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Does methionine enhance immunity in Mycoplasma gallispeticum F strain vaccinated broiler breeder pullets? J APPL POULTRY RES 2021. [DOI: 10.1016/j.japr.2021.100172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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2
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Redweik GAJ, Jochum J, Mellata M. Live Bacterial Prophylactics in Modern Poultry. Front Vet Sci 2020; 7:592312. [PMID: 33195630 PMCID: PMC7655978 DOI: 10.3389/fvets.2020.592312] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 09/21/2020] [Indexed: 11/25/2022] Open
Abstract
Commercial poultry farms frequently use live bacterial prophylactics like vaccines and probiotics to prevent bacterial infections. Due to the emergence of antibiotic-resistant bacteria in poultry animals, a closer examination into the health benefits and limitations of commercial, live prophylactics as an alternative to antibiotics is urgently needed. In this review, we summarize the peer-reviewed literature of several commercial live bacterial vaccines and probiotics. Per our estimation, there is a paucity of peer-reviewed published research regarding these products, making repeatability, product-comparison, and understanding biological mechanisms difficult. Furthermore, we briefly-outline significant issues such as probiotic-label accuracy, lack of commercially available live bacterial vaccines for major poultry-related bacteria such as Campylobacter and Clostridium perfringens, as well research gaps (i.e., probiotic-mediated vaccine adjuvancy, gut-brain-microbiota axis). Increased emphasis on these areas would open several avenues for research, ranging from improving protection against bacterial pathogens to using these prophylactics to modulate animal behavior.
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Affiliation(s)
- Graham A. J. Redweik
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA, United States
- Interdepartmental Microbiology Graduate Program, Iowa State University, Ames, IA, United States
| | - Jared Jochum
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA, United States
- Interdepartmental Microbiology Graduate Program, Iowa State University, Ames, IA, United States
| | - Melha Mellata
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA, United States
- Interdepartmental Microbiology Graduate Program, Iowa State University, Ames, IA, United States
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3
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Bao J, Wu Z, Ishfaq M, Miao Y, Li R, Clifton AC, Ding L, Li J. Comparison of Experimental Infection of Normal and Immunosuppressed Chickens with Mycoplasma gallisepticum. J Comp Pathol 2020; 175:5-12. [PMID: 32138843 DOI: 10.1016/j.jcpa.2019.12.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 12/02/2019] [Accepted: 12/05/2019] [Indexed: 01/15/2023]
Abstract
Four different models of infection of chickens with Mycoplasma gallisepticum (MG) were evaluated. Normal or immunosuppressed chicks (10 days old) were infected with the MG Rlow strain via eye and nasal drops or by direct air sac injection. Bacterial load in the lungs was quantified and air sac and tracheal lesion scores, tracheal mucosal thickness and humoral immune responses were assessed. Serum antibody responses were assessed by use of a serum plate agglutination test. Three days post infection (dpi), all immunosuppressed chicks had developed significant respiratory signs. Chicks infected via air sac injection had significant differences in serum antibody and gross lesion scores at 5 dpi. All chicks had developed pathological changes by 7 dpi. Air sac inoculation of immunosuppressed chicks produced more significant (P ≤0.05) lesions, and these birds had the highest bacterial load in the lungs compared with other groups.
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Affiliation(s)
- J Bao
- College of Veterinary Medicine, China
| | - Z Wu
- College of Veterinary Medicine, China
| | - M Ishfaq
- College of Veterinary Medicine, China
| | - Y Miao
- College of Veterinary Medicine, China
| | - R Li
- College of Veterinary Medicine, China
| | | | - L Ding
- College of Life Sciences, Northeast Agricultural University, 600 Changjiang Road, Xiangfang District, Harbin, China
| | - J Li
- College of Veterinary Medicine, China; Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, 600 Changjiang Road, Xiangfang District, Harbin, China.
