scholarly journals Experimental Transmission of Bovine Digital Dermatitis to Sheep: Development of an Infection Model

2017 ◽  
Vol 55 (2) ◽  
pp. 245-257 ◽  
Author(s):  
Jennifer H. Wilson-Welder ◽  
Jarlath E. Nally ◽  
David P. Alt ◽  
Mitchell V. Palmer ◽  
John Coatney ◽  
...  
Keyword(s):  
Anaerobic Bacteria ◽  
Diagnostic Methods ◽  
Laboratory Model ◽  
Infection Model ◽  
Digital Dermatitis ◽  
Sheep Model ◽  
Experimental Transmission ◽  
Exact Etiology ◽  
Key Aspects ◽  
Anaerobic Environment

Digital dermatitis is an infectious cause of lameness primarily affecting cattle but also described in sheep, goats, and wild elk. Digital dermatitis is a polymicrobial infection, involving several Treponema species and other anaerobic bacteria. Although the exact etiology has not been demonstrated, a number of bacterial, host, and environmental factors are thought to contribute to disease development. To study host–bacterial interactions, a reproducible laboratory model of infection is required. The objective of this study was to demonstrate key aspects of bovine digital dermatitis lesions in an easy-to-handle sheep model. Crossbred sheep were obtained from a flock free of hoof disease. Skin between the heel bulb and dewclaw was abraded before wrapping to emulate a moist, anaerobic environment. After 3 days, abraded areas were inoculated with macerated lesion material from active bovine digital dermatitis and remained wrapped. By 2 weeks postinoculation, experimentally inoculated feet developed erosive, erythematous lesions. At 4 weeks postinoculation, microscopic changes in the dermis and epidermis were consistent with those described for bovine digital dermatitis, including erosion, ulceration, hyperkeratosis, ballooning degeneration of keratinocytes, and the presence of neutrophilic infiltrates. Silver staining of lesion biopsy sections confirmed that spirochetes had penetrated the host epidermis. The model was then perpetuated by passaging lesion material from experimentally infected sheep into naïve sheep. This model of bovine digital dermatitis will allow for future novel insights into pathogenic mechanisms of infection, as well as the development of improved diagnostic methods and therapeutics for all affected ruminants.

scholarly journals Lesion Material From Treponema-Associated Hoof Disease of Wild Elk Induces Disease Pathology in the Sheep Digital Dermatitis Model

2022 ◽  
Vol 8 ◽  
Author(s):  
Jennifer H. Wilson-Welder ◽  
Kristin Mansfield ◽  
Sushan Han ◽  
Darrell O. Bayles ◽  
David P. Alt ◽  
...  
Keyword(s):  
Cervus Elaphus ◽  
Anaerobic Bacteria ◽  
Premature Death ◽  
Negative Control ◽  
Rrna Gene ◽  
Post Inoculation ◽  
Digital Dermatitis ◽  
Sheep Model ◽  
Specific Pcr ◽  
Bacterial Microbiome

A hoof disease among wild elk (Cervus elaphus) in the western United States has been reported since 2008. Now present in Washington, Oregon, Idaho, and California, this hoof disease continues to spread among elk herds suggesting an infectious etiology. Causing severe lesions at the hoof-skin junction, lesions can penetrate the hoof-horn structure causing severe lameness, misshapen hooves, and in some cases, sloughed hooves leaving the elk prone to infection, malnutrition, and premature death. Isolated to the feet, this disease has been termed treponeme-associated hoof disease due to the numerous Treponema spp. found within lesions. In addition to the Treponema spp., treponeme-associated hoof disease shares many similarities with digital dermatitis of cattle and livestock including association with several groups of anaerobic bacteria such as Bacteroides, Clostridia, and Fusobacterium, neutrophilic inflammatory infiltrate, and restriction of the disease to the foot and hoof tissues. To determine if there was a transmissible infectious component to this disease syndrome, elk lesion homogenate was used in a sheep model of digital dermatitis. Ten animals were inoculated with lesion material and lesion development was followed over 7 weeks. Most inoculated feet developed moderate to severe lesions at 2- or 4-weeks post-inoculation timepoints, with 16 of 18 feet at 4 weeks also had spirochetes associated within the lesions. Histopathology demonstrated spirochetes at the invading edge of the lesions along with other hallmarks of elk hoof disease, neutrophilic inflammatory infiltrates, and keratinocyte erosion. Treponema-specific PCR demonstrated three phylotypes associated with elk hoof disease and digital dermatitis were present. Serum of infected sheep had increased anti-Treponema IgG when compared to negative control sheep and pre-exposure samples. Analysis of the bacterial microbiome by sequencing of the bacterial 16S rRNA gene showed a community structure in sheep lesions that was highly similar to the elk lesion homogenate used as inoculum. Bacteroidies, Fusobacterium, and Clostridia were among the bacterial taxa overrepresented in infected samples as compared to negative control samples. In conclusion, there is a highly transmissible, infectious bacterial component to elk treponeme-associated hoof disease which includes several species of Treponema as well as other bacteria previously associated with digital dermatitis.

