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In Vitro Assessment of Anticoccidials: Methods and Molecules. Animals (Basel) 2021; 11:ani11071962. [PMID: 34209100 PMCID: PMC8300270 DOI: 10.3390/ani11071962] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 06/25/2021] [Indexed: 12/13/2022] Open
Abstract
Simple Summary Coccidiosis is a major problem in poultry production, leading to significant economic losses. Due to the outbreak of resistance to the available treatments, research is focusing on finding new molecules that work against the pathogen. Botanical compounds represent promising alternatives, but reliable in vitro tests are needed for their screening and to understand their mechanism of action. Research in vitro involves studies on the environmental phase of the parasite and studies on the endogenous development, which occurs inside the host cells and that requires cell cultures or in ovo models to be studied. This review aims to summarize the protocols that have been successfully applied so far, as well as to suggest potential cues to improve research on this field. Moreover, as the surge of botanicals as anticoccidial molecules is on the rise, the intent is to provide an overview of the methods to assess their effectiveness in vitro in comparison with conventional drugs. Abstract Avian coccidiosis is a disease causing considerable economic losses in the poultry industry. It is caused by Eimeria spp., protozoan parasites characterized by an exogenous–endogenous lifecycle. In vitro research on these pathogens is very complicated and lacks standardization. This review provides a description of the main in vitro protocols so far assessed focusing on the exogenous phase, with oocyst viability and sporulation assays, and on the endogenous phase, with invasion and developmental assays in cell cultures and in ovo. An overview of these in vitro applications to screen both old and new remedies and to understand the relative mode of action is also discussed.
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Zhang JF, Wei B, Cha SY, Shang K, Jang HK, Kang M. The use of embryonic chicken eggs as an alternative model to evaluate the virulence of Salmonella enterica serovar Gallinarum. PLoS One 2020; 15:e0238630. [PMID: 32911523 PMCID: PMC7500061 DOI: 10.1371/journal.pone.0238630] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 08/19/2020] [Indexed: 11/25/2022] Open
Abstract
Salmonella enterica serovar Gallinarum (S.
Gallinarum) can cause fowl typhoid, a severe systemic disease responsible for
considerable economic losses. Chicken pathogenicity test is the traditional
method for assessing the virulence of S. Gallinarum. However,
this method is limited by several factors, including ethical considerations,
costs, and the need for specialized facilities. Hence, we established a chicken
embryo lethality assay (ELA) model to determine the virulence of
S. Gallinarum. Three virulent and three avirulent
representative strains, which were confirmed by the chicken pathogenicity test,
were used to perform the ELA. The most significant difference between the
virulent and avirulent strains could be observed when 13-day-old embryos were
inoculated via the AC route and incubated for 5 days. Based on a 50% embryo
lethal dose (ELD50), isolates considered to be virulent had a
Log10ELD50 of ≤ 4.0, moderately virulent strains had a
Log10ELD50 of 4.0−6.1, and avirulent isolates had a
Log10ELD50 of ≥ 6.1. Different abilities to invade the
liver of embryos were found between the virulent and avirulent strains by a
growth curve experiment in vitro. The maximum colony-forming
units (CFU) of the virulent strain was about 10,000 times higher than that of
the avirulent strain in the liver at 5 days post infection. The ELA results of
42 field strains showed that thirty-two strains (76.2%) were virulent, nine were
moderately virulent (21.4%), and one strain was avirulent (2.4%). In conclusion,
these results suggest that the ELA can be used as an alternative method to
assess the virulence of S. Gallinarum, which will contribute to
the study of virulence genes, virulence evolution, pathogenic mechanisms and
vaccine development.
