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Abstract
Background: Infections by Staphylococcus aureus are continued as a real issue especially in hospital-acquired disease. It can produce virulent factors that can be controlled by the accessory gene regulator (agr), and it can be affected by mobile genetic elements (MGEs). It should be known their mechanism in local isolates as it is crucial for monitoring infections and treatment approaches.
Objectives: To evaluate S. aureus prevalence in clinical samples and to discover the consequence of the agr system and MGEs in regulating virulence.
Methods: Microbiological procedures were used to gather clinical samples. Also, molecular assays were accomplished to determine agr types, key virulence-associated genes, and MGEs. The data of this study was evaluated to estimate the association among agr function, virulence gene distribution, and resistance traits.
Results: Most clinical samples contain active agr system, with major of agr group I. Virulence factors like enterotoxins, hemolysins, and adhesion-associated genes were extensively spread. MGEs such as pathogenic islands and plasmids were detected and cause antimicrobial resistance and virulence expression. Interestingly, in the isolated samples, active agr systems present a significant association with toxin production more than those with dysfunctional variants.
Conclusion: S. aureus samples show high dominance and genetic variant. Virulence measurements are strongly affected by the agr system and MGEs. Molecular monitoring is important step to display these influences and support active therapeutic and infection-control measures.
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Copyright (c) 2026 Hanaa Neamah Abdullah, Nada Ahmed Fairooz, Bushra Hamad Obaid, Sura A Al-Ganahi, Robeena Farzand (Author)

This work is licensed under a Creative Commons Attribution 4.0 International License.
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References
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- Bakry MM, Mohamed NA, Mohamed N. Accessory gene regulator quorum sensing system in Staphylococcus aureus. Sohag Medical Journal. 2025;29(1):1-6. https://doi.org/10.21608/smj.2024.317398.1498.
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- Obaid BH, Al-Ganahi SA, Kadhim BA. Effective Factors Associated with Epidemiological Analysis of Widespread Crimean-Congo Hemorrhagic Fever in Nasiriyah, Iraq in 2023.African Journal of Biomedical Research. 2025;28(3S):68-73. https://doi.org/10.53555/AJBR.v28i3S.7313.
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References
Hegazy EE, ElNaghy WS, Shalaby MM, Shoeib SM, Abdeen NS, Fouda MH, et al. Study of class 1, 2, and 3 integrons, antibiotic resistance patterns, and biofilm formation in clinical Staphylococcus aureus isolates from hospital-acquired infections. Pathogens. 2025;14(7):705. https://doi.org/10.3390/pathogens14070705.
Mustafa AM, Salih RQ, Yaseen HA, Hamadameen WA, Kakamad SH, Abdullah F, et al. Evolution of antimicrobial resistance in community vs. hospital-acquired infections. Barw Medical Journal. 2025.
Hazra K, Roy S, Maitra S, Ghosh I. Variable presentations of staphylococcal infections with diagnostic dilemma: a case series. Bengal Physician Journal. 2025;12(3):150-155.
DiMaggio DA Jr. Investigating the regulation of secreted virulence factors by the Sae two-component system in Staphylococcus aureus [dissertation]. Washington (DC): Georgetown University; 2025.
Bakry MM, Mohamed NA, Mohamed N. Accessory gene regulator quorum sensing system in Staphylococcus aureus. Sohag Medical Journal. 2025;29(1):1-6. https://doi.org/10.21608/smj.2024.317398.1498.
Solís N, Pérez C, Ramírez M, Castro J, Rodríguez C. Clinical presentation and microbiological characteristics of community-acquired Staphylococcus aureus bacteraemia at a tertiary hospital in Costa Rica. Journal of Medical Microbiology. 2024;73(9):001883. https://doi.org/10.1099/jmm.0.001883.
Fairooz NA, Alganahi SA, Obaid BH. Evaluation of the anticandidal activity of methanolic and ethyl acetate extracts of Syzygium aromaticum on Candida albicans isolated from pregnant women with vulvovaginal candidiasis in Diwaniyah, Iraq. Microbes and Infectious Diseases. 2025. https://doi.org/10.21608/mid.2025.407921.3063.