scholarly journals The infection-tolerant mammalian reservoir of Lyme disease and other zoonoses broadly counters the inflammatory effects of endotoxin

2020 ◽  
Author(s):  
Gabriela Balderrama-Gutierrez ◽  
Ana Milovic ◽  
Vanessa J. Cook ◽  
M. Nurul Islam ◽  
Youwen Zhang ◽  
...  
Keyword(s):  
Expression Profiles ◽  
Laboratory Model ◽  
Infection Model ◽  
Rna Seq ◽  
Acute Phase Reactants ◽  
Macrophage Response ◽  
Reactive Protein ◽  
Arginase 1 ◽  
The Difference ◽  
The Cost

ABSTRACTAnimals that are competent natural reservoirs of zoonotic diseases commonly suffer little morbidity from the pathogens they persistently harbor. The mechanisms of this infection tolerance and the trade-off costs are poorly understood. We used exposure to a single dose of lipopolysaccharide (LPS) endotoxin as an experimental model of inflammation to compare the responses of the cricentine rodent Peromyscus leucopus, the white-footed deermouse, to that of Mus musculus, the standard laboratory model for pathogenesis studies. Four hours after injection with either LPS or saline, blood and spleen and liver tissues were collected postmortem and subjected to RNA-seq, untargeted metabolomics, and specific RT-qPCR. This was followed by analysis of differential expression at the gene, pathway, and empirical network levels. The deermice showed the same signs of sickness as the mice with LPS exposure, and in addition demonstrated comparable increases in levels of corticosterone and expression of interleukin (IL)-6, tumor necrosis factor, IL-1β, and acute phase reactants, including C-reactive protein. But whereas the M. musculus response to LPS was best-characterized by network analysis as cytokine-associated, the P. leucopus response was dominated by pathway terms associated with neutrophil activity. Dichotomies between the species in expression profiles of arginase 1 and nitric oxide synthase 2, as well as the ratios of IL-10 to IL-12, were consistent with a type M1 polarized macrophage response in the mice and a type M2 or alternatively-activated response in the deermice. Analysis of metabolites in the plasma and RNA in the tissues revealed differences between the two species in tryptophan metabolism during response to LPS. Two up-regulated genes in particular signified the difference between the species: Slpi (secretory leukocyte proteinase inhibitor) and Ibsp (integrin-binding protein sialoprotein). The latter was previously unrecognized in the context of inflammation or infection. Key RNA-seq findings in P. leucopus were replicated in a second LPS experiment with older animals, in a systemic bacterial infection model, and with cultivated fibroblasts. Taken together, the results indicate that the deermouse possesses several adaptive traits to moderate effects of inflammation and oxidative stress ensuing from infection. This seems to be at the cost of infection persistence and that is to the benefit of the pathogen.

scholarly journals Whip-LAMP: a novel LAMP assay for the detection of Trichuris muris-derived DNA in stool and urine samples in a murine experimental infection model

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Pedro Fernández-Soto ◽  
Carlos Fernández-Medina ◽  
Susana Cruz-Fernández ◽  
Beatriz Crego-Vicente ◽  
Begoña Febrer-Sendra ◽  
...  
Keyword(s):  
Molecular Diagnosis ◽  
Experimental Infection ◽  
Lamp Assay ◽  
Diagnostic Methods ◽  
Urine Samples ◽  
Infection Model ◽  
Trichuris Muris ◽  
Stool Samples ◽  
First Time ◽  
Experimental Infection Model