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4
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Hashemi S, Mahzounieh M, Sheikhi N, Ebrahimi A. Application of high-resolution melting-curve analysis on pvpA gene for detection and classification of Mycoplasma gallisepticum strains. Microb Pathog 2018; 124:365-371. [PMID: 29959042 DOI: 10.1016/j.micpath.2018.06.032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 06/19/2018] [Accepted: 06/21/2018] [Indexed: 11/25/2022]
Abstract
Mycoplasma gallisepticum (MG) is an avian species pathogen which causes heavy economic losses in the poultry industry. The purpose of this study was to determine genomic diversity of 14 MG field strains from chicken, Chuker partridge and peacock collected during 2009-2012 in Iran by polymerase chain reaction and partial sequencing of the pvpA gene. A High-Resolution Melting (HRM) technique was also developed and applied to differentiate between field and vaccine strains. Sequencing of the pvpA gene revealed a 51 nucleotide deletion, within DR-1 and DR-2, among MG strains from chicken and partridge whilst 63 nucleotides were deleted in MG strain from peacock. One nucleotide substitution was also observed among chicken MG strains. Phylogenetic analysis of the sequences clustered all of the Iranian MG strains into two clades or phylogeny groups; the strains from chicken and partridge in one group (group 1) and the strain from peacock into another group (group 4). HRM analysis has also produced comparable outcome to those of sequencing; four distinct melting curves which correspond to the three MG strains from chicken, Chukar partridge and peacock and ts-11 vaccine strain. Overall, findings of this study point towards a single source of infection for the chicken and partridge MG strains and likelihood of the strains being native and endemic in Iran. Peacock considered as an exotic species in Iran, hence the genetic distance for the pvpA gene. MG can be transmitted easily among different avian species and this distinct peacock strain may pose a threat to poultry industry. Our findings also show that molecular variation among pvpA gene of MG strains could be revealed using the relatively rapid and affordable HRM technique.
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Affiliation(s)
- Shabnam Hashemi
- Research Institute for Zoonotic Diseases and Department of Pathobiology, Faculty of Veterinary Medicine, Shahrekord University, Shahrekord, Iran.
| | - Mohammadreza Mahzounieh
- Research Institute for Zoonotic Diseases and Department of Pathobiology, Faculty of Veterinary Medicine, Shahrekord University, Shahrekord, Iran
| | - Nariman Sheikhi
- Department of Clinical Sciences, Faculty of Specialized Veterinary Sciences, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Azizollah Ebrahimi
- Research Institute for Zoonotic Diseases and Department of Pathobiology, Faculty of Veterinary Medicine, Shahrekord University, Shahrekord, Iran
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Prezotto CF, Marin SY, Araújo TS, Barbosa FO, Barrios PR, Gomes AM, Peconick AP, Resende M, Sousa RV, Martins NRS. Experimental Coinfection of Chicken Anemia Virus and Mycoplasma gallisepticum Vaccine Strains in Broiler Chicks. BRAZILIAN JOURNAL OF POULTRY SCIENCE 2016. [DOI: 10.1590/1806-9061-2016-0235] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- CF Prezotto
- Universidade Federal de Minas Gerais, Brazil
| | - SY Marin
- Universidade Federal de Minas Gerais, Brazil
| | - TS Araújo
- Universidade Federal de Lavras, Brazil
| | - FO Barbosa
- Universidade Federal de Minas Gerais, Brazil
| | | | - AM Gomes
- Universidade Federal de Lavras, Brazil
| | | | - M Resende
- Universidade Federal de Minas Gerais, Brazil
| | - RV Sousa
- Universidade Federal de Lavras, Brazil
| | - NRS Martins
- Universidade Federal de Minas Gerais, Brazil
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Evaluation of the Capacity of PCR and High-Resolution Melt Curve Analysis for Identification of Mixed Infection with Mycoplasma gallisepticum Strains. PLoS One 2015; 10:e0126824. [PMID: 25970590 PMCID: PMC4430288 DOI: 10.1371/journal.pone.0126824] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 04/07/2015] [Indexed: 11/27/2022] Open
