الفهرس 
Introduction and Aim of workOnly 14 pages are availabe for public view
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Abstract
The term endophthalmitis refers to an infection in the interior of the eyeball (globe), involving the ocular fluids either vitreous or aqueous humor or both. Normally the interior of the eye is a sealed and sacred space. It is a sterile environment that never receives direct contact with the external environment. This is in contrast with the outside of the eye, which is always in contact with viruses, fungi and bacteria. Because the tissues within the eyeball are very delicate, endophthalmitis is very serious and can lead to blindness and even loss of the eye itself. There are two types of endophthalmitis, exogenous and endogenous endophthalmitis. Exogenous endophthalmitis is the most common form and occurs only after penetration of the eyeball following trauma, surgery or erosion. It is among the most feared complications of eye surgery. In contrast, endogenous endophthalmitis occurs when blood-born organisms seed the interior of the eye from the bloodstream and establish an internal eye infection. This latter situation occurs most commonly in individuals with severe blood born infections, especially in immunosuppressed cases. Prompt diagnosis is essential, as the inside of the globe is filled with very delicate tissue such as the retina. It is an enclosed, compartmentalized space, and there is no where for an infection inside the globe to drain. If treatment delays even for few hours, it may end in an unsuccessful outcome. The aim of this study was to isolate and identify the microorganisms causing endophthalmitis and also to determine their antibiotic susceptibilities to provide a basis for choosing initial empiric antibiotic therapy for future cases of endophthalmitis. The present study was carried out on 23 patients (13 males and 10 females) and 65% of them were resident of rural areas. Samples of vitreous and aqueous aspirates were inoculated into different media. The results showed that vitreous fluid was more sensitive than aqueous humor in the diagnostic approach, where the yield for positive culture in vitreous samples was 12 out of 19 (63%), while aqueous aspirates were positive in 1 out of 8 cases (12.5%). The rate of culture positive cases in post-traumatic endophthalmitis was higher than that of postoperative type. Where in postoperative cases, 60% (6/10) of vitreous samples had positive culture , of these 6 culture-positive cases, 5 (83%) Gram-negative bacilli were isolated where (3/6) 50% grew Pseudomonas fluorescens. Pseudomonas fluorescens can survive in moist conditions and is found in water even in distilled water or aqueous solutions used in medical care as normal saline as well as in hospital disinfectants which may be considered as the main sources of infection. Other Gram-negative bacilli such as Alcaligenes faecalis and Alcaligenes denitrificans, were isolated in similar percentage (16.6%). These microorganisms were considered non-pathogenic and of little clinical significance. However, cases of postoperative endophthalmitis caused by these bacteria have been previously reported. Candida was also isolated in 16.6% of cases. In post-traumatic endophthalmitis, 66% (6/9) of vitreous samples had positive culture, of these 6 culture-positive cases, 5 (83%) Gram-positive cocci were isolated where (4/6) 66.6% grew Staphylococcus aureus, 1 (16.6%) grew Staphylococcus epidermidis and the remaining isolate (16.6%) was the Gram-negative bacilli, Enterobacter cloacae, which was isolated from a child of 4 years old. Blood culture bottles were found to be superior to the conventional media where the yield of positive culture was 63.2% and 52%, respectively. This superiority was attributed to a volume-related and dilution effect. Conjunctival swab gave positive resullts only in 2 out of 23 samples (8.69%), which may be due to poor culture technique as the swab must be pressed firmly enough to pick up viable bacteria or may be due to prior use of topical antibiotics. A significant association between age and the risk of developing postoperative endophthalmitis was observed, as individuals older than 50 years old were 2.5 times more likely to develop endophthalmitis than those up to 50 year old individuals. This association was related to relevant physiological factors such as slower healing or reduced resistance to infection, or to longer surgical time due to a greater density of cataract. Significant association was found between diabetes mellitus and the incidence of endophthalmitis. Susceptibility studies showed that 86% of Gram-negative isolates were susceptible to gatifloxacin and tobramycin and they were 100% susceptible to chloramphenicol, amikacin and gentamycin, while they were poorly susceptible to ceftazidime (43%) and cefotaxime (14%). Gram-positive isolates were susceptible to ciprofloxacin, ofloxacin and chloramphenicol (80%) and they were 100% susceptible to gatifloxacin, vancomycin and methicillin. Therefore chloramphenicol is recommended to be used as an alternative medication to the current antibiotic policy at Mansoura Ophthalmology Center. In this study, it has been proved that Gatifloxacin exhibit excellent in vitro activity against Gram-positive cocci, particularly Staphylococcus epidermedis, but may be less effective against Gram-negative bacilli, such as Pseudomonas fluorescens and Alcaligenes denitrificans. Recommendations: We support the development of an Egyptian-wide standard operating policy for investigation and treatment of endophthalmitis. Direct inoculation of vitreous fluid into a blood culture bottle should be recommended as an acceptable adjunct for optimum microbiological diagnosis. Further investigations are needed to investigate the possibility of using gatifloxacin as intravitreal injection. Chloramphenicol is recommended to be used as an alternative medication to the drugs commonly used in the current treatment policy of Mansoura Ophthalmology Center.