Different virulence levels of Enterococcus cecorum strains in experimentally infected meat-type chickens

In recent years, pathogenic strains of Enterococcus cecorum (EC) have emerged as a causing agent of septicemia and skeletal infection in broiler chickens with a high economic impact worldwide. Although research has been conducted, many aspects of the pathogenesis of the EC-associated disease are still unknown. In the present study, an experimental infection model was established in broiler chickens. Two different EC strains (EC14 and EC15) were compared in two different concentrations of each strain (2 × 106 and 2 × 108 colony-forming units per milliliter (CFU/mL)) after oral infection of one-day-old chicks. Clinical signs and gross lesions of the EC-associated disease were monitored in the following seven weeks. Although both EC strains were originally isolated from clinical disease outbreaks and had a high embryonic lethality, only EC14 successfully induced the typical course of the EC-associated disease with characteristic clinical signs and gross lesions. In total, 23% of the birds in the two EC14-groups were EC-positive in extraintestinal organs on culture, and no differences were found between the two infectious doses. EC14 was frequently detected via real-time PCR in the free thoracic vertebra (FTV) and femoral heads without any detectable gross lesions. The number of EC positive spleens from infected broilers was comparable using bacterial isolation and a specific real-time PCR. Interestingly, EC15 was not detected in extraintestinal organs, although birds in the EC15 groups were colonized by EC in the ceca after experimental infection. The present study represents first proof that virulence differs among EC strains in experimentally infected chickens, and emphasizes the need to further characterize virulence factors and pathogenic mechanisms of EC. The strain EC14 at a dose of 106 CFU is suitable for reproduction of the EC-associated disease. The experimental infection model reported here provides the basis for further research on the EC pathogenesis and possible prevention and intervention strategies.

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Interaction between nutrition and Eimeria acervulina infection in broiler chickens: diet compositions that improve fat digestion during Eimeria acervulina infection

British Journal Of Nutrition ◽

10.1079/bjn19960193 ◽

1996 ◽

Vol 75 (6) ◽

pp. 875-880 ◽

Cited By ~ 18

Author(s):

C. Adams ◽

H. A. Vahl ◽

A. Veldman

Keyword(s):

Cholic Acid ◽

Experimental Infection ◽

Broiler Chickens ◽

Coconut Oil ◽

Infection Model ◽

Eimeria Acervulina ◽

Animal Fat ◽

Fat Digestion ◽

Performance Results ◽

Experimental Infection Model

Previously an experimental infection model was developed in which broiler chickens were inoculated with sporulated Eimeria acervufina oocysts at an age of 18 d. The infection resulted in adverse performance results and reduced nutrient digestion. In two new experiments with the infection model effects of diet adjustments on fat digestion were investigated. In the first experiment addition of 0·4 g cholic acid/kg to a diet rich in animal fat resulted in increased fat digestion during the infection. In the second experiment replacing animal fat by coconut oil resulted in improved fat digestion during the coccidiosis infection. However, replacement of animal fat by soyabean oil did not improve fat digestion.

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Porcine Gammaherpesviruses in Italian Commercial Swine Population: Frequent but Harmless

Pathogens ◽

10.3390/pathogens10010047 ◽

2021 ◽

Vol 10 (1) ◽

pp. 47

Author(s):

Giovanni Franzo ◽

Michele Drigo ◽

Matteo Legnardi ◽

Laura Grassi ◽

Maria Luisa Menandro ◽

...

Keyword(s):

