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Cornejo S, Barber C, Thoresen M, Lawrence M, Seo KS, Woolums A. Synthetic antimicrobial peptides Bac-5, BMAP-28, and Syn-1 can inhibit bovine respiratory disease pathogens in vitro. Front Vet Sci 2024; 11:1430919. [PMID: 39188903 PMCID: PMC11345158 DOI: 10.3389/fvets.2024.1430919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Accepted: 07/25/2024] [Indexed: 08/28/2024] Open
Abstract
Mass treatment with antibiotics at arrival has been the mainstay for bovine respiratory disease (BRD) control but there is an increase in antimicrobial-resistant bacteria being shed from treated cattle. BRD is a disease complex that results from the interaction of viruses or bacteria and susceptible animals with inappropriate immunity. With bacteria being the only feasibly treatable agent and the emergence of antimicrobial resistance, decreased efficacy of commonly used antibiotics could threaten livestock health. There is a need for new antimicrobial alternatives that could be used to control disease. Naturally occurring antimicrobial peptides (AMP) have been proposed to address this need. Here we tested the effect of bovine myeloid antimicrobial peptide-28 (BMAP-28), a synthetic BMAP-28 analog Syn-1, and bactenecin 5 (Bac-5) on Mannheimia haemolytica (Mh) using a quantitative culture method and the broth microdilution method to determine minimum inhibitory and bactericidal concentrations (MIC and MBC). We also tested the antiviral effect of these AMP against bovine herpes-1 (BHV-1) and bovine respiratory syncytial virus (BRSV) using the Reed and Muench method to calculate the viral titers after treatment. We demonstrated that BMAP-28 and Syn-1 can inhibit Mh growth and BMAP-28 can inhibit replication of BHV-1 and BRSV. Moreover, we showed that BMAP-28 and Bac-5 can be used together to inhibit Mh growth. When used alone, the MIC of BMAP-28 and Bac-5 was 64 and 128 μg/mL respectively, but when applied together, their MIC ranged from 0.25-16 for BMAP-28 and 8-64 μg/mL for Bac-5, resulting in a decrease in concentration of up to 256 and 16-fold, respectively. The synergistic interaction between those peptides resulted in concentrations that could be well tolerated by cells. Our results demonstrate that bovine cathelicidins could be used as alternatives to antimicrobials against BRD pathogens. These findings introduce a path to discovering new antimicrobials and determining how these peptides could be tailored to improve cattle health.
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Affiliation(s)
- Santiago Cornejo
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - Cassandra Barber
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - Merrilee Thoresen
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - Mark Lawrence
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - Keun Seok Seo
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - Amelia Woolums
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
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Noel A, Zhang J, Shen H, Saxena A, Groeltz-Thrush J, Li G, Rahe MC. Bovine Rhinitis B Virus Variant as the Putative Cause of Bronchitis in Goat Kids. Viruses 2024; 16:1023. [PMID: 39066186 PMCID: PMC11281505 DOI: 10.3390/v16071023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 06/21/2024] [Accepted: 06/21/2024] [Indexed: 07/28/2024] Open
Abstract
A diagnostic investigation into an outbreak of fatal respiratory disease among young goats in Iowa, USA revealed bronchitis lesions of unknown etiology and secondary bacterial bronchopneumonia. Hypothesis-free metagenomics identified a previously unreported picornavirus (USA/IA26017/2023), and further phylogenetic analysis classified USA/IA26017/2023 as an aphthovirus related to bovine rhinitis B virus. Viral nucleic acid was localized to lesions of bronchitis using in situ hybridization. This marks the first report of a picornavirus putatively causing respiratory disease in goats and highlights the potential for cross-species transmission of aphthoviruses.
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Affiliation(s)
- Andrew Noel
- Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA; (A.N.)
| | - Jianqiang Zhang
- Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA; (A.N.)
| | - Huigang Shen
- Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA; (A.N.)
| | - Anugrah Saxena
- Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA; (A.N.)
| | - Jennifer Groeltz-Thrush
- Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA; (A.N.)
| | - Ganwu Li
- Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA; (A.N.)
| | - Michael C. Rahe
- Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA; (A.N.)
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607, USA
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Isolation of the various serotypes of Mannheimia haemolytica and preparation of the first vaccine candidate in Iran. Mol Biol Rep 2022; 49:10367-10375. [PMID: 36097127 DOI: 10.1007/s11033-022-07890-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 08/16/2022] [Accepted: 08/18/2022] [Indexed: 10/14/2022]
Abstract
BACKGROUND Mannheimia haemolytica is one of the main agents of domestic pneumonic mannheimiosis, but a proper vaccine has not been explored in IRAN. METHODS AND RESULTS 362 lung and nasal samples from sick domestic animal were detected by culture and PCR methods. Totally, 71 M. haemolytica isolates were identified in three main serotypes (A1, A2, and A6). Serotypes A2 (38/71; 54%) and A1 (25/71; 39%) were the most frequently detected, whereas the A6 serotype was detected with a frequency of less than 1% (1/71; 1%) and 7 isolates remained unknown (7/71; 10%). Subsequently, M. haemolytica vaccinal strain was developed and then formalin-killed vaccine was prepared. It provided the best protection against mannheimiosis in sheep which was proved by indirect ELISA. CONCLUSIONS Our results suggest that the efficacy and safety of vaccine strain are remarkable and may serve as a new therapeutic target in mannheimiosis.
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In-vitro antibiotic resistance phenotypes of respiratory and enteric bacterial isolates from weaned dairy heifers in California. PLoS One 2021; 16:e0260292. [PMID: 34818352 PMCID: PMC8612539 DOI: 10.1371/journal.pone.0260292] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 11/05/2021] [Indexed: 11/19/2022] Open
Abstract
Antimicrobial drug (AMD) use for bovine respiratory disease (BRD) continues to be concerning for development of antimicrobial resistance (AMR) in respiratory and enteric bacteria of cattle. This study aimed to provide data regarding AMR in respiratory isolates, and identify relationships between respiratory and enteric AMD susceptibility, in weaned dairy heifers. A cross-sectional study was performed between June of 2019 and February 2020, on 6 calf rearing facilities in California. Deep nasopharyngeal and rectal swabs were collected from 341 weaned heifers and submitted for selective bacterial culture and AMR testing. Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni were selectively isolated from respiratory samples; Escherichia coli and Enterococcus spp. were selectively isolated from rectal swabs. Minimum inhibitory concentrations (MIC) were determined for selected isolates against 19 AMD. The proportion of resistant isolates was calculated using Clinical Laboratory Standards Institute (respiratory) or USDA NARMS (enteric) breakpoints; when no applicable breakpoint was available, the distribution of MIC was described and compared. Association between AMR in a calf’s respiratory isolate and a higher or lower MIC of the matched enteric isolates was determined. More than 50% of P. multocida isolates were resistant to each of 7 AMD commonly used to treat BRD (florfenicol, gamithromycin, tildipirosin, tilmicosin, danofloxacin, enrofloxacin and tetracycline). Resistance in respiratory isolates was only associated with higher matched enteric MIC for gamithromycin and tulathromycin. Multidrug resistance was reported in >70% of P. multocida and M. haemolytica isolates. Antimicrobial resistance, including multidrug resistance, in respiratory isolates appears to be widespread in weaned dairy heifers; this finding has not previously been reported and raises concern for the future efficacy of AMD used to treat respiratory diseases in weaned dairy heifers. Enteric bacterial MIC appear to have limited direct association with respiratory isolate AMR classification.
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Comparative Genomics of Actinobacillus pleuropneumoniae Serotype 8 Reveals the Importance of Prophages in the Genetic Variability of the Species. Int J Genomics 2020; 2020:9354204. [PMID: 32149072 PMCID: PMC7049842 DOI: 10.1155/2020/9354204] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 01/03/2020] [Indexed: 12/30/2022] Open
Abstract
Actinobacillus pleuropneumoniae is the etiologic agent of porcine pleuropneumonia. Currently, there are 18 different serotypes; the serotype 8 is the most widely distributed in the United States, Canada, United Kingdom, and southeastern Brazil. In this study, genomes of seven A. pleuropneumoniae serotype 8 clinical isolates were compared to the other genomes of twelve serotypes. The analyses of serotype 8 genomes resulted in a set of 2352 protein-coding sequences. Of these sequences, 76.6% are present in all serotypes, 18.5% are shared with some serotypes, and 4.9% were differential. This differential portion was characterized as a series of hypothetical and regulatory protein sequences: mobile element sequence. Synteny analysis demonstrated possible events of gene recombination and acquisition by horizontal gene transfer (HGT) in this species. A total of 30 sequences related to prophages were identified in the genomes. These sequences represented 0.3 to 3.5% of the genome of the strains analyzed, and 16 of them contained complete prophages. Similarity analysis between complete prophage sequences evidenced a possible HGT with species belonging to the family Pasteurellaceae. Thus, mobile genetic elements, such as prophages, are important components of the differential portion of the A. pleuropneumoniae genome and demonstrate a central role in the evolution of the species. This study represents the first study done to understand the genome of A. pleuropneumoniae serotype 8.
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Frey J. RTX Toxins of Animal Pathogens and Their Role as Antigens in Vaccines and Diagnostics. Toxins (Basel) 2019; 11:toxins11120719. [PMID: 31835534 PMCID: PMC6950323 DOI: 10.3390/toxins11120719] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 12/03/2019] [Accepted: 12/04/2019] [Indexed: 01/19/2023] Open
Abstract
Exotoxins play a central role in the pathologies caused by most major bacterial animal pathogens. The large variety of vertebrate and invertebrate hosts in the animal kingdom is reflected by a large variety of bacterial pathogens and toxins. The group of repeats in the structural toxin (RTX) toxins is particularly abundant among bacterial pathogens of animals. Many of these toxins are described as hemolysins due to their capacity to lyse erythrocytes in vitro. Hemolysis by RTX toxins is due to the formation of cation-selective pores in the cell membrane and serves as an important marker for virulence in bacterial diagnostics. However, their physiologic relevant targets are leukocytes expressing β2 integrins, which act as specific receptors for RTX toxins. For various RTX toxins, the binding to the CD18 moiety of β2 integrins has been shown to be host specific, reflecting the molecular basis of the host range of RTX toxins expressed by bacterial pathogens. Due to the key role of RTX toxins in the pathogenesis of many bacteria, antibodies directed against specific RTX toxins protect against disease, hence, making RTX toxins valuable targets in vaccine research and development. Due to their specificity, several structural genes encoding for RTX toxins have proven to be essential in modern diagnostic applications in veterinary medicine.
