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Zadoks RN, Middleton JR, McDougall S, Katholm J, Schukken YH. Molecular epidemiology of mastitis pathogens of dairy cattle and comparative relevance to humans. J Mammary Gland Biol Neoplasia 2011; 16:357-72. [PMID: 21968538 PMCID: PMC3208832 DOI: 10.1007/s10911-011-9236-y] [Citation(s) in RCA: 262] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Accepted: 09/21/2011] [Indexed: 11/30/2022] Open
Abstract
Mastitis, inflammation of the mammary gland, can be caused by a wide range of organisms, including gram-negative and gram-positive bacteria, mycoplasmas and algae. Many microbial species that are common causes of bovine mastitis, such as Escherichia coli, Klebsiella pneumoniae, Streptococcus agalactiae and Staphylococcus aureus also occur as commensals or pathogens of humans whereas other causative species, such as Streptococcus uberis, Streptococcus dysgalactiae subsp. dysgalactiae or Staphylococcus chromogenes, are almost exclusively found in animals. A wide range of molecular typing methods have been used in the past two decades to investigate the epidemiology of bovine mastitis at the subspecies level. These include comparative typing methods that are based on electrophoretic banding patterns, library typing methods that are based on the sequence of selected genes, virulence gene arrays and whole genome sequencing projects. The strain distribution of mastitis pathogens has been investigated within individual animals and across animals, herds, countries and host species, with consideration of the mammary gland, other animal or human body sites, and environmental sources. Molecular epidemiological studies have contributed considerably to our understanding of sources, transmission routes, and prognosis for many bovine mastitis pathogens and to our understanding of mechanisms of host-adaptation and disease causation. In this review, we summarize knowledge gleaned from two decades of molecular epidemiological studies of mastitis pathogens in dairy cattle and discuss aspects of comparative relevance to human medicine.
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Affiliation(s)
- Ruth N Zadoks
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik EH26 0PZ, UK.
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Deletion of sua gene reduces the ability of Streptococcus uberis to adhere to and internalize into bovine mammary epithelial cells. Vet Microbiol 2010; 147:426-34. [PMID: 20708860 DOI: 10.1016/j.vetmic.2010.07.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2009] [Revised: 07/06/2010] [Accepted: 07/07/2010] [Indexed: 11/22/2022]
Abstract
To elucidate the role of Streptococcus uberis adhesion molecule (SUAM) in the pathogenesis of S. uberis mastitis, sua deletion in S. uberis UT888 was achieved by homologous recombination using a thermosensitive plasmid. The deletion mutant was analyzed for sua deletion by PCR, southern blot and DNA sequencing, and was designated Δsua S. uberis UT888. As compared to the isogenic parent strain, Δsua S. uberis UT888 did not produce SUAM based on SDS-PAGE gel and western blot. Deletion of sua and lack of expression of SUAM by Δsua S. uberis UT888 markedly reduced the ability of the sua gene deletion mutant of S. uberis to adhere to and internalize into mammary epithelial cells. These results confirm the central role of SUAM in adherence to and internalization of S. uberis into host cells.
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Abstract
The global dairy industry, the predominant pathogens causing mastitis, our understanding of mastitis pathogens and the host response to intramammary infection are changing rapidly. This paper aims to discuss changes in each of these aspects. Globalisation, energy demands, human population growth and climate change all affect the dairy industry. In many western countries, control programs for contagious mastitis have been in place for decades, resulting in a decrease in occurrence of Streptococcus agalactiae and Staphylococcus aureus mastitis and an increase in the relative impact of Streptococcus uberis and Escherichia coli mastitis. In some countries, Klebsiella spp. or Streptococcus dysgalactiae are appearing as important causes of mastitis. Differences between countries in legislation, veterinary and laboratory services and farmers' management practices affect the distribution and impact of mastitis pathogens. For pathogens that have traditionally been categorised as contagious, strain adaptation to human and bovine hosts has been recognised. For pathogens that are often categorised as environmental, strains causing transient and chronic infections are distinguished. The genetic basis underlying host adaptation and mechanisms of infection is being unravelled. Genomic information on pathogens and their hosts and improved knowledge of the host's innate and acquired immune responses to intramammary infections provide opportunities to expand our understanding of bovine mastitis. These developments will undoubtedly contribute to novel approaches to mastitis diagnostics and control.
