Egyptian Journal of Medical Microbiology Volume 24 / No. 2 / April 2015 19-27 Egyptian Journal of Medical Microbiology 19 ORIGINAL ARTICLE Conjunctival microbiota and Antibiotic Resistance Pattern in Patients Submitted to Cataract Surgery and Antibacterial Activity of Some Plant Essential Oils 1 Rasha H. Bassyouni*, 2 Maha Mohssen Abdelfattah, 3 Zeinat Kamel, 3 Eman Mostafa Mostafa, 4 Iman Abdelfattah Fahmy, 4 Ebrahim Salah Elborgy 1 Medical Microbiology and Immunology Department, Faculty of Medicine, Fayoum University, Egypt 2 Microbiology Department, Research Institute of Ophthalmology, Cairo, Egypt 3 Botany Department, Faculty of Science, Cairo University, Egypt 4 Opthalmology Department, Research Institute of Ophthalmology, Cairo, Egypt ABSTRACT Key words: Conjunctival microbiota, Antibacterial, Essential oils, Cataract Objective: The objective of this study was to identify the conjunctival microbiota of patients undergoing cataract surgery and evaluate its antibiotic resistance pattern. Also to in-vitro evaluate the antimicrobial effects of some essential oils against multidrug resistant isolates. Methodology: Ocular samples were collected using swabs and polymethyl-metaacrylate (PMMA) intraocular lenses from seventy patients submitted to cataract surgery. Isolation and identification of bacteria was performed using conventional microbiological methods. Antibiotic sensitivity was done by disc diffusion method. The sensitivity of 16 essential oils against isolated bacteria was tested using well diffusion method. Results: Thirty six strains were isolated from patients submitted to cataract surgery. Gram positive microorganisms represent 75% of the isolates with coagulase-negative Staphylococci (CoNS) the most common isolate (47.2%) followed by S.aureus (19.4%), whereas gram negative occurred in 25% of cases, with Moraxella spp. the most frequent Gram negative isolate. Antibiotic sensitivity test revealed that the highest antibiotic resistance was exhibited against ceftazidime (100%) followed by clindamycin (86%), ampicillin (80.5%), erythromycin (72.2%) and tetracycline (69.4%). Gentamycin displayed the best activity (55.5%) followed by chloramphenicol (44.4%) and vancomycin (38.88%). Fifteen essential oils showed antibacterial effect against one or more bacterial strains. The most potent oils were peppermint oil, dill oil, cinnamon oil which showed promising inhibitory activity against most tested bacterial species, whereas cotton, ginger, chamomile, blue green, cod liver and parsley oil were the least active against tested strains. Olive oil failed to inhibit any of the tested strains. In general, St. pneumoniae was the most susceptible organism as it inhibited by ten oils. Conclusion: Our results indicate a promising antibacterial effect of peppermint oil, dill oil and cinnamon oil against conjunctival microorganisms. INTRODUCTION One of the most serious complications of cataract surgery is endophthalmitis that, as although it is infrequent, it leads to high visual morbidity even with appropriate therapy. So ophthalmologists adopt several measures for its prophylaxis 1,2 . Postoperative endophthalmitis reflects in part quality and safety aspects of cataract surgery 2,3 . *Corresponding Author: Rasha H. Bassyouni Department of Medical Microbiology and Immunology, Faculty of Medicine, Fayoum University Email: rashabassyoni@yahoo.com, Tel: +2 012 23640107 Bacteria are the most common group of causative agents of endophthalmitis and gram-positive pathogens are responsible for 60 to 80% of acute infections 2,3 .. Previous studies have shown that most bacteria responsible for postoperative ocular infection are part of the normal microbial flora of the conjunctiva and eyelids of the patients 1,2 . The culture is positive in about 50 to 85% of the vitreous aspirates with coagulase- negative Staphylococci (CoNS) the most frequently isolated organism, followed by S.aureus and Streptococcus spp. Gram-negative organisms are implicated in 20% of the infections. 2