Distribution of Leukocidins, Exfoliative Toxins, and Selected Resistance Genes Among Methicillin-resistant and Methicillin-sensitive Staphylococcus aureus Clinical Strains in Egypt release_virwpgj34vhlvlq4vgdqjzmm4y

Abstract

<jats:sec> <jats:title>Background:</jats:title> Infection with <jats:italic>Staphylococcus aureus</jats:italic> (<jats:italic>S.aureus</jats:italic>) is an increasing health problem worldwide. This pathogen has multiple virulence factors that contribute to its pathogenesis in a wide range of diseases. The present study aimed to investigate the prevalence of leukocidins, exfoliative toxins, and common antimicrobial resistance genes among Methicillin-Resistant <jats:italic>Staphylococcus aureus</jats:italic> (MRSA) and Methicillin-Sensitive <jats:italic>Staphylococcus aureus</jats:italic> (MSSA) strains collected from various clinical sources in Egypt. </jats:sec> <jats:sec> <jats:title>Methods:</jats:title> Isolates were identified as <jats:italic>S.aureus</jats:italic> by the standard microbiological methods. Methicillin resistance was detected phenotypically by cefoxitin disc diffusion method and genotypically by PCR for detection of <jats:italic>mecA</jats:italic> gene. PCR was also used to detect the presence of leukocidin genes (<jats:italic>LukD</jats:italic>, <jats:italic>LukE</jats:italic>, <jats:italic>LukF-PV</jats:italic>, and <jats:italic>LukS-PV</jats:italic>), exfoliative toxin genes (<jats:italic>eta</jats:italic> and <jats:italic>etb</jats:italic>), and antibiotic resistance genes (<jats:italic>tetK</jats:italic>, <jats:italic>tetM</jats:italic>, <jats:italic>ermA, ermC</jats:italic>, <jats:italic>msrA,</jats:italic> and <jats:italic>aacA-aphD</jats:italic>). </jats:sec> <jats:sec> <jats:title>Results:</jats:title> About 50.5% of tested isolates were methicillin resistant by cefoxitin disc assay, while <jats:italic>mecA</jats:italic> gene was amplified in 64.6% of isolates. The highest prevalent toxin gene was <jats:italic>lukE</jats:italic> (93%) and the least prevalent one was <jats:italic>eta</jats:italic> (1%). The resistance genes <jats:italic>tetK</jats:italic> and <jats:italic>tetM</jats:italic> were detected in nearly 50% of the tested strains but lower prevalence rates were recorded for <jats:italic>aacA-aphD</jats:italic>, <jats:italic>msrA</jats:italic>, <jats:italic>ermA</jats:italic>, and <jats:italic>ermC</jats:italic> genes. </jats:sec> <jats:sec> <jats:title>Conclusion:</jats:title> Methicillin resistance was highly prevalent among tested <jats:italic>S.aureus</jats:italic> strains. Regarding the studied virulence and resistance genes, no significant difference was detected between MRSA and MSSA strains, except for <jats:italic>ermA</jats:italic> gene p&lt;0.05 which was highly prevalent in MRSA strains. So, the variation between MRSA and MSSA strains in the response to treatment may be attributed to the resistance of MRSA strains to all β-lactams in addition to other possible acquired resistance mechanisms. Accordingly, fewer options of antimicrobial medications are available to treat MRSA infections. </jats:sec>
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