosymbiont candidate, Comamonas sp, which was detected in P. ovis by both ITS PCR and endosymbiont-specific PCR. Disruption of these bacteria within P. ovis, through the use of antibiotics, was explored; with significant reduction in mean mite survival when administered antibiotic diets compared with controls (LR4 = 23.12, P < 0.001). The antibiotic treatments also significantly affected the bacterial density (CFU/mite) within P. ovis, indicating that mite survival may be linked to the bacterial communities that they harbour. Although antibiotics are not suitable for practical application, these results suggest disrupting bacteria associated with P. ovis should be further investigated for novel control.
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Bacterias/aislamiento & purificación , Infestaciones por Ácaros/veterinaria , Psoroptidae/microbiología , Enfermedades de las Ovejas/prevención & control , Animales , Antibacterianos/farmacología , Bacterias/clasificación , Bacterias/efectos de los fármacos , ADN Bacteriano/aislamiento & purificación , Heces/microbiología , Femenino , Gentamicinas/farmacología , Masculino , Infestaciones por Ácaros/microbiología , Infestaciones por Ácaros/prevención & control , Filogenia , Ovinos , Enfermedades de las Ovejas/microbiología , Enfermedades de las Ovejas/parasitología , Simbiosis , Tetraciclina/farmacología , Lana/microbiologíaRESUMEN
A novel inorganic nanocomposite material, called BOA, which has the form of small building blocks composed of gold nanoparticles embedded in a polyoxoborate matrix, is presented. It is demonstrated that cotton wool decorated with the BOA nanocomposite displays strong antibacterial activity toward both Gram-positive and -negative bacteria strains. Importantly, the modified cotton does not release any toxic substances, and the bacteria are killed upon contact with the fibers coated with the BOA. Toxicity tests show that the nanocomposite--in spite of its antiseptic properties--is harmless for mammalian cells. The presented method of surface modification utilizes mild, environmentally friendly fabrication conditions. Thus, it offers a facile approach to obtain durable nontoxic antiseptic coatings for biomedical applications.
Asunto(s)
Antibacterianos/química , Boratos/química , Oro/farmacología , Nanocompuestos/química , Animales , Antibacterianos/síntesis química , Antibacterianos/farmacología , Boratos/farmacología , Escherichia coli/efectos de los fármacos , Oro/química , Humanos , Staphylococcus aureus/efectos de los fármacos , Textiles/análisis , Textiles/microbiología , Lana/química , Lana/microbiologíaRESUMEN
Novel keratin-degrading bacteria were isolated from sand soil samples collected from Minia Governorate, Egypt. In this study, the isolates were identified as Bacillus amyloliquefaciens MA20 and Bacillus subtilis MA21 based on morphological and biochemical characteristics as well as 16S rRNA gene sequencing. B. amyloliquefaciens MA20 and B. subtilis MA21 produced alkaline keratinolytic serine protease when cultivated in mineral medium containing 1% of wool straight off sheep as sole carbon and nitrogen source. The two strains were observed to degrade wool completely to powder at pH 7 and 37°C within 5 days. Under these conditions the maximum activity of proteases produced by B. amyloliquefaciens MA20 and B. subtilis MA21 was 922 and 814 U/ml, respectively. The proteases exhibited optimum temperature and pH at 60°C and 9, respectively. However, the keratinolytic proteases were stable in broad range of temperature and pH values towards casein Hammerstein. Furthermore the protease inhibitor studies indicated that the produced proteases belong to serine protease because of their sensitivity to PMSF while they were inhibited partially in presence of EDTA. The two proteases are stable in most of the used organic solvents and enhanced by metals suggesting their potential use in biotechnological applications such as wool industry.
Asunto(s)
Bacillus/enzimología , Ecosistema , Péptido Hidrolasas/química , Lana/microbiología , Animales , Egipto , Péptido Hidrolasas/genética , Péptido Hidrolasas/aislamiento & purificación , Estabilidad Proteica , ARN Ribosómico 16S/genética , Ovinos , Microbiología del Suelo , TemperaturaRESUMEN
Monochloro-triazine ß-cyclodextrin (MCT-ßCD) was successfully utilized to modify the wool fabric structure. The modified wool exhibited better post-printing, using different dyestuffs, and outstanding antibacterial activities most probably due to the remarkable capacity of grafted ßCD moieties to form guest-host inclusion complexes in addition to the positive role of wool's active sites. The following treatment sequence: pre-modification, post-printing, followed by after-treatment with Ag-NP's colloid or triclosan derivatives was investigated. The extent of improvement in the aforementioned properties is governed by the degree of pre-modification, type of dyestuff and extent of fixation, type of antibacterial agent, its mode of interaction and extent of loading onto the modified printed wool. The imparted antibacterial functionalities were retained, more than 75%, even after 15 washing cycles.