Abstract Background Trichuris trichiura (human whipworm) infects an estimated 477 million individuals worldwide. In addition to T. trichiura, other Trichuris species can cause an uncommon zoonosis and a number of human cases have been reported. The diagnosis of trichuriasis has relied traditionally on microscopy. Recently, there is an effort to use molecular diagnostic methods, mainly qPCR. LAMP technology could be an alternative for qPCR especially in low-income endemic areas. Trichuris muris, the causative agent of trichuriasis in mice, is of great importance as a model for human trichuriasis. Here, we evaluate the diagnostic utility of a new LAMP assay in an active experimental mouse trichuriasis in parallel with parasitological method by using stool and, for the first time, urine samples. Methods Stool and urine samples were collected from mice infected with eggs of T. muris. The dynamics of infection was determined by counting the number of eggs per gram of faeces. A LAMP based on the 18S rRNA gene from T. muris was designed. Sensitivity and specificity of LAMP was tested and compared with PCR. Stool and urine samples were analysed by both LAMP and PCR techniques. Results Trichuris muris eggs were detected for the first time in faeces 35 days post-infection. LAMP resulted specific and no cross-reactions were found when using 18 DNA samples from different parasites. The detection limit of the LAMP assay was 2 pg of T. muris DNA. When testing stool samples by LAMP we obtained positive results on day 35 p.i. and urine samples showed amplification results on day 20 p.i., i.e. 15 days before the onset of T. muris eggs in faeces. Conclusions To the best of our knowledge, we report, for the first time, a novel LAMP assay (Whip-LAMP) for sensitive detection of T. muris DNA in both stool and urine samples in a well-established mice experimental infection model. Considering the advantages of urine in molecular diagnosis in comparison to stool samples, should make us consider the possibility of starting the use urine specimens in molecular diagnosis and for field-based studies of human trichuriasis where possible. Further studies with clinical samples are still needed.

scholarly journals An experimental infection model to induce digital dermatitis infection in cattle

2012 ◽  
Vol 95 (4) ◽  
pp. 1821-1830 ◽  
Author(s):  
A. Gomez ◽  
N.B. Cook ◽  
N.D. Bernardoni ◽  
J. Rieman ◽  
A.F. Dusick ◽  
...  
Keyword(s):  
Experimental Infection ◽  
Infection Model ◽  
Digital Dermatitis ◽  
Experimental Infection Model

scholarly journals ANTIBACTERIAL THERAPY OF PYOGENIC LIVER ABSCESSES

2021 ◽  
Vol 48 (1) ◽  
Author(s):  
V. V. Novak ◽  
V. O. Belinska
Keyword(s):  
Body Temperature ◽  
Antibiotic Therapy ◽  
Antibacterial Therapy ◽  
Anaerobic Bacteria ◽  
Main Group ◽  
Diagnostic Methods ◽  
Control Group ◽  
Liver Abscesses ◽  
Microbiological Examination ◽  
Facultative Anaerobic Bacteria

Abstract Purpose of the study. To study the features of the microbial landscape, to develop an algorithm for antibacterial therapy in patients with pyogenic liver abscesses. Prove the effectiveness of the developed algorithm in the treatment of such patients. Materials and methods. The results of treatment of 79 patients with pyogenic liver abscesses were analyzed. The mean age of patients was 48,4 ± 4,7 years, with men predominating (62,9%). The inclusion criterion was the presence of pyogenic liver abscesses, the exclusion criteria were cholangiogenic and specific abscesses. The main group consisted of 44 patients operated on minimally invasive technologies based on modern diagnostic methods. They received a comprehensive conservative therapy, which took into account antibacterial treatment according to the developed algorithm. The tactics of surgical treatment of 35 patients in the control group did not differ from the main one. The groups did not differ significantly in age, sex, comorbidity, severity of the disease and the results of microbiological examination. Results. The number of inoculations of microorganisms from the purulent center was dominated by monoinfection – 86,4–88,6% of cases, which was mostly aerobic. Most of them were facultative anaerobic bacteria of the genus Enterobacteriaceae, namely Kl. pneumoniae – 34,1–40,1%. Less than a quarter of patients (11,4–13,6%) isolated cultures are represented by microbial associations – aerobic-anaerobic and aerobicaerobic. However, aerobic-aerobic infection prevailed – 75,0–83,3%. MRSA strains of staphylococci were isolated in 5,7–6,8% of patients. Treatment began on the first day of hospitalization. Empirical treatment was immediately prescribed, followed by antibiotic replacement, if necessary, based on the results of microbiological examination and determination of the sensitivity of the isolated cultures. According to microbiological studies, in patients with AP most of the isolated microorganisms (71,4–90,9%) were sensitive to linezalide and taigecycline. These antibacterial drugs were reserve drugs and were prescribed in extremely severe cases in the absence of sensitivity to other drugs. The effectiveness of treatment was evaluated by clinical data and improvement of laboratory parameters (normalization of body temperature and leukocyte formula). Conclusion. Carrying out adequate combined antibiotic therapy for patients with AP according to the developed algorithms, along with surgery, allowed to reduce the recovery time of patients: for 2–3 days normalization of body temperature (t = 5,66176; P < 0,000001) and leukocyte formula (t = 8, 56860; P < 0,000001) patients of the main group in comparison with control patients. In turn, this contributed to a probable reduction in the length of stay of the patient in the hospital for 3 days (t = 3,95561; P = 0,000116). Keywords: liver abscess, ultrasound semiotics, sonography intervention, classification of abscesses, antibiotic therapy.

