Phenotypic and Genotypic Characterization with MALDI-TOF-MS Based Identification of Staphylococcus spp. Isolated from Mobile Phones with their Antibiotic Susceptibility, Biofilm Formation, and Adhesion Properties

Abstract

Cell phones, smartphones, and tablets are extensively used in social and professional life, so they are frequently exposed to bacteria. The main goal of the present work was to isolate and characterize <i>Staphylococci</i> strains from students' cell phone mobiles. Subsequently, 24 <i>Staphylococci</i> strains were tested against a wide range of antibiotics, for the distribution of some virulence-related genes and their ability to form biofilm. <i>Staphylococcus</i> spp. were cultured from all studied devices on chromogenic medium and identified using the matrix-assisted laser desorption/ionization (MALDI), time-of-flight (TOF) mass spectrometry (MS) technique (MALDI-TOF-MS). The results obtained showed that <i>S.</i><i>aureus</i> was the dominant species (19 strains, 79.1%), followed by <i>S.</i><i>warneri</i> (3 strains, 12.5%), and <i>S.</i><i>haemolyticus</i> (2 strains, 8.3%). Isolated strains showed high percentages of hydrolytic enzymes production, resistance to many tested antibiotics, and 37.5% expressed the <i>mec</i><i>A</i> gene. The tested strains were highly adhesive to polystyrene and glass and expressed implicated <i>ica</i><i>A</i> (62.5%) and <i>ica</i><i>D</i> (66.6%) genes. All <i>Staphylococcus</i> spp. strains tested were found to possess proteases and the α-hemolysin gene. Our results highlighted the importance of mobile phones as a great source of <i>Staphylococcus</i> spp., and these species were found to be resistant to many antibiotics with multiple antibiotic resistance (MAR) index ranging from (0.444) to (0.812). Most of the studied strains are able to form biofilm and expressed many virulence genes. Phylogenetic analysis based on the phenotypic and genetic characters highlighted the phenotypic and genetic heterogeneity of the <i>S</i><i>.</i><i>aureus</i> population studied. Further analyses are needed to elucidate the human health risks associated with the identified <i>Staphylococci</i> strains.