Abstract
Pathogenicity and presentation of Mycoplasma gallisepticum (MG) infection may differ from one strain to another and this may have implications on control measures. Infection of individual birds with more than one MG strain has been reported. A PCR followed by high resolution melt (HRM) curve analysis has been developed in our laboratory and routinely used for detection and differentiation of MG strains. However the potential of this test for identification of MG strains in a mixed specimen has not been evaluated. In the present study, the capability of PCR-HRM curve analysis technique, targeting vlhA and pvpA genes was assessed for identification of individual MG strains in a mixed population. Different DNA ratios of two MG strains from 1 to 10-4 ng were tested with some generated conventional and normalized curves distinct from those of individual strains alone. Using genotype confidence percentages (GCP) generated from HRM curve analysis, it was found that vlhA PCR-HRM was more consistent than pvpA PCR-HRM for the detection of MG ts-11 vaccine strain mixed with any of the MG strains 6/85, F, S6 or a field isolate. The potential of vlhA PCR-HRM to detect mixed MG strains in a specimen was found to be primarily dependent on quantity and proportion of the target DNAs in the mixture. This is the first study examining the capacity of PCR-HRM technique for identification of individual MG strains in a mixed strain population.
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7
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Peebles E, Branton S. Mycoplasma gallisepticum in the commercial egg-laying hen: A historical perspective considering the effects of pathogen strain, age of the bird at inoculation, and diet on performance and physiology. J APPL POULTRY RES 2012. [DOI: 10.3382/japr.2012-00555] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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8
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Leigh SA, Branton SL, Evans JD, Collier SD. Effect of infection route and concurrent infectious bronchitis virus vaccination onMycoplasma gallisepticumdisease pathology in an experimental model. Avian Pathol 2012; 41:497-503. [DOI: 10.1080/03079457.2012.721925] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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9
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Sprygin AV, Elatkin NP, Kolotilov AN, Volkov MS, Sorokina MI, Borisova AV, Andreychuk DB, Mudrak NS, Irza VN, Borisov AV, Drygin VV. Biological characterization of RussianMycoplasma gallisepticumfield isolates. Avian Pathol 2011; 40:213-9. [DOI: 10.1080/03079457.2011.554795] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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10
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Raviv Z, Callison SA, Ferguson-Noel N, Kleven SH. Strain differentiating real-time PCR for Mycoplasma gallisepticum live vaccine evaluation studies. Vet Microbiol 2008; 129:179-87. [DOI: 10.1016/j.vetmic.2007.11.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2007] [Revised: 11/14/2007] [Accepted: 11/16/2007] [Indexed: 11/28/2022]
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11
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Salisch H, Hinz K, Graack H, Ryll M. A comparison of a commercial PCR‐based test to culture methods for detection of Mycoplasma gallisepticum and Mycoplasma synoviae in concurrently infected chickens. Avian Pathol 2007; 27:142-7. [DOI: 10.1080/03079459808419315] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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12
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Levisohn S, Hyman H, Perelman D, Razin S. The use of a specific dna probe for detection ofMycoplasma gallisepticumin field outbreaks. Avian Pathol 2007; 18:535-41. [DOI: 10.1080/03079458908418625] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- S. Levisohn
- a Kimron Veterinary Institute , Beit Dagan, 50250, Israel
| | - H. Hyman
- b Hadassah Medical School , The Hebrew University , Jerusalem, 91010, Israel