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Affiliation(s)
- Jun-feng Zhang
- Department of Veterinary Infectious Diseases and Avian Diseases, College
of Veterinary Medicine and Center for Poultry Diseases Control, Jeonbuk National
University, Iksan, South Korea
| | - Bai Wei
- Department of Veterinary Infectious Diseases and Avian Diseases, College
of Veterinary Medicine and Center for Poultry Diseases Control, Jeonbuk National
University, Iksan, South Korea
| | - Se-Yeoun Cha
- Department of Veterinary Infectious Diseases and Avian Diseases, College
of Veterinary Medicine and Center for Poultry Diseases Control, Jeonbuk National
University, Iksan, South Korea
| | - Ke Shang
- Department of Veterinary Infectious Diseases and Avian Diseases, College
of Veterinary Medicine and Center for Poultry Diseases Control, Jeonbuk National
University, Iksan, South Korea
| | - Hyung-Kwan Jang
- Department of Veterinary Infectious Diseases and Avian Diseases, College
of Veterinary Medicine and Center for Poultry Diseases Control, Jeonbuk National
University, Iksan, South Korea
- Bio Disease Control(BIOD) Co., Ltd., Iksan, Republic of
Korea
- * E-mail: (MK); (HKJ)
| | - Min Kang
- Department of Veterinary Infectious Diseases and Avian Diseases, College
of Veterinary Medicine and Center for Poultry Diseases Control, Jeonbuk National
University, Iksan, South Korea
- Bio Disease Control(BIOD) Co., Ltd., Iksan, Republic of
Korea
- * E-mail: (MK); (HKJ)
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Insertional mutagenesis in the zoonotic pathogen Chlamydia caviae. PLoS One 2019; 14:e0224324. [PMID: 31697687 PMCID: PMC6837515 DOI: 10.1371/journal.pone.0224324] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 10/11/2019] [Indexed: 11/19/2022] Open
Abstract
The ability to introduce targeted genetic modifications in microbial genomes has revolutionized our ability to study the role and mode of action of individual bacterial virulence factors. Although the fastidious lifestyle of obligate intracellular bacterial pathogens poses a technical challenge to such manipulations, the last decade has produced significant advances in our ability to conduct molecular genetic analysis in Chlamydia trachomatis, a major bacterial agent of infertility and blindness. Similar approaches have not been established for the closely related veterinary Chlamydia spp., which cause significant economic damage, as well as rare but potentially life-threatening infections in humans. Here we demonstrate the feasibility of conducting site-specific mutagenesis for disrupting virulence genes in C. caviae, an agent of guinea pig inclusion conjunctivitis that was recently identified as a zoonotic agent in cases of severe community-acquired pneumonia. Using this approach, we generated C. caviae mutants deficient for the secreted effector proteins IncA and SinC. We demonstrate that C. caviae IncA plays a role in mediating fusion of the bacteria-containing vacuoles inhabited by C. caviae. Moreover, using a chicken embryo infection model, we provide first evidence for a role of SinC in C. caviae virulence in vivo.
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Trotereau A, Schouler C. Use of a Chicken Embryo Lethality Assay to Assess the Efficacy of Phage Therapy. Methods Mol Biol 2019; 1898:199-205. [PMID: 30570735 DOI: 10.1007/978-1-4939-8940-9_17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
To combat infectious diseases induced by antibiotic-resistant bacteria in human and animals, phage therapy has regained attention by the scientific community. Before phages can be widely accepted as therapeutics in the same way as antibiotics, convincing detailed applied experimental evidence must be available. The embryonated chicken egg model has been used to study the virulence of many pathogens. We describe here a procedure to test the efficacy of phage therapy to treat colibacillosis using a chicken embryo lethality assay, this being potentially applied to others bacterial infection.
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Huang Q, Gao X, Liu P, Lin H, Liu W, Liu G, Zhang J, Deng G, Zhang C, Cao H, Guo X, Hu G. The relationship between liver-kidney impairment and viral load after nephropathogenic infectious bronchitis virus infection in embryonic chickens. Poult Sci 2018; 96:1589-1597. [PMID: 28108730 PMCID: PMC7107109 DOI: 10.3382/ps/pew455] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 12/07/2016] [Indexed: 12/30/2022] Open
Abstract
To examine the relationship of impairments of the liver and kidney with viral load after nephropathogenic infectious bronchitis virus (NIBV) infection in embryonic chickens, 120 specific-pathogen-free Leghorn embryonated chicken eggs were randomly divided into two groups (infected and control), with three replicates per group and 20 eggs in each replicate. The eggs in the infected and control groups were challenged with 0.2 mL of 105.5 ELD50 NIBV and sterile saline solution, respectively. The embryonic chickens' plasma and liver and kidney tissues were collected at 1, 3, and 5 days post-inoculation (dpi), the liver and kidney functional parameters were quantified, and the tissue viral loads were determined with real-time PCR. The results showed that plasma potassium, sodium, chlorine, magnesium, calcium, and phosphorus levels were increased. The infected group exhibited significantly higher plasma uric acid, blood urea nitrogen, and creatinine levels than the control group at 3 dpi. The plasma concentrations of aspartate aminotransferase and alanine aminotransferase were significantly increased in the infected group. The total protein, albumin, and globulin levels in the infected group were significantly lower than those in the control group. The liver-kidney viral load in the infected group peaked at 3 dpi, at which time the kidney viral load was significantly higher than that of the liver. Our results indicated that NIBV infection caused liver and kidney damage in the embryonic chickens, and the results also demonstrated that the liver and kidney damage was strongly related to the tissue viral load following NIBV infection in embryonic chickens.
