Molecular Typing of Streptococcus uberis Strains Isolated from Cases of Bovine Mastitis

Wieliczko, R.J.; Williamson, J.; Cursons, Raymond T.; Lacy-Hulbert, S.J.; Woolford, M. W.

doi:10.3168/jds.s0022-0302(02)74293-8

Cited by 26 publications

(39 citation statements)

References 15 publications

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“…The observation of different S. aureus strains dominating within mammary quarters was not reflected within animals, with the two dominant strains able to infect different quarters of the same cow. This agrees with the findings presented in a previous report for S. aureus (46) and has also been demonstrated for cases of Escherichia coli (3) and S. uberis (14,44) mastitis.…”

Section: Discussionsupporting

confidence: 83%

Multilocus Sequence Typing of Staphylococcus aureus Isolated from High-Somatic-Cell-Count Cows and the Environment of an Organic Dairy Farm in the United Kingdom

et al. 2005

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An outbreak of Staphylococcus aureus intramammary infections on an organic dairy farm was monitored for 10 months. Environmental and milk samples were collected from a total of 26 cows and a group of 21 purchased heifers about to be introduced into the milking herd. There was variation in the rate of isolation of S. aureus (9.5 to 43.8%) from individual mammary quarters, although no S. aureus isolates were detected in the milk samples collected from the heifers. One hundred ninety-one S. aureus isolates were detected from cow milk samples (n ‫؍‬ 182), milking machine clusters (n ‫؍‬ 4), farm personnel (n ‫؍‬ 4), and the environment (n ‫؍‬ 1). Multilocus sequence typing (MLST) had a typeability of 100% when it was applied to the 191 isolates. Among the 191 isolates there was limited strain diversity, with seven sequence types (STs) dominated by two strains with closely related STs that differed at a single locus. Within individual mammary quarters there were naturally occurring dual infections, although this was identified in only 0.4% of milk samples. Different strains were associated with variable persistence within quarters. MLST is clearly a very suitable tool for the differentiation and analysis of S. aureus populations detected on dairy cattle farms.Mastitis is the most frequently occurring health problem in organic dairy cattle herds, with Staphylococcus aureus and Streptococcus uberis being the most frequently isolated pathogens (41, 43). Control of contagious mastitis is more difficult on organic dairy farms than on conventional dairy farms because the routine use of antibiotic dry cow therapy (DCT) at the end of lactation is not permitted (12) and DCT is currently the most effective method of reducing contagious pathogen infections (32).The lactating mammary gland is the primary reservoir of S. aureus (5, 24), although environmental S. aureus isolates have been detected on heifer body sites and in the dairy farm environment (20,29). While nonmilk isolates may not form a large reservoir of infection (29), their presence may improve the ability of S. aureus to circumvent control mechanisms and persist within a herd, and their importance can be investigated through strain typing.Molecular epidemiological investigations of S. aureus isolated from intramammary infections (IMIs) on individual dairy farms have identified clonal populations characterized by dominant strains and low strain diversity (16, 49). Strain dominance is likely to be associated with virulence and persistence within the mammary gland (31). Although some studies have reported the genetic diversity of S. aureus on individual farms (15, 34), these contrasting results may be due to variations in sampling and typing protocols or to differences in herd sizes and management techniques.A range of different typing techniques have been employed to understand the epidemiology of S. aureus infections. Random amplified polymorphic DNA analysis, ribotyping, biotyping, pulsed-field gel electrophoresis, and binary typing are the major techniques previous...

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Section: Discussionsupporting

confidence: 83%

Multilocus Sequence Typing of Staphylococcus aureus Isolated from High-Somatic-Cell-Count Cows and the Environment of an Organic Dairy Farm in the United Kingdom

et al. 2005

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“…The strain collection contained 57 different sequence types (STs), showing that the population was heterogeneous. This is in agreement with a number of other studies using different typing methods to differentiate sets of S. uberis isolates (5,10,15,17). However, the MLST analysis, unlike most previous typing methods, provided useful information about the genetic relationships between the strains.…”

supporting

confidence: 79%

Application of Streptococcus uberis Multilocus Sequence Typing: Analysis of the Population Structure Detected among Environmental and Bovine Isolates from New Zealand and the United Kingdom

Pullinger

Lopez-Benavides²,

Coffey

et al. 2006

Appl Environ Microbiol

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We recently developed a multilocus sequence typing (MLST) scheme to differentiate S. uberis isolates and facilitate an understanding of the population biology of this pathogen. The scheme was initially used to study a collection of 160 bovine milk isolates from the United Kingdom and showed that the majority of isolates were from one clonal complex (designated the ST-5 complex). Here we describe the MLST analysis of a collection of New Zealand isolates. These were obtained from diverse sources, including bovine milk, other bovine anatomical sites, and environmental sources. The complete allelic profiles of 253 isolates were determined. The collection was highly diverse and included 131 different sequence types (STs). The New Zealand and United Kingdom populations were distinct, since none of the 131 STs were represented within the previously studied collection of 160 United Kingdom S. uberis isolates. However, seven of the STs were members of the ST-5 clonal complex, the major complex within the United Kingdom collection. Two new clonal complexes were identified: ST-143 and ST-86. All three major complexes were isolated from milk, other bovine sites, and the environment. Carriage of the hasA gene, which is necessary for capsule formation, correlated with clonal complex and isolation from clinical cases of mastitis.

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“…Udder infections can result from the cow-to-cow spread of the pathogen (38,56) or, more likely, originate from environmental sources of S. uberis (2,29,53). Skin, bedding material, and feces can harbor S. uberis (1).…”

mentioning

confidence: 99%

“…Many phenotypic and DNA banding pattern-based typing methods have been used to characterize S. uberis, including bacteriocin typing (18), restriction endonuclease fingerprinting (18), rapidly amplified polymorphic DNA (RAPD) typing (37,53,56), repetitive element polymorphism-PCR (53), and pulsed-field gel electrophoresis (2,38). While these methods have contributed to insights into the epidemiology of S. uberis mastitis, they have limitations in terms of typeability, discriminatory power, and reproducibility.…”

mentioning

confidence: 99%

Multilocus Sequence Typing of Streptococcus uberis Provides Sensitive and Epidemiologically Relevant Subtype Information and Reveals Positive Selection in the Virulence Gene pauA

Zadoks

Schukken

Wiedmann³

2005

J Clin Microbiol

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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 (d N /d S ) (1.2) compared to the other genes sequenced (d N /d S < 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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Molecular Typing of Streptococcus uberis Strains Isolated from Cases of Bovine Mastitis

Cited by 26 publications

References 15 publications

Multilocus Sequence Typing of Staphylococcus aureus Isolated from High-Somatic-Cell-Count Cows and the Environment of an Organic Dairy Farm in the United Kingdom

Multilocus Sequence Typing of Staphylococcus aureus Isolated from High-Somatic-Cell-Count Cows and the Environment of an Organic Dairy Farm in the United Kingdom

Application of Streptococcus uberis Multilocus Sequence Typing: Analysis of the Population Structure Detected among Environmental and Bovine Isolates from New Zealand and the United Kingdom

Multilocus Sequence Typing of Streptococcus uberis Provides Sensitive and Epidemiologically Relevant Subtype Information and Reveals Positive Selection in the Virulence Gene pauA

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