RISING ANTIBIOTIC RESISTANCE: HIGH-LEVEL AMINOGLYCOSIDE RESISTANCE IN ENTEROCOCCUS CLINICAL ISOLATES.

Introduction: Enterococcus species have emerged as signicant nosocomial pathogens due to their increasing antibiotic resistance, particularly High-Level Aminoglycoside Resistance (HLAR). HLAR compromises the efcacy of aminoglycoside- -lactam synergistic therapy, making infections difcult to treat. This study aims to determine the prevalence and genetic mechanisms of HLAR among clinical Enterococcus isolates. Methodology: This observational, laboratory based study was conducted at a Index Medical College Hospital and Research Centre in Indore, Madhya Pradesh, India, over a period of 18 months . A total of 150 non-repetitive Enterococcus isolates were collected from urine, blood, wound swabs, and body uids. Bacterial identication was performed using Gram staining, biochemical tests, and growth conditions. HLAR was detected using the Kirby-Bauer disk diffusion method with high-level gentamicin (120 g) and streptomycin (300 g) discs, following CLSI guidelines. Minimum inhibitory concentration (MIC) was determined, and PCR was performed to detect aminoglycoside-modifying enzyme (AME) genes. Results: Among 150 isolates, E. faecalis (45.3%) and E. faecium (34.7%) were predominant. HLGR was found in 38.0%, HLSR in 30.0%, and combined HLGR & HLSR in 18.7%. The aac(6')-Ie-aph(2”)-Ia gene was detected in 66.2% of HLGR isolates, while aph(3')-IIIa was found in 85.4% of HLSR isolates. Conclusion: HLAR is highly prevalent among Enterococcus isolates, emphasizing the need for routine surveillance, strict infection control, and antimicrobial stewardship to limit its spread.