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Affiliation(s)
- Rn Zadoks
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, EH26 0PZ Scotland, UK.
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Ward PN, Holden MTG, Leigh JA, Lennard N, Bignell A, Barron A, Clark L, Quail MA, Woodward J, Barrell BG, Egan SA, Field TR, Maskell D, Kehoe M, Dowson CG, Chanter N, Whatmore AM, Bentley SD, Parkhill J. Evidence for niche adaptation in the genome of the bovine pathogen Streptococcus uberis. BMC Genomics 2009; 10:54. [PMID: 19175920 PMCID: PMC2657157 DOI: 10.1186/1471-2164-10-54] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Accepted: 01/28/2009] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Streptococcus uberis, a Gram positive bacterial pathogen responsible for a significant proportion of bovine mastitis in commercial dairy herds, colonises multiple body sites of the cow including the gut, genital tract and mammary gland. Comparative analysis of the complete genome sequence of S. uberis strain 0140J was undertaken to help elucidate the biology of this effective bovine pathogen. RESULTS The genome revealed 1,825 predicted coding sequences (CDSs) of which 62 were identified as pseudogenes or gene fragments. Comparisons with related pyogenic streptococci identified a conserved core (40%) of orthologous CDSs. Intriguingly, S. uberis 0140J displayed a lower number of mobile genetic elements when compared with other pyogenic streptococci, however bacteriophage-derived islands and a putative genomic island were identified. Comparative genomics analysis revealed most similarity to the genomes of Streptococcus agalactiae and Streptococcus equi subsp. zooepidemicus. In contrast, streptococcal orthologs were not identified for 11% of the CDSs, indicating either unique retention of ancestral sequence, or acquisition of sequence from alternative sources. Functions including transport, catabolism, regulation and CDSs encoding cell envelope proteins were over-represented in this unique gene set; a limited array of putative virulence CDSs were identified. CONCLUSION S. uberis utilises nutritional flexibility derived from a diversity of metabolic options to successfully occupy a discrete ecological niche. The features observed in S. uberis are strongly suggestive of an opportunistic pathogen adapted to challenging and changing environmental parameters.
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Affiliation(s)
- Philip N Ward
- Nuffield Department of Clinical Laboratory Sciences, Oxford University, John Radcliffe Hospital, Headington, Oxford, OX3 9DU, UK
| | - Matthew TG Holden
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - James A Leigh
- The School of Veterinary Medicine and Science, The University of Nottingham, Sutton Bonington Campus, Sutton Bonington, Leicestershire, LE12 5RD, UK
| | - Nicola Lennard
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Alexandra Bignell
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Andy Barron
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Louise Clark
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Michael A Quail
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - John Woodward
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Bart G Barrell
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Sharon A Egan
- The School of Veterinary Medicine and Science, The University of Nottingham, Sutton Bonington Campus, Sutton Bonington, Leicestershire, LE12 5RD, UK
| | - Terence R Field
- Institute for Animal Health, Compton Laboratory, Compton, Newbury, Berks, RG20 7NN, UK
| | - Duncan Maskell
- Dept. of Veterinary Medicine, The University of Cambridge, Cambridge, CB3 0ES, UK
| | - Michael Kehoe
- Institute for Cell and Molecular Biosciences, The Medical School, University of Newcastle upon Tyne, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | | | - Neil Chanter
- Centre for Preventative Medicine, Animal Health Trust, Newmarket, Suffolk, CB8 7UU, UK
| | - Adrian M Whatmore
- Department of Biological Sciences, University of Warwick, Coventry, CV4 7AL, UK
- Veterinary Laboratories Agency, Weybridge, UK
| | - Stephen D Bentley
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Julian Parkhill
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
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Luther DA, Almeida RA, Oliver SP. Elucidation of the DNA sequence of Streptococcus uberis adhesion molecule gene (sua) and detection of sua in strains of Streptococcus uberis isolated from geographically diverse locations. Vet Microbiol 2007; 128:304-12. [PMID: 18082978 DOI: 10.1016/j.vetmic.2007.10.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2007] [Revised: 09/12/2007] [Accepted: 10/16/2007] [Indexed: 10/22/2022]
