Borrelia lusitaniae OspA Gene Heterogeneity in Mediterranean Basin Area

Abstract

In this study, Borrelia lusitaniae DNA extracted from ticks and lizards was used to amplify the outer surface protein A (OspA) gene in order to increase knowledge about sequence variability in the Mediterranean basin area, to better understand how Borrelia lusitaniae has evolved and how its distribution has expanded. Phylogenetic trees including Italian and reference sequences showed a clear separation of B. lusitaniae OspA strains in two different major clades. North African isolates form a clade with Portuguese POTIB strains, whereas Italian samples are grouped with German strains and a human Portuguese strain. This subdivision was supported by very high posterior probability values in the trees, by both analysis of molecular variance and selective pressure. These results, based on phylogenetic information contained in the OspA gene sequences, show the presence of two different B. lusitaniae strains circulating in the Mediterranean basin area, suggesting two different evolution paths.

Lyme Borreliosis, Po River Valley, Italy

“…Neighbor-joining phylogenetic analysis, using SeaView 4.2 ( 9 ), confirmed placements of the obtained sequences into the clusters of B. afzelii and B. lusitaniae (data not shown). The relative prevalence of the 2 species of borreliae that we detected differs from those reported in other studies ( 10 ), probably because of environmental conditions, particularly the presence and relative abundance of the different reservoir hosts ( 11 ). …”

Diversity of Lyme borreliosis spirochetes isolated from ticks in Serbia

“…Five strains from the present study clustered with B. lusitaniae strain PoHL1 (human isolate from Portugal) and RB-La1N1 (tick isolate from Germany), whereas 11 strains clustered with an Italian isolate from a tick (ITAh03), separating strains from the 'North African' clade (including samples from Morocco and Tunisia, and the Portuguese strain POTIB5) and the European clade. These findings support the presence of two main groups, 'North African' and European clades, as suggested by Richter & Matuschka (2006) and Grego et al (2007).…”

“…To amplify the ospA gene, OspAf forward primer (5'-ATGAAAAAATATTTATTGGGAATA-3') and OspAr reverse primer (5'-TTATTTTAAAGCAGTTTTGAGATC-3') were used (Grego et al 2007). PCR was performed in a 50 μL volume, using 6 μL of extracted DNA.…”

Fine-Scale Phylogeographic Structure of Borrelia lusitaniae Revealed by Multilocus Sequence Typing

“…In another study the heterogeneity of B. lusitaniae was examined at a broader geographic scale compared with our study using ospA as marker [32], suggesting the existence of two major lineages in the Mediterranean Basin. According to that study, Italian and German strains form a ‘European’ lineage and the Portuguese strains PotiB1-3 and North African strains an ‘African’ lineage, with the Portuguese patient isolate PoHL1 being an exception as it was placed in the European clade.…”