From Microbial Masterpieces to Resistance Roadblocks: Understanding the 8 Year Evolution Against Antimicrobials by Enterococcus faecalis

Introduction: E. faecalis is a Gram-positive, facultative anaerobe from the phylum Bacillota. While part of the normal gastrointestinal flora, it can become opportunistic, causing urinary tract infections, endocarditis, and other conditions. It shows resistance to a wide range of antibiotics and tolerates extreme conditions, making it a significant nosocomial pathogen. Objectives: This study aimed to determine the effectiveness of commonly used antibiotics, identify emerging resistance trends, and analyze antimicrobial susceptibility patterns of Enterococcus faecalis isolates over an eight-year period at Fauji Foundation Hospital to inform treatment strategies and antibiotic stewardship. Material and Method: Samples were collected from multiple wards. Cysteine, Lactose, and Electrolyte Deficient (CLED) agar was used to culture specimens, incubated for 24 hours at 37°C. Antibiotic susceptibility testing was performed according to standard protocols, and results were analyzed using Microsoft Excel. Results: A total of 1916 isolates were assessed. Most were from urine cultures (1008), followed by pus and HVS cultures. Vancomycin showed 100% effectiveness, followed by linezolid (98.02%), fusidic acid (81.25%), and nitrofurantoin (79.23%). Ciprofloxacin and gentamicin showed concerning resistance. Ampicillin sensitivity was 61.17%, with resistance rising over time. Erythromycin (76.53%) and norfloxacin (95.45%) demonstrated high resistance, suggesting misuse. Augmentin showed moderate effectiveness. Conclusion: This 8-year study revealed a rise in antimicrobial resistance among E. faecalis isolates in a Pakistani tertiary care hospital. Vancomycin and linezolid remained effective, but increasing resistance to ciprofloxacin, gentamicin, erythromycin, and norfloxacin indicated misuse and shrinking options. Findings highlight the urgent need for antibiotic stewardship, regular surveillance, and tailored treatment guidelines to preserve last-resort antibiotics.