Longitudinal monitoring of the dynamics of infections due to Bartonella species in UK woodland rodents

Blood samples were repeatedly collected from 12 sympatric woodland rodents over a 12-month period and DNA extracts from each were incorporated into a bartonella-specific PCR targeting a fragment of the 16S/23S rRNA intergenic spacer region (ISR). The composition of each amplicon was analysed using r estriction enzyme analysis (REA) and base sequence comparison. Bartonella D NA was detected in 70 of 109 samples. Eleven samples contained DNA derived from more than one strain. Sequence analysis of 62 samples found 12 sequenc e variants (ISR genotypes) that were provisionally assigned to 5 different species, 2 of which were newly recognized. Up to five different species wer e detected in each animal. On about two-thirds of occasions, a species dete cted 1 month was not there the next, but never was a genotype superseded by another of the same species. However, a genotype could be re-encountered m onths later in the same animal, even if interim samples contained other gen otypes. Our results suggest that although most animals are bacteraemic most of the time, specific infections are often superseded and that a complex a nd dynamic epidemiology of bartonella bacteraemias exists in woodland roden ts.