| | - D. Perelman
- c The Poultry Breeders Union of Israel , Tel Aviv, Israel
| | - S. Razin
- b Hadassah Medical School , The Hebrew University , Jerusalem, 91010, Israel
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13
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Sanei B, Barnes HJ, Vaillancourt JP, Leyc DH. Experimental Infection of Chickens and Turkeys with Mycoplasma gallisepticum Reference Strain S6 and North Carolina Field Isolate RAPD Type B. Avian Dis 2007; 51:106-11. [PMID: 17461274 DOI: 10.1637/0005-2086(2007)051[0106:eiocat]2.0.co;2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
During an epidemic of mycoplasmosis in chicken and turkey flocks in North Carolina between 1999 and 2001, isolates of Mycoplasma gallisepticum (MG) from affected flocks were characterized by random amplification of polymorphic DNA (RAPD), and eight distinct RAPD types were identified. MG RAPD type B accounted for more than 90% of the isolates and was associated with moderate-to-severe clinical signs and mortality. The virulence of MG RAPD type B for chickens and turkeys was compared with sham-inoculated negative controls and MG S6 (a virulent strain)-inoculated positive controls. Clinical signs occurred in chickens and turkeys inoculated with either MG RAPD type B or MG S6. However, they were not as frequent or severe as those seen in naturally affected flocks, and there was no mortality in the experimental groups. Based on gross and microscopic findings, MG RAPD type B was equal to or more virulent than MG S6. All MG-inoculated birds were culture and PCR positive at 7 and 14 days postinoculation (PI). Among serological tests, the serum plate agglutination test was positive for the majority of chickens and turkeys (58%-100%) infected with either strain of MG at both 7 and 14 days PI. The hemagglutination inhibition test was negative for all birds at 7 days PI and positive for a few chickens (8%-17%) and several turkey sera (40%-60%) at 14 days PI. Only a single serum was positive by enzyme-linked immunosorbent assay (an MG S6-infected turkey) at 14 days PI.
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Affiliation(s)
- B Sanei
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606, USA
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Callison SA, Riblet SM, Sun S, Ikuta N, Hilt D, Leiting V, Kleven SH, Suarez DL, García M. Development and Validation of a Real-Time Taqman®Polymerase Chain Reaction Assay for the Detection of Mycoplasma gallisepticum in Naturally Infected Birds. Avian Dis 2006; 50:537-44. [PMID: 17274291 DOI: 10.1637/7639-050106r.1] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
In this study, we report the development and validation of a real-time polymerase chain reaction (PCR) assay using a Taqman-labeled probe for the detection of Mycoplasma gallisepticum (MGLP assay). The MGLP assay was highly specific with a detection limit of 25 template copies per reaction and a quantification limit of 100 template copies per reaction. Validation of the assay was completed with 1247 samples (palatine cleft and tracheal swabs) from M. gallisepticum-positive and -negative chicken flocks. The MGLP assay was compared to an enzyme-linked immunosorbent assay (ELISA), a conventional polymerase chain reaction assay (mgc2 PCR), and isolation of M. gallisepticum from naturally infected flocks. A total of 805 samples collected from negative flocks, as verified by ELISA and/or mgc2 PCR, were negative by the MGLP assay. A total of 442 samples were collected from positive flocks, of which a total of 228 samples were positive by the MGLP assay. These results agreed for 98.87% of the samples when tested by mgc2 PCR. When comparing the MGLP assay with M gallisepticum isolation, the MGLP assay was more sensitive than isolation for detecting positive birds from a positive flock, 172/265 and 50/265, respectively. Overall, the MGLP assay and M. gallisepticum isolation agreed for 52.8% of the samples tested. In conclusion, the MGLP assay was highly specific, sensitive, and reproducible, and allowed the quantification of template copies directly from clinical samples.
