Changes in antimicrobial resistance of clinical isolates of Acinetobacter baumannii group isolated in Greece, 2010-2015

In recent years, hospitals in southeastern Europe have faced dramatically high rates of antibiotic-resistant Acinetobacter baumannii. We analysed the evolution of resistance among clinical isolates of A. baumannii group obtained from nine tertiary hospitals throughout Greece over 6 years (2010-2015). Identification and antimicrobial susceptibility testing were performed using Vitek 2 or Microscan walkaway automated systems. Between 2010 and 2015, resistance to ampicillin/sulbactam increased from 46.2 to 88.2% (P = 0.021), resistance to gentamicin increased from 69.3 to 86.4% (P = 0.014) and resistance to tobramycin increased from 59.8 to 76.8% (P = 0.011). Imipenem resistance rates were consistently very high, ranging from 90.3% in 2010 to 94.5% in 2015 (P = 0.198), while meropenem resistance rates increased from 82.6% in 2010 to 94.8% in 2015 (P = 0.006). Resistance rates to trimethoprim/sulfamethoxazole showed a remarkable decreasing trend, declining from 90.2% in 2010 to 69.1% in 2015 (P = 0.035). These evolutions render the treatment of A. baumannii infections particularly challenging and underline the need for enhanced infection control measures.