Asunto(s)
Impresión , Triazinas/química , Lana/química , beta-Ciclodextrinas/química , Aminas/química , Animales , Antibacterianos/química , Antibacterianos/farmacología , Catálisis , Nanopartículas del Metal/química , Nylons/química , Plata/química , Triclosán/química , Triclosán/farmacología , Lana/microbiologíaRESUMEN
There are many missed biotechnological opportunities in the developmental countries. Wool quality improvement is one of them. This study is concerning with improving the wool quality using technical enzymes. White wool proves to be more susceptible to the enzymatic treatment than blackish brown wool. This proves that the enzymatic reaction is sensitive to the natural color differences between wool fibers. A simple enzymatic method has been used to improve the wool quality as well as to investigate the changes happened in the wool fibers. Geobacillus stearothermophilus has been used under mesophilic and static cultivation conditions using wool as the main carbon source. These conditions prove to be more suitable for maintaining the fiber structure, less expensive, and reliable as an in-house biotechnological process that can be adapted everywhere. The enzyme activity in case of white wool was 4 Units/ml and for blackish brown wool was 1.5 Units/ml. Electron microscope has been used to evaluate the end result. By following the process included in this paper using probable microbial strain(s), the wool quality improvement can be applied globally and can add another value to the economy of the developmental countries.
Asunto(s)
Proteínas Bacterianas/química , Color , Enzimas/química , Geobacillus/enzimología , Color del Cabello , Lana/química , Lana/microbiología , Animales , Activación Enzimática , OvinosRESUMEN
AIMS: To investigate the influence of yeast extract, peptone, temperature and pH upon protease productivity by Bacillus sp. HTS102--a novel wild strain isolated from wool of a Portuguese sheep breed (Merino). METHODS AND RESULTS: A 2(4) full factorial, central composite design together with response surface methodology was used to carry out the experiments and analyse the results, respectively. Among the individual parameters tested, temperature and peptone concentration produced significant effects upon protease productivity. A high correlation coefficient (R(2 ) = 0·994, P < 0·01) indicated that the empiric second-order polynomial model postulated was adequate to predict said productivity, with the optimum loci characterized by: temperature of 43°C, peptone content of 1·4 g l(-1) , pH of 5·1 and yeast extract concentration of 10·0 g l(-1) . CONCLUSIONS: Protease synthesis depends chiefly on temperature and peptone level. The maximum protease activity was more than twice that obtained with the basal medium, so the experimental design and analysis undertaken were effective towards process optimization. SIGNIFICANCE AND IMPACT OF THE STUDY: Rational choice of processing conditions for maximum protease productivity will be relevant if an economically feasible fermentation process based on Bacillus sp. HTS102 is intended.
Asunto(s)
Bacillus/enzimología , Endopeptidasas/biosíntesis , Microbiología Industrial/métodos , Modelos Estadísticos , Lana/microbiología , Animales , Medios de Cultivo/química , Fermentación , Concentración de Iones de Hidrógeno , Peptonas/química , Ovinos/microbiología , TemperaturaRESUMEN
Twenty-one bacterial strains were isolated from imported cattle hide and rabbit wool using two types of media, nutrient broth, and nutrient broth with serum. The bacteria identified were Brevibacillus laterosporus, Leclercia adecarboxylata, Peptococcus niger, Bacillus circulans, Raoultella ornithinolytica, Bacillus subtilis, Bacillus cereus, Bacillus thermobacillus, Bacillus choshinensis, Bacillus sphaericus, Acinetobacter haemolyticus, Sphingomonas paucimobilis, Bacillus thuringiensis, Staphylococcus intermedius, Mycobacteria, Moraxella, Klebsiella pneumoniae, Ralstonia pickettii, Staphylococcus chromogenes, Comamonas testosteroni, and Cupriavidus pauculus. The 16s rDNA gene of each bacterium was amplified using the universal primers 27f and 1492r. The amplicons were digested with AvaI, BamHI, BgII, DraI, EcoRI, EcoRV, HindIII, HinfI, HpaI, PstI, SmaI, TaqII, XbaI, XmaI, AluI, XhoI, and PvuI individually. A specific fingerprint from the PCR-restriction fragment length polymorphism method based on 16s rDNA was obtained for each bacterium. The results showed that the method developed was useful not only for bacterial identification but also for the etiological investigation of pathogens in imported animal hair and wool.
