In vitro studies with dimethyldithiocarbamate, possible new antimicrobial for use in poultry

Tests were conducted to determine the in vitro efficacy of the dithiocarbamate analogue, dimethyldithiocarbamate (DmDTC), against selected poultry pathogens. Organisms studied were two bacteria, Pasteurella multocida and Escherichia coli, and a mold, Aspergillus fumigatus. Zone of inhibition and the minimum inhibitory concentration were determined for each organism. DmDTC was effective in vitro against all organisms tested, with A. fumigatus showing greatest overall sensitivity.     

In vitro and in vivo studies of the use of some medicinal herbals against the pathogen Aeromonas hydrophila in goldfish

Aeromonas hydrophila is a ubiquitous and opportunistic bacterial pathogen that produces ulcerative dermatitis under stress conditions and inflicts severe losses on global fisheries and fish culture. This study evaluates the antimicrobial potency of aqueous and ethanolic decoction (individual extract) and concoction (mixed extract) of three common medicinal herbs, turmeric Curcuma longa, Tulsi plant Ocimum sanctum, and neem Azadirachta indica, against the in vitro growth of A. hydrophila. Among the decoctions, A. indica exhibited the most potent antibacterial property (P < 0.05) against A. hydrophila. Among the concoctions, both the aqueous and ethanolic triherbal extracts mixed in the ratio of 1:1:1 had higher antibacterial activity (P < 0.05) than the other concoctions and decoctions. Goldfish Carassius auratus (10 +/- 2 g) were challenged with A. hydrophila intramuscularly in the caudal region with two separate doses (days 1 and 3) of 50 microL/fish (1.8 x 10(3) colony-forming units per milliliter). On days 9 (early) and 15 (late) of infection, fish were held in a net and dip treated for 5 min daily in a 1-L solution of 1% aqueous triherbal concoction. Red blood cell (RBC) count, hemoglobin, and hematocrit levels of the infected group were significantly higher (P < 0.05) than those of the control group. In the early treated group, all of the affected profile values returned to near normal, while the late-treated group registered a partial recovery, such as improved RBC count. The derived hematological values, such as mean corpuscular volume, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration, of the early and late-treated groups also significantly declined (P < 0.05) but were restored to near normal (P > 0.05) only in the early treated group. The results suggest that dip treatment of A. hydrophila-infected goldfish in an aqueous triherbal concoction had a synergistic restorative effect on the hematological variables.     

Cavitary pulmonary lesion associated with Aspergillus fumigatus infection in a German shepherd dog

A two-year-old female German shepherd dog was presented with chronic cough and haemoptysis. Thoracic radiographs revealed a thin-walled cavitary lesion within a consolidated left cranial lung lobe. Bronchoalveolar lavage confirmed a concurrent bacterial infection; however, despite antibiotic and anthelmintic therapy the clinical signs failed to resolve. A left cranial lung lobectomy was performed. Histopathology and fungal culture confirmed the presence of Aspergillus fumigatus. The necrotic cavity had features compatible with a bronchial origin, possibly a form of cystic bronchiectasis, arising either as a congenital anomaly or acquired secondary to infection. Surgery provided resolution of clinical signs for just over a year before the dog deteriorated again and was subsequently euthanised. Necropsy was declined by the owners. This case report presents a unique presentation in which the predominant clinical sign was coughing due to pulmonary involvement. Aspergillus fumigatus was isolated from the left cranial lung lobe.     

An original system for the continuous monitoring of antimicrobial use in poultry production in France

Data collection at the flock level on a continuous basis, for antimicrobial use surveillance purposes, provides a complex challenge. Using existing on-farm records, produced as part of the regulations for meat inspection, a sampling scheme was implemented to collect on a simple, representative and continuous basis, the forms providing history of antimicrobial consumption of poultry flocks slaughtered in Brittany. Relational database-stored information provided by the forms includes treatment purpose, antimicrobial drug administered, age at treatment and treatment duration. The aim of this study was to collect information describing antimicrobial drug use quantitatively and qualitatively, by computing the frequency of antimicrobial use according to species, therapeutic class, treatment purpose, duration, and animal age at treatment. A study was carried out to check the validity of farmers' declarations. Examples of data and results are presented such as the relative importance of the different antimicrobial classes in relation to the live weight treated, which shows that beta-lactams and tetracyclines are the main classes used in broilers and turkeys respectively. Average bird weight at treatment was 0.5 kg for a broiler and 3 kg for a turkey. Nevertheless, several 'at-risk' periods could be identified. Initial results after 1 year of data collection showed that this surveillance system provides valid, detailed and useful data about antimicrobial drug use in poultry production at a low cost and with only a moderate time involvement.     