Real Time ◽

Real Time Pcr ◽

Clinical Signs ◽

Northern Italy ◽

Porcine Circovirus ◽

Swine Industry ◽

Positive Interaction ◽

High Prevalence ◽

Swine Population ◽

Clinical Conditions

Differently from alpha- and betaherpesviruses affecting swine, interest in the recently discovered Suid gammaherpesvirus 3, Suid gammaherpesvirus 4, and Suid gammaherpesvirus 5, also known as porcine lymphotropic herpesviruses (PLHV-1, PLHV-2, and PLHV-3), has largely focused on their role as potential zoonotic agents in cases of xenotransplantation. However, their role as primary pathogens of swine or as co-factors for other lymphotropic infections has essentially been neglected. The present study aims at filling this gap, evaluating the association between PLHVs infection and different clinical conditions and/or porcine circovirus (PCV) co-infection. One hundred seventy-six samples were obtained from different animals located in a high-density pig area of Northern Italy in the period 2017–2020. The presence of PLHVs and PCVs was tested and quantified by specific real-time PCR: PLHVs were widespread among pigs (PLHV-1, PLHV-2, and PLHV-3 prevalence was 28.97%, 10.79%, and 4.54%, respectively) and detected in all considered tissues and clinical conditions. Frequent co-infections were also observed among PLHVs and with PCVs, although a significant association was not detected with the exception of a positive interaction between PLHV-1 and PLHV-3, and a negative one between PLHV-2 and PCV-2. Significantly, no association between PLHVs, alone or in co-infection, emerged with any of the considered clinical signs, their frequency being comparable between healthy and diseased animals. Based on these pieces of evidence and despite their high prevalence, PLHVs’ relevance for the swine industry appears negligible, either as primary pathogens or as predisposing factors for circovirus-induced diseases.

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A pasture-based experimental infection model for footrot in sheep

Small Ruminant Research ◽

10.1016/j.smallrumres.2020.106305 ◽

2020 ◽

pp. 106305

Author(s):

Andrew S. McPherson ◽

Richard J. Whittington ◽

Ruth M. Kennan ◽

Julian I. Rood ◽

Om P. Dhungyel

Keyword(s):

Experimental Infection ◽

Infection Model ◽

Experimental Infection Model

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Detection of Aspergillus species in bone marrow transplant patients

The Journal of Infection in Developing Countries ◽

10.3855/jidc.807 ◽

2010 ◽

Vol 4 (08) ◽

pp. 511-516 ◽

Cited By ~ 12

Author(s):

Parisa Badiee ◽

Abdolvahab Alborzi

Keyword(s):

Bone Marrow ◽

Real Time ◽

Bone Marrow Transplant ◽

Real Time Pcr ◽

Clinical Signs ◽

Marrow Transplant ◽

Aspergillus Species ◽

Pcr Assay ◽

Blood Samples ◽

Transplant Patients

Introduction: Invasive aspergillosis is a severe complication of cytotoxic chemotherapies and bone marrow transplantation (BMT). The aim of this study was to assess the utility of a real-time PCR assay for the early diagnosis of Aspergillus species in blood samples from BMT patients. Methodology: Blood specimens (n = 993) from patients (n = 82) scheduled for BMT were collected prior to transplant and for 100 days post transplantation. The specimens were later tested using an Aspergillus-specific real-time PCR assay. Cultures of clinical samples, along with sonography and computerized tomographic scans, were performed as standard of care. Results: Aspergillus DNA was positive in 94 sequential blood samples from 13 patients with clinical and radiological signs of infection. Samples from three of these patients were PCR-positive for Aspergillus in the first week of admission, prior to transplantation. Four patients with aspergillosis were cured with antifungal agents and nine died. An additional 12 patients without clinical signs of infection were PCR-positive on one occasion each, while two patients with clinical signs of infection were PCR-negative. Compared to routine methods of aspergillosis diagnosis, the respective sensitivity, specificity, negative, and positive predictive values of the PCR method by patient were 86.6%, 82%, 96.5% and 52%. Conclusions: The results show that Aspergillus infections in the blood of bone marrow transplant patients can be dectected by PCR methods. Early detection of Aspergillus infections by PCR has the potential to positively impact patient mortality rate and provide cost savings to hospitals.