Treponeme-Associated Hoof Disease of Free-Ranging Elk (Cervus elaphus) in Southwestern Washington State, USA

2018 ◽  
Vol 56 (1) ◽  
pp. 118-132 ◽  
Author(s):  
Sushan Han ◽  
Kristin G. Mansfield ◽  
Dan S. Bradway ◽  
Thomas E. Besser ◽  
Deryck H. Read ◽  
...  
Keyword(s):  
Cervus Elaphus ◽  
Anaerobic Bacteria ◽  
Washington State ◽  
Enzyme Linked Immunosorbent Assay ◽  
Digital Dermatitis ◽  
Antibody Titers ◽  
Foot Disease ◽  
Sole Ulcers ◽  
Free Ranging ◽  
Suppurative Inflammation

A novel foot disease in free-ranging elk ( Cervus elaphus) in southwestern Washington State emerged in 2008 and spread throughout the region. Initial studies showed adult elk had chronic hoof overgrowth, sole ulcers, and sloughed hoof capsules, but no cause was determined. To identify possible causes and characterize the earliest lesions, 9-, 7-, and 3-month-old elk were collected. Nine-month-old elk had sole ulcers (3/9 elk) and sloughed/overgrown hoof capsules (4/9 elk) similar to adults. Histologically, lesions consisted of coronary, heel bulb, and interdigital ulcers with suppurative inflammation, epithelial hyperplasia, deeply invasive spirochetes, and underrunning of the hoof capsule and heel-sole junction. Spirochetes were identified as Treponema via immunohistochemistry and polymerase chain reaction (PCR). Seven-month-old elk had similar underrunning foot ulcers (6/8 elk) with Treponema identified in all lesions but no chronic overgrowth or sloughed hoof capsules. Three-month-old calves had superficial coronary erosions with no inflammation or identifiable spirochetes (3/5 elk) but were culture/PCR positive for Treponema, suggesting possible early lesions. Lesions from 9- and 7-month-old elk included aerobic and anaerobic bacteria, many of which are associated with infectious foot disease in livestock. Antibody enzyme-linked immunosorbent assay of 7- and 3-month-old elk from the enzootic region showed a trend toward increased Treponema antibody titers compared to normal control elk from outside the region, further supporting the significance of Treponema in the pathogenesis of foot disease. Treponeme-associated hoof disease (TAHD) in elk, a debilitating and progressive condition, shares similarities to bovine digital dermatitis and contagious ovine digital dermatitis.

scholarly journals Amixicile, a Novel Inhibitor of Pyruvate:Ferredoxin Oxidoreductase, Shows Efficacy against Clostridium difficile in a Mouse Infection Model

2012 ◽  
Vol 56 (8) ◽  
pp. 4103-4111 ◽  
Author(s):  
Cirle A. Warren ◽  
Edward van Opstal ◽  
T. Eric Ballard ◽  
Andrew Kennedy ◽  
Xia Wang ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Diarrheal Disease ◽  
Anaerobic Bacteria ◽  
Disease Recurrence ◽  
High Rate ◽  
Infection Model ◽  
Content Type ◽  
Mouse Infection Model ◽  
Pyruvate:Ferredoxin Oxidoreductase