In vitro comparison of the activity of various antifungal drugs against new yeast isolates causing thrush in poultry

Of 44 representative isolates of yeast isolated from the poultry upper digestive tract from 40 clinical thrush cases in Taiwan during 1985-87, 39 (89%) isolates were classified as Candida albicans, and 5 (11%) were classified as Torulopsis pintolopesii. Fifteen commercial antifungal drugs, incorporated individually in Sabouraud's dextrose agar by serial twofold dilutions, were tested for their inhibitory effect against the 44 isolates. The MIC50 of these drugs in increasing order was less than or equal to 2 ppm GV-11, 6 ppm gentian violet, less than 16 ppm amphotericin B, 16 ppm hyamine 1622, 25 ppm econazole, 35 ppm chlorohydroxyquinoline, 40 ppm nystatin, 64 ppm miconazole, 747 ppm malachite green, 1550 ppm benzoic acid, 1536 ppm copper sulfate, 3144 ppm Monoprop, 4951 ppm Mold Zap, greater than 16,384 ppm propionic acid, and greater than 16,384 ppm sodium propionate.     

Development of a method for the identification, using the polymerase chain reaction, of Aspergillus fumigatus isolated from ostriches

Objective To develop a method for identifying DNA of Aspergillus fumigatus from ostriches, using the polymerase chain reaction (PCR). A fumigatus is the principal causative agent of avian aspergillosis.
Design A biochemical trial.
Sample population Twelve Aspergillus fumigatus isolates and three other Aspergillus species.
Procedure PCR primers that were based on the sequence of the alkaline protease gene from human isolates of A fumigatus were used.
Results We successfully tested the method on ostrich isolates from five states and showed that the test is specific for A fumigatus.
Conclusions In most cases the DNA sequence of A fumigatus isolates from ostriches is similar to that of human isolates. DNA sequences vary significantly among A fumigatus isolates, including those from affected ostriches in the same flock. The genetic variation may be used to trace aspergillus infections in ostrich flocks and determine if the disease is transmitted by contact with infected birds.     

The use of a new phage set for typing poultry strains of Staphylococcus aureus obtained from seven countries

1. Eighty per cent of poultry strains of Staphylococcus aureus tested from French, Belgian, English, West German, Japanese and Argentinian sources were typable using a set of typing phages isolated in this laboratory. Strains from Bulgaria, however, with few exceptions were not typable with this phage set. 2. Strains isolated from lesions generally resembled those from apparently healthy poultry. 3. The existence of two distinct Staph. aureus biotypes on poultry was confirmed by isolates from six of the countries; one of these biotypes closely resembled Staph. aureus variety gallinae as described by Witte et al. (1977).     

In vitro evaluation,in vivo quantification,and microbial diversity studies of nutritional strategies for reducing enteric methane production