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Affiliation(s)
- Joachim Frey
- Vetsuisse Facutly, University of Bern, 3012 Bern, Switzerland
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7
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Ayalew S, Murdock BK, Snider TA, Confer AW. Mannheimia haemolytica IgA-specific proteases. Vet Microbiol 2019; 239:108487. [PMID: 31767097 DOI: 10.1016/j.vetmic.2019.108487] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 10/24/2019] [Accepted: 10/27/2019] [Indexed: 12/25/2022]
Abstract
Mannheimia haemolytica colonizes the nasopharynx of cattle and can cause severe fibrinous pleuropneumonia. IgA proteases are metalloendopeptidases released by bacteria that cleave IgA, enhancing colonization of mucosa. The objectives of these studies were to characterize M. haemolytica IgA1 and IgA2 proteases in vitro and in silico, to clone and sequence the genes for these proteases, and to demonstrate immunogenicity of components of the entire IgA protease molecule. Both IgA protease genes were cloned, expressed, and sequenced. Sequences were compared to other published sequences. Components were used to immunize mice to determine immunogenicity. Sera from healthy cattle and cattle that recovered from respiratory disease were examined for antibodies to IgA proteases. In order to assay the cleavage of bovine IgA with IgA1 protease, M. haemolytica culture supernatant was incubated with bovine IgA. Culture supernatant cleaved purified bovine IgA in the presence of ZnCl2. Both IgA proteases contain three domains, 1) IgA peptidase, 2) PL1_Passenger_AT and 3) autotransporter. IgA1 and IgA2 peptidases have molecular weights of 96.5 and 87 kDa, respectively. Convalescent bovine sera with naturally high anti-M. haemolytica antibody titers had high antibodies against all IgA1 & IgA2 protease components. Mouse immunizations indicated high antibodies to the IgA peptidases and autotransporters but not to PL1_Passenger_AT. These data indicate that M. haemolytica produces two IgA proteases that are immunogenic, can cleave bovine IgA, and are produced in vivo, as evidenced by antibodies in convalescent bovine sera. Further studies could focus on IgA protease importance in pathogenesis and immunity.
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Affiliation(s)
- Sahlu Ayalew
- Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK, 74078-2007, USA
| | - Betsy K Murdock
- Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK, 74078-2007, USA
| | - Timothy A Snider
- Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK, 74078-2007, USA
| | - Anthony W Confer
- Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK, 74078-2007, USA.
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8
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Mannheimia haemolytica in bovine respiratory disease: immunogens, potential immunogens, and vaccines. Anim Health Res Rev 2019; 19:79-99. [PMID: 30683173 DOI: 10.1017/s1466252318000142] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Mannheimia haemolytica is the major cause of severe pneumonia in bovine respiratory disease (BRD). Early M. haemolytica bacterins were either ineffective or even enhanced disease in vaccinated cattle, which led to studies of the bacterium's virulence factors and potential immunogens to determine ways to improve vaccines. Studies have focused on the capsule, lipopolysaccharide, various adhesins, extracellular enzymes, outer membrane proteins, and leukotoxin (LKT) resulting in a strong database for understanding immune responses to the bacterium and production of more efficacious vaccines. The importance of immunity to LKT and to surface antigens in stimulating immunity led to studies of individual native or recombinant antigens, bacterial extracts, live-attenuated or mutant organisms, culture supernatants, combined bacterin-toxoids, outer membrane vesicles, and bacterial ghosts. Efficacy of several of these potential vaccines can be shown following experimental M. haemolytica challenge; however, efficacy in field trials is harder to determine due to the complexity of factors and etiologic agents involved in naturally occurring BRD. Studies of potential vaccines have led current commercial vaccines, which are composed primarily of culture supernatant, bacterin-toxoid, or live mutant bacteria. Several of those can be augmented experimentally by addition of recombinant LKT or outer membrane proteins.
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Lim A, Naidenov B, Bates H, Willyerd K, Snider T, Couger MB, Chen C, Ramachandran A. Nanopore ultra-long read sequencing technology for antimicrobial resistance detection in Mannheimia haemolytica. J Microbiol Methods 2019; 159:138-147. [PMID: 30849421 DOI: 10.1016/j.mimet.2019.03.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Revised: 03/02/2019] [Accepted: 03/04/2019] [Indexed: 02/02/2023]
Abstract
Disruptive innovations in long-range, cost-effective direct template nucleic acid sequencing are transforming clinical and diagnostic medicine. A multidrug resistant strain and a pan-susceptible strain of Mannheimia haemolytica, isolated from pneumonic bovine lung samples, were sequenced at 146× and 111× coverage, respectively with Oxford Nanopore Technologies MinION. De novo assembly produced a complete genome for the non-resistant strain and a nearly complete assembly for the drug resistant strain. Functional annotation using RAST (Rapid Annotations using Subsystems Technology), CARD (Comprehensive Antibiotic Resistance Database) and ResFinder databases identified genes conferring resistance to different classes of antibiotics including β-lactams, tetracyclines, lincosamides, phenicols, aminoglycosides, sulfonamides and macrolides. Resistance phenotypes of the M. haemolytica strains were determined by minimum inhibitory concentration (MIC) of the antibiotics. Sequencing with a highly portable MinION device corresponded to MIC assays with most of the antimicrobial resistant determinants being identified with as few as 5437 reads, except for the genes responsible for resistance to Fluoroquinolones. The resulting quality assemblies and AMR gene annotation highlight the efficiency of ultra-long read, whole-genome sequencing (WGS) as a valuable tool in diagnostic veterinary medicine.
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Affiliation(s)
- Alexander Lim
- Department of Biochemistry and Molecular Biology, Oklahoma State University, 246 Noble Research Center, Stillwater, OK 74078, United States
| | - Bryan Naidenov
- Department of Biochemistry and Molecular Biology, Oklahoma State University, 246 Noble Research Center, Stillwater, OK 74078, United States
| | - Haley Bates
- Oklahoma Animal Disease Diagnostic Laboratory, Center for Veterinary Health Sciences, 1950 W. Farm Road, Stillwater, OK 74078, United States
| | - Karyn Willyerd
- Department of Biochemistry and Molecular Biology, Oklahoma State University, 246 Noble Research Center, Stillwater, OK 74078, United States
| | - Timothy Snider
- Oklahoma Animal Disease Diagnostic Laboratory, Center for Veterinary Health Sciences, 1950 W. Farm Road, Stillwater, OK 74078, United States
| | - Matthew Brian Couger
- Department of Microbiology and Molecular Genetics, Oklahoma State University, 307 Life Sciences East, Stillwater, OK 74078, United States
| | - Charles Chen
- Department of Biochemistry and Molecular Biology, Oklahoma State University, 246 Noble Research Center, Stillwater, OK 74078, United States.
| | - Akhilesh Ramachandran
- Oklahoma Animal Disease Diagnostic Laboratory, Center for Veterinary Health Sciences, 1950 W. Farm Road, Stillwater, OK 74078, United States.
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Sahay S, Shome R, Sankarasubramanian J, Vishnu US, Prajapati A, Natesan K, Shome BR, Rahman H, Rajendhran J. Genome sequence analysis of the Indian strain Mannheimia haemolytica serotype A2 from ovine pneumonic pasteurellosis. ANN MICROBIOL 2018. [DOI: 10.1007/s13213-018-1410-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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Mozzi A, Forni D, Clerici M, Cagliani R, Sironi M. The Diversity of Mammalian Hemoproteins and Microbial Heme Scavengers Is Shaped by an Arms Race for Iron Piracy. Front Immunol 2018; 9:2086. [PMID: 30271410 PMCID: PMC6142043 DOI: 10.3389/fimmu.2018.02086] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 08/23/2018] [Indexed: 11/13/2022] Open
Abstract
Iron is an essential micronutrient for most living species. In mammals, hemoglobin (Hb) stores more than two thirds of the body's iron content. In the bloodstream, haptoglobin (Hp) and hemopexin (Hpx) sequester free Hb or heme. Pathogenic microorganisms usually acquire iron from their hosts and have evolved complex systems of iron piracy to circumvent nutritional immunity. Herein, we performed an evolutionary analysis of genes coding for mammalian heme-binding proteins and heme-scavengers in pathogen species. The underlying hypothesis is that these molecules are engaged in a molecular arms race. We show that positive selection drove the evolution of mammalian Hb and Hpx. Positively selected sites in Hb are located at the interaction surface with Neisseria meningitidis heme scavenger HpuA and with Staphylococcus aureus iron-regulated surface determinant B (IsdB). In turn, positively selected sites in HpuA and IsdB are located in the flexible protein regions that contact Hb. A residue in Hb (S45H) was also selected on the Caprinae branch. This site stabilizes the interaction with Trypanosoma brucei hemoglobin-haptoglobin (HbHp) receptor (TbHpHbR), a molecule that also mediates trypanosome lytic factor (TLF) entry. In TbHpHbR, positive selection drove the evolution of a variant (L210S) which allows evasion from TLF but reduces affinity for HbHp. Finally, selected sites in Hpx are located at the interaction surface with the Haemophilus influenzae hemophore HxuA, which in turn displays fast evolving sites at the Hpx-binding interface. These results shed light into host-pathogens conflicts and establish the importance of nutritional immunity as an evolutionary force.
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Affiliation(s)
- Alessandra Mozzi
- Scientific Institute, IRCCS E. Medea, Bioinformatics, Lecco, Italy
| | - Diego Forni
- Scientific Institute, IRCCS E. Medea, Bioinformatics, Lecco, Italy
| | - Mario Clerici
- Department of Physiopathology and Transplantation, University of Milan, Milan, Italy.,Don C. Gnocchi Foundation ONLUS, IRCCS, Milan, Italy
| | - Rachele Cagliani
- Scientific Institute, IRCCS E. Medea, Bioinformatics, Lecco, Italy
| | - Manuela Sironi
- Scientific Institute, IRCCS E. Medea, Bioinformatics, Lecco, Italy
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SAHAY SWATI, JAYARAM POOJAKP, NATESAN KRITHIGA, DOLEY JUWAR, REDDY GBMANJUNATHA, PATIL SHARANS, SHOME BIBEKRANJAN, SHOME RAJESWARI. Respiratory infections in yak (Bos grunniens): a pilot study on isolation and direct PCR diagnosis for pasteurellosis, mannheimiosis and histophilosis. THE INDIAN JOURNAL OF ANIMAL SCIENCES 2018. [DOI: 10.56093/ijans.v88i9.83540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Bovine respiratory disease (BRD) is a condition of severe pneumonia caused due to environmental stress followed by a multiple viral and bacterial pathogens.The present study aimed to detect the BRD agents such as Mannhaeimia haemolytica, Pasteurella multocida and Histophilus somni and IBR in yaks suffering from respiratory infections. For the study, 157 deep nasal and blood samples were collected from yak of Arunachal Pradesh and processed for isolation and PCR detection of respiratory bacterial pathogens such as M. haemolytica, P. multocida and H. somni and seroscreening of IBR. From 157 samples, one M. haemolytica and two H. somni isolates were recovered. This is the first report of H. somni and M. haemolytica isolation from yak nasal samples from India. In mPCR, 23 yak nasal samples (14.6%) amplified for M. haemolytica, two (1.2%) for P. multocida and six samples for H. somni (4.6%) by simplex PCR. Concurrence of H. somni and M. haemolytica in three samples, and M. haemolytica and P. multocida type B in two samples was also observed.Very high seroprevalence for IBR (37%) by Indirect ABELISA was recorded.The study concluded that highest number of samples were positive for M. haemolytica (14.6%) and emphasizes its role in respiratory infections along with high seroprevalence of IBR. It also reflected the diagnostic importance of mPCR/PCR in regions inaccessible for fresh sample collection and transportation as an alternate to isolation procedures.
