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Graefes Arch Clin Exp Ophthalmol (2012) 250:369374 DOI 10.1007/s00417-011-1722-9
CORNEA
Microbiological findings and predisposing risk factors in corneal ulcers
Verena Prokosch & Zisis Gatzioufas & Solon Thanos &
Tobias Stupp
Received: 14 September 2010 /Revised: 1 May 2011 /Accepted: 3 May 2011 /Published online: 25 November 2011 # Springer-Verlag 2011
AbstractBackground To identify the current bacterial spectrum, the specific resistances to commonly used antibiotics, and the predisposing risk factors causing bacterial keratitis. Methods We reviewed the microbiological results of cor-neal scrapes and predisposing risk factors from 346 patients with bacterial keratitis. Infectious bacteria was isolated from corneal samples and sensitivity testing was subsequently performed.
Results In total, 346 samples were obtained from 174 female and 172 male patients (median age: 64 years; range 5 105 years). A positive culture was obtained in 43% (148/346), recovering 199 isolates. Staphylococcus aureus was the most frequently occurring Gram-positive strain (32%) and Pseudomonas aeruginosa was the predominant Gram-negative strain (10%). Patients with specific local and systemic predisposing factors had an elevated risk for bacterial keratitis with a specific risk for certain strains. The sensitivity testing revealed that chloramphenicol and fusidic acid were the most effective monotherapy drugs, with overall resistances of 0 and 12%, respectively, followed by ciprofloxacin (22%), tobramycin (23%), and levofloxacin (24%).
Conclusions The bacterial spectrum is changing. The most effective drugs are chloramphenicol and fusidic acid, followed by ciprofloxacin. Specific systemic and local predisposing factors promote the risk of bacterial keratitis.
Keywords Corneal ulcer . Bacterial spectrum . Antibiotic resistance . Predisposing factor
Introduction
Microbial keratitis is a sight-threatening disease in which early determination of the infective organism and knowledge of its sensitivities to specific antibiotics is essential for appropriate treatment and outcome [1]. One principle in the treatment of bacterial corneal ulcers is prompt initiation of adequate antibiosis, which significantly reduces the incidence of both corneal scarring and severe complications [2]. In corneal ulceration, the prevalence of the bacterial spectrum and its resistance to antibiotics varies greatly over time and from area to area, which makes repeated examinations necessary [3, 4]. Different local and systemic factors reportedly compromise the protective mechanisms of the cornea [5]. Identifying such predisposing factors is important, and special attention should be paid to those patients who are at high risk....