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Piel/microbiología , Lana/microbiología , Animales , Bacterias/aislamiento & purificación , Bovinos , Dermatoglifia del ADN , ADN Ribosómico/química , ADN Ribosómico/genética , Bases de Datos Factuales , Cabello/microbiología , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de Restricción , ARN Ribosómico 16S/análisis , ARN Ribosómico 16S/genética , ConejosRESUMEN
In this study an effective nanocomposite antimicrobial agent for wool fabric was introduced. The silver loaded nano TiO(2) as a nanocomposite was prepared through UV irradiation in an ultrasonic bath. The nanocomposite was stabilized on the wool fabric surface by using citric acid as a friendly cross-linking agent. The treated wool fabrics indicated an antimicrobial activity against both Staphylococcus aureus and Escherichia coli bacteria. Increasing the concentration of Ag/TiO(2) nanocomposite led to an improvement in antibacterial activities of the treated fabrics. Also increasing the amount of citric acid improved the adsorption of Ag/TiO(2) on the wool fabric surface leading to enhance antibacterial activity. The EDS spectrum, SEM images, and XRD patterns was studied to confirm the presence of existence of nanocomposite on the fabric surface. The role of both cross-linking agent and nanocomposite concentrations on the results was investigated using response surface methodology (RSM).
Asunto(s)
Antiinfecciosos/farmacología , Escherichia coli/efectos de los fármacos , Plata/farmacología , Staphylococcus aureus/efectos de los fármacos , Titanio/farmacología , Rayos Ultravioleta , Lana/microbiología , Animales , Antiinfecciosos/química , Ácido Cítrico/química , Ácido Cítrico/farmacología , Reactivos de Enlaces Cruzados/química , Reactivos de Enlaces Cruzados/farmacología , Escherichia coli/efectos de la radiación , Microscopía Electrónica de Rastreo , Nanocompuestos/química , Plata/química , Staphylococcus aureus/efectos de la radiación , Titanio/química , Lana/efectos de los fármacos , Lana/efectos de la radiación , Difracción de Rayos XRESUMEN
The aim of this study was to quantify the hygienic status of a lamb slaughterhouse by means of multivariate statistical analysis, to demonstrate how the microbiological data could be exploited to improve the lamb slaughter process by constructing control charts and to evaluate the potential effect of an intervention step such as steam application on the microbiological quality of lamb carcasses. Results showed that pelt removal and evisceration were hygienically uncontrolled. TVC and Enterobacteriaceae progressively increased from the stage 'after pelt removal of hind and forelegs/before final pulling' to the stage 'after evisceration/before pluck removal' thus indicating possible deposition of microorganisms during these operations. It seems that the processing stages of freshly produced carcasses were better distinguished by Enterobacteriaceae, with evisceration contributing mostly to the final Enterobacteriaceae counts. Application of steam during the lamb slaughter process reduced microbial counts without adverse effects on the organoleptic characteristics of the carcasses. Moreover, the construction of control charts showed that decontamination with steam contributed to the maintenance of an in control process compared to that before the application of steam, suggesting the potential use of steam as an intervention step during the lamb slaughter process.
