Abstract
The majority of Streptococcus agalactiae strains express one or more surface-anchored proteins that vary by strain. These proteins, which are characteristic for S. agalactiae, and are able to induce protective antibodies, include the alpha C, Rib proteins, alpha-like protein 2, and alpha-like protein 3. In this study was developed multiplex PCR method for detection of genes encoding these proteins, and its occurrence within a various S. agalactiae isolates of bovine origin. Also are reported two new genes from bovine isolates of S. agalactiae amplified by PCR, encoding other putative members of the family, alphalike protein 6, and alpha-like protein 7. They contain an overall genetic organization highly similar to that of the alpha C and Rib proteins.
Highlights
The importance of Streptococcus agalactiae as a major perinatal pathogen for invasive disease has been well documented (BAKER and EDWARDS, 2000; ZALEZNIK et al, 2000; FERRIERI, 1997)
The S. agalactiae first received attention as a cause of bovine mastitis, a disease defined as ‘inflammation of the mammary gland’, that cause the losses in a diary industry associated with clinical and subclinical mastitis, which arise from the costs of treatment, culling, death and decreased milk production (BRADLEY, 2002)
Alpha proteins of Streptococcus agalactiae have typical repetition region consisted of about 80 amino acids, which are highly homologous (LINDHAL et al, 2005)
Summary
The importance of Streptococcus agalactiae as a major perinatal pathogen for invasive disease has been well documented (BAKER and EDWARDS, 2000; ZALEZNIK et al, 2000; FERRIERI, 1997). Epidemiological studies of S. agalactiae infections are mainly based on capsule serotyping. The capsule is an antigenic determinant and a major virulence factor as it interferes with complement mediated killing (EDWARDS et al, 1982). The S. agalactiae strains are classified into nine different serotypes based on differences in the capsular polysaccharide antigens Ia, Ib, and II through VIII (PAOLETTI et al, 2000). Serotype distribution varies with geographical region and ethnic origin, and the virulence of clinical isolates with similar capsular composition can vary widely, suggesting that other bacterial virulence factors, except a capsule, are involved in the pathogenesis of S. agalactiae (SPELLEBERG, 2000). Several surface–anchored proteins that vary by strain have been described for S. agalactiae (MOYO et al, 2002; KVAM et al, 1995)
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