Molecular characterization of Staphylococcus aureus nasal carriage among healthcare workers: insights for infection control

Abstract

The purpose of the study was to identify the nasal carriage of S. aureus in healthcare workers of the clinical wards of the County Emergency Hospital of Targu Mures and to characterize the bacterial isolates phenotypically and genotypically. This study included 64 medical staff from the County Emergency Hospital of Târgu-Mureș. Their data and nasal exsudates were collected. The multiplex PCR method was used to identify femA, PVL, mecA, eta, etb and tst genes. ERIC-PCR was used to evaluate the genetic similarity of the bacterial isolates. A prevalence of 25% of nasal carriage of S. aureus was obtained. Of these 12% were methicillin-resistant and 47% showed clindamycin-inducible resistance phenotype. Almost half of the isolates (47%) were from ICU (Intensive Care Unit) personnel. PCR results confirmed the species and the presence of the mecA gene in MRSA (Methicillin-Resistant Staphylococcus aureus) isolates. Except for 4 strains that showed the gene for exfoliatin A, no other virulence factor genes were detected. ERIC-PCR identified the partially common origin of the S. aureus strains, all having a similarity of 55%, with some reaching up to 100% similarity. Although the strains did not spread clonally and did not carry important virulence factors, there were associations between the nasal carriage and respiratory infections, previous diagnosis with S. aureus, Intensive Care Units and Nephrology wards.