DGGE Identification of Microorganisms Associated with Borrelia burgdorferi Sensu Lato- or Anaplasma phagocytophilum-Infected Ixodes ricinus Ticks from Northwest Norway

Abstract

Ticks acquire a wide range of microorganisms as a natural part of their lifecycle. Bacteria, viruses, and protozoa can be transmitted to ticks during feeding and free-living phases. DGGE profiling is a molecular method to describe the microbial population associated with ticks and demonstrate some of the complexity and variety of tick-borne microorganisms. The present study profiled a total of 120 I. ricinus ticks, which were divided into three equally sized groups. We found that B. burgdorferi s.l.-infected ticks presented a pattern consisting of bacterial Pseudomonas spp. (67.5%), Bacillus spp. (50%), and Sphingomonas spp. (77.5%), while A. phagocytophilum-infected ticks were associated with Pseudomonas spp. (82.5%) and Sphingomonas spp. (57.5%). All profiles had one or more Pseudomonas species present, and the intramitochondrial endosymbiont Candidatus Midichloria mitochondrii was present in more than 25% of the samples. Statistical analysis demonstrated that the microbial communities were not significantly different between the groups and that the groups could not be characterised by a specific microbial population.

Figure 1

(a) SYBR Green-stained 16S rDNA DGGE profile of bacteria found in ticks from group G1. The DGGE bands have been identified in the figure with numbers corresponding to Table 2. Each lane represents one profile from a specific individual tick. Each band represents a specific bacterium. (b) SYBR Green-stained 16S rDNA DGGE profile of bacteria found in ticks from group G2. The DGGE bands have been identified in the figure with numbers corresponding to Table 2. Each lane represents one profile from a specific individual tick. Each band represents a specific bacterium. (c) SYBR Green-stained 16S rDNA DGGE profile of bacteria found in ticks from group G3. The DGGE bands have been identified in the figure with numbers corresponding to Table 2. Each lane represents one profile from a specific individual tick. Each band represents a specific bacterium.

Figure 2

The scatter plot shows the distribution of bacterial species from groups G1, G2, and G3. Species are identified in the figure with a number corresponding to the species number in Table 2.