Evaluation of tRNA intergenic spacer length polymorphism analysis as a molecular method for species identification of streptococcal isolates from bovine mastitis

Abstract

Sixty-nine bovine mastitis streptococci belonging to the species Str. agalactiae (n = 13), Str. dysgalactiae (n = 16), Str. canis (n = 22), Str. uberis (n = 20) and Str. parauberis (n = 4) and six reference strains of the five streptococcal species were examined for their tRNA gene intergenic length polymorphism (tDNA-ILP) fingerprint pattern. Epidemiologically unrelated isolates from bovine mastitis cases were selected by macrorestriction analysis with pulsed-field gel electrophoresis (PFGE). Their results were compared with those obtained from biochemical and serological studies and with those obtained by PCR-mediated identification amplifying species-specific gene segments of the five streptococcal species. According to the present results tDNA-ILP allowed a correct identification of all Str. agalactiae, Str. uberis and Str. parauberis strains investigated also including the reference strains of each species showing species-specific banding pattern. However, all Str. dysgalactiae ssp. dysgalactiae and all Str. canis strains appeared with an undistinguishable pattern which did not allow an identification of the species.

Development of a Rapid PCR Test for Identification of Streptococcus agalactiae in Milk Samples Collected on Filter Paper Disks

“…For its rapidity, sensitivity and precision, several PCR techniques (Jayarao et al, 1992;Forsman et al, 1997;Bohnsack et al, 2004;Zhou et al, 2006) has been widely used to amplify DNA fragment of Strep. agalactiae (Estuningsih et al, 2002;Dmitriev et al, 2003;Zschock et al, 2005) in liquid milk samples.…”

Genotyping ofStreptococcus uberisisolates in healing process of bovine clinical mastitis

“…In order to confirm the data obtained from the phenotypic identification, all cultured S. uberis isolates were genotypically characterized using tDNA-ILP-PCR as described by Zschöck et al [15]. Confirmed isolates to be S. uberis field strains (n = 44, isolated from 13 lactating cows) were then subjected to fingerprinting based on macrorestriction analysis of the bacterial chromosomal DNA for genotyping of the field isolates according to Soedarmanto et al [16].…”