Increased Risk with Healthcare Setting Exposure
In the study, the MRSA keratitis patients were overwhelmingly people who had contact with healthcare settings and included a hospital lab technician and the spouse of a nursing home worker. However, three patients in the study denied any exposure to a healthcare environment. Most had undergone LASIK but two had undergone Photorefractive Keratectomy (PRK). All patients in the study experienced a decrease in visual acuity and pain or irritation in the affected eye between two and ten days after the procedure. The majority had been prescribed older-generation antibiotics and experienced no relief.
Dr. Solomon, in the study, emphasizes the warning, "MRSA infectious keratitis is a potentially serious complication following refractive surgery."
Bacterial Resistance and Corneal Scarring
MRSA typically occurs early, within 10 days of the LASIK or PRK procedure, and at this time the incidence of MRSA keratitis following refractive surgery is low but increasing quickly. The cases of MRSA keratitis seen thus far have been serious due to the bacteria's resistance to traditional, older-generation antibiotics. As an example, one 48-year-old male nurse experienced symptoms two days after surgery and sought medical treatment immediately after he felt pain and a foreign body sensation in his left eye. After taking antibiotics for weeks, he was diagnosed as having MRSA keratitis, but by then, he had suffered corneal scarring.
Corneal scarring, when dense enough to affect vision, may need a corneal transplant. These are done when vision is lost because the cornea is damaged by disease or traumatic injury. They are performed only when damage to the cornea is too severe to be treated with corrective lenses.
The cases of MRSA keratitis reported in the April 2007 issue of the American Journal of Ophthalmology are the first reports of the infection after antibiotic prophylaxis (medication used to prevent infections). Strains of MRSA are emerging rapidly amongst those who have had LASIK refractive surgery and those strains are demonstrating multiple drug resistance.
According the journal, "Community-acquired MRSA is becoming a significant problem, with the prevalence of MRSA among community isolates expected to reach as high as 25% in the next decade."