Asunto(s)
Mataderos , Enterobacteriaceae/aislamiento & purificación , Manipulación de Alimentos/métodos , Industria para Empaquetado de Carne/métodos , Carne/microbiología , Animales , Recuento de Colonia Microbiana , Contaminación de Alimentos/prevención & control , Microbiología de Alimentos , Higiene , Análisis Multivariante , Oveja Doméstica/microbiología , Vapor , Lana/microbiologíaRESUMEN
OVAT (one variable at a time) approach was applied in this study to screen the most important physicochemical key determinants involved in the process of sheep wool biodegradation. The process was directed by a keratinase-producing Bacillus subtilis DB 100 (p5.2) recombinant strain. Data indicate that, sheep wool could be degraded efficiently in cultures incubated at 30°C, with initial pH of 7 with agitation at 150 rpm. Two times autoclaved alkali treated and undefatted chopped sheep wool is more accessible to biodegradation. B. subtilis recombinant cells could utilize sheep wool as a sole source of carbon and nitrogen. Sheep wool-based modified basal medium II, lacking NH4Cl and yeast extract, could greatly support the growth of these bacterial cells. Sheep wool biodegradation was conducted efficiently in the absence of kanamycin consequently; high stability of the recombinant plasmid (p5.2) represents a great challenge upon scaling up this process. Three key determinants (sheep wool concentration, incubation time and inoculum size) imposing considerable constraints on the process are highlighted. Sheep wool-based tap water medium and sheep wool-based distilled water medium were formulated in this study. High levels of released end products, produced from sheep wool biodegradation are achieved upon using these two sheep wool-based water media. Data indicate that, sheep wool hydrolysate is rich in some amino acids, such as tyrosine, phenylalanine, lysine, proline, isoleucine, leucine, valine, aspartic acid and glutamic acid. Moreover, the resulting sheep wool hydrolysate contains soluble proteins of high and intermediate molecular weights. The present study demonstrates a feasible, cheap, reproducible, efficient and rapid biotechnological approach towards utilization of raw sheep wool waste through a recombinant bacterium.
Asunto(s)
Bacillus subtilis/enzimología , Bacillus subtilis/metabolismo , Proteínas Bacterianas/metabolismo , Péptido Hidrolasas/metabolismo , Eliminación de Residuos/métodos , Lana/microbiología , Animales , Bacillus subtilis/genética , Proteínas Bacterianas/genética , Biodegradación Ambiental , Ingeniería Genética , Péptido Hidrolasas/genética , Ovinos , Lana/química , Lana/metabolismoRESUMEN
A wool-degrading bacterium was isolated from decomposition wool fabrics in China. The strain, named 3096-4, showed excellent capability of removing cuticle layer of wool fibers, as demonstrated by removing cuticle layer completely within 48 h. According to the phenotypic characteristics and 16S rRNA profile, the isolate was classified as Pseudomonas. Bacteria growth and keratinase activity of the isolate were determined during cultivation on raw wool at different temperatures, initial pH, and rotation speed using orthogonal matrix method. Maximum growth and keratinase activity of the bacterium were observed under the condition including 30 °C, initial pH 7.6, and rotational speeds 160 rpm. The keratinase-containing crude enzyme prepared from 3096-4 was evaluated in the treatment of wool fabrics. The optimal condition of our enzymatic improvement of shrink resistance was the combination of 30 °C, initial pH 7.6, and rotation speeds 160 rpm. After the optimized treatment, the wool fabrics felting shrink was 4.1% at 6 h, and textile strength was not lost.
Asunto(s)
Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , Péptido Hidrolasas/química , Péptido Hidrolasas/metabolismo , Pseudomonas/enzimología , Pseudomonas/aislamiento & purificación , Lana/química , Animales , Proteínas Bacterianas/genética , Concentración de Iones de Hidrógeno , Microbiología Industrial , Datos de Secuencia Molecular , Péptido Hidrolasas/genética , Poliésteres/química , Pseudomonas/clasificación , Pseudomonas/genética , Temperatura , Resistencia a la Tracción , Lana/microbiologíaRESUMEN
OBJECTIVE: This study aimed to determine the presence and concentration of Escherichia coli O157 and Salmonella spp. on fleece, faeces and carcases of sheep during slaughter. PROCEDURE: Faeces, fleece and pre-chill carcase samples were collected from 164 sheep slaughtered at two Australian abattoirs. The presence of E. coli O157 and Salmonella spp. were determined by use of automated immunomagnetic separation (AIMS) with enumeration by use of the 'most probable number' (MPN) method. RESULTS: Escherichia coli O157 was isolated from 5% of faeces, 3% of fleeces and 0.6% of pre-chill carcases. The mean log(10) count of E. coli O157 positive faecal samples was 2.32 MPN/g, but counts on fleeces and carcases were below the countable limit (-1 log(10) MPN/cm(2) ). Salmonella spp. were isolated from 20% of faeces, 13% of fleeces and 1.3% of pre-chill carcases. The mean log(10) count of Salmonella spp. in faeces was 1.43 MPN/g and on fleece was -0.24 MPN/cm(2) , but counts on carcases were below the countable limit (-1 log(10) MPN/cm(2) ). CONCLUSION: The prevalence and concentration of pathogens were low in the sheep tested in this study, indicating a low risk of human infection from products derived from these animals.
