The antibiotic resistance profiles of Pseudomonas aeruginosa in the Asia Cornea Society Infectious Keratitis Study

Purpose To describe the prevalence and antibiotic resistance profiles of Pseudomonas aeruginosa isolated from the Asia Cornea Society Infectious Keratitis Study (ACSIKS). Methods All bacterial isolates from ACSIKS underwent repeat microbiological identification in a central repository in Singapore. Minimum inhibitory concentration (MIC) determination was conducted for isolates of P. aeruginosa against thirteen antibiotics from 6 different classes, and categorized based on Clinical Laboratory Standard Institutes’ reference ranges. The percentage rates of resistance (non-susceptibility) to each antibiotic included isolates of both intermediate and complete resistance. Multi-drug resistance (MDR) was defined as non-susceptibility to at least one agent in three or more antimicrobial classes. Results Of the 1493 unique bacterial specimens obtained from ACSIKS, 319 isolates were of P. aeruginosa. The majority of isolates were from centers in India (n = 118, 37%), Singapore (n = 90, 28.2%), Hong Kong (n = 31, 9.7%) and Thailand (n = 30, 9.4%). The cumulative antibiotic resistance rate was the greatest for polymyxin B (100%), ciprofloxacin (17.6%) and moxifloxacin (16.9%), and lowest for cefepime (11.6%) and amikacin (13.5%). Isolates from India demonstrated the highest antibiotic resistance rates of all the centers, and included moxifloxacin (47.5%) and ciprofloxacin (39.8%). Forty-eight of the 59 MDR isolates also originated from India. Antibiotic resistance rates were significantly lower in the other ACSIKS centers, and were typically less than 10%. Conclusions The antibiotic resistance profiles of P. aeruginosa varied between different countries. While it was low for most countries, substantial antibiotic resistance and a significant number of multi-drug resistant isolates were noted in the centers from India.