Identification of multi-resistant strains of Acinetobacter baumannii from an ICU in Greece using sequence-based typing and PFGE

Acinetobacter baumannii has emerged as an important nosocomial pathogen in many European countries, including Greece. In this study, we analysed 20 multi-resistant A. baumannii strains, derived from the First intensive care unit (ICU) of the General Hospital “G. Papanikolaou”, in order to investigate their epidemiology. Samples were taken from the pharynx and perineum of ICU patients for determination of their carrier status. Multilocus sequence typing (MLST)-based on the three-genes scheme (ompA, csuE and blaOXA-51-like) and pulsed field gel electrophoresis (PFGE) were the methods used to examine these isolates, after identification with VITEK 2. Using sequence-based typing, 16 out of 20 isolates (80%) were found to belong to the group ST 1 (EU-II), one (5%) belonged to ST 2 (EU-I) and three (15%) were ND (not determined) or sporadic strains. Using PFGE, nine strains were type Α, two were type Β and some strains could not be identified. ST group 1 prevailed (80%) among the other two groups. Both methods appear to yield similar results, though MLST seems to have more advantages. Sequence-based typing along with PFGE provides us with a powerful tool for identifying multi-resistant A. baumannii strains, which are more likely to induce problems in ICUs.