Abstract
Streptococcus uberis is an important environmental pathogen that causes subclinical and clinical mastitis in lactating and nonlactating cows throughout the world. S. uberis adhesion molecule (SUAM) was identified recently by our laboratory and we hypothesize that SUAM is a potential virulence factor involved in the pathogenesis of S. uberis mastitis. The first objective of the present study was to clone and sequence the SUAM gene (sua) from S. uberis UT888. The second objective was to determine the prevalence of sua in strains of S. uberis isolated from geographically diverse locations. The 20 amino acid N-terminal sequence of purified SUAM was utilized to identify a single open reading frame (ORF) in the S. uberis O140J (ATCC BAA-854) genome database. Three sets of primers were identified from this sequence for amplification of sub-fragments and the complete gene encoding SUAM. Restriction fragment analysis of the largest polymerase chain reaction (PCR) product confirmed the desired fragment had been amplified. This 2970bp PCR fragment was cloned into plasmid pCR-XL-TOPO and sequenced. The S. uberis UT888 sua sequence (NCBI Accession no. DQ232760) was 99% similar to the S. uberis O140J database sequence. The three pairs of PCR primers were used in a subsequent experiment to identify sua in 12 strains of S. uberis isolated in milk from dairy cows with mastitis in Tennessee (n=6), Colorado (n=1), Washington (n=1), New Zealand (n=1) and from the American Type Culture Collection (n=3). Primer pairs yielded the expected 2970, 2639 and 2362bp PCR fragments in all strains evaluated. In conclusion, we cloned and sequenced sua, which codes for the first described S. uberis adhesin, SUAM. sua was detected in all strains of S. uberis evaluated suggesting that it is conserved.
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Affiliation(s)
- Douglas A Luther
- Department of Animal Science and Food Safety Center of Excellence, The University of Tennessee, Knoxville, TN 37996, USA
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Zadoks RN, Schukken YH, Wiedmann M. Multilocus sequence typing of Streptococcus uberis provides sensitive and epidemiologically relevant subtype information and reveals positive selection in the virulence gene pauA. J Clin Microbiol 2005; 43:2407-17. [PMID: 15872274 PMCID: PMC1153724 DOI: 10.1128/jcm.43.5.2407-2417.2005] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2004] [Revised: 11/07/2004] [Accepted: 01/14/2005] [Indexed: 12/28/2022] Open
Abstract
Control of the bovine mastitis pathogen Streptococcus uberis requires sensitive and epidemiologically meaningful subtyping methods that can provide insight into this pathogen's epidemiology and evolution. Development of a multilocus sequence typing (MLST) scheme based on six housekeeping and virulence genes allowed differentiation of 40 sequence types among 50 S. uberis isolates from the United States (n = 30) and The Netherlands (n = 20). MLST was more discriminatory than EcoRI or PvuII ribotyping and provided subtype data with better epidemiological relevance, e.g., by discriminating isolates with identical ribotypes obtained from different farms. Phylogenetic analyses of MLST data revealed indications of reticulate evolution between genes, preventing construction of a core phylogeny based on concatenated DNA sequences. However, all individual gene phylogenies clearly identified a distinct pauA-negative subtaxon of S. uberis for which housekeeping alleles closely resembled those of Streptococcus parauberis. While the average GC content for five genes characterized was between 0.38 and 0.40, pauA showed a considerably lower GC content (0.34), suggesting acquisition through horizontal transfer. pauA also showed a higher nonsynonymous/synonymous rate ratio (dN/dS) (1.2) compared to the other genes sequenced (dN/dS < 0.12), indicating positive selection in this virulence gene. In conclusion, our data show that (i) MLST provides for highly discriminatory and epidemiologically relevant subtyping of S. uberis; (ii) S. uberis has a recombinatorial population structure; (iii) phylogenetic analysis of MLST data reveals an S. uberis subtaxon resembling S. parauberis; and (iv) horizontal gene transfer and positive selection contribute to evolution of certain S. uberis genes, such as the virulence gene pauA.
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Affiliation(s)
- Ruth N Zadoks
- Department of Food Service, Cornell University, Ithaca, NY 14850, USA.
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