Establishment of rapid diagnostic method for the identification of Staphylococcus aureus in bacterial conjunctivitis

Staphylococcus aureus is the most frequent cause of conjunctivitis and may lead to severe visual impairment. However, the tools available for the diagnosis, such as bacterial culture and cytology, are often inadequate. Therefore, the goal of the present work was to establish a rapid detection method for S. aureus in the secretions of the conjunctival sac to provide a basis for the early diagnosis of acute bacterial conjunctivitis. The study included 32 patients with acute bacterial conjunctivitis, 30 patients with viral conjunctivitis, and 28 control subjects. Extracted DNA was analyzed by conventional PCR and RT-PCR using primers specific for S. aureus DNA and two antibiotic resistance genes, mecA and femB. By this technique, S. aureus was found in 37.5% of patients with bacterial conjunctivitis, 20% of patients with viral conjunctivitis, and in 7.1% normal control subjects. Except for the control group in which the femB gene was not found, in most other cases S. aureus carried mecA and femB genes. The developed molecular biology approach is faster and more sensitive than the methods requiring bacterial cultures and is uniquely suited for the detection of an S. aureus infection in the eye.