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Boukahil I, Czuprynski CJ. Mutual antagonism between Mannheimia haemolytica and Pasteurella multocida when forming a biofilm on bovine bronchial epithelial cells in vitro. Vet Microbiol 2018. [PMID: 29519520 DOI: 10.1016/j.vetmic.2018.02.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Mannheimia haemolytica and Pasteurella multocida are two bacterial species implicated in the bovine respiratory disease complex (BRDC) that is costly to the beef and dairy cattle industries. Both bacterial species are thought to occupy a similar niche as commensals in the upper respiratory tract. Many bacteria are thought to exist as biofilms in their hosts, perhaps in close proximity with other bacterial species. We previously showed that M. haemolytica forms biofilm on bovine respiratory epithelial cells in vitro. We are interested in the possibility that M. haemolytica and P. multocida co-exist as biofilms in the upper respiratory tract of cattle. In this study, we begin to explore this possibility by assessing the ability of M. haemolytica and P. multocida to form a biofilm on bovine respiratory epithelial cells in vitro. We found that M. haemolytica and P. multocida are separately able to form biofilms on bovine respiratory epithelial cells, but mutually inhibit one another when incubated together as a biofilm. Both the biofilm matrix (crystal violet stain) and bacterial numbers (CFU and PCR) were reduced when M. haemolytica and P. multocida were incubated together on fixed epithelial cells. This inhibition does not appear to result from a soluble factor, as neither conditioned medium nor separation of the two species by a transwell filter membrane reproduced the effect. We infer that when located in close proximity on the epithelial surface, M. haemolytica and P. multocida mutually regulate one another.
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Affiliation(s)
- Ismail Boukahil
- Department of Pathobiological Sciences, University of Wisconsin-Madison, School of Veterinary Medicine, 2015 Linden Drive, Madison, WI 53706, USA.
| | - Charles J Czuprynski
- Department of Pathobiological Sciences, University of Wisconsin-Madison, School of Veterinary Medicine, 2015 Linden Drive, Madison, WI 53706, USA.
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Genome-Enabled Insights into the Ecophysiology of the Comammox Bacterium " Candidatus Nitrospira nitrosa". mSystems 2017; 2:mSystems00059-17. [PMID: 28905001 PMCID: PMC5596200 DOI: 10.1128/msystems.00059-17] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 08/15/2017] [Indexed: 02/03/2023] Open
Abstract
Nitrospira-like bacteria are among the most diverse and widespread nitrifiers in natural ecosystems and the dominant nitrite oxidizers in wastewater treatment plants (WWTPs). The recent discovery of comammox-like Nitrospira strains, capable of complete oxidation of ammonia to nitrate, raises new questions about specific traits responsible for the functional versatility and adaptation of this genus to a variety of environments. The availability of new Nitrospira genome sequences from both nitrite-oxidizing and comammox bacteria offers a way to analyze traits in different Nitrospira functional groups. Our comparative genomics analysis provided new insights into the adaptation of Nitrospira strains to specific lifestyles and environmental niches. The recently discovered comammox bacteria have the potential to completely oxidize ammonia to nitrate. These microorganisms are part of the Nitrospira genus and are present in a variety of environments, including biological nutrient removal (BNR) systems. However, the physiological traits within and between comammox and nitrite-oxidizing bacterium (NOB)-like Nitrospira species have not been analyzed in these ecosystems. In this study, we identified Nitrospira strains dominating the nitrifying community of a sequencing batch reactor (SBR) performing BNR under microaerobic conditions. We recovered metagenome-derived draft genomes from two Nitrospira strains: (i) Nitrospira sp. strain UW-LDO-01, a comammox-like organism classified as “Candidatus Nitrospira nitrosa,” and (ii) Nitrospira sp. strain UW-LDO-02, a nitrite-oxidizing strain belonging to the Nitrospira defluvii species. A comparative genomic analysis of these strains with other Nitrospira-like genomes identified genomic differences in “Ca. Nitrospira nitrosa” mainly attributed to each strain’s niche adaptation. Traits associated with energy metabolism also differentiate comammox from NOB-like genomes. We also identified several transcriptionally regulated adaptive traits, including stress tolerance, biofilm formation, and microaerobic metabolism, which might explain survival of Nitrospira under multiple environmental conditions. Overall, our analysis expanded our understanding of the genetic functional features of “Ca. Nitrospira nitrosa” and identified genomic traits that further illuminate the phylogenetic diversity and metabolic plasticity of the Nitrospira genus. IMPORTANCENitrospira-like bacteria are among the most diverse and widespread nitrifiers in natural ecosystems and the dominant nitrite oxidizers in wastewater treatment plants (WWTPs). The recent discovery of comammox-like Nitrospira strains, capable of complete oxidation of ammonia to nitrate, raises new questions about specific traits responsible for the functional versatility and adaptation of this genus to a variety of environments. The availability of new Nitrospira genome sequences from both nitrite-oxidizing and comammox bacteria offers a way to analyze traits in different Nitrospira functional groups. Our comparative genomics analysis provided new insights into the adaptation of Nitrospira strains to specific lifestyles and environmental niches. Author Video: An author video summary of this article is available.
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Klima CL, Zaheer R, Briggs RE, McAllister TA. A multiplex PCR assay for molecular capsular serotyping of Mannheimia haemolytica serotypes 1, 2, and 6. J Microbiol Methods 2017; 139:155-160. [DOI: 10.1016/j.mimet.2017.05.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 05/17/2017] [Accepted: 05/17/2017] [Indexed: 10/19/2022]
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Mannheimia haemolytica biofilm formation on bovine respiratory epithelial cells. Vet Microbiol 2016; 197:129-136. [PMID: 27938674 PMCID: PMC7126505 DOI: 10.1016/j.vetmic.2016.11.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 11/07/2016] [Accepted: 11/07/2016] [Indexed: 11/22/2022]
Abstract
We devise a novel system that allows M. haemolytica biofilms to form on epithelial cells. Mucin significantly decreased biofilm formation. Prior infection with several respiratory viruses does not alter biofilm formation. Biofilms on epithelial cells were more resistant to some antibiotics than biofilms on polystyrene.
Mannheimia haemolytica is the most important bacterial agent associated with the bovine respiratory disease complex (BRDC), which causes worldwide economic losses to the cattle industry. M. haemolytica cells initially colonize the tonsillar crypts in the upper respiratory tract of cattle, from where they can subsequently descend into the lungs to cause disease. Many bacteria exist as biofilms inside their hosts. We hypothesize that M. haemolytica colonization of cattle during its commensal state may include biofilm formation. To begin to assess this possibility, we developed an in vitro system to study biofilm formation directly on bovine respiratory epithelial cells. Using fixed primary bovine bronchial epithelial cells, we observed M. haemolytica biofilm formation after a 48 h incubation period at 37 °C. Addition of mucin, the main component of mucus present in the upper respiratory tract, decreased M. haemolytica biofilm formation on bovine epithelial cells. We investigated the effects of prior viral infection of the epithelial cells on subsequent biofilm formation by M. haemolytica and found negligible effects. Utilization of this model system will provide new insights into the potential role of biofilm formation by M. haemolytica in the pathogenesis of BRDC.
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Klima CL, Cook SR, Zaheer R, Laing C, Gannon VP, Xu Y, Rasmussen J, Potter A, Hendrick S, Alexander TW, McAllister TA. Comparative Genomic Analysis of Mannheimia haemolytica from Bovine Sources. PLoS One 2016; 11:e0149520. [PMID: 26926339 PMCID: PMC4771134 DOI: 10.1371/journal.pone.0149520] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 02/02/2016] [Indexed: 11/18/2022] Open
Abstract
Bovine respiratory disease is a common health problem in beef production. The primary bacterial agent involved, Mannheimia haemolytica, is a target for antimicrobial therapy and at risk for associated antimicrobial resistance development. The role of M. haemolytica in pathogenesis is linked to serotype with serotypes 1 (S1) and 6 (S6) isolated from pneumonic lesions and serotype 2 (S2) found in the upper respiratory tract of healthy animals. Here, we sequenced the genomes of 11 strains of M. haemolytica, representing all three serotypes and performed comparative genomics analysis to identify genetic features that may contribute to pathogenesis. Possible virulence associated genes were identified within 14 distinct prophage, including a periplasmic chaperone, a lipoprotein, peptidoglycan glycosyltransferase and a stress response protein. Prophage content ranged from 2–8 per genome, but was higher in S1 and S6 strains. A type I-C CRISPR-Cas system was identified in each strain with spacer diversity and organization conserved among serotypes. The majority of spacers occur in S1 and S6 strains and originate from phage suggesting that serotypes 1 and 6 may be more resistant to phage predation. However, two spacers complementary to the host chromosome targeting a UDP-N-acetylglucosamine 2-epimerase and a glycosyl transferases group 1 gene are present in S1 and S6 strains only indicating these serotypes may employ CRISPR-Cas to regulate gene expression to avoid host immune responses or enhance adhesion during infection. Integrative conjugative elements are present in nine of the eleven genomes. Three of these harbor extensive multi-drug resistance cassettes encoding resistance against the majority of drugs used to combat infection in beef cattle, including macrolides and tetracyclines used in human medicine. The findings here identify key features that are likely contributing to serotype related pathogenesis and specific targets for vaccine design intended to reduce the dependency on antibiotics to treat respiratory infection in cattle.