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Mataderos , Recuento de Colonia Microbiana/veterinaria , Escherichia coli O157/aislamiento & purificación , Salmonella/aislamiento & purificación , Ovinos/microbiología , Animales , Australia/epidemiología , Seguridad de Productos para el Consumidor , Heces/microbiología , Femenino , Masculino , Prevalencia , Lana/microbiologíaRESUMEN
The present study examined the incidence of Escherichia coli O:H7 and Salmonella in feedlot lambs. Fifty-six feedlot lambs from eight sheep farming operations were grouped in a single drylot pen, fed, and managed as is typical in the southwestern United States. Fecal samples were collected on days 0, 46, 87, and 122 of the feeding period via rectal palpation. Wool samples (ventral midline) were collected one time only at the feedlot, immediately prior to shipping to the processing plant, and carcass swabs were collected following slaughter. All samples were cultured for E. coli O157:H7, Salmonella, and fecal coliforms, and select isolates were examined for antimicrobial susceptibility. Overall, the percentages of fecal and wool samples positive for E. coli O157:H7 averaged 9 and 18%, respectively. One carcass swab was E. coli O157:H7 positive. Of the 155 fecal samples collected, 11 (7%) were Salmonella positive. Salmonella was detected in nearly 50% of the wool samples collected prior to slaughter, while none of the carcasses were Salmonella positive 24 h postslaughter. All isolates (E. coli O157:H7, Salmonella, and fecal coliforms) were susceptible to ceftiofur, enrofloxacin, and trimethoprim-sulfamethoxazole. One E. coli O157:H7 isolate cultured from a carcass swab was resistant to seven antibiotics, and seven wool E. coli O157:H7 isolates were multidrug resistant. Results of this research demonstrate that feedlot sheep are naturally colonized with E. coli O157:H7 and Salmonella and wool can be a source of carcass contamination; however, in-plant processing procedures and intervention strategies were largely effective in preventing carcass contamination.
Asunto(s)
Antibacterianos/farmacología , Farmacorresistencia Bacteriana , Escherichia coli O157/efectos de los fármacos , Salmonella/efectos de los fármacos , Ovinos/microbiología , Animales , Animales Recién Nacidos , Recuento de Colonia Microbiana , Farmacorresistencia Bacteriana Múltiple , Heces/microbiología , Contaminación de Alimentos/prevención & control , Pruebas de Sensibilidad Microbiana , Prevalencia , Salmonella/aislamiento & purificación , Lana/microbiologíaRESUMEN
OBJECTIVE: To test strategies for the application of dicyclanil and mid-season crutching to maximise protection of unmulesed sheep against breech strike. PROCEDURE: Three hundred and eighty unmulesed Merino weaners were randomly allocated to four groups either left untreated or treated by different strategies with 50 g/L dicyclanil. Treatments included breech treatment alone and breech plus body treatment, with two application times, immediately after shearing and 6 weeks after crutching or shearing. To assess protection, larval implants with newly hatched Lucilia cuprina larvae were applied to 10 different sheep from each group at 3, 4, 5 and 6 months after crutching and shearing and assessed for the development of strike at 48 hours. The concentration of dicyclanil was measured in wool samples clipped from the breeches of the test sheep. RESULTS: All dicyclanil treatments gave significant reduction in strike in comparison to controls up until 4 months after crutching but protection in the sheep treated immediately after shearing had waned at 5 months. Treating at 6 weeks after crutching provided significant reduction (P < 0.05) in strike for 6 months. Results for strike incidence immediately after shearing and concentration of dicyclanil in the breech wool also suggested improvements in protection by delaying treatment for 6 weeks. CONCLUSION: In most environments it should be possible to protect unmulesed sheep against breech strike with a carefully planned integrated control program incorporating strategically timed crutching, shearing and dicyclanil application. Delaying treatment with dicyclanil to at least 6 weeks after shearing or crutching increased the protection provided in comparison to treatment immediately after shearing.
