Abstract
Purpose: :
To study the effect of reduced oxygen on selected clinical and environmental Acanthamoeba isolates.
Methods: :
Non-nutrient agar saline plates (NNAS), streaked with live E. coli were inoculated with 15 molecularly typed pathogenic and environmental Acanthamoeba isolates. The 15 cultures were placed into both microaerophilic and anaerobic environments as well as ambient atmospheric conditions and grown at 23 C. Three random areas the size of the field of view on the microscope were used for counting. The number of trophozoites were counted at each of the three marked areas at 24 hr intervals over 8 days and the data analyzed with Student’s t-test for significance.
Results: :
All of the tested isolates displayed growth in the microaerophilic environment while none grew under anaerobic conditions. Certain clinical and environmental strains displayed significantly higher rates of growth (P≤.05) in low oxygen conditions when compared with normal atmospheric oxygen levels. Molecular type did not appear to be a factor in increased growth rates.
Conclusions: :
Microaerophilic oxygen conditions may be stimulatory to more aggressive growth of selected environmental and clinical Acanthamoeba strains. This may account for the increase in Acanthamoeba Keratitis (AK) secondary to Acanthamoeba adherence to a contact lens or the corneal surface in the presence of decreased oxygen conditions particularly in the closed eye condition. The importance of patient education, contact lens care compliance and proper contact lens hygiene to reduce the incidence of AK is emphasized.
Keywords: Acanthamoeba • anterior segment • microbial pathogenesis: experimental studies