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Affiliation(s)
- Cassidy L. Klima
- Agriculture and Agri-Food Canada Research Centre, Lethbridge, AB T1J 4B1, Canada
- Department of Large Animal Clinial Science, Western Colledge of Verterinary Medicine, University of Saskatoon, Saskatoon, Canada
| | - Shaun R. Cook
- Agriculture and Agri-Food Canada Research Centre, Lethbridge, AB T1J 4B1, Canada
| | - Rahat Zaheer
- Agriculture and Agri-Food Canada Research Centre, Lethbridge, AB T1J 4B1, Canada
| | - Chad Laing
- Laboratory for Foodborne Zoonoses, Public Health Agency of Canada, Lethbridge, Alberta, Canada
| | - Vick P. Gannon
- Laboratory for Foodborne Zoonoses, Public Health Agency of Canada, Lethbridge, Alberta, Canada
| | - Yong Xu
- Department of Biological Sciences, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Jay Rasmussen
- Agriculture and Agri-Food Canada Research Centre, Lethbridge, AB T1J 4B1, Canada
| | - Andrew Potter
- Vaccine and Infectious Disease Organization, Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Steve Hendrick
- Department of Large Animal Clinial Science, Western Colledge of Verterinary Medicine, University of Saskatoon, Saskatoon, Canada
| | - Trevor W. Alexander
- Agriculture and Agri-Food Canada Research Centre, Lethbridge, AB T1J 4B1, Canada
- * E-mail: (TAM); (TWA)
| | - Tim A. McAllister
- Agriculture and Agri-Food Canada Research Centre, Lethbridge, AB T1J 4B1, Canada
- * E-mail: (TAM); (TWA)
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Identification of a Hemagglutinin from Gallibacterium anatis. Curr Microbiol 2016; 72:450-6. [PMID: 26729352 DOI: 10.1007/s00284-015-0969-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 11/12/2015] [Indexed: 12/25/2022]
Abstract
Gallibacterium anatis has the ability to hemagglutinate rabbit erythrocytes; however, no bacterial component has yet been associated with this function. In the present work, a protein of approximately 65 kDa with hemagglutinating activity for glutaraldehyde-fixed chicken erythrocytes was purified by ion interchange chromatography from G. anatis F149(T) secreted proteins. The protein was recognized by a rabbit polyclonal serum against a hemagglutinin from Avibacterium paragallinarum. The 65 kDa purified protein presented identity with a G. anatis filamentous hemagglutinin by mass spectrometric analysis. As well, the bacterial surface of G. anatis was labeled by immune gold assays using a polyclonal serum against the 65-kDa protein. A similar protein was recognized in four other G. anatis strains by immunoblots using the same antiserum. The protein binds sheep or pig biotinylated fibrinogen, suggesting an interaction with basement membrane eukaryotic cells components, and the protein is present in G. anatis biofilms. Overall, the results suggest that the 65 kDa hemagglutinin is a common antigen and a potential virulence factor in G. anatis.
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Rai AN, Epperson WB, Nanduri B. Application of Functional Genomics for Bovine Respiratory Disease Diagnostics. Bioinform Biol Insights 2015; 9:13-23. [PMID: 26526746 PMCID: PMC4620937 DOI: 10.4137/bbi.s30525] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 08/24/2015] [Accepted: 08/26/2015] [Indexed: 12/27/2022] Open
Abstract
Bovine respiratory disease (BRD) is the most common economically important disease affecting cattle. For developing accurate diagnostics that can predict disease susceptibility/resistance and stratification, it is necessary to identify the molecular mechanisms that underlie BRD. To study the complex interactions among the bovine host and the multitude of viral and bacterial pathogens, as well as the environmental factors associated with BRD etiology, genome-scale high-throughput functional genomics methods such as microarrays, RNA-seq, and proteomics are helpful. In this review, we summarize the progress made in our understanding of BRD using functional genomics approaches. We also discuss some of the available bioinformatics resources for analyzing high-throughput data, in the context of biological pathways and molecular interactions. Although resources for studying host response to infection are avail-able, the corresponding information is lacking for majority of BRD pathogens, impeding progress in identifying diagnostic signatures for BRD using functional genomics approaches.
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Affiliation(s)
- Aswathy N Rai
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, MS, USA
| | - William B Epperson
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, MS, USA
| | - Bindu Nanduri
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, MS, USA. ; Institute for Genomics, Biocomputing, and Biotechnology, Mississippi State University, MS, USA
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Niu YD, Cook SR, Wang J, Klima CL, Hsu YH, Kropinski AM, Turner D, McAllister TA. Comparative analysis of multiple inducible phages from Mannheimia haemolytica. BMC Microbiol 2015; 15:175. [PMID: 26318735 PMCID: PMC4553209 DOI: 10.1186/s12866-015-0494-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Accepted: 07/24/2015] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Mannheimia haemolytica is a commensal bacterium that resides in the upper respiratory tract of cattle that can play a role in bovine respiratory disease. Prophages are common in the M. haemolytica genome and contribute significantly to host diversity. The objective of this research was to undertake comparative genomic analysis of phages induced from strains of M. haemolytica serotype A1 (535A and 2256A), A2 (587A and 1127A) and A6 (1152A and 3927A). RESULTS Overall, four P2-like (535AP1, 587AP1, 1127AP1 and 2256AP1; genomes: 34.9-35.7 kb; G+C content: 41.5-42.1 %; genes: 51-53 coding sequences, CDSs), four λ-like (535AP2, 587AP2, 1152AP2 and 3927AP1; genomes: 48.6-52.1 kb; 41.1-41.4 % mol G+C; genes: 77-83 CDSs and 2 tRNAs) and one Mu-like (3927AP2; genome: 33.8 kb; 43.1 % mol G+C; encoding 50 CDSs) phages were identified. All P2-like phages are collinear with the temperate phage φMhaA1-PHL101 with 535AP1, 2256AP1 and 1152AP1 being most closely related, followed by 587AP1 and 1127AP1. Lambdoid phages are not collinear with any other known λ-type phages, with 587AP2 being distinct from 535AP2, 3927AP1 and 1152AP2. All λ-like phages contain genes encoding a toxin-antitoxin (TA) system and cell-associated haemolysin XhlA. The Mu-like phage induced from 3927A is closely related to the phage remnant φMhaMu2 from M. haemolytica PHL21, with similar Mu-like phages existing in the genomes of M. haemolytica 535A and 587A. CONCLUSIONS This is among the first reports of both λ- and Mu-type phages being induced from M. haemolytica. Compared to phages induced from commensal strains of M. haemolytica serotype A2, those induced from the more virulent A1 and A6 serotypes are more closely related. Moreover, when P2-, λ- and Mu-like phages co-existed in the M. haemolytica genome, only P2- and λ-like phages were detected upon induction, suggesting that Mu-type phages may be more resistant to induction. Toxin-antitoxin gene cassettes in λ-like phages may contribute to their genomic persistence or the establishment of persister subpopulations of M. haemolytica. Further work is required to determine if the cell-associated haemolysin XhlA encoded by λ-like phages contributes to the pathogenicity and ecological fitness of M. haemolytica.
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Affiliation(s)
- Yan D Niu
- Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, T1J 4B1, Canada. .,Alberta Agriculture and Rural Development, Agriculture Centre, Lethbridge, AB, T1J 4V6, Canada.
| | - Shaun R Cook
- Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, T1J 4B1, Canada.
| | - Jiaying Wang
- Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, T1J 4B1, Canada. .,College of Veterinary Medicine, South China Agricultural University, Guangdong, 510642, People's Republic of China.
| | - Cassidy L Klima
- Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, T1J 4B1, Canada.
| | - Yu-hung Hsu
- Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, T1J 4B1, Canada. .,Department of Biological Sciences, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada.
| | - Andrew M Kropinski
- Public Health Agency of Canada, Laboratory for Foodborne Zoonoses, Guelph, ON, N1G 3W4, Canada. .,Department of Molecular Biology, Cellular Biology and Pathobiology, University of Guelph, Guelph, ON, N1G 2W1, Canada.
| | - Dann Turner
- Centre for Research in Biosciences, Department of Applied Sciences, University of the West of England, Coldharbour Lane, Bristol, BS16 1QY, UK.
| | - Tim A McAllister
- Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, T1J 4B1, Canada.
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Complete Genome Sequence of Mannheimia haemolytica Strain Mh10517, Isolated from Sheep in South Africa. GENOME ANNOUNCEMENTS 2015; 3:3/2/e00129-15. [PMID: 25858825 PMCID: PMC4392137 DOI: 10.1128/genomea.00129-15] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Respiratory disease caused by Mannheimia haemolytica is a major concern in the cattle and small stock industry worldwide. This problem arises due to the interaction of numerous contributing factors, including physical stresses associated with weaning, shipment, inclement weather, and overcrowding coupled with viral and bacterial infections. The whole genome of M. haemolytica strain Mh10517 was analyzed using an Illumina MiSeq high-throughput sequencing platform. The genome size is 2.67 Mb with 2,879 predicted gene sequences. The availability of this genome sequence will advance studies on various aspects of the biology of M. haemolytica in Africa and the world at large.
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Gaston JR, Roberts SA, Humphreys TL. Molecular phylogenetic analysis of non-sexually transmitted strains of Haemophilus ducreyi. PLoS One 2015; 10:e0118613. [PMID: 25774793 PMCID: PMC4361675 DOI: 10.1371/journal.pone.0118613] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 01/21/2015] [Indexed: 12/19/2022] Open
Abstract
Haemophilus ducreyi, the etiologic agent of chancroid, has been previously reported to show genetic variance in several key virulence factors, placing strains of the bacterium into two genetically distinct classes. Recent studies done in yaws-endemic areas of the South Pacific have shown that H. ducreyi is also a major cause of cutaneous limb ulcers (CLU) that are not sexually transmitted. To genetically assess CLU strains relative to the previously described class I, class II phylogenetic hierarchy, we examined nucleotide sequence diversity at 11 H. ducreyi loci, including virulence and housekeeping genes, which encompass approximately 1% of the H. ducreyi genome. Sequences for all 11 loci indicated that strains collected from leg ulcers exhibit DNA sequences homologous to class I strains of H. ducreyi. However, sequences for 3 loci, including a hemoglobin receptor (hgbA), serum resistance protein (dsrA), and a collagen adhesin (ncaA) contained informative amounts of variation. Phylogenetic analyses suggest that these non-sexually transmitted strains of H. ducreyi comprise a sub-clonal population within class I strains of H. ducreyi. Molecular dating suggests that CLU strains are the most recently developed, having diverged approximately 0.355 million years ago, fourteen times more recently than the class I/class II divergence. The CLU strains' divergence falls after the divergence of humans from chimpanzees, making it the first known H. ducreyi divergence event directly influenced by the selective pressures accompanying human hosts.
