Molecular investigation of quinolone-resistant genes among clinical Staphylococcus aureus isolates in Babylon hospitals

Abstract

Background: Staphylococcus aureus is considered an essential etiological factor in several human infections. Although fluoroquinolones are typically used to treat these illnesses, a growing average level of resistance to these medications has been found globally in recent years. Objective: S. aureus is considered a main etiological agent of many human infections. Fluoroquinolones are routinely used in the drugs for these infections; however, in latest years, a growing rate of resistance to these drugs has been reported worldwide. The current study aimed to investigate the molecular resistance of quinolone (qnrA and qnrS) genes among clinical S. aureus isolates in Babylon. Materials and Methods: During the research, 431 clinical samples were collected from hospitals in the Babylon Health Directorate between August 2022 and January 2023. Standard laboratory procedures and biochemical tests were used to identify the bacterial isolates. Antimicrobial susceptibility was determined by the standard disk diffusion method. Polymerase chain reaction (PCR) was used for detecting the qnrA and qnrS genes. Results: From a total of 78 S. aureus isolates, 18 (23.77%) and 19 (24.35%) isolates of S. aureus bacteria were sensitive and intermediate to quinolone compounds, respectively, whereas 41 (52.56%) isolates showed high-level quinolone resistance. The findings revealed that the majority of them were antibiotic-resistant. Most frequently, high resistance was noted for ciprofloxacin with a ratio of 75%, followed by levofloxacin with a ratio of 72%, and high sensitivity was shown for norfloxacin with an 85% and chloramphenicol with an 80%. From a total of 41 quinolones resistance S. aureus, the qnrA gene was identified in 10 (24.39%) and qnrS in 8 (19.51%). Conclusion: The results showed a high rate of qnr gene resistance among the isolates of S. aureus in the Babylon hospitals, which emphasizes the need for establishing careful policies. From a total of 41 quinolones resistance S. aureus, the qnrA gene was identified in 10 (24.39%) and qnrS in 8 (19.51%).