Staphylococcus aureus nasal carriage in Ukraine: antibacterial resistance and virulence factor encoding genes.

BMC infectious diseases

PubMedID: 24597648

Netsvyetayeva I, Fraczek M, Piskorska K, Golas M, Sikora M, Mlynarczyk A, Swoboda-Kopec E, Marusza W, Palmieri B, Iannitti T. Staphylococcus aureus nasal carriage in Ukraine: antibacterial resistance and virulence factor encoding genes. BMC Infect Dis. 2014;14(1):128.
BACKGROUND
The number of studies regarding the incidence of multidrug resistant strains and distribution of genes encoding virulence factors, which have colonized the post-Soviet states, is considerably limited. The aim of the study was (1) to assess the Staphylococcus (S.) aureus nasal carriage rate, including Methicillin Resistant S. aureus (MRSA) strains in adult Ukrainian population, (2) to determine antibiotic resistant pattern and (3) the occurrence of Panton Valentine Leukocidine (PVL)-, Fibronectin- Binding Protein A (FnBPA)- and Exfoliative Toxin (ET)-encoding genes.

METHODS
Nasal samples for S. aureus culture were obtained from 245 adults. The susceptibility pattern for several classes of antibiotics was determined by disk diffusion method according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) standards. The virulence factor encoding genes, mecA, lukF-lukS, Eta, Etb, Etd, fnbA, were detected by Polymerase Chain Reaction (PCR).

RESULTS
The S. aureus nasal carriage rate was 40%. The prevalence of nasal MRSA carriage in adults was 3.7%. PVL genes were detected in over 58% of strains. ET genes were detected in over 39% of strains and the most prevalent type was ETD. The FnBPA gene was detected in over 59% of strains. All MRSA isolates tested were positive for the mecA gene. LukS-lukF genes and the etd gene were commonly co-present in MRSA, while lukS-lukF genes and the fnb gene were commonly co-present in Methicillin Sensitive S. aureus (MSSA) isolates. No significant difference was detected between the occurrence of lukS-lukF genes (P > 0.05) and the etd gene (P > 0.05) when comparing MRSA and MSSA. The occurrence of the fnbA gene was significantly more frequent in MSSA strains (P < 0.05).

CONCLUSIONS
In Ukraine, S. aureus is a common cause of infection. The prevalence of S. aureus nasal carriage in our cohort of patients from Ukraine was 40.4%. We found that 9.1% of strains were classified as MRSA and all MRSA isolates and tested positive for the mecA gene. We also observed a high prevalence of PVL and ET encoding genes among S. aureus nasal carriage strains. A systematic surveillance system can help prevent transmission and spread of drug resistant toxin producing S. aureus strains.