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Using the chicken embryo to assess virulence of Listeria monocytogenes and to model other microbial infections. Nat Protoc 2015; 10:1155-64. [PMID: 26134955 DOI: 10.1038/nprot.2015.073] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Microbial infections are a global health problem, particularly as microbes are continually developing resistance to antimicrobial treatments. An effective and reliable method for testing the virulence of different microbial pathogens is therefore a useful research tool. This protocol describes how the chicken embryo can be used as a trustworthy, inexpensive, ethically desirable and quickly accessible model to assess the virulence of the human bacterial pathogen Listeria monocytogenes, which can also be extended to other microbial pathogens. We provide a step-by-step protocol and figures and videos detailing the method, including egg handling, infection strategies, pathogenicity screening and isolation of infected organs. From the start of incubation of the fertilized eggs, the protocol takes <4 weeks to complete, with the infection part taking only 3 d. We discuss the appropriate controls to use and potential adjustments needed for adapting the protocol for other microbial pathogens.
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Gripenland J, Andersson C, Johansson J. Exploring the chicken embryo as a possible model for studying Listeria monocytogenes pathogenicity. Front Cell Infect Microbiol 2014; 4:170. [PMID: 25540772 PMCID: PMC4261823 DOI: 10.3389/fcimb.2014.00170] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 11/17/2014] [Indexed: 11/13/2022] Open
Abstract
Listeria monocytogenes is a bacterial pathogen capable of causing severe infections in humans, often with fatal outcomes. Many different animal models exist to study L. monocytogenes pathogenicity, and we have investigated the chicken embryo as an infection model: What are the benefits and possible drawbacks? We have compared a defined wild-type strain with its isogenic strains lacking well-characterized virulence factors. Our results show that wild-type L. monocytogenes, already at a relatively low infection dose (~5 × 10(2) cfu), caused death of the chicken embryo within 36 h, in contrast to strains lacking the main transcriptional activator of virulence, PrfA, or the cytolysin LLO. Surprisingly, strains lacking the major adhesins InlA and InlB caused similar mortality as the wild-type strain. In conclusion, our results suggest that the chicken embryo is a practical model to study L. monocytogenes infections, especially when analyzing alternative virulence pathways independent of the InlA and InlB adhesins. However, the route of infection might be different from a human infection. The chicken embryo model and other Listeria infection models are discussed.
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Affiliation(s)
- Jonas Gripenland
- Department of Molecular Biology, Umeå University Umeå, Sweden ; Laboratory for Molecular Infection Medicine Sweden, Umeå University Umeå, Sweden ; Umeå Centre for Microbial Research, Umeå University Umeå, Sweden
| | - Christopher Andersson
- Department of Molecular Biology, Umeå University Umeå, Sweden ; Laboratory for Molecular Infection Medicine Sweden, Umeå University Umeå, Sweden ; Umeå Centre for Microbial Research, Umeå University Umeå, Sweden
| | - Jörgen Johansson
- Department of Molecular Biology, Umeå University Umeå, Sweden ; Laboratory for Molecular Infection Medicine Sweden, Umeå University Umeå, Sweden ; Umeå Centre for Microbial Research, Umeå University Umeå, Sweden
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Huang L, Zhu H, Zhang S, Wang R, Liu L, Jian F, Ning C, Zhang L. An in vitro model of infection of chicken embryos by Cryptosporidium baileyi. Exp Parasitol 2014; 147:41-7. [DOI: 10.1016/j.exppara.2014.10.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 10/01/2014] [Accepted: 10/16/2014] [Indexed: 11/16/2022]
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