Asunto(s)
Hormonas Juveniles/administración & dosificación , Miasis/veterinaria , Enfermedades de las Ovejas/prevención & control , Animales , Dípteros/microbiología , Femenino , Larva/microbiología , Modelos Lineales , Masculino , Miasis/prevención & control , Queensland , Distribución Aleatoria , Ovinos , Enfermedades de las Ovejas/parasitología , Resultado del Tratamiento , Lana/química , Lana/microbiologíaRESUMEN
AIMS: To characterize the secretion of proteolytic activities against keratin, collagen and elastin in liquid cultures of Bacillus cereus IZ-06b and IZ-06r isolated from wool. METHODS AND RESULTS: Growth of B. cereus IZ-06b and IZ-06r were characterized in batch culture. Both strains needed an organic nitrogen source, were able to grow on wool or peptone as sole carbon and nitrogen sources, and metabolized glucose, maltose and other simple sugars. Proteolytic activities were investigated in batch cultures grown in peptide-restricted, carbon-sufficient medium. Secretion of proteases was induced by peptide limitation while different proteolytic activities appeared sequentially in the growth medium. When the most available components of the peptone were depleted, collagenolytic and elastolytic proteases were produced. These were later replaced by the production of keratinolytic protease. CONCLUSIONS: B. cereus can adjust its proteolytic affinity profile in response to the supply of organic nitrogen and sequentially secrete proteases with activities targeted against increasingly inaccessible proteinous substrates as the nutritional availability in the environment deteriorates. SIGNIFICANCE AND IMPACT OF THE STUDY: Peptide-limited, carbon-sufficient growth media containing no proteinous substrates are well suited for protease production in B. cereus while growth conditions can be adjusted to optimize the proteolytic affinity profiles.
Asunto(s)
Bacillus cereus/enzimología , Péptido Hidrolasas/metabolismo , Lana/microbiología , Animales , Bacillus cereus/crecimiento & desarrollo , Bacillus cereus/aislamiento & purificación , Biomasa , Reactores Biológicos , Carbono/metabolismo , Colagenasas/metabolismo , Medios de Cultivo , Concentración de Iones de Hidrógeno , Ácido Láctico/metabolismo , Nitrógeno/metabolismo , TemperaturaRESUMEN
AIMS: To determine possible preslaughter and processing sources of psychrophilic and psychrotolerant clostridia causing spoilage of vacuum-packed chilled meats. METHODS AND RESULTS: Molecular methods based on the polymerase chain reaction (PCR) amplification of specific 16S rDNA fragments were used to detect the presence of Clostridium gasigenes, Clostridium estertheticum, Clostridium algidicarnis and Clostridium putrefaciens in a total of 357 samples collected from ten slaughter stock supply farms, slaughter stock, two lamb-processing plants, their environments, dressed carcasses and final vacuum-packed meat stored at -0.5 degrees C for 5(1/2) weeks. Clostridium gasigenes, C. estertheticum and C. algidicarnis/C. putrefaciens were commonly detected in farm, faeces, fleece and processing environmental samples collected at the slaughter floor operations prior to fleece removal, but all these micro-organisms were detected in only 4 out of 26 cooling floor and chiller environmental samples. One out of 42 boning room environmental samples tested positive for the presence of C. gasigenes and C. estertheticum, but 25 out of 42 of these samples were positive for C. algidicarnis/C. putrefaciens. Nearly all of the 31 faecal samples tested positive for the presence of C. gasigenes and C. estertheticum; however, only two of these samples were positive for C. algidicarnis and/or C. putrefaciens. Clostridial species that were subject to this investigation were frequently detected on chilled dressed carcasses. CONCLUSIONS: The major qualitative and quantitative differences between the results of PCR detection obtained with the primers specific for 'blown pack' -causing clostridia (C. gasigenes and C. estertheticum) and those obtained with primers specific for C. algidicarnis and C. putrefaciens suggest that the control of meat spoilage caused by different groups of meat clostridia is best approached individually for each group. SIGNIFICANCE AND IMPACT OF THE STUDY: This paper provides information significant for controlling meat spoilage-causing clostridia in the meat-processing plants.