The Genome of Staphylococcus epidermidis Isolated from Caseous Tuberculoma

A number of facultative-anaerobic lipophilic microorganisms, including representatives of Corynebacterium and Staphylococcaceae, inhabit the necrotic contents of tuberculomas. A strain of Staphylococcus epidermidis was isolated from caseum; its genome was fully sequenced and gene-mapped. The coagulase-negative Staphylococcus belonged to the MLST 73 genotype and was resistant to two antituberculosis drugs. The strain phenotypically had urease, gelatinase, and beta-hemolytic activities and possessed the corresponding genes. Similar to S. epidermidis O47, its genome consists of a single chromosome containing approximately 2.4 million base pairs, and oriC has the same orientation. A total of 2333 genes were identified, of which 2206 were coding genes. In contigs of the genome, sequences of plasmid replication genes were found: rep7a, rep13, rep5b, and pSK1. Phylogenetic analysis indicates the closeness of the analyzed genome to a large group of European strains. Considering the biochemical and microbiological properties of the isolated strain, we hypothesize that staphylococci and other facultative-anaerobic satellite microorganisms of tuberculosis foci may play an important role in caseum liquefaction owing to their own proteolytic activity and attraction of neutrophils to the focus of inflammation.