Medycyna Wet. 67 (5), 327-331, 2011
Grądzki Z., Ziętek-Barszcz A.
Suitability of PCR and culture for antemortem diagnosis of rhodococcosis in foals
The aim of the study was to assess the suitability of multiplex PCR and culture for the detection of virulent R.equi in tracheobronchial aspirate (TBA) and feces of foals from enzootic farms. Fecal and TBA samples were taken randomly from a representative group of foals aged between 1 and 6 months. The solid selective medium NANAT was used for culture examination. Multiplex PCR reaction was performed with the use of two sets of primers complementary to the conservative gene fragment encoding the 16S subunit of ribosomal RNA of R.equi and the plasmid gene encoding virulence associated protein A (VapA), which determines bacterial virulence. During clinical observations three experimental groups (A, B, C), differing in the intensity of respiratory signs, were selected for further studies. In foals from group A, showing no clinical signs from the respiratory tract, the results of the examinations of TBA and fecal samples were negative irrespective of the method used. In group B, showing moderate respiratory signs, 15 TBA and fecal samples were examined. PCR results were positive for 7 TBA samples and 2 fecal samples, whereas culture examinations were positive for only 3 TBA samples from this group. In group C, consisting of 6 foals with severe respiratory signs, positive PCR and culture results were obtained for all TBA samples and for 3 fecal samples.
Keywords: Rhodococcus equi, foals, diagnostics, PCR, culture