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Affiliation(s)
- Jordan R. Gaston
- Department of Biology, Allegheny College, Meadville, Pennsylvania, United States of America
| | - Sally A. Roberts
- Department of Microbiology, Auckland District Health Board, Auckland, New Zealand
| | - Tricia L. Humphreys
- Department of Biology, Allegheny College, Meadville, Pennsylvania, United States of America
- * E-mail:
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Phylogenomic and molecular demarcation of the core members of the polyphyletic pasteurellaceae genera actinobacillus, haemophilus, and pasteurella. Int J Genomics 2015; 2015:198560. [PMID: 25821780 PMCID: PMC4363679 DOI: 10.1155/2015/198560] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 01/19/2015] [Accepted: 01/26/2015] [Indexed: 12/18/2022] Open
Abstract
The genera Actinobacillus, Haemophilus, and Pasteurella exhibit extensive polyphyletic branching in phylogenetic trees and do not represent coherent clusters of species. In this study, we have utilized molecular signatures identified through comparative genomic analyses in conjunction with genome based and multilocus sequence based phylogenetic analyses to clarify the phylogenetic and taxonomic boundary of these genera. We have identified large clusters of Actinobacillus, Haemophilus, and Pasteurella species which represent the “sensu stricto” members of these genera. We have identified 3, 7, and 6 conserved signature indels (CSIs), which are specifically shared by sensu stricto members of Actinobacillus, Haemophilus, and Pasteurella, respectively. We have also identified two different sets of CSIs that are unique characteristics of the pathogen containing genera Aggregatibacter and Mannheimia, respectively. It is now possible to demarcate the genera Actinobacillus sensu stricto, Haemophilus sensu stricto, and Pasteurella sensu stricto on the basis of discrete molecular signatures. The other members of the genera Actinobacillus, Haemophilus, and Pasteurella that do not fall within the “sensu stricto” clades and do not contain these molecular signatures should be reclassified as other genera. The CSIs identified here also provide useful diagnostic targets for the identification of current and novel members of the indicated genera.
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Boukahil I, Czuprynski CJ. Characterization of Mannheimia haemolytica biofilm formation in vitro. Vet Microbiol 2014; 175:114-22. [PMID: 25480166 DOI: 10.1016/j.vetmic.2014.11.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 11/04/2014] [Accepted: 11/12/2014] [Indexed: 01/12/2023]
Abstract
Mannheimia haemolytica is the primary bacterial agent in the bovine respiratory disease complex. It is thought that M. haemolytica colonizes the tonsillar crypts of cattle as a commensal and subsequently descends into the lungs to cause disease. Many bacterial species persist in the host as biofilms. There is limited information about the ability of M. haemolytica to form biofilms. The aim of this study was to develop an in vitro model for M. haemolytica biofilm formation. We found that M. haemolytica required at least 36 h to form robust biofilms on plastic in vitro when incubated in RPMI-1640 tissue culture medium at 37 °C, with maximal biofilm formation being evident at 48 h. Biofilm formation was inhibited by adding the monosaccharides d(+) galactose and d(+) mannose to the growth medium. Addition of antibodies to the M. haemolytica surface protein OmpA also reduced biofilm formation. Upon evaluating the macromolecules within the biofilm extracellular polymeric substance we found it contained 9.7 μg/cm(2) of protein, 0.81 μg/cm(2) of total carbohydrate, and 0.47 μg/cm(2) of extracellular DNA. Furthermore, proteinase K treatment significantly decreased biofilms (P<0.05) while α-amylase and micrococcal nuclease decreased biofilms to a lesser extent. M. haemolytica biofilm cells were more resistant than planktonic cells to the antibiotics florfenicol, gentamicin, and tulathromycin. These results provide evidence that M. haemolytica can form biofilms, which could contribute to its ability to persist as a commensal in the bovine upper respiratory tract.
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Affiliation(s)
- Ismail Boukahil
- Department of Pathobiological Sciences, University of Wisconsin-Madison, School of Veterinary Medicine, 2015 Linden Drive, Madison, WI 53706, USA.
| | - Charles J Czuprynski
- Department of Pathobiological Sciences, University of Wisconsin-Madison, School of Veterinary Medicine, 2015 Linden Drive, Madison, WI 53706, USA.
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Klima CL, Alexander TW, Hendrick S, McAllister TA. Characterization of Mannheimia haemolytica isolated from feedlot cattle that were healthy or treated for bovine respiratory disease. CANADIAN JOURNAL OF VETERINARY RESEARCH = REVUE CANADIENNE DE RECHERCHE VETERINAIRE 2014; 78:38-45. [PMID: 24396179 PMCID: PMC3878007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Accepted: 12/10/2012] [Indexed: 06/03/2023]
Abstract
Mannheimia haemolytica is the principal bacterial pathogen associated with bovine respiratory disease (BRD). As an opportunistic pathogen, M. haemolytica is also frequently isolated from the respiratory tract of healthy cattle. This study examined the characteristics of M. haemolytica collected using deep nasal swabs from healthy cattle (n = 49) and cattle diagnosed with BRD (n = 41). Isolates were analyzed by pulsed-field gel electrophoresis (PFGE), serotyped, and tested for antimicrobial susceptibility. Polymerase chain reaction (PCR) was used to screen isolates for virulence [leukotoxin C (lktC), putative adhesin (ahs), outer-membrane lipoprotein (gs60), O-sialoglycoprotease (gcp), transferring-binding protein B (tbpB) and UDP-N-acetyl-D-glucosamine-2-epimerase (nmaA)] and antimicrobial resistance [tet(H), bla ROB-1, erm(X), erm(42), msr(E)-mph(E) and aphA-1] genes. Isolates were genetically diverse but in three instances, M. haemolytica with the same pulsotype, resistance phenotype, and genotype were collected from cattle with BRD. This occurred once between cattle located in two different feedlots, once between cattle in the same feedlot, but in different pens, and once among cattle from the same feedlot in the same pen. Isolates from healthy cattle were primarily serotype 2 (75.5%) while those from individuals with BRD were serotype 1 (70.7%) or 6 (19.5%). Resistance to at least one antibiotic occurred more frequently (P < 0.001) in M. haemolytica collected from cattle with BRD (37%) compared with those that were healthy (2%). Overall, tetracycline resistance (18%) was the most prevalent resistant phenotype. All tetracycline-resistant M. haemolytica encoded tet(H). Ampicillin resistance (6%) and neomycin resistance (15%) were detected and corresponded to the presence of the bla ROB-1 and aphA-1 genes, respectively. Tilmicosin resistance (6%) was also detected, but the resistance genes responsible were not identified. The virulence genes lktC, ahs, gs60, and gcp were present in all isolates examined, while tbpB and nmaA were only detected in serotype 1 and serotype 6 isolates indicating they may be potential targets for serotype-specific identification or vaccine development. These results provide the first reported evidence of transmission and spread of antimicrobial-resistant M. haemolytica that have contributed to bovine respiratory disease in western Canadian feedlots.
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Affiliation(s)
| | - Trevor W. Alexander
- Address all correspondence to Dr. Trevor W. Alexander; telephone: +1-403-317-2158; fax: +1-403-317-2182; e-mail:
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Bragg R, van der Westhuizen W, Lee JY, Coetsee E, Boucher C. Bacteriophages as potential treatment option for antibiotic resistant bacteria. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 807:97-110. [PMID: 24619620 DOI: 10.1007/978-81-322-1777-0_7] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The world is facing an ever-increasing problem with antibiotic resistant bacteria and we are rapidly heading for a post-antibiotic era. There is an urgent need to investigate alterative treatment options while there are still a few antibiotics left. Bacteriophages are viruses that specifically target bacteria. Before the development of antibiotics, some efforts were made to use bacteriophages as a treatment option, but most of this research stopped soon after the discovery of antibiotics. There are two different replication options which bacteriophages employ. These are the lytic and lysogenic life cycles. Both these life cycles have potential as treatment options. There are various advantages and disadvantages to the use of bacteriophages as treatment options. The main advantage is the specificity of bacteriophages and treatments can be designed to specifically target pathogenic bacteria while not negatively affecting the normal microbiota. There are various advantages to this. However, the high level of specificity also creates potential problems, the main being the requirement of highly specific diagnostic procedures. Another potential problem with phage therapy includes the development of immunity and limitations with the registration of phage therapy options. The latter is driving research toward the expression of phage genes which break the bacterial cell wall, which could then be used as a treatment option. Various aspects of phage therapy have been investigated in studies undertaken by our research group. We have investigated specificity of phages to various avian pathogenic E. coli isolates. Furthermore, the exciting NanoSAM technology has been employed to investigate bacteriophage replication and aspects of this will be discussed.
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Affiliation(s)
- Robert Bragg
- Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, P.O. Box 399, Bloemfontein, 9300, South Africa,
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Caswell JL. Failure of respiratory defenses in the pathogenesis of bacterial pneumonia of cattle. Vet Pathol 2013; 51:393-409. [PMID: 24021557 DOI: 10.1177/0300985813502821] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The respiratory system is well defended against inhaled bacteria by a dynamic system of interacting layers, including mucociliary clearance, host defense factors including antimicrobial peptides in the epithelial lining fluid, proinflammatory responses of the respiratory epithelium, resident alveolar macrophages, and recruited neutrophils and monocytes. Nevertheless, these manifold defenses are susceptible to failure as a result of stress, glucocorticoids, viral infections, abrupt exposure to cold air, and poor air quality. When some of these defenses fail, the lung can be colonized by bacterial pathogens that are equipped to evade the remaining defenses, resulting in the development of pneumonia. This review considers the mechanisms by which these predisposing factors compromise the defenses of the lung, with a focus on the development of bacterial pneumonia in cattle and supplemented with advances based on mouse models and the study of human disease. Deepening our understanding of how the respiratory defenses fail is expected to lead to interventions that restore these dynamic immune responses and prevent disease.
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Affiliation(s)
- J L Caswell
- Department of Pathobiology, University of Guelph, Guelph, ON N1G 2W1, Canada.
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Abstract
In a world where most emerging and reemerging infectious diseases are zoonotic in nature and our contacts with both domestic and wild animals abound, there is growing awareness of the potential for human acquisition of animal diseases. Like other Pasteurellaceae, Pasteurella species are highly prevalent among animal populations, where they are often found as part of the normal microbiota of the oral, nasopharyngeal, and upper respiratory tracts. Many Pasteurella species are opportunistic pathogens that can cause endemic disease and are associated increasingly with epizootic outbreaks. Zoonotic transmission to humans usually occurs through animal bites or contact with nasal secretions, with P. multocida being the most prevalent isolate observed in human infections. Here we review recent comparative genomics and molecular pathogenesis studies that have advanced our understanding of the multiple virulence mechanisms employed by Pasteurella species to establish acute and chronic infections. We also summarize efforts being explored to enhance our ability to rapidly and accurately identify and distinguish among clinical isolates and to control pasteurellosis by improved development of new vaccines and treatment regimens.