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Affiliation(s)
- S A Callison
- Department of Population Health, Poultry Diagnostic and Research Center, College of Veterinary Medicine, The University of Georgia, 953 College Station Road, Athens, GA 30602, USA
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15
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Sydenstricker KV, Dhondt AA, Hawley DM, Jennelle CS, Kollias HW, Kollias GV. Characterization of Experimental Mycoplasma gallisepticum Infection in Captive House Finch Flocks. Avian Dis 2006; 50:39-44. [PMID: 16617979 DOI: 10.1637/7403-062805r.1] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The use of controlled, horizontal-transmission experiments provides detailed information on the spread of disease within fixed social groups, which informs our understanding of disease dynamics both in an empirical and theoretical context. For that reason, we characterized in 2002, horizontal transmission of Mycoplasma gallisepticum (MG) in two flocks of 11 wild-caught house finches housed in outdoor aviaries over a 6-mo period. All birds were initially free of MG by a polymerase chain reaction (PCR)-based test, rapid plate agglutination (RPA), and the scoring of physical signs. We inoculated one flock member bilaterally in the palpebral conjunctiva and reintroduced it into its cage. Index birds developed conjunctivitis within 3 to 5 days but died 13 and 20 days postinfection (PI) possibly because of very severe weather. The proportion of birds with physical signs increased gradually, reached 40% at 6 wk PI, and fluctuated around 40% until 21 wk PI. By the time our experiment ended at 24.5 wk PI, 28% of the birds still exhibited physical signs. Across both flocks, 80% of the birds developed unilateral or bilateral conjunctivitis, and several birds relapsed. The appearance of physical signs in new individuals occurred between 10 and 144 days PI (median 41 days PI). Physical signs lasted 1-172 days (median 42 days). Birds that became infected earlier during the experiment developed more severe conjunctivitis, and there was a tendency for birds that developed bilateral conjunctivitis to develop physical signs earlier. Most birds that developed physical signs of MG were also PCR- and RPA-positive, although we detected a single asymptomatic carrier and a single symptomatic false negative. No birds died as a result of secondary MG infection.
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Affiliation(s)
- Keila V Sydenstricker
- Wildlife Health Laboratory, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
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Evans J, Leigh S, Branton S, Collier S, Pharr G, Bearson S. Mycoplasma gallisepticum: Current and Developing Means to Control the Avian Pathogen. J APPL POULTRY RES 2005. [DOI: 10.1093/japr/14.4.757] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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17
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Lysnyansky I, Garcia M, Levisohn S. Use of mgc2-polymerase chain reaction-restriction fragment length polymorphism for rapid differentiation between field isolates and vaccine strains of Mycoplasma gallisepticum in Israel. Avian Dis 2005; 49:238-45. [PMID: 16094829 DOI: 10.1637/7285-10020r] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Increasing use of Mycoplasma gallisepticum (MG) live vaccines has led to a need for a rapid test for differentiation of MG field strains from the live vaccine strains ts-11 and 6/85. We examined the differentiating potential of diagnostic polymerase chain reaction (PCR) primers targeted to the gene mgc2, encoding a cytadherence-related surface protein uniquely present in MG. The mgc2-PCR diagnostic primers are specific for MG in tests of all avian mycoplasmas or bacteria present in the chicken trachea and are sensitive enough to readily detect MG in tracheal swabs from field outbreaks. Differentiation of vaccine strain ts-11 was based on identification of restriction enzyme sites in the 300-base-pair (bp) mgc2-PCR amplicon present in ts-11 and missing in MG isolates from field outbreaks in Israel. Restriction sites for the enzymes HaeII and SfaN1 were identified in the amplified region in strain ts-11 and were not found in 28 field isolates of MG, comprising a representative cross section of all the MG isolates from the period 1997-2003. In practice, differential diagnosis of MG is achieved within 1 day of submission of tracheal swab samples by mgc2-PCR amplification and restriction of the amplicon with HaeII, giving a 270-bp fragment for ts-11 or no restriction for other MG strains tested. Application of the mgc2-PCR-restriction fragment length polymorphism (mgc2-PCR-RFLP) assay enabled differential diagnosis of both components of a mixture of ts-11 and non-ts-11 DNA, detecting the field strain in the presence of a large excess of ts-11. The test was successfully applied in vivo for monitoring vaccinates in a ts-11 vaccine trial. In principle, the test may also be used to identify the 6/85 vaccine strain, which yields a 237-bp product, readily differentiated from the approximately 300-bp PCR product of all other strains tested. Further testing of field isolates will be necessary to determine the applicability of this test in the United States and other countries.