Kumavath R, Gupta P, Tatta ER, Mohan M, Salim SA, Busi S. Unraveling the role of mobile genetic elements in antibiotic resistance transmission and defense strategies in bacteria. Frontiers in Systems Biology. 2025;5:1557413. https://doi.org/10.3389/fsysb.2025.1557413.
Kadhim BA, Saeed ZF, Al-Ganahi SA. Evaluation of the efficiency of ciprofloxacin against S. Typhi by altering cytokine production in acute typhoid fever. Malaysian Journal of Microbiology. 2022;18(5). https://doi.org/ 10.21161/mjm.221504.
Alharbi S, Aldawood E, Jamil NM, AlShehri F, Ashour ML, Elfaky MA. Mobile genetic elements and the evolution of microbes. In: Microbial Genetics. Boca Raton (FL): CRC Press; 2024. p.72-100.
Schuetz AN, Ferrell A, Hindler JA, Humphries R, Bobenchik AM. Overview of changes in CLSI performance standards for antimicrobial susceptibility testing: M100 32nd and 33rd editions. Journal of Clinical Microbiology. 2025;e01623-23. https://doi.org/10.1128/jcm.01623-23.
Dilawer Issa K, Dlshad Muhsin M. Beta-lactam drug resistance pattern in Staphylococcus aureus isolates: a review. Eurasian Journal of Science and Engineering. 2024;9(3):13. https://doi.org/10.23918/eajse.v9i3p13.
González-Machado C, Alonso-Calleja C, Capita R. Prevalence and types of methicillin-resistant Staphylococcus aureus (MRSA) in meat and meat products: a review. Food Microbiology. 2024;123:104580. https://doi.org/10.1016/j.fm.2024.104580.
Lai CH, Wong MY, Huang TY, Kao CC, Lin YH, Lu CH, et al. Exploration of agr types, virulence-associated genes, and biofilm formation ability in Staphylococcus aureus isolates from hemodialysis patients. Frontiers in Cellular and Infection Microbiology. 2024;14:1367016. https://doi.org/10.3389/fcimb.2024.1367016.
Chen Y, Zhu F, Hong Y, Liu Y, Wang H, Jiang S, et al. Characterization of virulence and adaptability in methicillin-resistant Staphylococcus aureus ST9 lineage. mSystems. 2025;e00282-25. https://doi.org/10.1128/msystems.00282-25.
Islam MM, Hossain MI, Islam MS, Azam MG, Sultana S. Prevalence, antibiotic resistance patterns, and virulence factors of Staphylococcus aureus in bovine mastitis. Heliyon. 2025;11(3). https://doi.org/10.1016/j.heliyon.2025.e42107.
Kadhim BA, Alqaseer K, Al-Ganahi SA. Identification and characterization of a novel lytic peptidoglycan transglycosylase in Shigella dysenteriae. Brazilian Journal of Microbiology. 2023;54(2):609-618. https://doi.org/ 10.1007/s42770-023-00957-9.
Mašlaňová I, Kovařovic V, Botka T, Švec P, Sedláček I, Šedo O, et al. Evidence of mecB-mediated β-lactam resistance transfer to Staphylococcus aureus. Applied and Environmental Microbiology. 2025;91(4):e01652-24. https://doi.org/10.1128/aem.01652-24.
Obaid BH, Al-Ganahi SA, Kadhim BA. Effective Factors Associated with Epidemiological Analysis of Widespread Crimean-Congo Hemorrhagic Fever in Nasiriyah, Iraq in 2023.African Journal of Biomedical Research. 2025;28(3S):68-73. https://doi.org/10.53555/AJBR.v28i3S.7313.
Chen J, Wu Y, Zhu Y, Zhang L, Xu Y, Liu Y. Adaptation of Staphylococcus aureus via insertion mutation in agrC gene. Microbiology Spectrum. 2025;13(1):e01497-24. https://doi.org/10.1128/spectrum.01497-24.
Touaitia R, Mairi A, Ibrahim NA, Basher NS, Idres T, Touati A. Staphylococcus aureus: a review of pathogenesis and virulence mechanisms. Antibiotics. 2025;14(5):470. https://doi.org/10.3390/antibiotics14050470.