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Affiliation(s)
- Brenda A Wilson
- Department of Microbiology and Host-Microbe Systems Theme of the Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
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Complete Closed Genome Sequences of Mannheimia haemolytica Serotypes A1 and A6, Isolated from Cattle. GENOME ANNOUNCEMENTS 2013; 1:1/3/e00188-13. [PMID: 23682137 PMCID: PMC3656199 DOI: 10.1128/genomea.00188-13] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Mannheimia haemolytica is a respiratory pathogen affecting cattle and related ruminants worldwide. M. haemolytica is commonly associated with bovine respiratory disease complex (BRDC), a polymicrobial multifactorial disease. We present the first two complete closed genome sequences of this species, determined using an automated assembly pipeline requiring no manual finishing.
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Roier S, Fenninger JC, Leitner DR, Rechberger GN, Reidl J, Schild S. Immunogenicity of Pasteurella multocida and Mannheimia haemolytica outer membrane vesicles. Int J Med Microbiol 2013; 303:247-56. [PMID: 23731905 PMCID: PMC3717205 DOI: 10.1016/j.ijmm.2013.05.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 04/29/2013] [Accepted: 05/05/2013] [Indexed: 01/29/2023] Open
Abstract
Pasteurella multocida is able to cause disease in humans and in a wide range of animal hosts, including fowl cholera in birds, atrophic rhinitis in pigs, and snuffles in rabbits. Together with Mannheimia haemolytica, P. multocida also represents a major bacterial causative agent of bovine respiratory disease (BRD), which is one of the most important causes for economic losses for the cattle backgrounding and feedlot industry. Commercially available vaccines only partially prevent infections caused by P. multocida and M. haemolytica. Thus, this study characterized the immunogenicity of P. multocida and M. haemolytica outer membrane vesicles (OMVs) upon intranasal immunization of BALB/c mice. Enzyme-linked immunosorbent assays (ELISA) revealed that OMVs derived from P. multocida or M. haemolytica are able to induce robust humoral and mucosal immune responses against the respective donor strain. In addition, also significant cross-immunogenic potential was observed for both OMV types. Colonization studies showed that a potential protective immune response against P. multocida is not only achieved by immunization with P. multocida OMVs, but also by immunization with OMVs derived from M. haemolytica. Immunoblot and immunoprecipitation analyses demonstrated that M. haemolytica OMVs induce a more complex immune response compared to P. multocida OMVs. The outer membrane proteins OmpA, OmpH, and P6 were identified as the three major immunogenic proteins of P. multocida OMVs. Amongst others, the serotype 1-specific antigen, an uncharacterized outer membrane protein, as well as the outer membrane proteins P2 and OmpA were found to be the most important antigens of M. haemolytica OMVs. These findings are useful for the future development of broad-spectrum OMV based vaccines against BRD and other infections caused by P. multocida or M. haemolytica.
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Affiliation(s)
- Sandro Roier
- Institute of Molecular Biosciences, University of Graz, Humboldtstraße 50, A-8010 Graz, Austria
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Draft Genome Sequence of a Mannheimia haemolytica Serotype 6 Isolate Collected from the Nasopharynx of a Beef Calf with Bovine Respiratory Disease. GENOME ANNOUNCEMENTS 2013; 1:e0005113. [PMID: 23558528 PMCID: PMC3622974 DOI: 10.1128/genomea.00051-13] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The draft genome of a Mannheimia haemolytica serotype 6 isolate obtained from the nasopharynx of a feedlot calf with bovine respiratory disease is described.
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Hsu YH, Cook SR, Alexander TW, Klima CL, Niu YD, Selinger LB, McAllister TA. Investigation of Mannheimia haemolytica bacteriophages relative to host diversity. J Appl Microbiol 2013; 114:1592-603. [PMID: 23489937 DOI: 10.1111/jam.12185] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 03/02/2013] [Accepted: 03/02/2013] [Indexed: 01/21/2023]
Abstract
AIMS This study aimed to characterize the impact of lytic and temperate bacteriophages on the genetic and phenotypic diversity of Mannheimia haemolytica from feedlot cattle. METHODS AND RESULTS Strictly lytic phages were not detected from bovine nasopharyngeal (n = 689) or water trough (n = 30) samples, but Myoviridae- or Siphoviridae-like phages were induced from 54 of 72 M. haemolytica strains by mitomycin C, occasionally from the same strain. Phages with similar restriction fragment length polymorphism profiles (RFLP ≥70% relatedness) shared common host serotypes 1 or 2 (P < 0·0001). Likewise, phages with similar RFLP tended to occur in genetically related host bacteria (70-79% similarity). Host range assays showed that seven phages from host serotypes 1, 2 and 6 lysed representative strains of serotypes 1, 2 or 8. The genome of vB_MhM_1152AP from serotype 6 was found to be collinear with P2-like phage φMhaA1-PHL101. CONCLUSIONS Prophages are a significant component of the genome of M. haemolytica and contribute significantly to host diversity. Further characterization of the role of prophage in virulence and persistence of M. haemolytica in cattle could provide insight into approaches to control this potential respiratory pathogen. SIGNIFICANCE AND IMPACT OF THE STUDY This study demonstrated that prophages are widespread within the genome of M. haemolytica isolates and emphasized the challenge of isolating lytic phage as a therapeutic against this pathogen.
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Affiliation(s)
- Y-H Hsu
- Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, AB, Canada
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Loera-Muro VM, Jacques M, Tremblay YDN, Avelar-González FJ, Loera Muro A, Ramírez-López EM, Medina-Figueroa A, González-Reynaga HM, Guerrero-Barrera AL. Detection of Actinobacillus pleuropneumoniae in drinking water from pig farms. MICROBIOLOGY-SGM 2013; 159:536-544. [PMID: 23347956 DOI: 10.1099/mic.0.057992-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Actinobacillus pleuropneumoniae is the aetiological agent of porcine pleuropneumonia and is normally transmitted by aerosols and direct contact between animals. A. pleuropneumoniae has traditionally been considered an obligate pathogen of pigs and its presence in the environment has yet to be investigated. Here, the presence of A. pleuropneumoniae was detected in drinking water of pig farms in Mexico using a PCR specific for the RTX toxin gene, apxIV. The presence of A. pleuropneumoniae in farm drinking water was confirmed by indirect immunofluorescence using an A. pleuropneumoniae-specific polyclonal antibody and by fluorescent in situ hybridization. Viable bacteria from the farm drinking water were detected using the Live/Dead BacLight stain. Additionally, viable A. pleuropneumoniae was selected and isolated using the cAMP test and the identity of the isolated bacteria were confirmed by Gram staining, a specific polyclonal antibody and an A. pleuropneumoniae-specific PCR. Furthermore, biofilms were observed by scanning electron microscopy in A. pleuropneumoniae-positive samples. In conclusion, our data suggest that viable A. pleuropneumoniae is present in the drinking water of swine farms and may use biofilm as a strategy to survive in the environment.
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Affiliation(s)
- Victor M Loera-Muro
- Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Aguascalientes, Ags., C. P. 20131, Mexico
| | - Mario Jacques
- Groupe de recherche sur la maladies infectieuses du porc, Faculté de médecine vétérinaire, Université de Montréal, St-Hyacinthe, QC J2S 7C6, Canada
| | - Yannick D N Tremblay
- Groupe de recherche sur la maladies infectieuses du porc, Faculté de médecine vétérinaire, Université de Montréal, St-Hyacinthe, QC J2S 7C6, Canada
| | - Francisco J Avelar-González
- Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Aguascalientes, Ags., C. P. 20131, Mexico
| | - Abraham Loera Muro
- Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Aguascalientes, Ags., C. P. 20131, Mexico
| | - Elsa M Ramírez-López
- Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Aguascalientes, Ags., C. P. 20131, Mexico
| | - Alejandra Medina-Figueroa
- Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Aguascalientes, Ags., C. P. 20131, Mexico
| | - Higinio M González-Reynaga
- Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Aguascalientes, Ags., C. P. 20131, Mexico
| | - Alma L Guerrero-Barrera
- Laboratorio de Biología Celular y Tisular, Departamento de Morfología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Aguascalientes, Ags., C. P. 20131, Mexico
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Reddy JS, Kumar R, Watt JM, Lawrence ML, Burgess SC, Nanduri B. Transcriptome profile of a bovine respiratory disease pathogen: Mannheimia haemolytica PHL213. BMC Bioinformatics 2012; 13 Suppl 15:S4. [PMID: 23046475 PMCID: PMC3439734 DOI: 10.1186/1471-2105-13-s15-s4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Background Computational methods for structural gene annotation have propelled gene discovery but face certain drawbacks with regards to prokaryotic genome annotation. Identification of transcriptional start sites, demarcating overlapping gene boundaries, and identifying regulatory elements such as small RNA are not accurate using these approaches. In this study, we re-visit the structural annotation of Mannheimia haemolytica PHL213, a bovine respiratory disease pathogen. M. haemolytica is one of the causative agents of bovine respiratory disease that results in about $3 billion annual losses to the cattle industry. We used RNA-Seq and analyzed the data using freely-available computational methods and resources. The aim was to identify previously unannotated regions of the genome using RNA-Seq based expression profile to complement the existing annotation of this pathogen. Results Using the Illumina Genome Analyzer, we generated 9,055,826 reads (average length ~76 bp) and aligned them to the reference genome using Bowtie. The transcribed regions were analyzed using SAMTOOLS and custom Perl scripts in conjunction with BLAST searches and available gene annotation information. The single nucleotide resolution map enabled the identification of 14 novel protein coding regions as well as 44 potential novel sRNA. The basal transcription profile revealed that 2,506 of the 2,837 annotated regions were expressed in vitro, at 95.25% coverage, representing all broad functional gene categories in the genome. The expression profile also helped identify 518 potential operon structures involving 1,086 co-expressed pairs. We also identified 11 proteins with mutated/alternate start codons. Conclusions The application of RNA-Seq based transcriptome profiling to structural gene annotation helped correct existing annotation errors and identify potential novel protein coding regions and sRNA. We used computational tools to predict regulatory elements such as promoters and terminators associated with the novel expressed regions for further characterization of these novel functional elements. Our study complements the existing structural annotation of Mannheimia haemolytica PHL213 based on experimental evidence. Given the role of sRNA in virulence gene regulation and stress response, potential novel sRNA described in this study can form the framework for future studies to determine the role of sRNA, if any, in M. haemolytica pathogenesis.