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Affiliation(s)
- Inna Lysnyansky
- Division of Avian and Fish Diseases, Kimron Veterinary Institute, Bet Dagan 50250, Israel
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Levisohn S, Rosengarten R, Yogev D. In vivo variation of Mycoplasma gallisepticum antigen expression in experimentally infected chickens. Vet Microbiol 1995; 45:219-31. [PMID: 7571373 DOI: 10.1016/0378-1135(95)00039-d] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The antigen expression profiles of Mycoplasma gallisepticum isolates obtained from tracheal swabs of chickens after aerosol-inoculation with M. gallisepticum strain R or clonal variant R/E were examined in western immunoblots. A reference anti-M. gallisepticum chicken antiserum and antisera from individual infected chickens as well as monoclonal antibodies (mAbs) specific for surface proteins were used to monitor in vivo antigenic variation. mAbs 1E5 and 12D8, recognizing PvpA and p67a, recently shown to undergo high-frequency in vitro phase variation, were used for consecutive staining of colony and western immunoblots in order to distinguish between the resultant phenotypes with respect to the corresponding epitopes. Marked differences in the expression of major immunogenic proteins, including p67a, were observed between the two inocula as well as among reisolates recovered at different times of infection. Comparative western immunoblot analysis of the rapidly changing chicken serum antibody response and reisolates recovered during the course of an experimental infection with M. gallisepticum R or clonal variant R/E suggest that immune modulation may have a key role in generating surface diversity. In addition, comparison of colony immunoblots of strain R inoculum and of reisolated colonies from tracheas of birds 8 days post infection indicated an in vivo selection of the PvpA+p67a- phenotype. This study established that surface antigens of M. gallisepticum are subjected in vivo to rapid alteration in their expression. This variability may function as a crucial adaptive mechanism, enabling the organism to escape from the host immune defense and to adapt to the changing host environment at different stages of a natural infection.
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Affiliation(s)
- S Levisohn
- Division of Avian Diseases, Kimron Veterinary Institute, Bet Dagan, Israel
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19
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Markham PF, Glew MD, Whithear KG, Walker ID. Molecular cloning of a member of the gene family that encodes pMGA, a hemagglutinin of Mycoplasma gallisepticum. Infect Immun 1993; 61:903-9. [PMID: 8432610 PMCID: PMC302818 DOI: 10.1128/iai.61.3.903-909.1993] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
A hemagglutinin with an M(r) of 67,000 (pMGA) from Mycoplasma gallisepticum S6 was purified by using monoclonal antibody affinity chromatography. Purified pMGA was treated with a number of enzymes, the resultant peptides were purified, and their amino acid sequence was determined by using an Applied Biosystems (model 471A) protein sequencer. The DNA sequence encoding two peptides was used to dictate the sequences of synthetic oligonucleotides which were used to screen a library of EcoRI-cut M. gallisepticum DNA in pUC18. A clone reactive to both probes was isolated and found to contain a recombinant insert of 10 kb. The clone was mapped by using restriction endonucleases and fragments subcloned into pUC18 for DNA sequencing. Analysis of part of the DNA sequence revealed an open reading frame containing 1,941 nucleotides which encoded 647 amino acids. The amino terminus was preceded by a putative leader sequence of 25 amino acids. A promoter region preceding the putative start codon GUG was also located. This gene would encode a mature protein of 67,660 Da. There were a number of differences between the predicted amino acid sequence and that determined by direct peptide sequencing. Also, two tryptic peptides of pMGA were not found in the DNA sequence. This suggested that the cloned gene did not encode pMGA but did encode a homolog (pMGA1.2). Furthermore, downstream of pMGA1.2 was a region of DNA encoding a leader sequence followed by an amino acid sequence with high homology to that encoded by the pMGA1.2 gene. The presence within M. gallisepticum of a family of pMGA genes is inferred from the DNA sequence and Southern transfer data. A possible role for this gene family in immune evasion is discussed.
