Virulence, biofilm formation ability and antimicrobial resistance of Staphylococcus aureus isolated from cell phones of university students

Abstract

Introduction: Contamination of cell phones can contribute to the dissemination of pathogens in the community and/or hospital environment. Objective: To characterize Staphylococcus aureus strains isolated from cell phones of university students. Methods: Samples were collected from 100 cell phones. Detection of genes associated with virulence factors such as biofilm formation (icaA and icaD), enterotoxins production (SEA, SEB, SEC, and SED), and resistance to methicillin (mecA and mecC) was performed in S. aureus isolates by PCR. Typing mecA gene performed by multiplex PCR. Susceptibility to antimicrobials and biofilm formation rate also evaluated by using disk diffusion test and crystal violet staining. Results: S. aureus was present in 40% of the total samples and about 70% of them belonged to Nursing students. Of the isolates, 85% presented resistance to penicillin and 50% were classified as moderate biofilm producers. In addition, 92.5% of isolates contained the gene icaA and 60% of the gene icaD. Approximately 25% of the isolates presented the mecA gene. Typing of the mecA gene showed the presence of staphylococcal chromosome cassette SCCmec I and c III respectively in 20% and 10% of the isolates. 70% of the samples could not be typed by the technique. Regarding the enterotoxins, the most prevalent gene was SEA (30%) followed by the SEC gene (2.5%). The presence of SED and SEB genes not observed in any of the isolates. Conclusion: The cleaning and periodic disinfection of cell phones can contribute to the reduction of the risk of nosocomial infection.

Keywords

• Biofilms
• cross infection
• drug resistance, microbial
• enterotoxins
• Methicillin-resistant Staphylococcus aureus
• virulence