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Use of quantitative real-time PCR for studying the dissemination of Leptospira interrogans in the guinea pig infection model of leptospirosis

Journal of Medical Microbiology ◽

10.1099/jmm.0.008169-0 ◽

2009 ◽

Vol 58 (5) ◽

pp. 648-655 ◽

Cited By ~ 39

Author(s):

Kristel Lourdault ◽

Florence Aviat ◽

Mathieu Picardeau

Keyword(s):

Guinea Pig ◽

Real Time ◽

Real Time Pcr ◽

Guinea Pigs ◽

Infection Model ◽

Avirulent Strain ◽

Leptospira Interrogans ◽

Quantitative Real Time Pcr ◽

Guinea Pig Model

The dynamics of leptospirosis infection have been poorly studied. The purpose of this study was to determine the LD50, rate of bacterial dissemination, histopathology and antibody responses against leptospira following inoculation with the highly virulent Leptospira interrogans Fiocruz L1-130 strain in a guinea pig model of leptospirosis. Three routes of infection (intraperitoneal, conjunctival and subcutaneous inoculation) were used to establish disease in guinea pigs. The size and kinetics of leptospiral burdens in the blood and tissues of infected animals were determined over a 1 week course of infection using quantitative real-time PCR (qPCR). Bacteraemia peaked at day 5 post-infection reaching more than 5×104 leptospires ml−1. The highest spirochaetal load was found in the liver and kidneys, and was associated with alterations in organ tissues and a decline in liver and kidney functions. In contrast, lesions and bacteria were not detected in guinea pigs infected with an avirulent strain derived from a high-passage-number in vitro-passaged variant of the Fiocruz L1-130 strain. The use of qPCR supports the findings of earlier studies and provides an easy and reliable method for the quantification of L. interrogans in the tissues of infected animals. qPCR will be used in future studies to evaluate the efficacy of vaccine candidates against leptospirosis and the virulence of selected L. interrogans mutants relative to the parental strain.

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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

Parasites & Vectors ◽

10.1186/s13071-020-04435-1 ◽

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.

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Objective pathogen monitoring in nursery and finisher pigs by monthly laboratory diagnostic testing

Porcine Health Management ◽

10.1186/s40813-020-00161-3 ◽

2020 ◽

Vol 6 (1) ◽

Author(s):

Nicole B. Goecke ◽

Maja Kobberø ◽

Thomas K. Kusk ◽

Charlotte K. Hjulsager ◽

Ken Steen Pedersen ◽

...

Keyword(s):

Real Time ◽

San Francisco ◽

Influenza A Virus ◽

High Throughput ◽

Real Time Pcr ◽

Influenza A ◽

Clinical Signs ◽

Swine Influenza ◽

Porcine Cytomegalovirus ◽

Swine Influenza A Virus

Abstract Background Infectious diseases are of great economic importance in commercial pig production, causing both clinical and subclinical disease, with influence on welfare, productivity, and antibiotic use. The causes of these diseases are often multifactorial and laboratory diagnostics are seldom routinely performed. The aim of the present study was to explore the benefits of monthly pathogen monitoring in nursery and finisher herds and to examine association between laboratory results and observed clinical signs, including coughing and diarrhoea. Three monthly samplings were conducted in three different age groups in six nursery and four finisher production units. For each unit, two pens were randomly selected in each age group and evaluated for coughing and diarrhoea events. Furthermore, faecal sock and oral fluid samples were collected in the selected pens and analysed for 18 respiratory and enteric viral and bacterial pathogens using the high-throughput real-time PCR BioMark HD platform (Fluidigm, South San Francisco, USA). Results In total, 174 pens were sampled in which eight coughing events and 77 diarrhoeic events were observed. The overall findings showed that swine influenza A virus, porcine circovirus 2, porcine cytomegalovirus, Brachyspira pilosicoli, Lawsonia intracellularis, Escherichia coli fimbria types F4 and F18 were found to be prevalent in several of the herds. Association between coughing events and the presence of swine influenza A virus, porcine cytomegalovirus (Cq ≤ 20) or a combination of these were found. Furthermore, an association between diarrhoeic events and the presence of L. intracellularis (Cq ≤ 24) or B. pilosicoli (Cq ≤ 26) was found. Conclusions The use of high-throughput real-time PCR analysis for continuous monitoring of pathogens and thereby dynamics of infections in a pig herd, provided the veterinarian and farmer with an objective knowledge on the distribution of pathogens in the herd. In addition, the use of a high-throughput method in combination with information about clinical signs, productivity, health status and antibiotic consumption, presents a new and innovative way of diagnosing and monitoring pig herds and even to a lower cost than the traditional method.

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