Abstract
PURPOSE: To analyze the pathogen distribution, epidemiological characteristics, and antimicrobial resistance patterns of bacterial conjunctivitis in a Shanghai secondary hospital from 2020 to 2024, providing evidence for clinical treatment optimization. PATIENTS AND METHODS: Conjunctival swab specimens from patients clinically diagnosed with bacterial conjunctivitis were collected between January 2020 and December 2024. Bacterial identification and antimicrobial susceptibility testing were performed using the VITEK 2 Compact system and Kirby-Bauer disk diffusion method, respectively. Statistical analyses were conducted using WHONET 5.6 and SPSS 26.0. RESULTS: Among the 611 specimens, 58 bacterial isolates were identified (9.5% positivity rate). Gram-positive cocci predominated (70.7%, 41/58), primarily Staphylococcus epidermidis (21 strains) and Staphylococcus aureus (10 strains). Gram-negative bacilli accounted for 15.5% (9/58), including Pseudomonas aeruginosa and multidrug-resistant Acinetobacter baumannii. A significant seasonal variation was observed, with higher incidence in summer-autumn (72.4%) than in winter (12.1%, P=0.005). Cases in 2023-2024 nearly doubled those in 2020-2022 (65.5% vs 34.5%). The detection rate of S. aureus increased significantly annually (P=0.043). High resistance rates were observed among Gram-positive cocci to penicillin (89.5%), oxacillin (60.5%), and erythromycin (55.3%). All Gram-positive isolates remained susceptible to vancomycin, linezolid, and tigecycline. Gram-negative isolates exhibited 100% resistance to ampicillin, with A. baumannii demonstrating pandrug-resistance. CONCLUSION: Gram-positive cocci, particularly Staphylococcus spp. were the predominant pathogens in bacterial conjunctivitis, with an increasing trend of S. aureus and multidrug-resistant A. baumannii. The significant seasonal pattern and high resistance to first-line antibiotics emphasize the necessity for culture-guided therapy and enhanced antimicrobial stewardship in ocular infections.