Susceptibility of 2,252 Pseudomonas aeruginosa Clinical Isolates Over 4 Years to 9 Antimicrobials in a Tertiary Greek Hospital

BACKGROUND: We determined the antimicrobial resistance of and changes over time in Pseudomonas aeruginosa isolates from hospitalized patients over the period of 2010-2013, in relation to the patient setting and clinical specimen origin, in a tertiary Greek hospital. METHODS: All P. aeruginosa isolates collected from patients with nosocomial infections were processed and cultured according to routine methods. The Vitek 2 automated system was used for antimicrobial susceptibility testing against 9 antimicrobials. RESULTS: Overall, 2,252 P. aeruginosa isolates were tested, and 1,124 (49.91%) were found to be fully susceptible. Among 1,128 resistant isolates, 638 (56.56%) were resistant to ≥3 classes of antipseudomonal antibiotics. Intensive care unit isolates were significantly more resistant than surgical and medical ward isolates, while blood and urine isolates demonstrated the highest resistance rates. Resistance was highest in 2012 and lowest in 2013. CONCLUSION: Continuous surveillance of antimicrobial resistance is extremely important for controlling P. aeruginosa infections in the hospital setting.