Purpose: To analyze the annual trends in antibiotic susceptibility of bacterial isolates from corneal lesions in patients with bacterial keratitis.
Methods: Bacterial isolates obtained from 312 patients (315 eyes) with bacterial keratitis were reviewed at the Miyata Eye Hospital between January 2014 and December 2016. The bacterial isolation rate, distribution of isolated bacteria, annual changes in the minimum inhibitory concentration (MIC) of antibiotics, and cumulative growth inhibition rate were examined.
Results: The bacterial isolation rate from the lesions of patients with bacterial keratitis was 64.1% in 2014, 72.5% in 2015, and 76.4% in 2016 (average 70.2%), and the number of isolates was 342. The most common isolates were gram-positive cocci and facultative anaerobic bacteria: 55 strains of Staphylococcus epidermidis, 28 strains of S. aureus including 4 strains of MRSA, 44 strains of Corynebacterium species, 129 strains of Propionibacterium acnes, and 86 strains of others. The average MIC value of moxifloxacin (MFLX), gatifloxacin (GFLX), and levofloxacin (LVFX) against all gram-positive cocci isolates increased from 0.42 (95% confidence interval 0.27-0.66) μg/mL, 0.50 (0.30-0.83) μg/mL, and 0.91 (0.51-1.63) μg/mL in 2014 to 0.98 (0.60-1.61) μg/mL, 1.20 (0.69-2.11) μg/mL, and 2.08 (1.09-3.98) μg/mL in 2016, respectively (p=0.01, p=0.02, and p=0.06, respectively, by mixed-effect model analysis).
Conclusion: The average MIC value of fluoroquinolone against gram-positive cocci increased over time.
Nippon Ganka Gakkai Zasshi (J Jpn Ophthalmol Soc) 123: 135-142, 2019.