Abstract
Purpose: :
Empiric therapy for infectious keratitis and antibiotic usage in ophthalmic surgical prophylaxis depend on the knowledge of the spectrum of pathogens as well their antibiotic susceptibilities in the immediate geographic area. The spectrum of pathogens as well as antibiotic effectiveness has evolved over the years. However, there are limited contemporary reports from different areas of the United States. We therefore sought to identify and evaluate the spectrum of organisms responsible for non–viral, infectious keratitis in the greater Saint Louis area as well as their antibiotic sensitivities.
Methods: :
The Saint Louis University Hospital microbiology records for all specimens submitted from the department of ophthalmology at Saint Louis University were identified for the period 1999 to 2003. The corresponding patient records were then reviewed to confirm the nature of the specimen(s) submitted. Non–viral, infectious keratitis cases were then extracted and studied to determine the spectrum of organisms isolated and their antibiotic sensitivities.
Results: :
343 specimens were received at the microbiology laboratory from the department of ophthalmology from Jan 1, 1999 to Dec 31, 2003. Of these specimens, 83 (24%) were from patients with the clinical diagnosis of non–viral, infectious corneal ulcers. Growth rate was 66% (55 specimens); however , 22 specimens were considered contaminants. Therefore, positive, non–contaminant growth rate was 39.8% (33 specimens). A total of 38 organisms were isolated: 3 fungal isolates (all molds), 21 Gram positive organisms, and 14 Gram negative organisms. The most common Gram positive organism isolated was Staphyloccocus aureus (24% of total). The most common Gram negative organisms isolated were Pseudomonas aeruginosa (13%) and Serratia marcescens (13%). The antibiotic sensitivities will be presented as an antibiogram.
Conclusions: :
This is the first report in recent years to document the spectrum of causative organisms involved in non–viral, infectious keratitis in the St. Louis area with associated antibiotic susceptibilities. While the individual antibiotic sensitivities are overall similar to those reported from other institutions, the proportion of causative organisms in non–viral, infectious keratitis in the St. Louis area is different from that reported from other locations in the United States. This information is important to practicing ophthalmologists in this era of continuing empiric therapy and surgical prophylaxis.
Keywords: keratitis • clinical (human) or epidemiologic studies: prevalence/incidence • antibiotics/antifungals/antiparasitics