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Affiliation(s)
- Joseph S Reddy
- College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
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Zehr ES, Lavrov DV, Tabatabai LB. Comparison of Haemophilus parasuis reference strains and field isolates by using random amplified polymorphic DNA and protein profiles. BMC Microbiol 2012; 12:108. [PMID: 22703293 PMCID: PMC3499290 DOI: 10.1186/1471-2180-12-108] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Accepted: 05/31/2012] [Indexed: 11/10/2022] Open
Abstract
Background Haemophilus parasuis is the causative agent of Glässer’s disease and is a pathogen of swine in high-health status herds. Reports on serotyping of field strains from outbreaks describe that approximately 30% of them are nontypeable and therefore cannot be traced. Molecular typing methods have been used as alternatives to serotyping. This study was done to compare random amplified polymorphic DNA (RAPD) profiles and whole cell protein (WCP) lysate profiles as methods for distinguishing H. parasuis reference strains and field isolates. Results The DNA and WCP lysate profiles of 15 reference strains and 31 field isolates of H. parasuis were analyzed using the Dice and neighbor joining algorithms. The results revealed unique and reproducible DNA and protein profiles among the reference strains and field isolates studied. Simpson’s index of diversity showed significant discrimination between isolates when three 10mer primers were combined for the RAPD method and also when both the RAPD and WCP lysate typing methods were combined. Conclusions The RAPD profiles seen among the reference strains and field isolates did not appear to change over time which may reflect a lack of DNA mutations in the genes of the samples. The recent field isolates had different WCP lysate profiles than the reference strains, possibly because the number of passages of the type strains may affect their protein expression.
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Affiliation(s)
- Emilie S Zehr
- Ruminant Diseases and Immunology, National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA 50010, USA.
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Lagergård T, Bölin I, Lindholm L. On the evolution of the sexually transmitted bacteria Haemophilus ducreyi and Klebsiella granulomatis. Ann N Y Acad Sci 2012; 1230:E1-E10. [PMID: 22239475 DOI: 10.1111/j.1749-6632.2011.06193.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Haemophilus ducreyi and Klebsiella (Calymmatobacterium) granulomatis are sexually transmitted bacteria that cause characteristic, persisting ulceration on external genitals called chancroid and granuloma inguinale, respectively. Those ulcers are endemic in developing countries or exist, as does granuloma inguinale, only in some geographic "hot spots."H. ducreyi is placed in the genus Haemophilus (family Pasteurellacae); however, this phylogenetic position is not obvious. The multiple ways in which the bacterium may be adapted to its econiche through specialized nutrient acquisitions; defenses against the immune system; and virulence factors that increase attachment, fitness, and persistence within genital tissue are discussed below. The analysis of K. granulomatis phylogeny demonstrated a high degree of identity with other Klebsiella species, and the name K. granulomatis comb. nov. was proposed. Because of the difficulty in growing this bacterium on artificial media, its characteristics have not been sufficiently defined. More studies are needed to understand bacterial genetics related to the pathogenesis and evolution of K. granulomatis.
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Affiliation(s)
- Teresa Lagergård
- Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden.
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Sialylation of lipooligosaccharides is dispensable for the virulence of Haemophilus ducreyi in humans. Infect Immun 2011; 80:679-87. [PMID: 22144477 DOI: 10.1128/iai.05826-11] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Sialylated glycoconjugates on the surfaces of mammalian cells play important roles in intercellular communication and self-recognition. The sialic acid preferentially expressed in human tissues is N-acetylneuraminic acid (Neu5Ac). In a process called molecular mimicry, many bacterial pathogens decorate their cell surface glycolipids with Neu5Ac. Incorporation of Neu5Ac into bacterial glycolipids promotes bacterial interactions with host cell receptors called Siglecs. These interactions affect bacterial adherence, resistance to serum killing and phagocytosis, and innate immune responses. Haemophilus ducreyi, the etiologic agent of chancroid, expresses lipooligosaccharides (LOS) that are highly sialylated. However, an H. ducreyi sialyltransferase (lst) mutant, whose LOS contain reduced levels of Neu5Ac, is fully virulent in human volunteers. Recently, a second sialyltransferase gene (Hd0053) was discovered in H. ducreyi, raising the possibility that Hd0053 compensated for the loss of lst during human infection. CMP-Neu5Ac is the obligate nucleotide sugar donor for all bacterial sialyltransferases; LOS derived from an H. ducreyi CMP-Neu5Ac synthetase (neuA) mutant has no detectable Neu5Ac. Here, we compared an H. ducreyi neuA mutant to its wild-type parent in several models of pathogenesis. In human inoculation experiments, the neuA mutant formed papules and pustules at rates that were no different than those of its parent. When grown in media with and without Neu5Ac supplementation, the neuA mutant and its parent had similar phenotypes in bactericidal, macrophage uptake, and dendritic cell activation assays. Although we cannot preclude a contribution of LOS sialylation to ulcerative disease, these data strongly suggest that sialylation of LOS is dispensable for H. ducreyi pathogenesis in humans.
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Reed DL, Currier RW, Walton SF, Conrad M, Sullivan SA, Carlton JM, Read TD, Severini A, Tyler S, Eberle R, Johnson WE, Silvestri G, Clarke IN, Lagergård T, Lukehart SA, Unemo M, Shafer WM, Beasley RP, Bergström T, Norberg P, Davison AJ, Sharp PM, Hahn BH, Blomberg J. The evolution of infectious agents in relation to sex in animals and humans: brief discussions of some individual organisms. Ann N Y Acad Sci 2011; 1230:74-107. [PMID: 21824167 DOI: 10.1111/j.1749-6632.2011.06133.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The following series of concise summaries addresses the evolution of infectious agents in relation to sex in animals and humans from the perspective of three specific questions: (1) what have we learned about the likely origin and phylogeny, up to the establishment of the infectious agent in the genital econiche, including the relative frequency of its sexual transmission; (2) what further research is needed to provide additional knowledge on some of these evolutionary aspects; and (3) what evolutionary considerations might aid in providing novel approaches to the more practical clinical and public health issues facing us currently and in the future?
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Affiliation(s)
- David L Reed
- Florida Museum of Natural History, University of Florida, Gainesville, Florida, USA
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Hounsome JDA, Baillie S, Noofeli M, Riboldi-Tunnicliffe A, Burchmore RJS, Isaacs NW, Davies RL. Outer membrane protein A of bovine and ovine isolates of Mannheimia haemolytica is surface exposed and contains host species-specific epitopes. Infect Immun 2011; 79:4332-41. [PMID: 21896777 PMCID: PMC3257919 DOI: 10.1128/iai.05469-11] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 06/23/2011] [Accepted: 08/08/2011] [Indexed: 01/21/2023] Open
Abstract
Mannheimia haemolytica is the etiological agent of pneumonic pasteurellosis of cattle and sheep; two different OmpA subclasses, OmpA1 and OmpA2, are associated with bovine and ovine isolates, respectively. These proteins differ at the distal ends of four external loops, are involved in adherence, and are likely to play important roles in host adaptation. M. haemolytica is surrounded by a polysaccharide capsule, and the degree of OmpA surface exposure is unknown. To investigate surface exposure and immune specificity of OmpA among bovine and ovine M. haemolytica isolates, recombinant proteins representing the transmembrane domain of OmpA from a bovine serotype A1 isolate (rOmpA1) and an ovine serotype A2 isolate (rOmpA2) were overexpressed, purified, and used to generate anti-rOmpA1 and anti-rOmpA2 antibodies, respectively. Immunogold electron microscopy and immunofluorescence techniques demonstrated that OmpA1 and OmpA2 are surface exposed, and are not masked by the polysaccharide capsule, in a selection of M. haemolytica isolates of various serotypes and grown under different growth conditions. To explore epitope specificity, anti-rOmpA1 and anti-rOmpA2 antibodies were cross-absorbed with the heterologous isolate to remove cross-reacting antibodies. These cross-absorbed antibodies were highly specific and recognized only the OmpA protein of the homologous isolate in Western blot assays. A wider examination of the binding specificities of these antibodies for M. haemolytica isolates representing different OmpA subclasses revealed that cross-absorbed anti-rOmpA1 antibodies recognized OmpA1-type proteins but not OmpA2-type proteins; conversely, cross-absorbed anti-rOmpA2 antibodies recognized OmpA2-type proteins but not OmpA1-type proteins. Our results demonstrate that OmpA1 and OmpA2 are surface exposed and could potentially bind to different receptors in cattle and sheep.
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Affiliation(s)
- Jonathan D. A. Hounsome
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Susan Baillie
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Mojtaba Noofeli
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Alan Riboldi-Tunnicliffe
- School of Chemistry, College of Science and Engineering, University of Glasgow, Glasgow, United Kingdom
| | - Richard J. S. Burchmore
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Neil W. Isaacs
- School of Chemistry, College of Science and Engineering, University of Glasgow, Glasgow, United Kingdom
| | - Robert L. Davies
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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Michael GB, Kadlec K, Sweeney MT, Brzuszkiewicz E, Liesegang H, Daniel R, Murray RW, Watts JL, Schwarz S. ICEPmu1, an integrative conjugative element (ICE) of Pasteurella multocida: structure and transfer. J Antimicrob Chemother 2011; 67:91-100. [DOI: 10.1093/jac/dkr411] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Sathiamoorthy S, Hodgins DC, Shewen PE, Highlander SK, Lo RY. A snap-shot of Mannheimia hemolyticaA1 gene expression during infection in the bovine host. FEMS Microbiol Lett 2011; 325:148-54. [DOI: 10.1111/j.1574-6968.2011.02422.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Affiliation(s)
| | | | | | - Sarah K. Highlander
- Department of Molecular Virology & Microbiology; Baylor College of Medicine; Houston; TX; USA
| | - Reggie Y.C. Lo
- Department of Molecular & Cellular Biology; University of Guelph; Guelph; ON; Canada
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Immunogenicity of Mannheimia haemolytica recombinant outer membrane proteins serotype 1-specific antigen, OmpA, OmpP2, and OmpD15. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2011; 18:2067-74. [PMID: 21976226 DOI: 10.1128/cvi.05332-11] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We previously identified Mannheimia haemolytica outer membrane proteins (OMPs) that may be important immunogens by using immunoproteomic analyses. Genes for serotype 1-specific antigen (SSA-1), OmpA, OmpP2, and OmpD15 were cloned and expressed, and recombinant proteins were purified. Objective 1 of this study was to demonstrate immunogenicity of the four recombinant OMPs in mice and cattle. Objective 2 was to determine if the addition of individual recombinant OMPs or combinations of them would modify immune responsiveness of mice to the recombinant chimeric protein SAC89, containing the main epitope from M. haemolytica outer membrane lipoprotein PlpE and the neutralizing epitope of M. haemolytica leukotoxin. Mice vaccinated with recombinant OmpA (rOmpA), rSSA-1, rOmpD15, and rOmpP2 developed significant antibody responses to M. haemolytica outer membranes and to the homologous recombinant OMP. Cattle vaccinated with rOmpA and rSSA-1 developed significant antibodies to M. haemolytica outer membranes by day 28, whereas cattle vaccinated with rOmpD15 and rOmpP2 developed only minimal responses. Sera from cattle vaccinated with each of the recombinant proteins stimulated complement-mediated killing of the bacterium. Concurrent vaccination with SAC89 plus any of the four rOMPs singly resulted in increased endpoint anti-SAC89 titers, and for the SAC89/rSSA-1 vaccinees, the response was increased significantly. In contrast, the SAC89/P2/SSA-1 and SAC89/OmpA/P2/D15/SSA-1 combination vaccines resulted in significant decreases in anti-SAC89 antibodies compared to SAC89 vaccination alone. In conclusion, under the conditions of these experiments, vaccination of mice and cattle with rOmpA and rSSA-1 stimulated high antibody responses and may have protective vaccine potential.