ABSTRACTClostridium difficileinfection (CDI) is a serious diarrheal disease that often develops following prior antibiotic usage. One of the major problems with current therapies (oral vancomycin and metronidazole) is the high rate of recurrence. Nitazoxanide (NTZ), an inhibitor of pyruvate:ferredoxin oxidoreductase (PFOR) in anaerobic bacteria, parasites,Helicobacter pylori, andCampylobacter jejuni, also shows clinical efficacy against CDI. From a library of ∼250 analogues of NTZ, we identified leads with increased potency for PFOR. MIC screens indicatedin vitroactivity in the 0.05- to 2-μg/ml range againstC. difficile. To improve solubility, we replaced the 2-acetoxy group with propylamine, producing amixicile, a soluble (10 mg/ml), nontoxic (cell-based assay) lead that produced no adverse effects in mice by oral or intraperitoneal (i.p.) routes at 200 mg/kg of body weight/day. In initial efficacy testing in mice treated (20 mg/kg/day, 5 days each) 1 day after receiving a lethal inoculum ofC. difficile, amixicile showed slightly less protection than did vancomycin by day 5. However, in an optimized CDI model, amixicile showed equivalence to vancomycin and fidaxomicin at day 5 and there was significantly greater survival produced by amixicile than by the other drugs on day 12. All three drugs were comparable by measures of weight loss/gain and severity of disease. Recurrence of CDI was common for mice treated with vancomycin or fidaxomicin but not for mice receiving amixicile or NTZ. These results suggest that gut repopulation with beneficial (non-PFOR) bacteria, considered essential for protection against CDI, rebounds much sooner with amixicile therapy than with vancomycin or fidaxomicin. If the mouse model is indeed predictive of human CDI disease, then amixicile, a novel PFOR inhibitor, appears to be a very promising new candidate for treatment of CDI.

scholarly journals Diagnosis of orthopaedic-implant-associated infections caused by slow-growing Gram-positive anaerobic bacteria – a clinical perspective

2021 ◽  
Vol 6 (8) ◽  
pp. 367-378
Author(s):  
Diana Salomi Ponraj ◽  
Thomas Falstie-Jensen ◽  
Nis Pedersen Jørgensen ◽  
Christen Ravn ◽  
Holger Brüggemann ◽  
...  
Keyword(s):  
Current Knowledge ◽  
Anaerobic Bacteria ◽  
Growth Conditions ◽  
Diagnostic Methods ◽  
Orthopaedic Implant ◽  
Gram Positive ◽  
Laboratory Findings ◽  
Cutibacterium Acnes ◽  
Causative Agents ◽  
Slow Growing

Abstract. Slow-growing Gram-positive anaerobic bacteria (SGAB) such as Cutibacterium acnes are increasingly recognized as causative agents of implant-associated infections (IAIs) in orthopaedic surgeries. SGAB IAIs are difficult to diagnose because of their non-specific clinical and laboratory findings as well as the fastidious growth conditions required by these bacteria. A high degree of clinical suspicion and awareness of the various available diagnostic methods is therefore important. This review gives an overview of the current knowledge regarding SGAB IAI, providing details about clinical features and available diagnostic methodologies. In recent years, new methods for the diagnosis of IAI were developed, but there is limited knowledge about their usefulness in SGAB IAI. Further studies are required to determine the ideal diagnostic methodology to identify these infections so that they are not overlooked and mistakenly classified as aseptic failure.

Design of Direct On-Seabed Sliding Foundations

2014 ◽  
Author(s):  
Andrew Deeks ◽  
Hongjie Zhou ◽  
Henry Krisdani ◽  
Fraser Bransby ◽  
Phil Watson
Keyword(s):  
Laboratory Model ◽  
Soil Conditions ◽  
Soil Parameters ◽  
Pipeline System ◽  
Shear Stresses ◽  
Foundation Settlement ◽  
Relative Significance ◽  
Cyclic Shear ◽  
Key Aspects ◽  
The Impact

This paper describes a new framework for the geotechnical design of pipeline-related foundations (e.g. foundations for PLETs and Tees) designed to slide directly over the seabed during pipeline operation. This approach can present considerable savings in terms of fabrication and construction costs because of reduced foundation sizes. Over the design life, a pipeline is likely to endure many thermal/ pressure load cycles due to product and flow rate variations during operation. These cycles result in the foundation sliding back and forth across the seabed within a footprint. These loads and corresponding motions impose cyclic shear stresses on the soil that can (i) degrade foundation bearing capacity and (ii) cause additional foundation settlement. Often the key design consideration is whether or not the cumulative settlements will eventually compromise the integrity of the pipeline system to which the PLET and its associated foundation are attached. In addition to consolidation and creep, two key mechanisms are shown to control cyclic foundation settlement: (i) bearing mechanism induced burial and (ii) cyclic shear stress driven soil volume reduction. Their relative significance depends on the soil conditions (soil state) and input pipeline movements. The paper presents key aspects required for the design of direct on-seabed sliding foundations, including the soil parameters and associated testing required. Validation of the design approach is illustrated by comparison to laboratory model tests performed on carbonate soils. The impact of soil properties on potential foundation performance is illustrated with a design example and the importance of conducting site specific soil testing and settlement analyses is emphasised. It is also illustrated that close integration of the pipeline, structural and geotechnical analysis is necessary to reliably quantify system performance of these novel foundations.

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