Genetic Characteristics of Staphylococcus Aureus Strains Isolated in an Obstetric Hospital

Purulent-septic skin infections occupy a leading position in the morbidity structure of newborns in obstetric hospitals, with Staphylococcus aureus identified as the primary etiological agent. Whole-genome sequencing (WGS) enables the acquisition of highly detailed genomic data on the spectra of pathogenicity genes, the mobilome, and the resistome of epidemic strains, as well as facilitating intraspecific typing of isolates. Aim of the study: To apply WGS technology to gain new insights into the genetic characteristics of S. aureus strains isolated during a period of epidemic occurrence in an obstetric hospital. This study employed WGS along with a range of bioinformatic tools, including dendrogram construction, calculation of average nucleotide identity (ANI) indices, and genetic mapping. The analysis established that the etiological agent of the epidemic outbreak of pemphigus neonatorum was a population of hospital-associated S. aureus ST121 t435 strains, isolated from both a healthcare worker and affected newborns. Strains of this genotype had not previously been associated with staphyloderma and were characterized by the presence of the eta gene (exfoliative toxin A) and two prophage-associated determinants of Panton-Valentine leukocidin, suggesting a high potential for horizontal gene transfer and dissemination among other S. aureus strains circulating within the hospital environment. Seven strains demonstrated resistance to oxacillin, attributed to modifications in native penicillin-binding proteins – an alternative mechanism to the well-known mec-mediated methicillin resistance pathway. These findings underscore the necessity of incorporating WGS technologies into molecular epidemiological surveillance in obstetric healthcare settings.