Genetic polymorphism of Staphylococcus epidermidis strains in patients of the Neonatal Intensive Care Unit
Staphylococcus epidermidis is a member of the normal bacterial flora of humans capable of causing potentially dangerous diseases in neonates with very or extremely low birth weight. The number of genes responsible for virulence and antibiotic resistance may vary in different S. epidermidis strains. We sequenced isolates of S. epidermidis to explore genetic diversity of 14 strains circulating in the Neonatal Intensive Care Unit of Kulakov Research Center for Obstetrics, Gynecology and Perinatology. Among the studied strains, 8 sequence types were identified, the most frequent being ST2 and ST59, both of which belong to the clonal complex CC2. Of 14 studied strains, 10 were of CC2 type. The studied strains revealed a variety of genes responsible for antibiotic resistance. We found 15 genes that provided resistance to aminoglycosides, beta-lactam antibiotics, fusidic acid, macrolides, lincosamides, streptogramin B, tetracycline, and trimethoprim. We identified a number of genes associated with virulence (aae, atlE, aap, embp), whose frequency in the studied isolates was varied. The insertion element IS256 was detected in 9 strains, and 7 strains revealed the presence of the ica-operon responsible for the biosynthesis of the biofilm matrix proteins.