Strain differentiation of isolates of streptococci from bovine mastitis by pulsed-field gel electrophoresis

Baseggio, Nina; Mansell, P.D.; Browning, Jeff W.; Browning, Glenn F.

doi:10.1006/mcpr.1997.0126

Cited by 48 publications

(53 citation statements)

References 12 publications

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“…Previous molecular studies have suggested that isolates of bovine origin have a high level of diversity (4,25), which is inconsistent with the data presented here. This may reflect the fact that previous studies used typing approaches, randomly amplified polymorphic DNA analysis (25) and pulsed-field gel electrophoresis (4) fingerprinting, which may show more variability than MLST, which is based on housekeeping genes.…”

Section: Discussioncontrasting

confidence: 99%

Hyperinvasive Neonatal Group B Streptococcus Has Arisen from a Bovine Ancestor

et al. 2004

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The genetic relatedness and evolutionary relationships between group B streptococcus (GBS) isolates from humans and those from bovines were investigated by phylogenetic analysis of multilocus sequence typing data. The collection of isolates consisted of 111 GBS isolates from cows with mastitis and a diverse global collection of GBS isolates from patients with invasive disease (n ‫؍‬ 83) and carriers (n ‫؍‬ 69). Cluster analysis showed that the majority of the bovine isolates (93%) grouped into one phylogenetic cluster. The human isolates showed greater diversity and clustered separately from the bovine population. However, the homogeneous human sequence type 17 (ST-17) complex, known to be significantly associated with invasive neonatal disease, was the only human lineage found to be clustered within the bovine population and was distinct from all the other human lineages. Split decomposition analysis revealed that the human isolate ST-17 complex, the major hyperinvasive neonatal clone, has recently arisen from a bovine lineage.

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Section: Discussioncontrasting

confidence: 99%

Hyperinvasive Neonatal Group B Streptococcus Has Arisen from a Bovine Ancestor

et al. 2004

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“…As shown in previous studies (2,7,27) PFGE was proven to be a highly discriminatory method. It was able to resolve many isolates that were indistinguishable by antimicrobial susceptibility testing.…”

Section: Discussionmentioning

confidence: 52%

“…It produces distinct patterns that are easy to interpret and is highly reproducible. The reproducibility of PFGE makes it useful for comparison of strains between laboratories, and it has been used successfully to investigate genomic diversity among strains of S. uberis (2,7,27).…”

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confidence: 99%

Molecular Epidemiology of Streptococcus uberis Isolates from Dairy Cows with Mastitis

Phuektes

Mansell

Dyson³

et al. 2001

J Clin Microbiol

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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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“…One system (PFGE using SmaI) is now considered a "gold standard" technique for typing several bacterial pathogens including the streptococci associated with bovine mastitis (2,23). The other system (RAPD-PCR using primer 1254) has been used for typing different microorganisms (1, 28) but has not previously been applied to type GBS isolates.…”

Section: Discussionmentioning

confidence: 99%

Phenotypic and Molecular Characteristics of Streptococcus agalactiae Isolates Recovered from Milk of Dairy Cows in Brazil

et al. 2004

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Information on the characteristics of Streptococcus agalactiae obtained from bovine sources in Brazil is still very limited. The aim of this study was to assess the phenotypic and genotypic diversity among S. agalactiae isolates from milk of dairy cows presenting clinical or subclinical mastitis in the southeast region of Brazil. Phenotypic characterization was based on physiological and serological tests. Antimicrobial susceptibility tests were carried out by the disk method. Genetic diversity was evaluated by using random amplified polymorphic DNA-PCR (RAPD-PCR) (by using the primer 1254) and pulsed-field gel electrophoresis (PFGE) (by using SmaI as the restriction enzyme) and by PCRs for detection of genes associated with resistance to erythromycin and tetracycline as well as PCRs for detection of genes coding for cell surface-associated proteins. According to the results of physiologic tests, 45 (52.9%) isolates showed beta-hemolysis and 44 (51.7%) were susceptible to bacitracin. Fourteen different biotypes were detected. The two most frequent biotypes comprised strains that were non-beta-hemolytic; fermented galactose, lactose, and salicin; produced protease; and were negative for DNase production. Serotype III was predominant (66 isolates [77.6%]), followed by serotypes II, Ia, Ib, and VI. Resistance to tetracycline and erythromycin was found in 38 (44.7%) and 9 (10.5%) isolates, respectively, with tet(O) (31.7%) and erm(B) (100%) being the most frequently occurring resistance genes. Three genes coding for surface proteins, bca, lmb, and scpB, were detected in 55 (64.7%), 7 (8.2%), and 43 (50.5%) isolates, respectively. In most cases, isolates from animals in the same herd presented closely related genetic profiles (determined by either RAPD-PCR or PFGE), which were distinct from those of isolates from different herds.Infectious mastitis is an important health problem affecting dairy cattle and constitutes a source of economic loss for the dairy industry due to the effects on milk quality and yield. Additionally, the impact of this disease extends to the financial cost of therapeutic strategies and laboratory and veterinary services involved in control programs (15,16). The availability of information about the prevalence and the biological and epidemiological characteristics of the etiologic agents is essential for developing appropriate prevention programs and successful therapy (16,20).Streptococcus agalactiae, or group B Streptococcus (GBS), is a well-recognized worldwide etiological agent of mastitis in bovines, causing both clinical and mild subclinical mastitis of long duration (10,20). Bacterial cells are shed in milk from infected quarters, and transmission to uninfected quarters and cows usually occurs during the milking period (15, 21).The prevalence of GBS in cattle has been investigated in many areas, and the highest frequencies have been found in regions where appropriate control measures have not been implemented (20). In Brazil, studies have been developed by Empresa Brasileira de Agropecuá...

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Strain differentiation of isolates of streptococci from bovine mastitis by pulsed-field gel electrophoresis

Cited by 48 publications

References 12 publications

Hyperinvasive Neonatal Group B Streptococcus Has Arisen from a Bovine Ancestor

Hyperinvasive Neonatal Group B Streptococcus Has Arisen from a Bovine Ancestor

Molecular Epidemiology of Streptococcus uberis Isolates from Dairy Cows with Mastitis

Phenotypic and Molecular Characteristics of Streptococcus agalactiae Isolates Recovered from Milk of Dairy Cows in Brazil

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