Fig 4. Acinetobacter baumannii from ancient head lice belonging to the Roman period.

a, Maximum-likelihood (ML) phylogenetic tree relationship based on 182-bp fragment rpoB gene of A. baumannii detected in ancient head lice was compared with the reference sequences strain, while Pseudomonas was used as an out group. Bootstrap values are indicated at the nodes. Bold indicates the taxonomic position of A. baumannii identified in this study. b, 182-bp of A. baumannii rpoB gene fragment sequenced from the four ancient head lice, exhibiting one mutation not present in the homologous gene sequence from its closest relative, the modern A. baumannii sequence in GenBank”.