Pathogenicity of two strains of Streptococcus uberis infused into lactating and non-lactating bovine mammary glands

Hill, Arthur W.

doi:10.1016/s0034-5288(18)30973-1

Cited by 45 publications

(44 citation statements)

References 13 publications

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“…These results are consistent with the results of previous studies on infection of the bovine mammary gland with wild-type S. uberis (5,6,10,14,15,19) but are in contrast to results obtained with other mastitis pathogens, such as E. coli (13) and Staphylococcus aureus (24), where an influx of neutrophils corresponds to a decrease in bacterial numbers and even elimination of the infecting organisms.…”

Section: Discussionsupporting

confidence: 92%

“…The virulence of a well-characterized strain of S. uberis, 0140J, and that of its mutant derivative, TRF0-6, which lacks the ability to produce hyaluronic acid due to insertional disruption of its single copy of hasA (26), were compared in a well-established experimental model (5,6,10,14,15,19) for bovine mastitis.…”

Section: Resultsmentioning

confidence: 99%

“…This infection model has been used on a number of occasions by various researchers (5,6,10,14,15,19) and typically yields clinical disease in approximately 90% of challenges with strain 0140J. Failure to generate clinical disease in two quarters (both on the same animal) out of eight quarters challenged with the hasA mutant may indicate a minor reduction in the virulence of this strain.…”

Section: Discussionmentioning

confidence: 99%

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The Hyaluronic Acid Capsule of Streptococcus uberis Is Not Required for the Development of Infection and Clinical Mastitis

Field¹,

Ward²,

Pedersen³

et al. 2003

Infect Immun

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The frequency at which the genes responsible for capsule biosynthesis occurred in field isolates of Streptococcus uberis was determined. Of the two genotypes detected (hasABC and hasC), the capsular genotype (hasABC) was more common. This genotype was present at a higher frequency in a population isolated from mastitis cases than in a population isolated from cattle bedding. The virulence of a mutant strain of S. uberis (TRF0-6) that lacked the ability to produce a hyaluronic acid capsule due to an insertion within its single copy of hasA ( ) was compared to that of the capsular parental strain (0140J). Strains TRF0-6 and 0140J infected all mammary gland quarters following experimental challenge. The wild type and the mutant induced overt signs of disease in four out of four and in six out of eight mammary gland quarters, respectively. Both the wild type and the hasA mutant were resistant to killing by bovine neutrophils following cultivation in bovine milk. The ability to withstand the bactericidal action of neutrophils following growth in milk was therefore independent of the capsule and coincided with the ability of supernatants from such cultures to prevent the bactericidal action of neutrophils. This investigation revealed that, in the absence of the capsule, S. uberis is able to withstand the bactericidal effect of bovine neutrophils and induce mastitis in dairy cows.

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Section: Discussionsupporting

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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The Hyaluronic Acid Capsule of Streptococcus uberis Is Not Required for the Development of Infection and Clinical Mastitis

Field¹,

Ward²,

Pedersen³

et al. 2003

Infect Immun

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“…It is also possible that this strain is more transmissible or has a greater capacity to adhere to the mammary epithelium than the others. Evidence of differing abilities to establish intramammary infection among strains of S. uberis has been reported previously (10,19). We were unable to demonstrate differences in the concentrations of these predominant strains compared to those of the other strains in milk from infected quarters.…”

Section: Discussioncontrasting

confidence: 60%

Molecular Epidemiology of Streptococcus uberis Isolates from Dairy Cows with Mastitis

Phuektes

Mansell

Dyson³

et al. 2001

J Clin Microbiol

124

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Pulsed-field gel electrophoresis and antimicrobial sensitivity testing were used as tools to investigate the epidemiology of Streptococcus uberis mastitis in dairy cows. A total of 62 different strains were found among 138 isolates from the four herds investigated, and between 10 and 26 different strains were found in each herd. There was no strain common to all four herds. Identical strains of S. uberis were detected from different quarters of individual cows and from cows within the same herd, suggesting that transmission from quarter to quarter and cow to cow had occurred. Despite the great variation in S. uberis strains, persistent infection with the same strain within a lactation was observed in most cows. Predominant strains were present in two herds. Preliminary investigations could not clarify why these particular strains might predominate, but in one herd there was a significant difference between the prevalence of clinical mastitis in quarters infected with the predominant strain and that in quarters infected with other strains, suggesting the greater virulence of the predominant strain. The wide variety of S. uberis strains found is consistent with an environmental source of S. uberis. However, evidence of direct transmission, the persistence of infection, and the predominance of particular strains in some herds indicate that S. uberis infections are epidemiologically complex and that the relative importance of these factors in the occurrence of mastitis may differ between herds.

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“…The role of phagocytes is less clear with regard to S. uberis infections. However, strains of S. uberis that resist phagocytosis in vitro can establish infection more effectively than susceptible strains (10,19). The hyaluronic acid capsule appears to contribute significantly toward the virulence of Streptococcus pyogenes or group A Streptococcus (GAS) (16).…”

mentioning

confidence: 99%

Identification and Disruption of Two Discrete Loci Encoding Hyaluronic Acid Capsule Biosynthesis Genes hasA , hasB , and hasC in Streptococcus uberis

Ward¹,

Field²,

Ditcham³

et al. 2001

Infect Immun

106

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The hyaluronic acid capsule of Streptococcus uberis has been implicated in conferring resistance to phagocytosis by bovine neutrophils. Construction of a bank of random insertion mutants of S. uberis (strain 0140J) was achieved using the pGh9::ISS1 mutagenesis system (22). Phenotypic screening of approximately 5,000 clones enabled the isolation of 11 acapsular mutants. Southern hybridization indicated that two mutants carried a lesion within a group of genes similar to those involved in the assembly of the hyaluronic acid capsule found in the group A Streptococcus (GAS) has operon. The DNA sequence flanking the points of insertion confirmed the presence of homologues of GAS hasA and hasB in S. uberis. The DNA sequence flanking the ISS1 insertion in another mutant identified a homologue of hasC in S. uberis. The GAS hasABC operon structure was not conserved in S. uberis, and two discrete loci comprising homologues of either hasAB or hasC were identified. Disruption of S. uberis hasA or hasC resulted in the complete cessation of hyaluronic acid capsule production. Correspondingly, these mutants were found to have lost their resistance to phagocytosis by bovine neutrophils. The bactericidal action of bovine neutrophils on S. uberis 0140J was shown unequivocally to depend upon the capsule status of the bacterium.

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Pathogenicity of two strains of Streptococcus uberis infused into lactating and non-lactating bovine mammary glands

Cited by 45 publications

References 13 publications

The Hyaluronic Acid Capsule of Streptococcus uberis Is Not Required for the Development of Infection and Clinical Mastitis

The Hyaluronic Acid Capsule of Streptococcus uberis Is Not Required for the Development of Infection and Clinical Mastitis

Molecular Epidemiology of Streptococcus uberis Isolates from Dairy Cows with Mastitis

Identification and Disruption of Two Discrete Loci Encoding Hyaluronic Acid Capsule Biosynthesis Genes hasA , hasB , and hasC in Streptococcus uberis

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