Epidemiological, laboratory and clinical results in microbial keratitis

Purpose: To describe the epidemiological, laboratory and clinical outcomes of microbial keratitis in our clinic besides to evaluating the organisms in our region and their in vitro antibiotic susceptibility. Methods: A total of 96 patients with microbial keratitis were analysed between May 2005 and June 2013. In 87 patients corneal scrapings were taken for diagnostic stains and culture. Data collected from medical records were age, sex, risk factors, preoperative and postoperative visual acuity, stained smears and culture results, requirements for surgery. Results: The mean age of patients was 47, 7 (5-95) years and male to female ratio was 5/3. Stained smears were positive in 31% of eyes. Gram stain sensitivity and specificity was 42,3% and 85,7% respectively. Positive culture was obtained in 52 (59, 8%) scrapings; 24(46, 2%) were Gram-positive bacteria, 16(30, 8%) were Gram-negative bacteria, 12(23%) were fungi. The most common bacterial species isolated were S epidermidis. Sixty-five (67, 7%) patients had predisposing factors. Contact lens wear was the major risk factor in 28 eyes (43, 1%). P aeruginosa was the most common causative organism in contact lens wearers. Other risk factors were previous surgery (23, 1%), organic trauma (15, 4%), mechanical trauma (13,8%) and lid pathology(4,6%). Time interval between initial symptoms and the first visit in our clinic was 1 week for 57 patients, 2 weeks for 11 patients, 3 weeks for 7 patients, 4 weeks for 12 patients and 1-2 months for 9 patients. Mean best corrected visual acuity (BCVA) was 2,0 logMAR before treatment and 1,5 logMAR after treatment which was found statistically significant (p<0.001). Recovery was achieved in 77% of patients with empirical therapy. Culture was positive in 18 of 22 patients who did not respond to empirical treatment. Six of 22 patients who were switched to different medication responded well. Among all patients we found good recovery in %83, three additional surgical treatments were performed in 16 patients, who were refractory to medical therapy. Most of the patients who required surgery were those with fungal keratitis (53, 8 %). Conclusions: Early diagnosis and timely management of keratitis is crucial for favorable prognosis. If there is no chance of collaboration with a rapid and reliable laboratory, successful management can still be achieved by choosing the appropriate empirical therapy after taking the risk factors and the most common local pathogens into consideration. In patients with no or limited response to treatment, direct microscopic examination and culture or even biopsy may provide useful information.