240 Phenotypic and Molecular Characterization of Staphylococcus aureus from Mobile Phones in Nigeria

Abstract

Abstract Introduction/Objective Mobile phones are indispensable in daily life due to their convenience, communication capabilities and access to various services and information. However, they are often handled but seldom cleaned and can thus serve as sources of pathogenic microorganisms. In hospital as well as in community environments, they can serve as fomites for transmitting antibiotic-resistant bacteria such as Staphyloc’occus aureus, including methicillin-resistant Staphylococcus aureus (MRSA). The rapid rise of antimicrobial resistance is also making it important to determine mobile devices as potential sites of infection, especially in community-acquired infections. The prevalence, antimicrobial resistance profiles and virulence determinants of Staphylococcus aureus from the mobile phones of users based on their professions in Ile-Ife, Nigeria was determined in this study. Methods/Case Report This research was conducted at the Department of Medical Microbiology, Obafemi Awolowo University (OAU), Ile-Ife, Nigeria. One-hundred (100) samples were collected aseptically with the use of sterile cotton swab sticks moistened with sterile saline by swabbing the surfaces of the keypad, mouthpiece and earpiece of mobile phones of different users based on their profession, including cleaners, abattoir workers, lecturers, students, nurses, food sellers, and marketers. The swabs were transported immediately to the laboratory for bacteriological analysis. The swabs were streaked onto mannitol salt agar (MSA) plates and incubated aerobically at 37 °C for 24–48hours. Colonies showing a characteristics golden yellow pigmentation on (MSA) were picked and streaked on fresh MSA plates and incubated at 37 °C for 24hours to obtain pure colonies which were presumptively identified as Staphylococcus aureus. Preliminary characterization of isolates were carried out using Gram staining and biochemical studies such as catalase, tube coagulase, nitrate reduction and DNase. Antibiotic susceptibility of isolates was determined on Mueller-Hinton agar plate by disk diffusion method. Twenty-eight (28) multiple antibiotic resistant isolates were randomly selected and profiled for plasmid analysis using the modified alkaline lysis (MAL) method. Results All the thirty-six (36) Staphylococcus aureus isolates recovered from the mobile phone of the investigated users were resistant to amoxicillin and augmentin. Also, 55.6%, 44.4% and 41.7% of the strains were resistant to cefriazone, erythromycin and chloramphenicol, respectively. The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) was 11.1% based on oxacillin resistance. For plasmid analysis, just one S. aureus was found to be positive. Four (4) of the 16 putative phenotypic MRSA strains had the mecA gene genetically confirmed, all 28 of the isolates under investigation had the nuc gene genetically validated, however none of the strains under investigation had the pvl gene. Several antibiotic-resistant strains of S. aureus, which cause significant human infections and may be challenging to treat with antibiotics, were found on mobile devices. Conclusion The detection of multidrug-resistant S. aureus (including MRSA) on personal mobile phones of various users represents a major public health threat. These results suggest that mobile phones can act as reservoirs and vectors of antibiotic resistant bacteria in the community and healthcare settings. The detection of resistance genes such as mecA, even in few isolates, would justify the necessity for continuous surveillance and molecular control. Common hand washing, regular wiping of mobile devices and compliance with infection control measures are essential to reduce transmission. The low frequency of plasmid-mediated resistance indicates chromosomal encoding, therefore minimum exchange of genetic material horizontally occurs but challenges of treatment for the longer term exist. Rigorous sensitization programs to enlighten the populace about mobile phone hygiene, especially health-care workers, food handlers, and students, are imperatively suggested. The addition of mobile device sanitation to existing infection control measures such as effective hand hygiene and care bundles would be a major benefit to reducing the threat of contamination and the battle against community antimicrobial resistance.