Further studies on Rhodococcus equi isolated from bovine lymphadenitis

We describe a comparative investigation of 13 Rhodococcus equi isolates fro m cases of bovine lymphadenitis. They were identified by cultural and bioch emical properties and by polymerase chain reaction (PCR) analysis. The latt er, targeted to the gene coding for 16S ribosomal RNA, revealed a species s pecific PCR-product. By serotyping, all 13 isolates could be classified as Nakazawa's serotype 15. They were further analysed by DNA-fingerprinting an d compared with 10 R. equi strains isolated from bovine lymphadenitis in th e same area in 1995. This was performed by macrorestriction analysis of chr omosomal DNA by pulsed-field gel electrophoresis (PFGE) after digestion of the DNA with AsnI. PFGE analysis of the chromosomal DNA of the 13 isolates revealed eight different restriction groups with DNA pattern I with five is olates, DNA pattern VI with two isolates and the remaining six DNA patterns with one isolate, respectively, DNA pattern I corresponded to DNA pattern I described for seven of the IO isolates previously investigated. The remai ning DNA patterns V to XI differed from DNA pattern II to TV described prev iously. Comparing the DNA pattern of all 23 R. equi by dendrogram analysis revealed that a single or at least related clones belonging to Nakazawa's s erotype 15 seem to be responsible for the cases of bovine lymphadenitis obs erved in one abattoir in 1995 and 1996. Med Sci Res 26:835-837. (C) 1998 Li ppincott Williams & Wilkins.