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Naushad HS, Gupta RS. Molecular signatures (conserved indels) in protein sequences that are specific for the order Pasteurellales and distinguish two of its main clades. Antonie van Leeuwenhoek 2011; 101:105-24. [DOI: 10.1007/s10482-011-9628-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Accepted: 07/29/2011] [Indexed: 10/17/2022]
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Frey J. The role of RTX toxins in host specificity of animal pathogenic Pasteurellaceae. Vet Microbiol 2011; 153:51-8. [PMID: 21645978 DOI: 10.1016/j.vetmic.2011.05.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Revised: 04/29/2011] [Accepted: 05/10/2011] [Indexed: 10/18/2022]
Abstract
RTX toxins are bacterial pore-forming toxins that are particularly abundant among pathogenic species of Pasteurellaceae, in which they play a major role in virulence. RTX toxins of several primary pathogens of the family of Pasteurellaceae are directly involved in causing necrotic lesions in the target organs. Many RTX toxins are known as haemolysins because they lyse erythrocytes in vitro, an effect that is non-specific, but which serves as a useful marker in bacteriological identification and as an easily measurable signal in vitro in experimental studies. More recent studies have shown that the specific targets of most RTX toxins are leukocytes, with RTX toxins binding to the corresponding β-subunit (CD18) of β2 integrins and then exerting cytotoxic activity. After uptake by the target cell, at sub-lytic concentrations, some RTX toxins are transported to mitochondria and induce apoptosis. For several RTX toxins the binding to CD18 has been shown to be host specific and this seems to be the basis for the host range specificity of these RTX toxins. Observations on two very closely related species of the Pasteurellaceae family, Actinobacillus suis, a porcine pathogen particularly affecting suckling pigs, and Actinobacillus equuli subsp. haemolytica, which causes pyosepticaemia in new-born foals (sleepy foal disease), have revealed that they express different RTX toxins, named ApxI/II and Aqx, respectively. These RTX toxins are specifically cytotoxic for porcine and equine leukocytes, respectively. Furthermore, the ApxI and Aqx toxins of these species, when expressed in an isogenetic background in Escherichia coli, are specifically cytotoxic for leukocytes of their respective hosts. These data indicate the determinative role of RTX toxins in host specificity of pathogenic species of Pasteurellaceae.
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Affiliation(s)
- Joachim Frey
- Institute of Veterinary Bacteriology, University of Bern, Laenggasstrasse 122, CH-3012 Bern, Switzerland.
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Xu Z, Yue M, Zhou R, Jin Q, Fan Y, Bei W, Chen H. Genomic characterization of Haemophilus parasuis SH0165, a highly virulent strain of serovar 5 prevalent in China. PLoS One 2011; 6:e19631. [PMID: 21611187 PMCID: PMC3096633 DOI: 10.1371/journal.pone.0019631] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Accepted: 04/11/2011] [Indexed: 11/19/2022] Open
Abstract
Haemophilus parasuis can be either a commensal bacterium of the porcine respiratory tract or an opportunistic pathogen causing Glässer's disease, a severe systemic disease that has led to significant economical losses in the pig industry worldwide. We determined the complete genomic sequence of H. parasuis SH0165, a highly virulent strain of serovar 5, which was isolated from a hog pen in North China. The single circular chromosome was 2,269,156 base pairs in length and contained 2,031 protein-coding genes. Together with the full spectrum of genes detected by the analysis of metabolic pathways, we confirmed that H. parasuis generates ATP via both fermentation and respiration, and possesses an intact TCA cycle for anabolism. In addition to possessing the complete pathway essential for the biosynthesis of heme, this pathogen was also found to be well-equipped with different iron acquisition systems, such as the TonB system and ABC-type transport complexes, to overcome iron limitation during infection and persistence. We identified a number of genes encoding potential virulence factors, such as type IV fimbriae and surface polysaccharides. Analysis of the genome confirmed that H. parasuis is naturally competent, as genes related to DNA uptake are present. A nine-mer DNA uptake signal sequence (ACAAGCGGT), identical to that found in Actinobacillus pleuropneumoniae and Mannheimia haemolytica, followed by similar downstream motifs, was identified in the SH0165 genome. Genomic and phylogenetic comparisons with other Pasteurellaceae species further indicated that H. parasuis was closely related to another swine pathogenic bacteria A. pleuropneumoniae. The comprehensive genetic analysis presented here provides a foundation for future research on the metabolism, natural competence and virulence of H. parasuis.
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Affiliation(s)
- Zhuofei Xu
- State Key Laboratory of Agricultural Microbiology, Division of Animal Infectious Disease, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Min Yue
- State Key Laboratory of Agricultural Microbiology, Division of Animal Infectious Disease, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Rui Zhou
- State Key Laboratory of Agricultural Microbiology, Division of Animal Infectious Disease, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Qi Jin
- State Key Laboratory for Molecular Virology and Genetic Engineering, Institute of Pathogen Biology, Chinese Academy of Medical Sciences, Beijing, China
| | - Yang Fan
- State Key Laboratory for Molecular Virology and Genetic Engineering, Institute of Pathogen Biology, Chinese Academy of Medical Sciences, Beijing, China
| | - Weicheng Bei
- State Key Laboratory of Agricultural Microbiology, Division of Animal Infectious Disease, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Huanchun Chen
- State Key Laboratory of Agricultural Microbiology, Division of Animal Infectious Disease, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
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Klima C, Alexander T, Read R, Gow S, Booker C, Hannon S, Sheedy C, McAllister T, Selinger L. Genetic characterization and antimicrobial susceptibility of Mannheimia haemolytica isolated from the nasopharynx of feedlot cattle. Vet Microbiol 2011; 149:390-8. [DOI: 10.1016/j.vetmic.2010.11.018] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Revised: 10/28/2010] [Accepted: 11/10/2010] [Indexed: 10/18/2022]
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Abstract
Haemophilus ducreyi, the etiologic agent of chancroid, expresses variants of several key virulence factors. While previous reports suggested that H. ducreyi strains formed two clonal populations, the differences between, and diversity within, these populations were unclear. To assess their variability, we examined sequence diversity at 11 H. ducreyi loci, including virulence and housekeeping genes, augmenting published data sets with PCR-amplified genes to acquire data for at least 10 strains at each locus. While sequences from all 11 loci place strains into two distinct groups, there was very little variation within each group. The difference between alleles of the two groups was variable and large at 3 loci encoding surface-exposed proteins (0.4 < K(S) < 1.3, where K(S) is divergence at synonymous sites) but consistently small at genes encoding cytoplasmic or periplasmic proteins (K(S) < 0.09). The data suggest that the two classes have recently diverged, that recombination has introduced variant alleles into at least 3 distinct loci, and that these alleles have been confined to one of the two classes. In addition, recombination is evident among alleles within, but not between, classes. Rather than clones of the same species, these properties indicate that the two classes may form distinct species.
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Omaleki L, Browning GF, Allen JL, Barber SR. The role of Mannheimia species in ovine mastitis. Vet Microbiol 2011; 153:67-72. [PMID: 21511411 DOI: 10.1016/j.vetmic.2011.03.024] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2010] [Revised: 03/11/2011] [Accepted: 03/17/2011] [Indexed: 11/19/2022]
Abstract
Mannheimia haemolytica is known to be an important cause of intramammary infection in sheep. It usually causes severe clinical mastitis, followed by toxaemia and gangrenous necrosis of the udder. However there are limited data available on the epidemiology and pathogenesis of mastitis associated with Mannheimia species. These organisms can be more significant as a cause of mastitis than Staphylococcus aureus in some flocks. Some data suggest the possibility of horizontal transmission of Mannheimia species between ewes via lamb sucking. There is no vaccine available for prevention, and the sudden onset of mastitis and its peracute nature renders most treatments unsuccessful. This review examines the significance of the species within this genus in sheep mastitis.
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Affiliation(s)
- Lida Omaleki
- Veterinary Preclinical Centre, Department of Veterinary Science, The University of Melbourne, Corner Flemington Road and Park Drive, Parkville, Victoria 3010, Australia.
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Linhartová I, Bumba L, Mašín J, Basler M, Osička R, Kamanová J, Procházková K, Adkins I, Hejnová-Holubová J, Sadílková L, Morová J, Sebo P. RTX proteins: a highly diverse family secreted by a common mechanism. FEMS Microbiol Rev 2011; 34:1076-112. [PMID: 20528947 PMCID: PMC3034196 DOI: 10.1111/j.1574-6976.2010.00231.x] [Citation(s) in RCA: 360] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Repeats-in-toxin (RTX) exoproteins of Gram-negative bacteria form a steadily growing family of proteins with diverse biological functions. Their common feature is the unique mode of export across the bacterial envelope via the type I secretion system and the characteristic, typically nonapeptide, glycine- and aspartate-rich repeats binding Ca2+ ions. In this review, we summarize the current state of knowledge on the organization of rtx loci and on the biological and biochemical activities of therein encoded proteins. Applying several types of bioinformatic screens on the steadily growing set of sequenced bacterial genomes, over 1000 RTX family members were detected, with the biological functions of most of them remaining to be characterized. Activities of the so far characterized RTX family members are then discussed and classified according to functional categories, ranging from the historically first characterized pore-forming RTX leukotoxins, through the large multifunctional enzymatic toxins, bacteriocins, nodulation proteins, surface layer proteins, up to secreted hydrolytic enzymes exhibiting metalloprotease or lipase activities of industrial interest.
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Affiliation(s)
- Irena Linhartová
- Institute of Microbiology AS CR v.v.i., Academy of Sciences of the Czech Republic, Prague, Czech Republic
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