The main objective of the present work was to study nutritive strategies for lessening the CH₄ formation associated to ruminant tropical diets. In vitro gas production technique was used for evaluating the effect of tannin-rich plants, essential oils, and biodiesel co-products on CH₄ formation in three individual studies and a small chamber system to measure CH₄ released by sheep for in vivo studies was developed. Microbial rumen population diversity from in vitro assays was studied using qPCR. In vitro studies with tanniniferous plants, herbal plant essential oils derived from thyme, fennel, ginger, black seed, and Eucalyptus oil (EuO) added to the basal diet and cakes of oleaginous plants (cotton, palm, castor plant, turnip, and lupine), which were included in the basal diet to replace soybean meal, presented significant differences regarding fermentation gas production and CH₄ formation. In vivo assays were performed according to the results of the in vitro assays. Mimosa caesalpineaefolia, when supplemented to a basal diet (Tifton-85 hay Cynodon sp, corn grain, soybean meal, cotton seed meal, and mineral mixture) fed to adult Santa Ines sheep reduced enteric CH₄ emission but the supplementation of the basal diet with EuO did not affect (P > 0.05) methane released. Regarding the microbial studies of rumen population diversity using qPCR with DNA samples collected from the in vitro trials, the results showed shifts in microbial communities of the tannin-rich plants in relation to control plant. This research demonstrated that tannin-rich M. caesepineapholia, essential oil from eucalyptus, and biodiesel co-products either in vitro or in vivo assays showed potential to mitigate CH₄ emission in ruminants. The microbial community study suggested that the reduction in CH₄ production may be attributed to a decrease in fermentable substrate rather than to a direct effect on methanogenesis.     

Medetomidine, a new sedative-analgesic for use in the dog and its reversal with atipamezole

The sedative and physiological effects of intramuscular medetomidine (20 and 40 μg/kg) in dogs were compared with those of xylazine (2 mg/kg). The efficacy of atipamezole (200 μg/kg), as an antagonist given 15 or 45 minutes after medetomidine (40 μg/kg) was studied. Following medetomidine, onset of sedation was rapid, and depth and duration of sedation were dose dependent. The higher dose produced jaw relaxation, depression of the pedal reflex, downward rotation of the eye and dogs could be positioned for radiography of the hips. Side effects were similar after either medetomidine or xylazine, and included bradycardia, a fall in respiratory rate and muscle tremor. Vomiting during induction was less frequent after medetomidine than after xylazine. Intramuscular administration of atipamezole rapidly reversed the sedative effects of medetomidine. Signs of arousal were seen within three minutes; all dogs could stand within 10 minutes and appeared clinically normal. Heart and respiratory rates rose, but did not return to presedation values. Relapse to sedation was not noted.     

In vivo metabolism of Talosin A, new isoflavonol glycoside from Kitasatospora kifunensis, in rats

The isoflavonol glycoside Talosin A, genistein (GT)-7-α-L-6-deoxy talopyranose (GT-Tal), was first isolated from the culture broth of Kitasatospora kifunensis MJM341. The aim of the present study was to evaluate the oral absorption and metabolism of the newly isolated isoflavonol glycoside, GT-Tal compared to genistin (GT-7-O-β-D-glucopyranoside; GT-Glu). Free GT-Glu and GT-Tal could not be detected prior to enzymatic hydrolysis of the corresponding conjugates in rat plasma. Following oral administration of GT-Tal (15 min), GT-Tal was rapidly absorbed through the gastrointestinal tract and metabolized into GT-Tal conjugates with a mean C_max of 2.74 µg/mL. GT-Tal was further metabolized to its aglycone, free GT and conjugated GT. After oral administration, GT-Glu was absorbed after being convereted to its aglycone and then further metabolized into its conjugate metabolites (free GT with a mean C_max of 0.24 mg/mL at 1.25 h; conjugated GT with a mean C_max of 1.31 mg/mL at 2.00 h). Significant differences in absorption and metabolism of GT-Tal and GT-Glu were observed. GT-Tal was metabolized into its corresponding conjugates or underwent deglycosylation to form GT, whereas GT-Glu was metabolized into its aglycone, GT.     

In vitro efficacy of a buffered chelating solution as an antimicrobial potentiator for antifungal drugs against fungal pathogens obtained from horses with mycotic keratitis

