Assessment of bacterial isolates and antimicrobial susceptibility patterns in external ocular infections among patients attending eye clinic at Kafrelsheikh University Hospitals

Background: Ocular infections can harm the eye's anatomic structure on numerous levels. They are a global health issue. Endophthalmitis, a serious complication following cataract surgery, can result in substantial ocular morbidity and vision loss despite the administration of antibiotics. Bacterial ocular flora are the primary causative agents. This study aimed to assess the types of bacterial isolates on the external ocular surface and evaluate their antimicrobial susceptibility patterns in pre-operative cataract patients at Kafrelsheikh University Hospitals.

Methods: This cross-sectional study enrolled 691 patients scheduled for routine cataract surgery in the Department of Ophthalmology at Kafrelsheikh University Hospitals, Egypt. Each patient underwent a comprehensive assessment of medical history, including the use of traditional medicine, past eye trauma, and any prior eye surgeries, as well as ophthalmic clinical data such as visual acuity and ocular surface disorders. Conjunctival swabs were collected and processed using standard microbiological procedures to identify bacterial isolates and their respective antimicrobial susceptibility patterns.

Results: Among the 691 patients enrolled (median age 60 years, IQR 54-66), 59.8% were female. Conjunctival cultures yielded positive results in 38 cases (5.6%). The most frequently isolated organisms were Staphylococcus aureus, accounting for 52.6% of isolates, followed by Staphylococcus epidermidis at 15.8%. Notably, S. aureus demonstrated the highest resistance to erythromycin and vancomycin, with all 20 isolates showing resistance. In contrast, linezolid exhibited high efficacy, with 19 isolates showing sensitivity and only one displaying resistance.

Conclusion: This study indicated that ocular conditions such as dry eye syndrome, Meibomian gland dysfunction, and scaly blepharitis are strongly associated with the prevalence of culture-confirmed ocular infections. Regarding antibiotic susceptibility, most Staphylococcus species demonstrated the greatest sensitivity to linezolid and trimethoprim/sulfamethoxazole.