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Affiliation(s)
- P F Markham
- School of Veterinary Science, University of Melbourne, Victoria, Australia
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Forsyth MH, Tourtellotte ME, Geary SJ. Localization of an immunodominant 64 kDa lipoprotein (LP 64) in the membrane of Mycoplasma gallisepticum and its role in cytadherence. Mol Microbiol 1992; 6:2099-106. [PMID: 1406251 DOI: 10.1111/j.1365-2958.1992.tb01383.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A 64 kDa lipoprotein (LP 64) haemagglutinin (pI 4.9-5.0) was isolated from the membrane of Mycoplasma gallisepticum. Triton X-114 phase partitioning has demonstrated that the hydrophobic nature of this haemagglutinin is due to a lipid portion of the molecule. Autoradiography of [3H]-palmitate-labelled M. gallisepticum revealed the presence of several additional lipoproteins. Immunoelectron microscopy demonstrated the localization of LP 64 to the base of the terminal structure. Densitometric scans of stained polyacrylamide gels of M. gallisepticum showed that LP 64 constitutes 1.7% of the total protein. Scans of immunoblots of M. gallisepticum indicate that LP 64 is highly immunogenic in chickens, accounting for 7.4% of the total serum IgG response at four weeks post-infection. A quantitative value for the IgG response to LP 64, relative to the percentage of total protein (the Relative Immunogenicity Index) was 4.4. LP 64 is conserved among several strains of M. gallisepticum, but its presence could not be detected in Mycoplasma synoviae. Antiserum raised to electroeluted LP 64 reacted specifically with this lipoprotein when assessed on either one- or two-dimensional immunoblots of M. gallisepticum. This antiserum, as well as Fab fragments, inhibited haemagglutination of chicken erythrocytes and inhibited the attachment of 14C-labelled M. gallisepticum to chicken tracheal epithelium in vitro by 62%.
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Affiliation(s)
- M H Forsyth
- Department of Pathobiology, University of Connecticut, Storrs 06268
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Hyman HC, Levisohn S, Yogev D, Razin S. DNA probes for Mycoplasma gallisepticum and Mycoplasma synoviae: application in experimentally infected chickens. Vet Microbiol 1989; 20:323-37. [PMID: 2800306 DOI: 10.1016/0378-1135(89)90057-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
DNA probes specific for Mycoplasma gallisepticum and M. synoviae were selected from genomic libraries prepared in the pUC13 vector. The probes hybridized with the DNA of a wide spectrum of strains within each homologous species, but did not react with the heterologous species or with DNA from any other avian mycoplasma or bacteria tested. Experimental infection and contact exposure of chickens to M. gallisepticum served as models to test the effectiveness of the DNA probe in diagnosis as compared with serological and culture detection methods carried out in parallel. A correlation was generally found between the level of M. gallisepticum in tracheal swabs and the effectiveness of the probe, although a predictably reactive level of mycoplasmas was not always detected. Treatment of clinical specimens with acetylcysteine to disrupt mucus improved the detection rate. Dot-blot hybridization with probe pMG4 enabled positive identification of M. gallisepticum at an early stage of infection, prior to the development of a serological response in the infected chicken. Results are obtainable within 4 days of sampling, much more rapidly than culture, and also in clinical specimens from which mycoplasma isolation is impossible, such as carcasses. The results indicate that the use of DNA probes for the early and rapid detection of M. gallisepticum infection is feasible; a development which can replace laborious culture techniques and less effective serological methods, and thus reduce the time required for diagnosis.
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Affiliation(s)
- H C Hyman
- Department of Membrane and Ultrastructure Research, Hadassah Medical School, Hebrew University, Jerusalem, Israel
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