OBJECTIVE: To determine whether a novel third-generation chelating agent (8 mM disodium EDTA dehydrate and 20 mM 2-amino-2-hydroxymethyl-1, 3-propanediol) would act as an antimicrobial potentiator to enhance in vitro activity of antifungal medications against fungal isolates obtained from horses with mycotic keratitis. SAMPLE POPULATION: Fungal isolates (3 Aspergillus isolates, 5 Fusarium isolates, 1 Penicillium isolate, 1 Cladosporium isolate, and 1 Curvularia isolate) obtained from horses with mycotic keratitis and 2 quality-control strains obtained from the American Type Culture Collection (ATCC; Candida albicans ATCC 90028 and Paecilomyces variotii ATCC 36257). PROCEDURE: Minimum inhibitory concentrations (MICs) against fungal isolates for 4 antifungal drugs (miconazole, ketoconazole, itraconazole, and natamycin) were compared with MICs against fungal isolates for the combinations of each of the 4 antifungal drugs and the chelating agent. The Clinical and Laboratory Standards Institute microdilution assay method was performed by use of reference-grade antifungal powders against the fungal isolates and quality-control strains of fungi. RESULTS: Values for the MIC at which the antifungal drugs decreased the growth of an organism by 50% (MIC50) and 90% (MIC90) were decreased for the control strains and ophthalmic fungal isolates by 50% to 100% when the drugs were used in combination with the chelating agent at a concentration of up to 540 microg/mL. CONCLUSIONS AND CLINICAL RELEVANCE: The chelating agent increased in vitro activity of antifungal drugs against common fungal pathogens isolated from eyes of horses with mycotic keratitis.     

In vivo measurement of flatulence and nutrient digestibility in dogs fed poultry by-product meal, conventional soybean meal, and low-oligosaccharide low-phytate soybean meal

OBJECTIVE: To determine an optimal window for determining peak flatulence and evaluate the effects of oligosaccharides and supplemental beta-mannanase in soybean meal-based diets on nutrient availability and flatulence. ANIMALS: 6 dogs. PROCEDURES: Dogs were used in a 2 x 3 factorial arrangement of treatments in a 6 x 6 Latin square experiment to evaluate the digestibility, flatulence, and fecal odor metabolites of low-oligosaccharide low-phytate soybean meal (LLM), conventional soybean meal (SBM), and poultry by-product (PBP) meal diets with or without supplemental beta-mannanase (5 g/kg). RESULTS: Enzyme supplementation had no effect on total tract dry matter (DM), nitrogen digestibility, or digestible energy; however, differences between protein sources did exist for total tract DM digestibility and digestible energy. The PBP meal had higher DM digestibility and digestible energy (mean, 0.913 and 4,255 cal/g), compared with soy-based diets (mean, 0.870 and 4,049 cal/g). No differences were detected for any treatment regardless of protein source or addition of supplemental enzyme for any flatulence components analyzed. No differences were detected for all fecal odor metabolites regardless of addition of supplemental enzyme; however, differences between protein sources were detected. The PBP meal had lower concentrations of carboxylic acids and esters and higher concentrations of heterocycles, phenols, thio and sulfides, ketones, alcohols, and indoles than LLM and SBM. CONCLUSIONS AND CLINICAL RELEVANCE: Diets containing < 22.4 g of stachyose/kg and < 2 g of raffinose/kg did not alter digestibility or increase flatulence in dogs.     

Aspergillus fumigatus infection in two wild Eurasian black vultures (Aegypius monachus Linnaeus) with carbofuran insecticide poisoning: a case report

Aspergillus spp. are opportunistic pathogens which cause pulmonary aspergillosis in animals and humans with compromised immune systems. Two Eurasian black vultures (Aegypius monachus Linnaeus) were found dead or clinically ill from carbofuran insecticide during the winter of 2004. Carbofuran was detected in the stomach contents by gas chromatograph-mass spectrometry. Gross lesions showed severe granulomatous pneumonia and serofibrinous pleuropneumonia in both birds, with most lesions restricted to the pulmonary system. Histological lesions included pyogranulomatous pneumonia and suppurative parabronchiolitis/pleuritis/air sacculitis with a number of septated fungal hyphae, suggesting severe pulmonary aspergillosis. Fungal isolates from each vulture were identified as Aspergillus fumigatus by both lactophenol cotton blue staining and genetic analysis. This is the first report of pulmonary aspergillosis caused by A. fumigatus in wild Eurasian black vultures and suggests that Aspergillus infection could be an important cause of death in these birds which migrate from Mongolia to Korea during the winter. The incidence of the disease may be related to impaired immunity caused directly or indirectly by carbofuran poisoning.